JP5743208B2 - Circuit board manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a circuit board having a circuit pattern coated with a solder resist pattern.

  When forming a solder resist pattern on a circuit board, first apply a liquid solder resist ink and pre-cure, or laminate a dry film solder resist film to form an unexposed solder resist on the circuit board. Form. Next, pattern exposure is performed on the unexposed solder resist.

  As a method for performing pattern exposure on an unexposed solder resist, conventionally, a method in which a film photomask is brought into contact with an unexposed solder resist to perform pattern exposure (hereinafter referred to as “contact pattern exposure”) is used. However, in recent years, a highly accurate pattern is also required for the solder resist pattern, and a pattern exposure method (hereinafter referred to as “non-contact type”) is performed without bringing the photomask into contact with the unexposed solder resist. "Pattern exposure") has been applied. Examples of non-contact pattern exposure include projection exposure using a glass mask as a photomask, or a direct drawing method in which a pattern is directly drawn on an unexposed solder resist with a laser or the like without using a photomask. .

  Conventionally, as shown in FIG. 3, a solder resist ink is applied on the circuit pattern 3 of the circuit board 10 to form an unexposed solder resist 12 (FIG. 3A), and the unexposed solder resist 12 is formed. When pattern exposure is performed on the solder, the resist resist 11 subjected to the contact pattern exposure is formed by performing one contact pattern exposure using predetermined exposure conditions (FIG. 3B). ), And developing the desired solder resist pattern (FIG. 3C). As a pattern exposure method, non-contact pattern exposure is also performed. In this case as well, a predetermined non-contact pattern exposure is performed using predetermined exposure conditions. A solder resist 2 subjected to pattern exposure is formed (not shown) and developed to form a target solder resist pattern 20 (FIG. 3C). However, when the exposure amount is increased, the adhesion of the solder resist pattern 20 after development is improved, but the formability (resolution) of the fine solder resist pattern 20 is deteriorated and the exposure amount is decreased. Although the formability (resolution) of the fine solder resist pattern 20 is improved, the adhesiveness is lowered.

  When using contact pattern exposure, as a method for improving the adhesion and formability (resolution) of the solder resist pattern, pattern exposure is performed when pattern exposure is performed on an unexposed solder resist. In the first exposure, a photomask provided with an exposure pattern that shields light a little larger than the target opening pattern is used. In the second exposure, the target is used. A method is disclosed in which pattern exposure is performed using a photomask provided with an exposure pattern according to the opening pattern, thereby ensuring the formability (resolution) of the opening pattern and the adhesion of the region other than the opening ( Patent Document 1).

JP 2005-142254 A

  However, when a more accurate solder resist pattern is required, non-contact pattern exposure is used. In the case of this non-contact type pattern exposure, it is necessary to firmly attract and fix the circuit board on the work table of the exposure apparatus as compared with the contact type pattern exposure. The unexposed solder resist before pattern exposure is in a state where it is not cured only by applying a pre-cure for drying the solvent in the ink after applying the solder resist ink. In general, the unexposed solder resist is formed on both the front and back surfaces of the circuit board before pattern exposure for the purpose of reducing the number of steps. For this reason, in non-contact type pattern exposure, the unexposed solder resist on the back side of the circuit board is easily transferred from the circuit board to the work table when attracted and fixed to the work table. There may be a problem that the solder resist for exposure falls off.

  The present invention has been made in view of the above problems, and even when non-contact pattern exposure is applied to an unexposed solder resist, it is possible to reduce the dropout of the unexposed solder resist with high accuracy. In addition, the present invention provides a circuit board manufacturing method capable of improving yield and reliability.

The present invention is characterized by the following.
(1) In the method of manufacturing a circuit board having a circuit pattern covered with a solder resist pattern, a step of forming an unexposed solder resist on the circuit pattern, and a contact type for the unexposed solder resist Performing pattern exposure and non-contact pattern exposure to form a pattern-exposed solder resist, and developing the pattern-exposed solder resist to form a target solder resist pattern Yes, and in the step of forming a solder resist which is patterned exposure, contact after pattern exposure, method of manufacturing a circuit board for performing location and is overlapped with the non-contact type pattern exposure was carried out the contact pattern exposure.
(2) In the step (1), in the step of forming the pattern-exposed solder resist, when non-contact pattern exposure is performed, the region including the end of the target solder resist pattern is finally exposed. A method for manufacturing a circuit board.
(3) In the step (1) or (2), in the step of forming the pattern-exposed solder resist , when the non- contact pattern exposure is performed, the exposed portion is partially overlapped with the portion where the contact pattern exposure is performed. A method for manufacturing a circuit board.
(4) In any one of the above (1) to (3), in the step of forming the pattern-exposed solder resist, the area of the pattern exposure is exposed when performing contact pattern exposure and non-contact pattern exposure. A method of manufacturing a circuit board that is reduced each time the number is increased.
(5) In any one of the above (1) to (4), in the step of forming an unexposed solder resist on the circuit pattern, a liquid solder resist ink is applied on the circuit pattern and precured or dried. A circuit board manufacturing method for forming an unexposed solder resist by laminating a film-like solder resist film.

  According to the present invention, even when non-contact pattern exposure is applied to an unexposed solder resist, it is possible to reduce the dropout of the unexposed solder resist, and to improve the yield and reliability with high accuracy. It is possible to provide a method of manufacturing a circuit board that can be achieved.

It is a flowchart using sectional drawing which shows the manufacturing process of the wiring board of this invention. It is a flowchart using sectional drawing which shows the manufacturing process of the wiring board of this invention. It is a flowchart using sectional drawing which shows the manufacturing process of the conventional wiring board.

  As one form of the manufacturing method of the circuit board of this invention, as shown in FIG. 2, the process (FIG. 2 (A)) which forms the unexposed solder resist 12 on the circuit pattern 3, and an unexposed solder resist 12 is subjected to contact pattern exposure (FIG. 2 (B)) and non-contact pattern exposure (FIG. 2 (C)), and the solder resist 11 and non-contact pattern exposure exposed by contact pattern exposure. The step of forming the solder resist 2 formed in step 1 and the step of forming the target solder resist pattern 20 by developing the pattern-exposed solder resists 11 and 2 (FIG. 2D) are included. A method for manufacturing the circuit board 16 may be mentioned.

  Solder resist is mainly provided on the surface of the circuit board, covers the circuit pattern provided on the surface, protects the circuit pattern against solder used for connection with electronic components, and provides openings in some parts Then, a part of the circuit pattern is exposed to form a connection terminal. As the solder resist, a solder resist pattern includes a development type formed by so-called photolithography and a non-development type formed by printing. However, the solder resist used in the present invention is the former development type. Is. Such development-type solder resists are roughly classified into two types: a dry film type laminated on a circuit board, and a liquid type coated on a circuit board and precured. Development type solder resist materials are mainly composed of photosensitive epoxy acrylate resin and photosensitive polyimide, both of which can be developed with alkaline aqueous solution such as sodium carbonate aqueous solution. The negative type is the mainstream.

  A circuit pattern is provided on an insulating resin layer of a circuit board, and functions by electrically connecting electronic components mounted on the circuit board, or electronic components mounted on the circuit board and other electronic devices. It is. The circuit pattern in this invention can be comprised with metals, such as copper and aluminum, similarly to a general wiring board. In addition, the circuit pattern is formed by a subtractive method in which a dry film is used to protect a necessary portion of a metal foil such as copper or aluminum formed on an insulating resin layer and an unnecessary portion is removed with an etching solution. It is also possible to use an additive method in which a dry film formed on the insulating resin layer is used as a copper plating resist and copper plating is deposited at a required location.

  The circuit board includes an insulating resin layer and a circuit pattern, and forms a circuit by mounting electronic components. The circuit board in which the circuit pattern is formed on one side or both sides of the insulating resin layer and the circuit board in which the circuit pattern and the insulating resin layer are alternately laminated are included. The insulating resin layer used for the circuit board in the present invention preferably uses a thermosetting resin and thermoplasticity. Examples of the thermosetting resin include, but are not limited to, a phenol resin, an epoxy resin, a polyimide resin, a cyanate resin, a maleimide resin, an isocyanate resin, a benzocyclobutene resin, and a vinyl resin. One type of thermosetting resin may be used alone, or two or more types may be mixed and used. Examples of the thermoplastic resin include fluororesin, polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide, polycarbonate, polyether imide, polyether ether ketone, polyarylate, polyamide, polyamide imide, polybutadiene, and polyimide. It is not limited. One type of thermoplastic resin may be used alone, or two or more types may be mixed and used. Moreover, the inorganic filler may be included.

  The present invention includes a step of forming an unexposed solder resist on a circuit pattern. The unexposed solder resist is a solder resist that has not been subjected to pattern exposure, and that has not been cured by light (mainly ultraviolet light) during pattern exposure. The step of forming the unexposed solder resist on the circuit pattern can be performed, for example, by applying a liquid solder resist ink on the circuit pattern and pre-curing, or by laminating a dry film-like solder resist film. it can. The solder resist may be applied or laminated on one side or on both sides simultaneously. When applying the solder resist ink, the application method may be a screen method using a plate, a roll coating method using a roll, or a curtain coating method using a spray. Moreover, the circuit pattern of the circuit board before applying or laminating the solder resist may or may not be subjected to a roughening treatment. When the roughening process is performed, the roughening process may be a chemical process or a physical process. Metal plating may be applied on the circuit pattern of the circuit board.

  The present invention includes a step of forming a pattern-exposed solder resist by performing contact pattern exposure and non-contact pattern exposure on an unexposed solder resist. Performing contact-type pattern exposure and non-contact-type pattern exposure means performing each of contact-type pattern exposure and non-contact-type pattern exposure at least once, and each may be performed a plurality of times. In non-contact pattern exposure, when the solder resist is unexposed, the solder resist is likely to drop off because the circuit board is firmly fixed to the work table. However, by selectively using contact pattern exposure and non-contact pattern exposure for locations that require high accuracy and locations that do not require high accuracy, the area of unexposed solder resist is reduced before non-contact pattern exposure. Therefore, it is possible to form a highly accurate solder resist pattern while suppressing the drop-off from the solder resist.

  Pattern exposure refers to exposing a pattern to be a solder resist pattern to an unexposed solder resist. The contact type pattern exposure and the non-contact type pattern exposure in the present invention may be performed in batches for the work size of the circuit board, or may be performed for each sheet to be a product.

Exposure pattern exposure to unexposed solder resist in the present invention, depending on the sensitivity of the solder resist, in general, preferably per 100 mJ / cm ² or more times, more preferably 300~600mJ / cm ^2. The pattern exposure onto the unexposed solder resist in the present invention may be a scattered light system in which light is diffused from the exposure apparatus light source, or a parallel light system in which the light from the exposure apparatus light source is in a fixed direction. It is desirable to use a scattered light method for contact pattern exposure that does not require relatively high accuracy, and to use a parallel light method for non-contact pattern exposure that requires relatively high accuracy.

  Contact-type pattern exposure refers to a method in which a photomask is brought into contact with an unexposed solder resist to perform pattern exposure. Contact-type pattern exposure can be performed by overlaying a photomask on an unexposed solder resist formed on a circuit board, bringing it into close contact with a relatively low degree of vacuum, and exposing ultraviolet light from above the photomask. A film mask and a glass mask can be used as the photomask.

  Non-contact pattern exposure refers to a method of performing pattern exposure without bringing a photomask into contact with an unexposed solder resist. In non-contact pattern exposure, the circuit board on which the unexposed solder resist is formed is firmly adhered to the work table at a relatively high degree of vacuum, and is placed above the unexposed solder resist formed on the circuit board. This can be done by positioning the photomask and projecting and exposing ultraviolet rays from above the photomask. In this case, a glass mask is used as the photomask. Moreover, direct drawing which pattern-exposes a soldering resist pattern directly with respect to an unexposed soldering resist using a laser etc. can also be used.

  A photomask refers to an original (mask) for forming a solder resist pattern by pattern exposure. A film mask or a glass mask can be used as the photomask. The film mask is made of PET (polyethylene terephthalate) or the like as the base material, the glass mask is made of soda lime glass or the like, and a light shielding film that shields light (mainly ultraviolet light) during pattern exposure is formed by providing a desired pattern. it can. When pattern exposure is performed on a portion requiring high accuracy, it is desirable to use a glass mask. On the other hand, when pattern exposure is performed on a portion that does not require high precision, it is possible to sufficiently cope with the use of a film photomask, and it is desirable in terms of low cost.

  For example, the location where high accuracy is required means that the solder resist formed for the purpose of providing a connection terminal on the circuit pattern or the like, or the solder used for connection with the electronic component does not bridge in the gap of the circuit pattern serving as the connection terminal. In the solder resist pattern such as a solder resist dam provided as described above, it means a region including the end of the final solder resist pattern. On the other hand, a location that does not require high accuracy refers to a location that is 100 μm or more away from the end of the final solder resist pattern. Since such a place is not a place for finally determining a target solder resist pattern, relatively rough pattern exposure may be performed. For this reason, it is suitable to use a film mask.

  This invention has the process of forming the target soldering resist pattern by developing the soldering resist by which pattern exposure was carried out. Development is to remove a non-exposed portion of the pattern-exposed solder with a developer, and finally form a target solder resist pattern. The developing solution is selected depending on the type of solder resist. In a so-called alkali developing type solder resist, which is generally used, an aqueous sodium carbonate solution of about 1% by mass is used. The target solder resist pattern is a solder resist pattern required for a circuit board when shipped as a product. The developed solder resist is generally subjected to final curing so that the solder resist reaches a curing degree having a practical level of mechanical strength, chemical resistance, heat resistance, and the like. The treatment for the final curing is selected depending on the type of solder resist, but a so-called alkali development type solder resist that is generally used is subjected to heat treatment at about 150 ° C. for about 1 hour.

  In the step of forming the pattern-exposed solder resist, it is desirable to perform non-contact pattern exposure after performing contact pattern exposure. Usually, of the entire area where the solder resist is formed, a part requiring high precision is a part, and a part not requiring high precision is most. For this reason, when performing pattern exposure on unexposed solder resists formed on both the front and back sides of a circuit board, first, contact pattern exposure is applied to locations that do not require high precision on both the front and back sides of the circuit board. Then, non-contact pattern exposure is performed on the portions of the circuit board that require high precision on both the front and back surfaces. As a result, when non-contact pattern exposure is performed, the unexposed solder resist is hardened at locations that do not require high accuracy, which occupies most of the circuit board. Transfer to the work table of the exposure apparatus can be reduced, and a highly accurate solder resist pattern can be formed.

  In the step of forming the pattern-exposed solder resist, it is desirable to partially overlap the exposed portions when performing contact-type pattern exposure and non-contact-type pattern exposure. Usually, of the entire area where the solder resist is formed, a part requiring high precision is a part, and a part not requiring high precision is most. For this reason, when performing pattern exposure on unexposed solder resists formed on both the front and back sides of a circuit board, first, contact pattern exposure is applied to locations that do not require high precision on both the front and back sides of the circuit board. Then, non-contact type pattern exposure is performed on both of the parts that require high precision on both the front and back surfaces of the circuit board and the parts that do not require high precision that have already undergone contact type pattern exposure. In this case, the portions that do not require high accuracy on both the front and back sides of the circuit board do not need to be overlapped entirely, and only necessary portions may be overlapped. As a result, when non-contact pattern exposure is performed, the unexposed solder resist is hardened at locations that do not require high accuracy, which occupies most of the circuit board. Transfer to the work table of the exposure apparatus can be reduced, and a highly accurate solder resist pattern can be formed. In addition, since the pattern exposure is performed twice for the portion that does not require high accuracy that occupies most, the adhesion after development can be ensured and the surface of the solder resist is attacked by the developer and whitened. Can be prevented.

In the step of forming the pattern-exposed solder resist, when performing contact pattern exposure and non-contact pattern exposure, it is preferable to reduce the area of the pattern exposure every time the number of exposures is increased. In other words, the exposure area of the n-th _S n, (n + 1) the time of exposure area when the _{S (n + 1),} it is preferable that the _{S n> S (n + 1} ). Usually, of the entire area where the solder resist is formed, a part requiring high precision is a part, and a part not requiring high precision is most. For this reason, when performing pattern exposure to unexposed solder resist formed on both the front and back sides of the circuit board, first contact the parts that do not require high precision that occupy most of the front and back sides of the circuit board. Then, pattern contact exposure is performed, and then non-contact pattern exposure is performed on portions of the circuit board that require high accuracy on both the front and back surfaces. In this case, in the non-contact pattern exposure, portions that do not require high accuracy on both the front and back surfaces of the circuit board may be partially overlapped. As a result, when non-contact pattern exposure is performed on a portion requiring high accuracy, the unexposed solder resist is hardened at a portion not requiring high accuracy that occupies most of the circuit board. Therefore, it is possible to reduce the transfer of the solder resist from the back surface side of the circuit board to the work table of the exposure apparatus, and it is possible to form a highly accurate solder resist pattern. In the case of direct drawing using a laser or the like, the drawing time can be shortened.

  Examples of the present invention will be described below, but the present invention is not limited to the examples.

Example 1
As shown in FIG. 1, MCL-E-679FG (Hitachi), which is a glass cloth base epoxy resin copper clad laminate having a nominal thickness of 0.2 mm of an insulating resin layer 5 bonded with a copper foil 21 having a thickness of 3 μm. A through hole 22 having a diameter of 0.15 mm was formed by drilling in Kasei Kogyo Co., Ltd. (trade name), and smear removal was performed by potassium permanganate treatment. Next, electroless copper plating of about 1 μm is applied, and a dry film for etching resist NIT225 (product name, manufactured by Nichigo Morton Co., Ltd.) is temporarily pressure-bonded with a laminator, and a film-like photomask mask is bonded thereto, so that an exposure amount is 140 mJ / cm. ^The pattern which becomes the circuit pattern 3 on both surfaces was baked with ultraviolet rays of ² , and developed with a 0.9 mass% sodium carbonate aqueous solution to form a plating resist. Next, electrolytic copper plating 23 is deposited on the portion where there is no plating resist, the plating resist is peeled off with an amine-based aqueous solution, and the underlying copper at the place where the plating resist was formed with an aqueous solution of sulfuric acid-hydrogen peroxide solution is removed by etching. Thus, a circuit pattern 3 was formed to form a first circuit board 4 (FIG. 1A).

  The surface of the circuit pattern 3 of the first circuit board 4 is roughened, and a prepreg GEA-679FG having a nominal thickness of 0.04 mm in which glass cloth is impregnated with epoxy resin on both surfaces of the first circuit board 4 ( Via a Hitachi Chemical Co., Ltd. product name), 18 μm 3 μm copper foil with carrier copper foil MT18SDH3 (Mitsui Metal Mining Co., Ltd. product name) is maintained at a pressure of 2.5 MPa and a temperature of 175 ° C. in a vacuum press. After the lamination for 1.5 hours, the carrier copper foil was peeled off to obtain the second circuit board 6 having the copper foil 21 and the insulating resin layer 5 (FIG. 1B).

A dry film NIT225 (product name, manufactured by Nichigo Morton Co., Ltd.) is temporarily bonded to both surfaces of the second circuit board 6 with a laminator, and a film-like photomask is attached to both surfaces with an ultraviolet ray having an exposure amount of 90 mJ / cm ^2. The circuit pattern was baked and developed with a 1% by mass aqueous sodium carbonate solution to form an etching resist. Next, the copper portion without the etching resist is removed with an aqueous ferric chloride solution, and the etching resist is peeled off with a 3% by mass sodium hydroxide aqueous solution. A laser position recognition pattern (not shown) was formed to form a third circuit board 8 (FIG. 1C).

  Cyclic machining on both surfaces of the third circuit board 8 with a carbon dioxide laser machine LC-1C / 21 (trade name, manufactured by Hitachi Via Mechanics Co., Ltd.) under conditions of a beam irradiation diameter of 0.2 mm, a pulse width of 11 μs, and 4 shots. Then, a non-through hole 24 having a diameter of 0.1 mm was formed to form the fourth circuit board 9 (FIG. 1D). Cyclic machining is a method of machining one hole / shot at a time for a certain area, moving to the next area after repeating the specified number of times (four times in this embodiment), and machining in the same way. is there.

The fourth circuit board 9 is subjected to smear removal by potassium permanganate treatment, followed by electroless copper plating of about 1 μm, and an etching resist dry film NIT225 (product name, manufactured by Nichigo Morton Co., Ltd.) is temporarily used with a laminator Then, a film-like photomask was attached, and a pattern to be a circuit pattern 3 was printed on both surfaces with an ultraviolet ray having an exposure amount of 140 mJ / cm ² , and developed with a 0.9 mass% sodium carbonate aqueous solution to form a plating resist. Next, electrolytic copper plating 23 is deposited on the portion where there is no plating resist, the plating resist is peeled off with an amine-based aqueous solution, and the base copper that has formed the plating resist with an aqueous solution of sulfuric acid-hydrogen peroxide solution is removed by etching. A circuit pattern 3 was formed to form a fifth circuit board 10 (FIG. 1E).

  The surface of the circuit pattern 3 of the fifth circuit board 10 is roughened, and a development type solder resist ink PSR-4000AUS308 (trade name, manufactured by Taiyo Ink Manufacturing Co., Ltd.) is applied to both sides, and the temperature is about 80 ° C. for about 20 minutes Precure was performed to obtain a sixth circuit board 13 (FIG. 2A).

A large portion of the unexposed solder resist 12 is obtained by applying a film-like photomask on both surfaces of the sixth circuit board 13 and performing pattern exposure with ultraviolet rays with an exposure amount of 540 mJ / cm ² (contact pattern exposure). The solder resist 1 subjected to contact-type pattern exposure was formed at (a place where high accuracy is not required) to form a seventh circuit board 14 (FIG. 2B).

On the seventh circuit board 14, a part of the unexposed solder resist 12 (a portion requiring high accuracy) and an already contact-type pattern with ultraviolet light having an exposure amount of 450 mJ / cm ² using projection exposure with a glass mask Pattern exposure was performed on the exposed solder resist 1 (location that does not require high accuracy) (pattern exposure by a non-contact method). As a result, a part of the unexposed solder resist 12 (a place requiring high accuracy) is applied with the solder resist 2 that has been subjected to non-contact pattern exposure, and the solder resist that has already been subjected to contact type pattern exposure. The solder resist 1 subjected to the non-contact pattern exposure after the contact type pattern exposure is formed at 1 (a place where high accuracy is not required) to form an eighth circuit board 15 (FIG. 2C). .

The eighth circuit board 15 is developed with a 1% by mass aqueous sodium carbonate solution to form a solder resist pattern 20, cured by irradiating with 2000 mJ / cm ^{2 of} ultraviolet rays, and dried at 150 ° C. for 1 hour for thermal curing. Thus, a ninth circuit board 16 was obtained (FIG. 2D).

(Example 2)
The same process as in Example 1 was performed until the fifth circuit board 10 was manufactured. The surface of the circuit pattern 3 of the fifth circuit board 10 is roughened, and a development type solder resist film PFR-800AUS402 (trade name, manufactured by Taiyo Ink Mfg. Co., Ltd.) is vacuum-bonded on both sides with a laminator to form a sixth circuit. A substrate 13 was obtained (FIG. 2A). The seventh circuit board 14, the eighth circuit board 15 and the ninth circuit board 16 were produced in the same manner as in Example 1.

(Comparative example)
Hereinafter, a conventional manufacturing method will be described as a comparative example.
As in Example 1, the fifth circuit board 10 is prepared, the surface of the circuit pattern 3 of the fifth circuit board 10 is roughened, and development type solder resist ink PSR-4000AUS308 (manufactured by Taiyo Ink Manufacturing Co., Ltd.) , Product name) was applied to both sides, and pre-curing was performed at 80 ° C. for about 20 minutes to obtain a sixth circuit board 13 (FIG. 3A).

A film-like photomask is attached to both surfaces of the sixth circuit board 13 and pattern exposure is performed with ultraviolet rays having an exposure amount of 540 mJ / cm ² (pattern exposure by contact type), thereby making it possible to form an unexposed solder resist 12. The pattern exposure of the pattern which becomes the solder resist pattern 20 to be performed was performed. As a result, the solder resist 11 subjected to the pattern exposure by the contact method is formed on the unexposed solder resist 12 (both the portion requiring high accuracy and the portion not requiring high accuracy), and the tenth circuit board is formed. 17 (FIG. 3B).

The tenth circuit board 17 is developed with a 1% by mass aqueous sodium carbonate solution to form the intended solder resist pattern 20, cured by irradiating with 2000 mJ / cm ^{2 of} ultraviolet rays, and dried at 150 ° C. for 1 hour. Thus, an eleventh circuit board was obtained by thermosetting (FIG. 3C).

  As a result of Examples 1 and 2 and the comparative example, the product defect rate due to the drop of the solder resist pattern 20 could be reduced from 4.0% (Comparative Example) to 0.2% (Examples 1 and 2). .

1: Solder resist (with non-contact pattern exposure after contact pattern exposure) 2: Solder resist (with non-contact pattern exposure) 3: Circuit pattern 4: First circuit board 5: Insulation Resin layer 6: 2nd circuit board 7: Conformal mask 8: 3rd circuit board 9: 4th circuit board 10: 5th circuit board 11: Solder resist 12 (pattern exposure by contact type was made) : Unexposed solder resist 13: 6th circuit board or circuit board 14: 7th circuit board 15: 8th circuit board 16: 9th circuit board 17: 10th circuit board 18: 11th circuit Substrate 20: Solder resist pattern 21: Copper foil 22: Through hole 23: Electrolytic copper plating 24: Non-through hole

Claims (5)

In a method for manufacturing a circuit board having a circuit pattern coated with a solder resist pattern,
Forming an unexposed solder resist on the circuit pattern;
For the unexposed solder resist, performing a contact pattern exposure and a non-contact pattern exposure to form a pattern exposed solder resist;
By developing the pattern exposed solder resist, possess a step of forming a solder resist pattern of interest, and
In the step of forming the pattern-exposed solder resist, after performing contact type pattern exposure, a method of manufacturing a circuit board that performs non-contact type pattern exposure overlapping with a portion where the contact type pattern exposure is performed . 2. The circuit board according to claim 1, wherein, in the step of forming the pattern-exposed solder resist, when performing non-contact pattern exposure, the circuit substrate that finally exposes an area including an end portion of the target solder resist pattern Manufacturing method. 3. The method of manufacturing a circuit board according to claim 1 or 2, wherein in the step of forming the pattern-exposed solder resist , when the non- contact pattern exposure is performed, the exposed portion is partially overlapped with the portion where the contact pattern exposure is performed. .   4. The contact pattern exposure and non-contact pattern exposure are performed in the step of forming a pattern-exposed solder resist in any one of claims 1 to 3, and the pattern exposure area is reduced each time the number of exposures is increased. Circuit board manufacturing method.   5. The process of forming an unexposed solder resist on a circuit pattern according to claim 1, wherein a liquid solder resist ink is applied on the circuit pattern and precured, or a dry film solder resist film is formed. A circuit board manufacturing method for forming an unexposed solder resist by laminating a substrate.

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