HUTCHINSON EXHIBIT 1003

Liza M. Walsh Christine I. Gannon Eleonore Ofosu-Antwi WALSH PIZZI O’REILLY FALANGA LLP One Riverfront Plaza 1037 Raymond Boulevard, 6th Floor Newark, NJ 07102 (973) 757-1100 Attorneys for Plaintiff

IN THE UNITED STATES DISTRICT COURT FOR THE DISTRICT OF NEW JERSEY

Nitto Denko Corporation,

Plaintiff,

v.

Hutchinson Technology Incorporated,

Defendant.

Civil Action No. Electronically Filed

COMPLAINT FOR PATENT INFRINGEMENT

Nitto Denko Corporation (“Nitto”) brings this action against Hutchinson Technology

Incorporated (“HTI”) and alleges as follows:

PARTIES

1. Nitto Denko Corporation is a Japanese corporation with its principle place of

business located at 33rd Floor, Grand Front Osaka, 4-20, Ofuka-cho, Kita-ku, Osaka 530-0011,

Japan.

Case 2:16-cv-03595-CCC-MF Document 1 Filed 06/20/16 Page 1 of 138 PageID: 1

HUTCHINSON EXHIBIT 1003

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2. On information and belief, Defendant HTI is incorporated in the State of Minnesota

with its principal place of business at 40 West Highland Park Drive NE, Hutchinson, Minnesota

55350.

BACKGROUND

Nitto Denko Corporation’s Technological Leadership

3. Since its foundation in 1918, Nitto has conducted business globally across various

industries including the electronics, automotive, housing, infrastructure, environmental, and

medical sectors.

4. To remain a market leader, Nitto spends tens of millions of dollars on research and

development annually. Indeed, last year alone, Nitto spent the equivalent of over $250 million on

research and development.

5. Because innovation is key to Nitto’s success, Nitto is a leader in filing for, and

receiving, patents on its inventions. Nitto files hundreds of patent applications a year and, annually,

is issued, on average, over 1,000 patents a year. To date, Nitto owns over 10,000 patents, including

over 6,500 patents in countries outside Japan, including the United States.

Nitto’s Market-Defining Flexure Technology

6. Nitto is the market leader in researching and developing “flexures,” a key

component of suspension assembly mounted on high-end hard disk drives. Generally speaking, a

flexure is a flexible strip that, at one end, supports a disk drive’s magnetic head for reading and

writing data on a disk and, at the other end, connects to the hard drive’s circuit board. The

technology in the flexure is critical to a hard disk drive’s performance, given the requirements that

it carry high-speed data to and from the read-write head without interference, and that it position

the read-write head at a precise location above a disk for reading and writing data.



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7. In order to protect its technology, Nitto filed over 250 patent applications on its

flexure technology in the United States alone. This has resulted, to date, in over 160 issued United

States patents.

Hutchinson Technology’s Infringement of Nitto’s Technology

8. HTI markets disk drive components, including flexures. Indeed, HTI sometimes

purchases Nitto flexures to incorporate into its suspension assemblies for its customers.

9. This lawsuit does not concern those flexures that HTI purchases from Nitto.

10. Rather, this lawsuit concerns certain flexures that HTI is producing itself. HTI is

making, using and selling flexures by infringing on Nitto’s patented technology. This includes

Nitto’s technology for:

novel and strengthened flexure terminals for connections to magnetic heads and

hard drive circuitry;

novel wiring patterns for the wiring traces in high-density disk drive flexures for

reducing impedance of wiring patterns;

novel designs for “reference holes” in a flexure, used for more accurately

positioning a magnetic head;

a novel configuration for lead wires in a flexure for reducing an electrical signal’s

“blunt waveform” without increasing manufacturing cost;

a novel flexure production method, controlling the variation in thickness at low

cost; and

a novel design of a suspension board assembly sheet with flexures, for preventing

the assembly sheet from being warped in the manufacturing process.



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JURISDICTION AND VENUE

11. HTI designs, manufactures, uses, markets, imports into the United States, sells,

and/or offers for sale in the United States suspension assemblies incorporating “flexures” for hard

disk drives.

12. This action for patent infringement arising under the patent laws of the United

States, 35 U.S.C. § 1 et seq., including but not limited to 35 U.S.C. § 271.

13. This Court has subject matter jurisdiction over this controversy under 28 U.S.C. §§

1331 and 1338(a).

14. This court has personal jurisdiction over HTI because, upon information and belief,

HTI does and has done substantial business in this District, including both independently and

through and with third parties by placing its products, including those that infringe Nitto’s patents,

into the stream of commerce, which stream is directed at the State of New Jersey and this District,

with the knowledge and/or understanding that such products would be sold in the State of New

Jersey and this District. These acts have caused and continue to cause injury to Nitto within this

District.

15. HTI derives substantial revenue from the sale of infringing products distributed

within the District, and/or expect or should reasonably expect their actions to have consequences

within the District, and derive substantial revenue from interstate and international commerce. In

addition, HTI has induced and continues to knowingly induce infringement within this District by

contracting with others to market and sell infringing products with the knowledge and intent to

facilitate infringing sales of the products by others within this District and by creating and/or

disseminating instructions and other materials for the products with like mind and intent.



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16. On information and belief, HTI has sufficient minimum contacts with the District

that an exercise of personal jurisdiction over HTI would not offend traditional notions of fair play

and substantial justice and would be appropriate under the long-arm statute of this state.

17. Venue is proper in this judicial district under 28 U.S.C. §§ 1391(b) and (c) and/or

and 1400(b).

COUNT I

INFRINGEMENT OF THE ’737 PATENT

18. Nitto repeats, realleges, and incorporates by reference as if fully set forth herein

each and every allegation in paragraphs 1-17 above.

19. Nitto owns United States Patent No. 6,841,737 (“the ’737 patent”), entitled “Wired

circuit board,” which was duly and legally issued on January 11, 2005. A certified copy of the ’737

patent is attached as Exhibit A.

20. HTI’s infringing activities in the United States and this District include the

development, manufacture, use, importation, sale, and/or offer for sale of products, including but

not limited to HTI products incorporated in hard drives identified as “WD Blue 3.5 inch / 500GB

(WD5000AAKX)” made by Western Digital Corporation and being sold in the United States.

21. On information and belief, HTI’s infringement has been, and continues to be,

willful and deliberate, and has caused substantial damage to Nitto.

COUNT II



each and every allegation in paragraphs 1- 17 above.



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23. Nitto owns United States Patent No. 7,923,644 (“the’644 patent”), entitled “Printed

circuit board and method of manufacture the same,” which was duly and legally issued on April

12, 2011. A certified copy of the ’644 patent is attached as Exhibit B.



not limited to HTI products incorporated in hard drives identified as “WD Blue 2.5 inch / 1.0 TB

(WD10JPVX)” made by Western Digital Corporation and being sold in the United States.



COUNT III




27. Nitto owns United States Patent No. 8,692,126 (“the ’126 patent”), entitled “Wired

circuit board and producing method thereof,” which was duly and legally issued on April 8, 2014.

A certified copy of the ’126 patent is attached as Exhibit C.



not limited to the HTI products incorporated in hard drives identified as “WD Blue 2.5 inch/1TB






7

COUNT IV




31. Nitto owns United States Patent No. 8,895,870 (“the ’870 patent”), entitled “Printed

circuit board and method of manufacture the same,” which was duly and legally issued on

November 25, 2014. A certified copy of the ’870 patent is attached as Exhibit D.



not limited to the HTI products incorporated in hard drives identified as “WD Blue 2.5 inch / 1TB




COUNT V




35. Nitto owns United States Patent No. 7,007,379 (“the ’379 patent”), entitled

“Production method of printed circuit board,” which was duly and legally issued on March 7, 2006.

A certified copy of the ’379 patent is attached as Exhibit E.





8

not limited to HTI products incorporated in hard drives identified as “WD Red 3.5 inch / 3TB

(WD30EFRX)” made by Western Digital Corporation and being sold in the United States.



COUNT VI




39. Nitto owns United States Patent No. 8,658,906 (“the ’906 patent”), entitled “Printed

circuit board assembly sheet and method for manufacturing the same,” which was duly and legally

issued on February 25, 2014. A certified copy of the ’906 patent is attached as Exhibit F.



not limited to HTI products incorporated in hard drives identified as “WD Red 3.5 inch / 3TB

(WD30EFRX)” made by Western Digital Corporation and being sold in the United States.



PRAYER FOR RELIEF

WHEREFORE, Plaintiff prays for the following relief:

A. That the Court render judgment declaring that HTI has infringed the ’737 patent,

the ’644 patent, the ’126 patent, the ’870 patent, the ’379 patent, and the ’906 patent (collectively,

“the Nitto Patents”) in violation of 35 U.S.C. § 271;



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B. That the Court render judgment declaring HTI’s infringement of the Nitto Patents

willful and deliberate;

C. That Nitto be awarded damages adequate to compensate Nitto for HTI’s

infringement of the Nitto Patents;

D. That Nitto be awarded enhanced damages pursuant to 35 U.S.C. § 284;

E. That Nitto be awarded pre-judgment and post-judgment interest to the full extent

allowed under the law, as well as its costs and disbursements;

F. That the Court enter an order finding that this is an exceptional case and awarding

Nitto its reasonable attorney fees pursuant to 35 U.S.C. § 285;

G. That the Court preliminarily and permanently enjoin HTI, its parents, affiliates,

successors, assigns, subsidiaries and transferees, and its officers, directors, agents, servants, and

employees, and all those persons in active concert or participation with them, or any of them, from

making, using, importing, exporting, distributing, supplying, selling or offering to sell, or causing

to be sold any product falling within the scope of the claims of the Nitto Patents, or otherwise

contributing to or inducing the infringement of any claim thereof;

H. That the Court award, in the absence of an injunction, an ongoing royalty; and

I. That the Court award such other relief as it may deem appropriate and just under

the circumstances.



10

Dated: June 20, 2016

WALSH PIZZI O’REILLY FALANGA LLP s/ Liza M. Walsh Liza M. Walsh Christine I. Gannon Eleonore Ofosu-Antwi One Riverfront Plaza 1037 Raymond Boulevard, 6th Floor Newark, NJ 07102 (973) 757-1100 OF COUNSEL: ORRICK, HERRINGTON & SUTCLIFFE LLP Alex V. Chachkes Hiroshi Sarumida Catrina W. Wang 51 West 52nd Street New York, NY 10019 (212) 506-5000 David E. Case Izumi Garden Tower, 28th Floor 6-1 Roppongi 1-Chome Minato-ku, Tokyo, 106-6028 Japan 81-3-3224-2900 Hsiwen Lo 2050 Main Street, Suite 1100 Irvine, CA 92614-8255 (949) 567-6700 Attorneys for Plaintiff



11

RULE 11.2 CERTIFICATION

I certify that, to the best of my knowledge, the matter in controversy is not the subject of

any other pending or anticipated litigation in any court or arbitration proceeding, nor are there any

non-parties known to Plaintiff that should be joined to this action. In addition, I recognize a

continuing obligation during the course of this litigation to file and to serve on all other parties and

with the Court an amended certification if there is a change in the facts stated in this original

certification.

Dated: June 20, 2016 WALSH PIZZI O’REILLY FALANGA LLP s/ Liza M. Walsh Liza M. Walsh



12

RULE 201.1 CERTIFICATION

We hereby certify that the above-captioned matter is not subject to compulsory arbitration.

Dated: June 20, 2016 WALSH PIZZI O’REILLY FALANGA LLP s/ Liza M. Walsh Liza M. Walsh



EXHIBIT A



























































EXHIBIT B





















































EXHIBIT C











































EXHIBIT D

































EXHIBIT E



(12) United States Patent

US007007379B2

(10) Patent N0.: US 7,007,379 B2 Komatsubara et al. (45) Date of Patent: Mar. 7, 2006

(54) PRODUCTION METHOD OF PRINTED (56) References Cited CIRCUIT BOARD U.S. PATENT DOCUMENTS

75 _ - _ 3,932,932 A * 1/1976 Goodman .................. .. 29/852

( ) Inventors‘ Makotf) Komatsllbara’ 1W1? UP)’ 5,120,384 A * 6/1992 Yoshimitsu e161. ...... .. 156/242 Yasuhltf) ohvfalfl’ Ibaral? (JP), 5,633,532 A * 5/1997 Sohara e161. ............. .. 257/700 Takeshl Y?shlml, Ibarakl (JP); 6,317,948 B1 * 11/2001 K018. e161. ...... .. .. 29/2542

Shigenori Morita, Ibaraki (JP) 6,571,467 B1 * 6/2003 Haze 618.1. ................. .. 29/852

(73) Assignee: Nitto Denko Corporation, Ibaraki (JP)

ot1ce: u ect to an 1sc a1mer, t e term 0 t is * N' Sbj yd'l' h fh' patent is extended or adjusted under 35 U.S.C. 154(b) by 297 days.

(21) Appl. N0.: 10/385,172

(22) Filed: Mar. 10, 2003

(65) Prior Publication Data

US 2003/0172526 A1 Sep. 18, 2003

(30) Foreign Application Priority Data

Mar. 12, 2002 (JP) ........................... .. 2002-067245

(51) Int. Cl. H05K 3/10 (2006.01)

(52) US. Cl. ........................... .. 29/846; 29/825; 29/830 (58) Field of Classi?cation Search ................ .. 427/97,

427/99; 29/825, 846, 852, 830, 831 See application ?le for complete search history.

7

1B 9

FOREIGN PATENT DOCUMENTS

JP 09-260844 A 10/ 1997 JP 2001-101637 4/2001 JP 2001-185849 A 7/2001

* cited by examiner

Primary Examiner—Rick Kiltae Chang (74) Attorney, Agent, or Firm—Leydig, Voit & Mayer, Ltd.

(57) ABSTRACT

The present invention provides a production method of a printed circuit board having a circuit pattern With a little variation in the thickness at a loW cost Without a special step for removal of a dummy pattern. The present invention is characterized in that an insulating layer 2 is formed in a given pattern on one surface of a supporting substrate 1, a circuit pattern 6 is formed on the insulating layer 2 While forming a dummy pattern 7 in an area free of the insulating layer 2 on the one surface of the supporting substrate 1, and an unnecessary part of the supporting substrate 1, Which is free of the insulating layer 2 and the circuit pattern 6, is removed by dissolution together With the dummy pattern 7.

4 Claims, 8 Drawing Sheets



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US 7,007,379 B2 1

PRODUCTION METHOD OF PRINTED CIRCUIT BOARD

FIELD OF THE INVENTION

The present invention relates to a production method of a printed circuit board. More particularly, this invention relates to a production method of a printed circuit board, Which can reduce variation in the thickness of a circuit pattern.

BACKGROUND OF THE INVENTION

To meet the request for miniaturiZation and high integra tion of electric devices and electronic devices in recent years, the pitch of circuit patterns on a printed circuit board has been made smaller. A circuit pattern having a ?ne pitch (distance betWeen neighboring patterns) of not more than about 75 pm is formed by an additive method, a semi additive method and the like.

According to the additive method, for eXample, a resist pattern is formed on an insulating substrate, a conductive layer made of copper is formed in an area other than the resist pattern by plating, and the resist pattern is removed. In this Way, a circuit pattern is formed in an area other than the resist pattern.

According to the semi-additive method, a metal backing layer of Cr and the like is ?rst formed on an insulating substrate by plating, vapor-deposition and the like, and a resist pattern is formed on the metal backing layer. Subse quently, Cu layer is formed on the metal backing layer in the area other than the resist pattern by plating, and the resist pattern is removed to form a circuit pattern. Then, using the circuit pattern as a mask, the metal backing layer is etched. In this Way, a circuit pattern is formed in the area other than the resist pattern. In the printed circuit board produced by the semi-additive method, elution of a metal ion constituting the circuit pattern into the insulating substrate, Which is What is called ion migration, can be prevented, because the circuit pattern is formed on the insulating substrate via the metal backing layer of Cr layer and the like.

In the production of a printed circuit board according to the additive method or the semi-additive method, variation in the thickness of circuit pattern has become a problem. That is, a pattern present in the central area of a printed circuit board Where a number of circuit patterns are dis posed, and a pattern present in the outer peripheral area of the printed circuit board surrounded by an area free of a circuit pattern shoW different current densities during plat ing. As a result, despite the fact that they have been formed by the same process, the pattern present in the central area and that present in the outer peripheral area have different thicknesses. To solve this problem, a dummy pattern has been conventionally formed on the outside of the circuit

pattern (JP-A-2001-101637). FIG. 9(a)—FIG. 9(c) shoW concrete eXample of such

dummy pattern. FIG. 9(a) shoWs an embodiment Wherein a solid dummy

pattern is disposed near a circuit pattern, FIG. 9(b) shoWs an embodiment Wherein a circuit pattern is surrounded by a solid dummy pattern, and FIG. 9(a) shows an embodiment Wherein a dummy pattern having the same shape as a circuit pattern is arranged near the circuit pattern.

HoWever, the dummy pattern is inherently unnecessary for the printed circuit board and needs to be removed ultimately. When a dummy pattern is simultaneously removed (dissolved) along With an insulating substrate in an

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2 etching step for the insulating substrate, Without particularly applying a step for exclusively removing the dummy pat tern, the dummy pattern is not completely dissolved and remains as a residue. In the above-mentioned case, therefore, after forming a circuit pattern (dummy pattern), the dummy pattern is removed by etching and the like. In other Words, forming a dummy pattern necessitates a removal step of the dummy pattern, Which in turn makes the production cost of a printed circuit board eXpensive.

SUMMARY OF THE INVENTION

In vieW of the above-mentioned situation, it is an object of the present invention to provide a production method capable of removing a dummy pattern Without a special dummy pattern removal step and affording a printed circuit board having a circuit pattern With a little variation in the thickness. The present invention is characteriZed by the folloWing to

achieve the above-mentioned object. (1) A production method of a printed circuit board, Which

comprises the steps of forming an insulating layer in a given pattern on one

surface of a supporting substrate, forming a circuit pattern on the insulating layer While

forming a dummy pattern in an area free of the insu lating layer on said surface of the supporting substrate, and removing by dissolving an unnecessary part of the supporting substrate, Which is free of the insulating layer and the circuit pattern, together With the dummy pattern.

(2) The production method of the printed circuit board of the above-mentioned (1), Wherein the dummy pattern has a Width of the pattern of not more than 200 pm.

(3) The production method of the printed circuit board of the above-mentioned (1), Wherein the above-mentioned sup porting substrate is made of stainless steel, Ni—Fe alloy, copper, aluminum, copper-beryllium or phosphor bronZe.

(4) The production method of the printed circuit board of the above-mentioned (1), Wherein the above-mentioned insu lating layer is made from a polyimide resin containing a photosensitive material. In the present invention, a circuit pattern and a dummy

pattern are not formed on the same plane, unlike the con ventional manner. In the present invention, a supporting substrate (metal foil, metal thin plate etc.) planned to be partly removed by dissolving (Wet etching) is used, an insulating layer is formed in a given area on one surface of the supporting substrate, and a circuit pattern is formed on the insulating layer While forming a dummy pattern in an area free of the insulating layer on said surface of the supporting substrate. Thereafter, an unnecessary part of the supporting substrate, Which is free of the insulating layer and the circuit pattern, is removed by Wet etching together With the dummy pattern, Whereby the conventional step for removing the dummy pattern becomes unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shoWs a schematic sectional vieW of one embodi ment of the printed circuit board produced by the production method of the present invention, Where an insulating layer having a given pattern is formed on a supporting substrate.

FIG. 2 shoWs a schematic sectional vieW of the state Where a conductive layer is formed on the entirety of one surface of a supporting substrate to cover the insulating layer after the state shoWn in FIG. 1.



US 7,007,379 B2 3

FIG. 3 shows a schematic sectional vieW of the state Where a circuit pattern and a resist pattern for forming a dummy pattern have been formed after the state shoWn in FIG. 2.

FIG. 4 shoWs a schematic sectional vieW of the state Where a metal for Wiring is deposited on the opening in the resist, thereby to form a circuit pattern and a dummy pattern, after the state shoWn in FIG. 3.

FIG. 5 shoWs a schematic sectional vieW of the state Where the resist pattern 4 is removed and the unnecessary part of the conductive layer is removed after the state shoWn in FIG. 4.

FIG. 6(a)—FIG. 6(a) shoW a schematic sectional vieW of a series of steps for removing the dummy pattern along With the unnecessary part of the supporting substrate by Wet etching after the state shoWn in FIG. 5.

FIG. 7(a)—FIG. 7(c) shoW variation in the pattern of the opening for forming a dummy pattern.

FIG. 8 is a layout of the circuit pattern and the dummy pattern in Examples.

FIG. 9(a)—FIG. 9(c) schematically shoW positional rela tionship betWeen a circuit pattern and a dummy pattern in a conventional printed circuit board.

In the Figures, 1 shoWs a supporting substrate, 2 shoWs an insulating layer, 3 shoWs a conductive layer, 4 shoWs a resist pattern, 6 shoWs a circuit pattern, 7 shoWs a dummy pattern, and 100 shoWs a printed circuit board.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is explained in detail in the follow ing.

The production method of the printed circuit board of the present invention characteristically comprises the folloWing Step 1 to Step 3. Step 1: formation of an insulating layer in a given pattern on

one surface of a supporting substrate. Step 2: formation of a circuit pattern on the above-men

tioned insulating layer While forming a dummy pattern in an area free of the insulating layer on said surface of the supporting substrate.

Step 3: removal by dissolution of an unnecessary part (including the dummy pattern) of the supporting sub strate, Which is free of the insulating layer and the circuit pattern. The production method of the printed circuit board of the

present invention encompasses both the “additive method” and the “semi-additive method”. The present invention is explained in more detail in the folloWing by one example of the production step of a printed circuit board by the semi additive method.

FIGS. 1—6 are sectional vieWs schematically shoWing production of a printed circuit board according to the method of the present invention. [Step 1] As shoWn in FIG. 1, an insulating layer 2 having a given

pattern is formed on one surface (top surface) 1A of a supporting substrate 1. As the supporting substrate 1, a metal foil and a metal thin

plate made of various metals can be used. Of these, a metal foil and a metal thin plate made of stainless steel, Ni—Fe alloys such as 42 alloy (42% Ni—Fe alloy), copper, alumi num, copper-beryllium, phosphor bronZe and the like are preferable from the aspects of anti-corrosion, elasticity and the like. Particularly, stainless steel and 42 alloy are pref erable. The supporting substrate 1 preferably has a thickness

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4 of about 10—60 pm, more preferably 15—30 pm, for achiev ing ef?cient removal by dissolution (Wet etching) of the supporting substrate to be mentioned later, and vibration characteristic of a printed circuit board. The supporting substrate 1 has a Width of generally about 50—500 mm, preferably about 125—300 mm. As used herein, the “Width of the supporting substrate” means the length of each of the orthogonal tWo sides When the outer shape of the supporting substrate 1 is tetragon (square, rectangle), and the length of diameter, major axis or minor axis When the outer shape of the supporting substrate 1 is a circle, an ellipse or a shape similar thereto.

While the material (insulator) of the insulating layer 2 is not particularly limited, it is preferably a synthetic resin such as polyimide resin, acrylic resin, polyether nitrile resin, polyether sulfone resin, polyethylene terephthalate resin, polyethylene naphthalate resin, polyvinyl chloride resin and the like. Of these, polyimide resin is preferable, and poly imide resin, to Which a photosensitive material such as dihydropyridine derivative and the like has been added to impart photosensitivity (affording patterning by exposure and development), is particularly preferable, because heat resistance, mechanical strength and dimensional stability become superior. When a resin Without photosensitivity is used, an insulating layer 2 having a given pattern is formed on one surface of a supporting substrate 1A by adhering a ?lm formed into a given shape by a suitable method to one surface 1A of the supporting substrate 1 With an adhesive (thermosetting adhesive, thermoplastic adhesive etc.). The thickness of the insulating layer 2 is preferably 2—20

pm, more preferably 5—15 pm, from the aspect of insulating property. Amethod for forming an insulating layer 2 having a given

pattern, using a polyimide resin having photosensitivity is explained in the folloWing. First, a polyimide precursor solution is applied onto the entirety of one surface of a supporting substrate, and dried at, for example, 60—150° C., preferably 80—120° C., to form a coating of a polyimide precursor. Then, the coating is exposed to light via a photomask and the exposed part is heated and developed for given patterning of the coating. The light to be irradiated for the above-mentioned expo

sure preferably has an exposure Wavelength of 300—450 nm, more preferably 350—420 nm. The exposure accumulated energy is preferably 100—1000 mJ/cm2, more preferably 200—700 mJ/cm2. Of the coating, the part exposed to light and heated at a

temperature of not less than 130° C. and less than 150° C. is dissolved during development (the part not exposed to light is insolubiliZed, positive-type) and the part exposed to light and heated at a temperature of not less than 150° C. and less than 180° C. does not dissolve during development (the part not exposed to light is solubiliZed, negative-type). The development is conducted using a knoWn developing solu tion such as an alkaline developing solution and the like, according to a knoWn method such as immersion method, spray method and the like.

The coating after patterning in the above-mentioned man ner is heated to 250° C. or higher (preferably 250—400° C.) for setting (imidiZation), Whereby an insulating layer 2 made of a polyimide resin and having a given pattern is obtained. When an insulating layer 2 having a given pattern is formed from a polyimide resin in this Way, the thickness thereof is preferably 2—20 pm, more preferably 5—15 pm. The forego ing is Step 1.



US 7,007,379 B2 5

[Step 2] After forming an insulating layer 2 having a given pattern,

a circuit pattern is formed by the following steps. As shoWn in FIG. 2, a conductive layer 3 is formed on the

entirety of one surface 1A of the supporting substrate 1, thereby to cover, the insulating layer 2. The material (con ductor) for forming a conductive layer 3 is not particularly limited and Cr, Cu, Ni, Ti, Ni—Cr alloy and the like are exempli?ed. Of these, Cr and Cu are preferable from the aspect of adhesion to insulating layer 2. Such conductive layer 3 may consist of a single layer or a laminate of tWo or more layers (?lms) made of different metals. In the case of constitution of a laminate of tWo or more layers (?lms), a Cr layer (?lm), then a Cu layer (?lm) are preferably laminated in this order to cover the insulating layer 2 to achieve strong adhesion. While the thickness of conductive layer 3 is not particularly limited, it is preferably about 600—6000 A, more preferably about 1300—3700 A, from the aspect of improve ment of adhesion. When the conductive layer 3 consists of a laminate of the above-mentioned Cr layer (?lm) and Cu layer (?lm), the thickness of the Cr layer (?lm) is preferably 100 —1000 A (more preferably 300—700 A), the thickness of the Cu layer (?lm) is preferably 500—5000 A (more prefer ably 1000—3000 A).

The method for forming the conductive layer 3 is not particularly limited and nonelectrolytic plating method, sputtering vapor-deposited method and the like are exem pli?ed. As shoWn in FIG. 3, a resist pattern 4 for forming a circuit

pattern and for forming a dummy pattern on the above mentioned conductive layer 3 is formed. The resist used for forming a resist pattern 4 is exempli?ed by a dry ?lm resist and a liquid resist, With preference given to a dry ?lm resist from the aspect of production cost and the like. Of the dry ?lm resists, an acrylic dry ?lm resist is preferable for acid resistance. In the case of a liquid resist, a resist ?lm is formed by a method such as screen printing, spin coater and the like. In the case of a dry ?lm resist, it is ?xed on the conductive layer 3 by pressing With a suitable roller.

The thickness of the resist pattern 4 is preferably about 1—50 pm, more preferably about 20—40 pm, in consideration of easy deposition of the plating metal during electroplating to form a circuit pattern and a dummy pattern to be men tioned later and the thickness of the ?nal circuit pattern. Amethod of forming a resist pattern 4 (method of forming

an opening in a resist ?lm) is exempli?ed by laser process ing, photolithography processing and the like. In vieW of the dimensional precision and processing cost, photolithogra phy processing (forming an opening by exposure via a photomask and development) is preferable. The Width of the opening 5A for forming a circuit pattern (=Width of pattern of circuit pattern 6 to be mentioned beloW) is generally in the range of 1—2000 pm, preferably 5—200 pm. In contrast, the Width of an opening 5B for forming a dummy pattern (=Width of pattern of dummy pattern 7 to be mentioned beloW) is preferably not more than 200 pm, more preferably 10—60 pm. By employing such preferable Width, the dummy pattern can be certainly dissolved for removal in the step for dissolving (Wet etching) the supporting substrate to be mentioned beloW. In FIG. 3, tWo openings 5B for forming a dummy pattern are formed, but the number and shape of the opening are not particularly limited and can be changed as appropriate depending on the shape, number, layout and the like of the circuit pattern.

FIG. 7(a)—FIG. 7(c) shoW concrete examples of variation in the pattern of the opening for forming a dummy pattern. In FIG. 7(a), one linear opening 5B-1 has been formed, in

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6 FIG. 7(b), plural linear openings 5B-1 have been formed, and in FIG. 7(c), lattice opening for forming a dummy pattern 5B-2 has been formed.

The shape of the opening for forming a dummy pattern is linear such as a straight line (e.g., FIG. 7(a), FIG. 7(b)), curve, ZigZag and the like, lattice (the aforementioned FIG. 7(c)), circle, ellipse, polygonal, a combination of these shapes and the like. In the case of lattice as shoWn in FIG. 7(a), the shape of the resist Where linear openings cross is not particularly limited and may be any shape such as tetragon, circle, ellipse and the like.

In the present invention, the Width of the opening for forming a dummy pattern (=pattern Width of dummy pat tern) corresponds to the line Width (in case of lattice, the Width of line forming the lattice) When the shape of the opening is linear or lattice. In the case of the aforementioned FIG. 7(a) —FIG. 7(c), W1 therein shoWs the Width of the opening (=pattern Width of dummy pattern). When the shape of the opening is circle, it shoWs a diameter, When the shape of the opening is ellipse, it shoWs a minor axis thereof, and When the shape of the opening is polygonal, it shoWs a Width of the minimum Width part. As used herein, the “minimum Width part of polygon” corresponds to, When the polygon has an odd number of vertexes (triangle, pentagon etc.), the length of (a path of) the minimum perpendicular of all the perpendiculars draWn from respective vertexes to their fac ing sides. In the case of a polygon having an even number of vertexes (quadrangle, hexagon etc.), the minimum Width part of the polygon corresponds to the length of (a path of) the minimum perpendicular of all the perpendiculars With respect to the sides, from the middle point of Which they are drawn, to the point of intersection With their facing sides. As mentioned above, the Width of the opening for forming

a dummy pattern (=pattern Width of dummy pattern) is preferably set for not more than 200 pm in the present invention, Whereby the dummy pattern can be certainly dissolved and removed by etching along With the supporting substrate. The etching of the dummy pattern is conducted along With the penetration of an etching solution betWeen the resist and the dummy pattern. When the dummy pattern forms an ellipse or polygon, the minor axis of not more than 200 pm, or the minimum Width part of polygon of not more than 200 pm permits suf?cient penetration of the etching solution betWeen the dummy pattern and the resist even in a short etching time, thus resulting in the removal of the dummy pattern.

After forming the opening for forming a circuit pattern and an opening for forming a dummy pattern in the above mentioned manner, a circuit pattern and a dummy pattern are formed as shoWn in the folloWing. That is, a metal (alloy) for Wiring is deposited by electroplating in an opening 5A for forming a circuit pattern and an opening for forming a dummy pattern 5B, in the above-mentioned resist 4, thereby to form a circuit pattern 6 and a dummy pattern 7 (FIG. 4). Examples of the metal (alloy) for Wiring include metals such as Cu, Au, stainless steel, Al, Ni and the like, and alloy obtained by adding Be, Ni, Co, Ag, Pb, Cr and the like to these metals are preferable. of these, Cu is more preferable from the mechanical properties such as strength, elastic modulus and the like, and the electrical properties such as electric conductivity and the like. The thickness of the circuit pattern 6 is preferably 2—30 pm, more preferably 5—20 pm.

Then, after removing the resist pattern 4 by Wet etching using, for example, an alkaline solution and the like, the unnecessary part of the conductive layer 3 is removed (FIG. 5). While the method for removing the unnecessary part of



US 7,007,379 B2 7

the conductive layer 3 is not particularly limited, for example, a method comprising masking the entirety of the exposed part of the supporting substrate 1, the entirety of the circuit pattern 6 and a part of the dummy pattern 7, and applying Wet etching and the like are exempli?ed. In this method, for example, a mask made of an acrylic dry ?lm resist is preferably used and an aqueous solution of potas sium ferricyanide type, potassium permanganate type, sodium metasilicate type and the like are preferably used as an etching solution. The above constitutes Step 2. [Step 3]

After forming the circuit pattern 6 and the dummy pattern 7 in the above-mentioned manner, the dummy pattern 7 is removed together. With the unnecessary part of the support ing substrate 1 by the folloWing steps. As shoWn in FIG. 6(a), on one surface (top surface) 1A of

the supporting substrate 1, all the conductive layer 2, circuit pattern 6 and dummy pattern 7 are covered With a resist (?lm) 8 and the entire surface of the other surface (bottom surface) 1B of the supporting substrate 1 is covered With a resist (?lm) 9. As the resists (?lms) 8 and 9, for example, a dry ?lm resist, a liquid resist and the like are preferably used, and the dry ?lm resist is more preferable. Of the dry ?lm resists, an acrylic dry ?lm resist is particularly preferable in vieW of acid resistance.

Then, as shoWn in FIG. 6(b), the resist (?lm) 9 covering the entire surface of the other surface (bottom surface) 1B of the supporting substrate 1 is subjected to photolithography processing to expose the unnecessary part D (part having a dummy pattern 7) free of the insulating layer 2 and the circuit pattern 6 on the supporting substrate 1.

Then, as shoWn in FIG. 6(a), the other surface (bottom surface) 1B of the supporting substrate 1 is subjected to Wet etching to remove the unnecessary part D of the supporting substrate simultaneously With the dummy pattern 7. While the etching solution for the Wet etching varies depending on the materials of the supporting substrate 1 and the dummy pattern 7 (circuit pattern 6), an aqueous solution and the like of ferric chloride, cupric chloride and the like are preferable.

Thereafter, the resists (?lms) 8 and 9 are completely removed to complete the printed circuit board 100 shoWn in FIG.

The production example of the printed circuit board 100 explained by referring to FIGS. 1—6 in the above is a production example by a semi-additive method. When a circuit board is produced by the additive method, the same steps except the above-mentioned conductive layer 3 are basically applied.

The printed circuit board to be produced by the produc tion method of the present invention has a structure Wherein (a pattern of) an insulating layer 2 is formed on a supporting substrate 1 (metal foil, metal thin plate etc.) and a circuit pattern 6 is formed on the insulating layer 2. As compared to a conventional one comprising a circuit pattern formed on an insulating substrate, it advantageously shoWs ?ne elas ticity and permits bending processing.

EXAMPLES

The present invention is explained in detail by referring to examples, Which are not to be construed as limitative.

Example 1

Apolyamide resin precursor solution having photosensi tivity Was applied on a 20 pm-thick stainless steel foil

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8 (SUS304 H-TA) such that the thickness after drying became 24 pm and dried at 130° C. to give a coating of a polyimide resin precursor.

This coating Was exposed to light via a photomask (Wavelength: 405 nm, exposure accumulated energy: 700 mJ/cm2). After heating the exposed part to 180° C., the coating Was developed With an alkaline developer for pat terning of a negative-type image. The patterned polyimide resin precursor coating Was heated at 350° C. for setting (imidiZation), Whereby a 10 pm-thick base layer (insulating layer) made from a polyimide resin and having a given pattern Was prepared.

Then, a 300 A-thick Cr thin ?lm and a 700 A-thick Cu thin ?lm Were formed in this order on the entirety of the stainless steel foil and the base layer (insulating layer) by the sputtering vapor-deposition method.

Thereafter, a 30 pm-thick acrylic type dry ?lm resist Was adhered to the above-mentioned Cu thin ?lm. The above-mentioned dry ?lm resist Was then subjected to

photolithographic processing to form an opening for form ing a circuit pattern and an opening for forming a dummy pattern. The opening pattern for forming a circuit pattern had a Width of 15—1500 pm, 4 per set, 84 sets arranged at pitch 3 mm and the opening for forming a dummy pattern Was straight and had a Width of 50 pm, plural openings arranged at pitch 120 pm. The opening for forming a dummy pattern Was formed at 100 pm—5 mm aWay from the circuit pattern. Cu Was deposited inside the above-mentioned opening

pattern by electroplating to form a 14 pm-thick circuit pattern and a dummy pattern. FIG. 8 is a layout of the circuit pattern 6 and the dummy pattern 7.

After complete removal of the above-mentioned dry resist ?lm by chemical etching (etchant: aqueous alkaline solu tion), the entire conductive pattern and a part of the dummy pattern Were masked With an acrylic type dry ?lm resist, and the Cr thin ?lm and Cu thin ?lm Were removed by Wet etching (etching solution: aqueous potassium permanganate solution). The entire exposed surface of the stainless steel foil,

circuit pattern, base layer and dummy pattern Was covered With an acrylic type dry ?lm resist from the top surface side and from the underside of the stainless steel foil, after Which the unnecessary part (the part free of base layer and circuit pattern) of the stainless steel foil Was exposed by photo lithographic processing.

Then, using an aqueous ferric chloride solution as an etching solution, Wet etching Was applied from the underside of the stainless steel foil to remove the unnecessary part of the stainless steel foil and the dummy pattern. The remaining resist ?lm Was removed to complete a printed circuit board.

Comparative Example 1

In the same manner as in Example 1 except that a step for forming a dummy pattern Was not included, a printed circuit board Was obtained.

(Evaluation) The thickness of the circuit pattern of the above-men

tioned printed circuit board and the variation thereof Were measured as in the folloWing. The Zero point of a linear gauge (ZC-101, NIKON COR

PORATION) Was set for the base layer (insulating layer) and the height of the circuit pattern measured from the base layer as the base point Was taken as the thickness of the circuit pattern. The circuit pattern to be measured had a Width of 100 pm, and the average of 162 measures and the standard deviation Were calculated. The results are as folloWs.



US 7,007,379 B2 9

Example 1: average thickness 14.0 pm, standard deviation 0.37 pm

Comparative Example 1: average thickness 14.0 pm, stan dard deviation 0.74 pm As is clear from the foregoing explanation, the production 5

method of the printed circuit board of the present invention does not require any special step for removal of a dummy pattern, thereby reducing the number of steps from the conventional methods. As a result, a printed circuit board having a circuit pattern With a little variation in the thickness can be produced at a loW cost. Because a dummy pattern can be formed irrespective of the shape of the circuit pattern, designing of the shape of the dummy pattern is advanta geously facilitated.

This application is based on patent application No. 2002 67245 ?led in Japan, the contents of Which are hereby incorporated by reference. What is claimed is: 1. A production method of a printed circuit board, Which

comprises the steps of forming an insulating layer in a given pattern on one

surface of a supporting substrate,

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10 forming a circuit pattern on the insulating layer While

forming a dummy pattern in an area free of the insu lating layer on said surface of the supporting substrate, and

simultaneously removing by dissolving an unnecessary part of the supporting substrate, Which is free of the insulating layer and the circuit pattern, and the dummy pattern.

2. The production method of the printed circuit board of claim 1, Wherein said dummy pattern has a Width of the pattern of not more than 200 pm.

3. The production method of the printed circuit board of claim 1, Wherein said supporting substrate is made of stainless steel, Ni—Fe alloy, copper, aluminum, copper beryllium or phosphor bronZe.

4. The production method of the printed circuit board of claim 1, Wherein said insulating layer is made from a polyimide resin containing a photosensitive material.



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