JPH09186430A - Printed wiring board and manufacturing method thereof - Google Patents

Abstract

(57) Abstract: Even when a wiring circuit pattern has a fine pitch, it is possible to suppress the occurrence of displacement of the formation position of the land portion and to perform good connection with an electronic component. SOLUTION: On the wiring circuit pattern 3 which is the outermost layer,
A resist layer 5 having an opening 4a having a predetermined shape for exposing a part of the wiring circuit pattern 3 is formed at a predetermined position, and a conductive material is plated in the opening 4a to form a land 6a. The wiring circuit pattern 3 is preferably formed by an additive method. The resist layer 5 is preferably formed by exposing and developing a photoresist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board on which a wiring circuit pattern having a land portion which is a connection portion with an electronic component is formed, and a manufacturing method thereof. More specifically, by forming a resist layer having an opening on a wiring circuit pattern and arranging a conductive material in the opening to form a land, a printed wiring board with improved land-position forming accuracy and a method for manufacturing the same are provided. Related to.

[0002]

2. Description of the Related Art Conventionally, in various electronic devices such as a television receiver, a radio receiver, a cassette tape recorder, etc., a printed wiring board on which a predetermined wiring circuit pattern is formed for mounting many electronic parts etc. It is used a lot.

In such a printed wiring board, a soldering connection portion called a land portion is formed in the wiring circuit pattern, and the land portion and the terminals of the electronic component are soldered to each other. I try to mount electronic parts.

As a typical method for manufacturing a printed wiring board, there is a so-called subtractive method or an additive method. For example, in a printed wiring board manufactured by the additive method, the land portion as described above is formed as follows. Are formed.

That is, in order to manufacture this printed wiring board, as shown in FIG. 7, first, a resist layer 103 is formed on a portion of the insulating layer 101 excluding a portion where the wiring circuit pattern 102 is formed, and this resist layer is formed. The wiring circuit pattern 102 is formed by disposing a conductive material such as copper by plating on a portion where the 103 is not formed. The resist layer 103 as described above is called a permanent resist.

To form the land portion, a resist material such as a photoresist such as a solder resist is applied on the wiring circuit pattern 102 and the resist layer 103, and the resist material is exposed and developed. A resist layer 104 having an opening 105 having a predetermined shape is formed at a predetermined position, a part of the wiring circuit pattern 102 is exposed through the opening 105, and this portion is formed as a land portion 106.

[0007]

By the way, in recent years, there has been a demand for miniaturization of printed wiring boards, and along with this, miniaturization of electronic components has progressed, and in accordance with the pitch between terminals of the electronic components. It has become necessary to reduce the pitch between wiring circuit patterns to 0.3 mm or less.

When the land portion is formed in the wiring circuit pattern of the printed wiring board as described above, the opening portion of the resist layer is provided corresponding to each land portion in consideration of the exposure and development accuracy of the solder resist. Rather, it is preferable to provide it as an opening having a size corresponding to the plurality of lands.

That is, as shown in FIG. 8, a plurality of (here, five) patterns 107a are formed on the resist layer 104 so as to be adjacent to each other in the wiring circuit pattern 102.
The first opening 109 for exposing a part of 107b, 107c, 107d, 107e collectively and the plurality of patterns 107a, 107b, 107c, 107d, 107e.
A plurality of (here, four) patterns 108a, 108b, 108 formed adjacent to each other in a direction orthogonal to
The second opening 110 is formed so as to collectively expose a part of c and 108d.

Then, the patterns 107a, 107b, 1
First opening 10 of 07c, 107d, 107e
A plurality of land portions 111a, 111b, 111c, 111d, 11 formed so that the portions exposed by 9 are adjacent to each other.
1e, and the patterns 108a, 108b, 108c,
The portion of 108d exposed by the second opening 110 is the land portions 111a, 111b, 111.
a plurality of land portions 112a, 112b, 112c formed adjacent to each other in the direction orthogonal to c, 111d, 111e,
It becomes 112d.

Further, as a matter of course, a part of the resist layer 103 existing between the patterns 107a, 107b, 107c, 107d, 107e and the patterns 108a, 108b, 108c, 108d is also exposed. Incidentally, these first and second openings 109, 11
0 is a plurality of patterns 107 with the resist layer 103 interposed therebetween.
a, 107b, 107c, 107d, 107e or a plurality of patterns 108a, 108b, 108c, 108d
Is formed to have a width wider than the entire width of.

Such first and second openings 109,
110 is formed by exposing and developing the solder resist as described above, but in this exposure step, exposure is naturally performed through a mask material. Therefore, in this exposure process, if a relative positional deviation occurs between the mask material and the wiring circuit pattern 102, a deviation occurs in the formation position of the opening and a deviation in the formation position of the land.

For example, the formation positions of the first and second openings 109 and 110 shown in FIG.
When the longitudinal direction of a, 107b, 107c, 107d, and 107e is the vertical direction, and there is a slight deviation in the upward direction in the figure, the land portions 112a, 112b, 112c, 112d.
The formation position of the first opening 109 is not changed, but the formation position of the first opening 109 is not changed.
07d, 107e are displaced in the longitudinal direction, and land portions 111a, 111b, 111c, 111d, 11
A shift occurs in the formation position of 1e. If such a deviation in the formation position of the land portion occurs as a deviation of several tens of μm,
In a printed wiring board having a fine pitch of 0.3 mm or less as described above, there is a high possibility that good connection with electronic components cannot be achieved.

Therefore, the present invention has been proposed in view of the conventional circumstances, and even when the wiring circuit pattern has a fine pitch, it is possible to suppress the occurrence of the deviation of the formation position of the land portion, and It is an object of the present invention to provide a printed wiring board and a method for manufacturing the printed wiring board, which are well connected.

[0015]

As a result of intensive studies made by the present inventors in order to achieve the above-mentioned object, as a result of the conventional method, when forming a land portion, the accuracy of the land portion forming position depends on the formation of the wiring circuit pattern. It was found that it depends on two factors, that is, the positional accuracy and the formation accuracy of the opening of the resist layer, and the formation accuracy of the land portion can be improved by reducing the factor that affects the formation accuracy of the land portion. I found it possible.

That is, in the printed wiring board of the present invention, a resist layer having an opening of a predetermined shape for exposing a part of the wiring circuit pattern is formed at a predetermined position on the wiring circuit pattern of the outermost layer, and the opening is formed. The land portion is formed by disposing a conductive material in the portion by plating.

In the printed wiring board of the present invention, the outermost wiring circuit pattern is preferably formed by an additive method.

Further, according to the method for manufacturing a printed wiring board of the present invention, a resist layer having an opening portion of a predetermined shape for exposing a part of the wiring circuit pattern is formed at a predetermined position on the outermost wiring circuit pattern. The land portion is formed by plating a conductive material in the opening to arrange the land portion.

In this printed wiring board manufacturing method, a photoresist is provided on the outermost wiring circuit pattern, and the photoresist is exposed and developed to expose a part of the wiring circuit pattern at a predetermined position. It is preferable to form a resist layer having an opening having a predetermined shape.

In the printed wiring board of the present invention, a resist layer having an opening having a predetermined shape for exposing a part of the wiring circuit pattern is formed at a predetermined position on the outermost wiring circuit pattern, and the inside of the opening is formed. A conductive material is plated on the surface of the resist, and this conductive material is connected to the wiring circuit pattern to form a land that is a soldering connection with an electronic component. The position of formation of the land portion is less likely to deviate because it depends only on the accuracy of the position of formation of the portion.

Even if a relative deviation occurs between the formation position of the opening of the resist layer and the formation position of the wiring circuit pattern, the accuracy of the formation position of the opening and the formation position of the wiring circuit pattern in the resist layer are taken into consideration. If so, the land portion formed in the opening and the wiring circuit pattern are sufficiently connected, and no inconvenience occurs.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings. In addition,
Here, the wiring circuit pattern of the single-sided printed wiring board,
A quad flat package (Quad F), which is formed by the so-called additive method and is a kind of flat package IC chip, in which a plurality of terminals are formed adjacent to each other on four sides of a flat rectangular electronic component.
lat Package; hereinafter referred to as QFP. ) An example of a printed wiring board having lands for mounting will be described.

In the printed wiring board of this example, as shown in FIG. 1, a resist layer 2 is formed on a portion other than a portion where a wiring circuit pattern 3 is formed on one main surface 1a which is an upper surface of an insulating substrate 1, A conductive material such as copper is plated on the portion where the resist layer 2 is not formed, and the wiring circuit pattern 3 is formed by this portion. The resist layer 2 is called a permanent resist.

In the printed wiring board of this embodiment, a part of the wiring circuit pattern 3 is exposed at a predetermined position on the resist layer 2 and the wiring circuit pattern 3 as shown in FIG. A resist layer 5 having an opening 4a having a predetermined shape is formed. Further, in this printed wiring board, a conductive material such as copper is provided in the opening 4a by plating to form a land portion 6a connected to the wiring circuit pattern 2.

Further, when the printed wiring board of this example is viewed from the resist layer 5 side, since the printed wiring board of this example has a land portion corresponding to QFP, as shown in FIG. In addition to the above-mentioned opening 4a, a plurality of (four here are three) openings 4 adjacent to the opening 4a.
b, 4c, 4d are formed in the same manner as the opening 4a, and a conductive material is also plated in these openings to connect the land portions 6b, 6c, 6d to the wiring circuit pattern 2.
Are formed.

Further, as shown in FIG. 2, the openings 7a, 6a, 6b, 6c, 6d are formed in the direction orthogonal to the lands 6a, 6b, 6c, 6d.
7b, 7c, 7d are provided in the same manner as the opening 4a,
The insides of these are also land portions 8a, 8b, 8c, 8d connected to the wiring circuit pattern 2. Further, openings 9a, 9b, 9c, 9d are provided in the same direction as the openings 4a in the direction orthogonal to the lands 6a, 6b, 6c, 6d, and the interiors thereof are also connected to the wiring circuit pattern 2. Land portions 10a, 10b, 10c and 10d are formed. Furthermore, the land portions 6a, 6b, 6c, 6
openings 11a, 11b, 11c, so as to face d.
11d is provided in the same manner as the opening 4a, and the inside of these is also connected to the wiring circuit pattern 2 and the land 12a,
12b, 12c, and 12d. That is, a plurality of adjacent land portions are formed on each side.

Next, a method of manufacturing the printed wiring board of this example will be described. First, as shown in FIG. 3, a resist layer 2 made of, for example, a photoresist and called a permanent resist is formed on a portion other than a portion where the wiring circuit pattern 3 is formed on one main surface 1a which is the upper surface of the insulating substrate 1. , The resist layer 2
The wiring circuit pattern 3 is formed by plating a conductive material such as copper on a portion where the wiring pattern is not formed.

Next, as shown in FIG. 4, for example, a liquid photoresist 13 is applied on the resist layer 2 and the wiring circuit pattern 3. As the liquid photoresist 13, it is preferable to use a material used for a permanent resist. Then, the liquid photoresist 13 is exposed through a mask that forms an opening having a predetermined shape at a predetermined position, and then developed. As a result, as shown in FIG. 5, a resist layer 5 having a plurality of openings (here, only the openings 4a are shown) having a predetermined shape for exposing a part of the wiring circuit pattern 3 is formed at a predetermined position. .

Further, after that, a conductive material such as copper is plated in the plurality of openings to connect to the wiring circuit pattern 3 as shown in FIG. 6 (here, a land portion in the opening 4a). 6a only) is formed.

The resist layers 2 and 5 may be formed by applying a liquid photoresist, or by adhering a dry film resist and exposing and developing it, or by using a UV curable resist.

Further, the wiring circuit pattern 3 and the land portion 6
Examples of the conductive material forming the plurality of lands such as a include copper, gold, solder, and the like, and of these, those capable of electroless plating are preferable.

Therefore, in the printed wiring board of the present example, for example, an opening 4 having a predetermined shape which exposes a part of the wiring circuit pattern 3 at a predetermined position on the wiring circuit pattern 3.
Since the resist layer 5 having a is formed and a conductive material is plated in the opening 4a and the conductive material portion is connected to the wiring circuit pattern, for example, the land portion 6a, the formation position of the land portion 6a is formed. The accuracy depends only on the accuracy of the formation position of the opening 4a of the resist layer 5, and the land 6
The position where a is formed does not easily deviate, and the wiring circuit pattern 3
It is also possible to deal with the case where the fine pitch is used.

Even if there is a relative deviation between the opening 4a of the resist layer 5 and the formation position of the wiring circuit pattern 3, for example, the accuracy of the formation position of the opening 4a in the resist layer 5 and the formation of the wiring circuit pattern 3 are formed. Considering the position accuracy,
The land portion 6a and the wiring circuit pattern 3 are sufficiently connected, and no inconvenience occurs.

When mounting an electronic component on this printed wiring board, since the deviation of the formation position of the land portion is suppressed, for example, supply of cream solder,
The accuracy of the mounting position of parts has also been improved, and the pitch of the terminals is 0.
It is also possible to adequately support mounting of fine pitch QFPs of 3 mm or less.

For example, when a QFP having a pitch of 0.3 mm is mounted, the size of the land portion of the printed wiring board of this example is about 0.5 to 1.0 mm in length indicated by L in FIG. It is sufficient that the width indicated by D is about 100 to 200 μm, and such a QFP can be sufficiently mounted.

In the above example, the wiring circuit pattern is formed by the additive method and the example of the single-sided printed wiring board having the land portion corresponding to the QFP is described. However, the present invention is not limited to the wiring circuit pattern as the uppermost layer. It is applicable to any printed wiring board as long as it is necessary to form the land portion. That is, it is applicable to both a double-sided printed wiring board and a multilayer printed wiring board. The multilayer printed wiring board may be formed by either a stacking press method or a buildup method.

Further, the present invention can be applied to both the land portion on which a land portion for bare chip mounting is formed and the outermost wiring circuit pattern formed by the subtractive method.

[0038]

As is apparent from the above description, in the printed wiring board of the present invention, an opening having a predetermined shape is formed on the outermost wiring circuit pattern to expose a part of the wiring circuit pattern at a predetermined position. Forming a resist layer having a part,
Since the conductive material is plated in the opening and the conductive material portion is connected to the wiring circuit pattern and serves as a land portion which is a connection portion for soldering with an electronic component, the formation position accuracy of the land portion is a resist. The position of the land is less likely to deviate because it depends only on the accuracy of the position of the opening of the layer.

Even if a relative deviation occurs between the formation position of the opening of the resist layer and the formation position of the wiring circuit pattern, the accuracy of the formation position of the opening and the formation position accuracy of the wiring circuit pattern in the resist layer are taken into consideration. If so, the land portion formed in the opening and the wiring circuit pattern are sufficiently connected, and no inconvenience occurs.

Therefore, in the printed wiring board of the present invention, it is possible to sufficiently cope with the case where the wiring circuit pattern has a fine pitch, and it is also possible to sufficiently mount an electronic component having fine pitch terminals. Its industrial value is very high.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of an essential part schematically showing a printed wiring board to which the present invention is applied.

FIG. 2 is an enlarged plan view of an essential part schematically showing a printed wiring board to which the present invention is applied.

FIG. 3 is a fragmentary enlarged cross-sectional view showing a method of manufacturing a printed wiring board to which the present invention is applied, in the order of steps, and schematically showing a step of forming a resist layer and a wiring circuit pattern on an insulating substrate.

FIG. 4 is a fragmentary enlarged cross-sectional view showing a method of manufacturing a printed wiring board to which the present invention is applied in order of steps, schematically showing a step of applying a liquid photoresist on a resist layer and a wiring circuit pattern. .

FIG. 5 is a fragmentary enlarged cross-sectional view showing a method of manufacturing a printed wiring board to which the present invention is applied, in order of steps, and schematically showing a state in which a resist layer is formed.

FIG. 6 is a fragmentary enlarged cross-sectional view showing a method of manufacturing a printed wiring board to which the present invention is applied, in order of steps, and schematically showing a state in which a land portion is formed.

FIG. 7 is an enlarged sectional view of an essential part schematically showing a conventional printed wiring board.

FIG. 8 is an enlarged plan view of an essential part schematically showing a conventional printed wiring board.

[Explanation of symbols]

 1 Insulating Substrate 2, 5 Resist Layer 3 Wiring Circuit Pattern 4a Opening 6a Land

Claims (4)

[Claims] 1. A resist layer having an opening of a predetermined shape exposing a part of the wiring circuit pattern at a predetermined position is formed on the wiring circuit pattern of the outermost layer, and a conductive material is plated in the opening. A printed wiring board, characterized in that the printed wiring boards are arranged to form land portions. 2. The printed wiring board according to claim 1, wherein the outermost wiring circuit pattern is formed by an additive method. 3. A resist layer having an opening of a predetermined shape exposing a part of the wiring circuit pattern at a predetermined position is formed on the wiring circuit pattern of the outermost layer, and a conductive material is plated in the opening. A method for manufacturing a printed wiring board, which comprises arranging and arranging land portions. 4. A photoresist layer is provided on the outermost wiring circuit pattern, and the photoresist is exposed and developed to form a resist layer having an opening of a predetermined shape to expose a part of the wiring circuit pattern at a predetermined position. The method for manufacturing a printed wiring board according to claim 3, wherein the printed wiring board is formed.