JP2005072458A - Circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board which evaluates characteristics of a conductive paste layer and decides normality/defectiveness, in a circuit board having the conductive paste layer. <P>SOLUTION: A circuit board 100 includes: conductor patterns 2b, 2d, 2e formed on a surface of an insulating base material 1; lower insulating layers 3a, 3b, 3c which are formed over the conductor patterns 2b, 2d, 2e, and include openings 3ah, 3ai partially exposing the conductor patterns 2b, 2d, 2e; a conductive paste layer 4 that is formed on the lower insulating layers 3a, 3b, 3c, and is connected to the conductor patterns 2d, 2e exposed in the opening 3ah; and an upper insulating layer 5 formed over the conductive paste layer 4. In the board, the circuit board 100 comprises a characteristic evaluation portion 10 for the conductive paste layer 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a circuit board having a conductive paste layer.

  A circuit board having a conductive paste layer connected to a conductor pattern formed on the surface of an insulating base material is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-140788 (Patent Document 1). FIG. 7 schematically shows a typical cross-sectional structure thereof.

  In the circuit board 90 of FIG. 7, conductor patterns 2a, 2b, 2c are formed on the surface of the insulating base 1, and lower insulating layers 3a, 3b, 3c are formed covering the conductor patterns 2a, 2b, 2c. Yes. The lower insulating layer 3a is a solder resist layer, and the conductor patterns 2a and 2c are partially exposed in the opening 3ah. The lower insulating layers 3b and 3c are undercoat layers formed in two layers for ensuring insulation separation from the conductor pattern 2b. A conductive paste layer 4 is formed on the lower insulating layers 3a, 3b, 3c. The conductive paste layer 4 is connected to the exposed conductor patterns 2a and 2c in the opening 3ah formed in the solder resist layer 3a which is a lower insulating layer. An upper insulating layer 5 is formed so as to cover the conductive paste layer 4. The upper insulating layer 5 is an overcoat layer for preventing migration or the like of the conductive paste layer 4.

As shown in FIG. 7, the conductive paste layer 4 is used as a jumper wiring that connects the conductor patterns 2a and 2c exposed in the opening, or is used as a shield for the conductor pattern 2b.
JP-A-6-140788

  The lower insulating layers 3a, 3b, 3c, the conductive paste layer 4 and the upper insulating layer 5 shown in FIG. 7 are formed on the conductor patterns 2a, 2b, 2c of the insulating substrate 1 by printing. The jumper wiring and shield formed by the conductive paste layer 4 have variations in performance due to variations in thickness during printing of the conductive paste layer 4. However, as shown in FIG. 7, the conductive paste layer 4 is completely surrounded by the lower insulating layers 3a, 3b, 3c and the upper insulating layer 5, and is used as a jumper wiring or a shield in the circuit board 90 of FIG. The property evaluation of the conductive paste layer 4 cannot be performed. For this reason, the quality of the circuit board which has the manufactured electrically conductive paste layer cannot be determined.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit board having a conductive paste layer, which can evaluate the characteristics of the conductive paste layer and can determine whether it is good or bad.

  The invention according to claim 1 is a conductor pattern formed on the surface of the insulating base, a lower insulating layer formed so as to cover the conductor pattern and having an opening partly exposing the conductor pattern; A circuit board having a conductive paste layer formed on a lower insulating layer and connected to a conductor pattern exposed in the opening, and an upper insulating layer formed to cover the conductive paste layer, the circuit board having A characteristic evaluation portion of the conductive paste layer is provided.

  According to this, even if the conductive paste layer is completely covered with the upper insulating layer, the characteristics of the formed conductive paste layer can be evaluated using the characteristic evaluation portion. Therefore, it is possible to evaluate the performance of the jumper wiring and shield formed by the conductive paste layer.

  For example, when the conductive paste layer is a jumper wiring that interconnects the conductive patterns exposed in the opening, the characteristic evaluation portion is measured as a resistance value of the jumper wiring. It can be used as a resistance measurement terminal.

  This resistance measurement terminal can be configured as described in claim 3, for example. That is, the opening includes a first opening in which a jumper wiring is connected to the exposed conductor pattern, and a second opening in which the conductive pattern is exposed to the surface of the circuit board without being connected to the conductive paste layer. The resistance measurement terminal is connected to a conductor pattern exposed in the first opening, and is a conductor pattern exposed in the second opening disposed near the first opening. Can be configured.

  The resistance of the jumper wiring formed by the conductive paste layer can be measured using the resistance measurement terminal configured as described above. Therefore, the quality of the circuit board can be determined by checking the jumper wiring resistance.

  In addition, for example, as described in claim 4, the characteristic evaluation site is a layer thickness for measuring each layer thickness of the lower insulating layer, the conductive paste layer, the upper insulating layer, or a combination thereof. It can be a measurement test coupon.

  The stress applied to the conductive paste layer by repeated cold heat greatly affects the durability performance of the conductive paste layer. The stress applied to the conductive paste layer depends not only on the layer thickness of the conductive paste layer but also on the layer thicknesses of the lower insulating layer and the upper insulating layer. If the lower insulating layer and the upper insulating layer have different layer thicknesses, the conductive paste layer Different stresses are applied to the surface. Therefore, using the layer thickness measurement test coupon, the durability performance of the conductive paste layer is evaluated by measuring each layer thickness of either the lower insulating layer, the conductive paste layer, the upper insulating layer, or a combination thereof. Can do. Thereby, the quality of a circuit board can be determined.

  The layer thickness measurement test coupon may be configured to have a portion for measuring a step between the insulating base material exposed on the surface of the circuit board and the lower insulating layer, as described in claim 5, for example. Thereby, the layer thickness of the lower insulating layer can be measured. Moreover, you may comprise so that it may have a site | part which measures the level | step difference of the conductor pattern exposed on the surface of a circuit board, and a lower-layer insulating layer, as described in Claim 6. Also by this, the layer thickness of the lower insulating layer can be measured.

  If the layer thickness measurement test coupon is configured to have a portion for measuring a step between the lower insulating layer exposed on the surface of the circuit board and the conductive paste layer, for example, as described in claim 7, the layer of the conductive paste layer Thickness can be measured. Further, for example, as described in claim 8, if it is configured to have a portion for measuring a step between the conductive paste layer exposed on the surface of the circuit board and the upper insulating layer, the layer thickness of the upper insulating layer is measured. Can do.

  The invention described in claim 9 is characterized in that the layer thickness measurement test coupon has a portion for measuring a step between the conductor pattern exposed on the surface of the circuit board and the upper insulating layer. According to this, the height from the conductor pattern to the highest upper insulating layer on the circuit board, which must be managed when components are mounted on the conductor pattern, is measured. Thereby, the quality of a circuit board can be determined.

  The invention described in claims 10 and 11 is an invention for improving the measurement accuracy of the layer thickness measurement. In the layer thickness measurement for measuring the step, when the reference step is inclined, the measurement becomes inaccurate as the distance from the step portion increases. On the other hand, the insulating base material and the conductor pattern in the circuit board are formed relatively flat. The inventions according to claims 10 and 11 use this insulating base material or conductor pattern as a step for measuring a step, and the insulating base material exposed on the surface of the circuit board at both ends of the layer thickness measurement test coupon or Arrange the conductor pattern. As a result, the line connecting the insulating substrates or conductor patterns arranged at both ends can be used as a height reference line, and each step of the lower insulating layer, conductive paste layer, and upper insulating layer between them can be accurately determined. Can be measured.

  The invention according to claim 12 includes a product portion from which the circuit board is cut out to become a product, and a frame portion for holding the product portion, and the layer thickness measurement test coupon is attached to the frame portion. It is characterized by being formed.

  As described above, when the circuit board includes the product portion and the frame portion, the layer thickness measurement test coupon is arranged in the frame portion, so that it is not necessary to occupy the region of the product portion where high density is required. Therefore, the thickness of each of the lower insulating layer, the conductive paste layer, and the upper insulating layer is measured and the durability performance of the conductive paste layer is evaluated. Can be used as a circuit board.

  Further, for example, as described in claim 13, the characteristic evaluation portion can be an adhesion measurement test coupon for measuring the adhesion of the conductive paste layer to the conductor pattern.

  The adhesion of the conductive paste layer to the conductor pattern also greatly affects the performance of the jumper wiring and shield formed by the conductive paste layer and the durability performance of the conductive paste layer against repeated cooling. Therefore, by using the adhesion measurement test coupon, the adhesion of the conductive paste layer to the conductor pattern can be measured to determine the durability performance of the conductive paste layer and the quality of the circuit board.

  The adhesion measurement test coupon may be formed of a conductive paste layer formed on the conductor pattern exposed in the opening and exposed on the surface of the circuit board, for example, as described in claim 14. it can. The adhesion of the conductive paste layer can be measured by performing a test using a conductive paste layer formed on the conductive pattern to peel off the tape.

  Further, when the circuit board is composed of the product part and the frame part as in the fifteenth aspect, the adhesion measurement test coupon can be arranged in the frame part in the same manner as the layer thickness measurement test coupon. As a result, it is not necessary to occupy the area of the product portion where high density is required. Accordingly, the circuit board is a circuit board on which the adhesiveness of the conductive paste layer to the conductive pattern is measured and the durability performance of the conductive paste layer is evaluated, and a high-density circuit is arranged in a product portion that is cut out to become a product. It can be a circuit board.

  In addition, for example, as described in claim 16, the characteristic evaluation portion can be an insulation resistance measurement test coupon for measuring an insulating characteristic of the lower insulating layer.

  The insulation characteristics of the lower insulating layer also have a great influence on the performance of the jumper wiring and shield formed by the conductive paste layer. Accordingly, the insulation resistance measurement test coupon can be used to measure the insulation resistance of the lower insulating layer to determine the performance of the conductive paste layer and the quality of the circuit board.

  The insulation resistance measurement test coupon is formed, for example, in a comb shape as described in claim 17, and a pair of the conductor patterns arranged so that side surfaces of the comb teeth face each other, and the pair of conductor patterns The lower insulating layer formed so as to cover the mutually facing comb teeth and the opening can be configured. Using the insulation resistance measurement test coupon configured as described above, the insulation resistance of the lower insulating layer formed so as to cover the comb teeth can be measured using the conductor pattern exposed in the opening as a measurement terminal. Therefore, the quality of the circuit board can be determined by checking the insulation resistance of the lower insulating layer.

  In addition, as described in claims 18 and 19, the lower insulating layer includes a first lower insulating layer which is a solder resist layer from the insulating base side, a second lower insulating layer and a third lower insulating layer which are undercoat layers. In some cases, it is formed of three layers. In this case, the insulation resistance measurement test coupon in which the lower insulating layer covering the comb tooth portion according to claim 18 is composed of a second lower insulating layer and a third lower insulating layer, and the comb tooth portion according to claim 19 It is preferable to provide an insulation resistance measurement test coupon in which the lower insulating layer covering the insulating layer comprises only the third lower insulating layer. Thereby, the insulation resistance of the lower insulating layer consisting of the lamination of the second lower insulating layer and the third lower insulating layer and the insulating resistance of the lower insulating layer consisting of only the third lower insulating layer can be individually evaluated.

  When the circuit board is composed of a product part and a frame part as in claim 20, the insulation resistance measurement test coupon is arranged in the frame part in the same manner as the layer thickness measurement test coupon and the adhesion measurement test coupon. can do. As a result, it is not necessary to occupy the area of the product portion where high density is required. Therefore, a circuit board in which the insulation resistance of the lower insulating layer is measured and the performance of the conductive paste layer is evaluated, and a circuit board in which a high-density circuit is arranged in a product portion that is cut out to become a product is used. be able to.

  Hereinafter, the circuit board of the present invention will be described with reference to the drawings.

  1A and 1B show a circuit board 100 of the present invention. FIG. 1A is a top view schematically showing a main part of the circuit board 100, and FIG. 1B is a cross-sectional view taken along line AA in FIG. In the circuit board 100 of FIGS. 1A and 1B, the same parts as those of the conventional circuit board 90 shown in FIG.

  The circuit board 100 of FIGS. 1A and 1B is similar to the circuit board 90 of FIG. 7, as shown in FIG. 1B, conductor patterns 2b, 2d, 2e, a lower insulating layer 3a, 3b, 3c, a conductive paste layer 4, and an upper insulating layer 5. In FIG. 1A, the lower insulating layers 3a, 3b, 3c and the upper insulating layer 5 are not shown.

  Conductive patterns 2b, 2d, and 2e are formed of a copper foil having a thickness of about 35 μm. The lower insulating layer 3a, which is a solder resist layer, is formed to a thickness of 12 to 17 μm. The lower insulating layers 3b and 3c, which are undercoat layers for ensuring insulation separation from the conductor pattern 2b, are also formed to a thickness of 12 to 17 μm.

  An opening 3ah is formed in the lower insulating layer 3a that is a solder resist layer, and the conductive paste layer 4 is connected to the conductor patterns 2d and 2e that are partially exposed. For the conductive paste layer 4, for example, a silver (Ag) -copper (Cu) composite paste is used, and is formed to a thickness of 15 to 25 μm. The conductive paste layer 4 shown in FIGS. 1A and 1B is a jumper wiring that connects the conductor patterns 2d and 2e exposed in the opening 3ah. An upper insulating layer 5 for preventing migration and the like is formed so as to cover the conductive paste layer 4. The upper insulating layer 5 as an overcoat layer is formed to a thickness of 12 to 17 μm. The conductive paste layer 4 is completely surrounded by the lower insulating layers 3a, 3b, 3c and the upper insulating layer 5 as in the circuit board 90 of FIG.

  On the other hand, unlike the circuit board 90 of FIG. 7, in the circuit board 100 of FIGS. 1A and 1B, not only the opening 3ah but also the second opening 3ai is arranged nearby, and the first opening 3ah. The second opening 3ai is connected by conductor patterns 2d and 2e. In the first opening 3ah, the conductive paste layer 4 that is a jumper wiring is connected to the exposed conductor patterns 2d and 2e. In the second opening 3ai, the conductive paste layer 4 is not connected to the conductor patterns 2d and 2e. The conductor patterns 2d and 2e are exposed as they are on the surface of the circuit board 100. The conductive patterns 2d and 2e exposed in the second opening 3ai are one of the characteristic evaluation portions of the conductive paste layer 4, and the resistance value of the conductive paste layer 4 in FIGS. 1A and 1B which is a jumper wiring. It is used as a resistance measurement terminal 10 for measuring.

  By providing the resistance measuring terminal 10 in this way, even if the conductive paste layer 4 is completely wrapped by the lower insulating layers 3a, 3b, 3c and the upper insulating layer 5, the resistance measuring terminal 10 is used to The resistance of the conductive paste layer 4 that is a wiring can be measured. Therefore, the quality of the circuit board 100 can be determined by checking the resistance of the jumper wiring.

  A circuit board 100 shown in FIGS. 1A and 1B is one of the characteristic evaluation portions of the conductive paste layer 4 and is a circuit board on which a resistance measurement terminal 10 is formed. On the other hand, the thickness of each of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4, and the upper insulating layer 5 shown in FIG. 1B is important as a characteristic factor related to the durability performance of the conductive paste layer 4. An example is shown in FIGS. 2 (a) and 2 (b).

  FIG. 2A shows the result of examining the relationship between the overall thickness of the lower insulating layers 3 a, 3 b, 3 c and the maximum strain generated in the conductive paste layer 4. 2A is a result obtained by FEM analysis of strain generated in the conductive paste layer 4 when a -30 to 80 ° C. cooling cycle is applied to the structure of FIG. 1B. is there. As can be seen from the figure, the maximum strain generated in the conductive paste layer 4 increases as the overall thickness of the lower insulating layers 3a, 3b, 3c increases and as the conductive paste layer 4 decreases. FIG. 2B shows the result of examining the relationship between the maximum strain generated in the conductive paste layer 4 and the lifetime when repetitive stress is applied. The result shown in FIG. 2B is obtained by using a configuration of a bending strength test in JIS C 6481, applying a constant repetitive stress (and thus a constant repetitive strain) to the conductive paste layer 4 until the breakage is reached. The number of cycles was measured. As can be seen from the figure, the smaller the strain generated in the conductive paste layer 4, the longer the life against repeated stress.

  As shown in FIG. 2B, the stress applied to the conductive paste layer 4 (and hence the strain generated in the conductive paste layer 4) greatly affects the durability performance of the conductive paste layer 4. As shown in FIG. 2A, the stress applied to the conductive paste layer 4 (and hence the strain generated in the conductive paste layer 4) is not only the thickness of the conductive paste layer 4, but also the lower insulating layers 3a, 3b, 3c and It also depends on the thickness of the upper insulating layer 5. Since the thicknesses of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4 and the upper insulating layer 5 vary during manufacturing, the thicknesses of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4 and the upper insulating layer 5 are measured. It is important to evaluate the durability performance of the conductive paste layer 4. However, in the circuit boards 90 and 100 shown in FIGS. 7 and 1B, it is difficult to measure the thicknesses of the lower insulating layers 3a, 3b, and 3c, the conductive paste layer 4, and the upper insulating layer 5 as they are. is there.

  Therefore, in the circuit boards 90 and 100 shown in FIGS. 7 and 1B, a layer thickness measurement test coupon is formed on the circuit board as one of the characteristic evaluation portions of the conductive paste layer 4.

  3A to 3C show an example of a layer thickness measurement test coupon and measurement results using the coupon. Fig.3 (a) is a top view of the layer thickness measurement test coupon 11, FIG.3 (b) is BB sectional drawing in Fig.3 (a). FIG. 3C shows the layer thicknesses of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4, and the upper insulating layer 5 using the layer thickness measurement test coupon 11 shown in FIGS. It is the result of having measured. In the layer thickness measurement test coupon 11 of FIGS. 3A and 3B, the same reference numerals are given to the same parts as those of the circuit board 100 shown in FIGS. 1A and 1B.

  The layer thickness measurement test coupon 11 shown in FIGS. 3A and 3B has four measurement sites.

  The measurement site 11a shown in FIG. 3B is composed of a conductor pattern 2f and lower insulating layers 3a, 3b, 3c, and is exposed on the surface of the circuit board and the conductor pattern 2f exposed to the surface of the circuit board through the opening 3ai. This is a site for measuring the level difference of the exposed lower insulating layer 3c. The layer thickness of the lower insulating layers 3a, 3b, and 3c on the conductor pattern 2g can be measured by measuring the level difference of the measurement site 11a. In order to measure the layer thickness of the lower insulating layers 3a, 3b, 3c, the measurement site may be constituted by the insulating base material 1 and the lower insulating layers 3a, 3b, 3c exposed on the surface of the circuit board.

  3B includes a lower insulating layer 3a, 3b, 3c and a conductive paste layer 4, and a lower insulating layer 3c exposed on the surface of the circuit board and a conductive paste exposed on the surface of the circuit board. This is a site for measuring the level difference of the layer 4. The thickness of the conductive paste layer 4 on the lower insulating layer 3c can be measured by measuring the level difference of the measurement site 11b.

  3B includes a conductive paste layer 4 and an upper insulating layer 5, and a step between the conductive paste layer 4 exposed on the surface of the circuit board and the upper insulating layer 5 exposed on the surface of the circuit board. It is a part which measures. The layer thickness of the upper insulating layer 5 on the conductive paste layer 4 can be measured by measuring the level difference of the measurement site 11c.

  The measurement site 11d shown in FIG. 3B is composed of the conductor pattern 2g and the upper insulating layer 5, and the conductor pattern 2g exposed on the surface of the circuit board through the opening 3ai and the upper insulating layer exposed on the surface of the circuit board. This is a site for measuring the level difference of the layer 5. By measuring the level difference of the measurement site 11d, the height from the conductor pattern 2g exposed on the surface of the circuit board to the highest upper insulating layer 5 on the circuit board is measured. This height is a height that needs to be managed when a component is mounted on the conductor pattern 2g.

  The layer thickness measurement test coupon 11 shown in FIGS. 3A and 3B has a structure having conductor patterns 2f and 2g exposed on the surface of the circuit board at both ends. This is used to improve the accuracy of the layer thickness measurement as follows. That is, in the above-described layer thickness measurement for measuring the step, when the reference step is inclined, the measurement becomes inaccurate as the distance from the step portion increases. On the other hand, the conductor patterns 2f and 2g made of metal foil are formed relatively flat. In the layer thickness measurement test coupon 11 shown in FIGS. 3 (a) and 3 (b), the conductor patterns 2f and 2g are used as a reference step for level difference measurement. Conductive patterns 2f and 2g exposed on the surface of the circuit board are arranged at both ends of the layer thickness measurement test coupon 11. As a result, as shown in FIG. 3C, a line connecting the conductor patterns 2f and 2g arranged at both ends can be used as a reference line for height. For this reason, each step of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4, and the upper insulating layer 5 between them can be measured accurately. In order to obtain a reference line for height, the insulating base material 1 exposed on the surface of the circuit board may be arranged at both ends to constitute a layer thickness measurement test coupon.

  FIG. 3C shows the result of measuring the layer thicknesses of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4 and the upper insulating layer 5 by using the layer thickness measurement test coupon 11 of FIGS. 3A and 3B. It is. The level difference in FIG. 3C was measured using a surface roughness measuring instrument. In FIG. 3C, the layer thicknesses of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4, and the upper insulating layer 5 are 45 μm, 18 μm, and 12 μm, respectively.

  As described above, as shown in FIGS. 3A to 3C, any one of the lower insulating layers 3 a, 3 b, 3 c, the conductive paste layer 4, the upper insulating layer 5, or these using the layer thickness measurement test coupon Each layer thickness of the combination can be measured. The durability performance of the conductive paste layer 4 can be evaluated by combining the measurement results of the respective layers with the relationship between the generated strain and the durability performance shown in FIGS. 2 (a) and 2 (b). Therefore, the quality of the circuit board can be determined by measuring the layer thickness of each layer using the layer thickness measurement test coupon.

  In FIG. 4, the typical top view of the circuit board 101 which has arrange | positioned the layer thickness measurement test coupon 11 is shown. The circuit board 101 in FIG. 4 includes a product part 101a that is cut out from a dotted line portion in the drawing to become a product, and a frame part 101b for holding the product part 101a.

  In the circuit board 101 of FIG. 4, the layer thickness measurement test coupon 11 shown in FIGS. 3A to 3C is formed on the frame portion 101b. When the circuit board is composed of the product part 101a and the frame part 101b as in the circuit board 101 of FIG. 4, the layer thickness measurement test coupon 11 is arranged in the frame part 101b, thereby requiring a high density. It is not necessary to occupy the area of the part 101a. Therefore, the circuit board 101 in FIG. 4 is a circuit board in which the thickness of each of the lower insulating layer, the conductive paste layer, and the upper insulating layer is measured and the durability performance of the conductive paste layer is evaluated, and the circuit board 101 is cut out as a product. The product portion 101a can be a circuit board on which high-density circuits are arranged. In addition, when the product part 101a has a margin, the layer thickness measurement test coupon 11 may be arranged in the product part 101a.

  The layer thickness measurement test coupon 11 shown in FIGS. 3A and 3B measures the thicknesses of the lower insulating layer, the conductive paste layer, and the upper insulating layer as characteristic factors relating to the durability performance of the conductive paste layer 4. Is. On the other hand, another characteristic factor related to the durability performance of the conductive paste layer 4 is the adhesion of the conductive paste layer 4 to the conductor pattern. In the circuit boards 90 and 100 shown in FIG. 7 and FIG. 1B, the adhesion of the conductive paste layer 4 to the conductor patterns 2a, 2c, 2d, and 2e is determined by the jumper wiring and shield formed by the conductive paste layer 4. It greatly affects the performance and durability against repeated heat and cold. Therefore, since the adhesiveness of the conductive paste layer to the conductor pattern also varies during manufacturing, it is important to measure the adhesiveness of each manufactured circuit board. However, in the circuit boards 90 and 100 shown in FIGS. 7 and 1B, it is difficult to measure the adhesion of the conductive paste layer 4 to the conductor patterns 2a, 2c, 2d, and 2e as it is. Therefore, in the circuit boards 90 and 100 shown in FIG. 7 and FIG. 1B, an adhesion measurement test coupon is formed on the circuit board as one of the characteristic evaluation portions of the conductive paste layer 4.

  An example of the adhesion measurement test coupon is shown in FIGS. 5A is a top view of the adhesion measurement test coupon 12, and FIG. 5B is a cross-sectional view taken along the line CC in FIG. 5A. In the adhesion measurement test coupon 12 of FIGS. 5A and 5B, the same reference numerals are given to the same parts as those of the circuit board 100 shown in FIGS. 1A and 1B.

  The adhesion measurement test coupon 12 shown in FIGS. 5A and 5B is formed from the conductive pattern 2h exposed in the opening 3ai and the conductive paste layer 4 formed on the conductive pattern 2h and exposed on the surface of the circuit board. Become. The size of the conductive paste layer 4 shown in FIG. 5A is about 10 mm square. In the adhesion measurement test coupon 12, for example, the adhesion of the conductive paste layer 4 formed on the conductor pattern 2 h is measured by performing a grid pattern processing as in JIS K 5600 and a tape peeling test. Can do. Therefore, it is possible to determine the durability performance of the conductive paste layer 4 and the quality of the circuit board.

  In the case where the circuit board includes the product portion 101a and the frame portion 101b as shown in FIG. 4, a large area is occupied as in the case of the layer thickness measurement test coupon 11 shown in FIGS. 3 (a) and 3 (b). The adhesion measurement test coupon 12 shown in FIGS. 5A and 5B can be disposed on the frame portion 101b. Thereby, the adhesion of the conductive paste layer to the conductive pattern is measured, and the durability performance of the conductive paste layer is evaluated, and a high-density circuit is arranged in a product part that is cut out to become a product. A circuit board can be obtained.

  Another characteristic factor affecting the performance of the jumper wiring and shield formed by the conductive paste layer 4 is the lower insulating layers 3a, 3b, 3c in the circuit boards 90, 100 shown in FIGS. 7 and 1B. Insulation characteristics. If the insulating properties of the lower insulating layers 3a, 3b, and 3c are not good, short circuit failure between the conductive paste layer 4 that is a jumper wiring and the conductive pattern 2b may occur, or necessary shielding performance may not be obtained.

  As for the insulating properties of the lower insulating layers 3a, 3b, and 3c, there is a possibility that the insulating properties may vary during manufacture or may deteriorate due to poor curing of the resin that becomes the lower insulating layers 3a, 3b, and 3c. . Therefore, it is important to measure the insulation resistance of the lower insulating layers 3a, 3b, and 3c on each manufactured circuit board. However, in the circuit boards 90 and 100 shown in FIGS. 7 and 1B, it is difficult to measure the insulation resistance of the lower insulating layers 3a, 3b, and 3c as it is. Therefore, in the circuit boards 90 and 100 shown in FIG. 7 and FIG. 1B, as one of the characteristic evaluation portions of the conductive paste layer 4, the insulating characteristics of the lower insulating layers 3a, 3b, and 3c are measured. An insulation resistance measurement test coupon is formed on the circuit boards 90 and 100.

  An example of an insulation resistance measurement test coupon is shown in FIGS. 6A is a top view of the insulation resistance measurement test coupons 13a and 13b. FIGS. 6B and 6C are respectively the insulation resistance measurement test coupons 13a and 13b in FIG. 6A. It is DD sectional drawing of. In addition, in the insulation resistance measurement test coupons 13a and 13b of FIGS. 6A to 6C, the same parts as those of the circuit board 100 shown in FIGS.

  The insulation resistance measurement test coupons 13a and 13b shown in FIGS. 6 (a) to 6 (c) are formed in a comb shape as shown in FIG. 6 (a), and are arranged with the side surfaces of the comb teeth facing each other. The pair of conductor patterns 2i and 2j, the lower insulating layers 3c and (3b) formed so as to cover the opposing comb teeth of the pair of conductor patterns 2i and 2j, and the opening 3ai.

  In the insulation resistance measurement test coupon 13a shown in FIGS. 6 (a) and 6 (b), the lower insulating layer covering the comb-tooth portion, which is the object of measurement of the insulating characteristics, includes the second lower insulating layer 3b and the third lower insulating layer 3c. The insulation resistance measurement test coupon 13b shown in FIGS. 6 (a) and 6 (c) is an insulation resistance measurement test coupon 13b. The insulation resistance measurement test coupon 13b includes only the third lower insulation layer 3c. It is a test coupon. If the two types of insulation resistance measurement test coupons 13a and 13b are provided in this way, it consists only of the lower insulating layer composed of the second lower insulating layer 3b and the third lower insulating layer 3c, and the third lower insulating layer 3c. The insulation resistance of the lower insulating layer can be individually evaluated.

  Using the insulation resistance measurement test coupons 13a and 13b shown in FIGS. 6 (a) to 6 (c), the conductor pattern 2i in which the insulation resistance of the lower insulating layer formed so as to cover the comb teeth is exposed to the opening 3ai. , 2j can be used as measurement terminals. Therefore, the quality of the circuit boards 90 and 100 shown in FIGS. 7 and 1B can be determined by checking the insulation resistance of the lower insulating layer.

  Note that the insulation resistance measurement test coupons 13a and 13b in FIGS. 6A to 6C also occupy a large area when the circuit board includes the product portion 101a and the frame portion 101b as shown in FIG. The insulation resistance measurement test coupon 13a can be placed on the frame portion 101b.

(Other embodiments)
1A and 1B, the resistance measurement terminal 10 has conductor patterns 2d, 2e formed by a second opening 3ai formed near the first openings 3ah of the conductor patterns 2d, 2e to which the conductive paste layer 4 is connected. Is exposed on the surface of the circuit board 100. The resistance measurement terminal is not limited to the conductor pattern 2d by partially forming the lower insulating layers 3a to 3c near the first openings 3ah of the conductor patterns 2d and 2e to which the conductive paste layer 4 is connected. , 2e may be exposed on the surface of the circuit board 100.

  The layer thickness measurement test coupon 11 shown in FIGS. 3A and 3B includes four measurement portions 11a to 11d for measuring the layer thicknesses of the lower insulating layers 3a, 3b and 3c, the conductive paste layer 4 and the upper insulating layer 5. It was a layer thickness measurement test coupon. Not limited to this, the layer thickness measurement test coupon may be configured to measure each layer thickness of any one of the lower insulating layers 3a, 3b, 3c, the conductive paste layer 4, the upper insulating layer 5, or any combination. Good.

  5 (a) and 5 (b) is composed of a conductive pattern 2h exposed at the opening 3ah and a conductive paste layer 4 formed on the conductive pattern 2h and exposed on the surface of the circuit board. It had been. Not only this but the upper insulating layer 5 may be further formed on the electrically conductive paste layer 4, and an adhesiveness measurement test coupon may be comprised.

  Insulation resistance measurement test coupons 13a and 13b in FIGS. 6A to 6C are respectively a lower insulating layer made of a laminate of a second lower insulating layer 3b and a third lower insulating layer 3c, and a third lower insulating layer 3c. It was an insulation resistance measurement test coupon for measuring the insulation resistance of the lower insulating layer consisting of only. Not only this but only the 1st lower layer insulating layer 3a and the 2nd lower layer insulating layer 3b are formed on a comb tooth part, and it is as an insulation resistance measurement test coupon of the 1st lower layer insulating layer 3a and the 2nd lower layer insulating layer 3b, respectively. Also good. In addition, an insulation resistance measurement test coupon is formed by forming, on the comb tooth portion, a lower insulating layer composed of three layers of the first lower insulating layer 3a, the second lower insulating layer 3b, and the third lower insulating layer 3c. May be.

(A) is a top view which shows typically the principal part of the circuit board of this invention, (b) is AA sectional drawing in (a). (A) is a figure which shows the relationship between the total thickness of a lower insulating layer, and the largest distortion generate | occur | produced in an electrically conductive paste layer, (b) is the case where the largest distortion and repeated stress which generate | occur | produce in an electrically conductive paste layer are applied. It is a figure which shows the relationship of a lifetime. (A) is a top view of a layer thickness measurement test coupon, (b) is BB sectional drawing in (a). (C) is the result of measuring each layer thickness of the lower insulating layer, the conductive paste layer, and the upper insulating layer using the layer thickness measurement test coupons of (a) and (b). FIG. 4 is a schematic top view of a circuit board of the present invention in which the layer thickness measurement test coupons of FIGS. 3 (a) and (b) are arranged. (A) is a top view of an adhesion measurement test coupon, (b) is a CC cross-sectional view in (a). (A) is a top view of an insulation resistance measurement test coupon, (b) and (c) are DD sectional views in (a). It is a figure which shows typically the typical cross-section of a circuit board.

Explanation of symbols

90, 100, 101 Circuit board 101a Product part 101b Frame part 10 Resistance measurement terminal 11 Layer thickness measurement test coupon 12 Adhesion measurement test coupon 13a, 13b Insulation resistance measurement test coupon 1 Insulation substrate 2a-2j Conductor pattern 3a-3c Lower layer Insulating layer 3ah, 3ai Opening 4 Conductive paste layer 5 Upper insulating layer

Claims (20)

A conductor pattern formed on the surface of the insulating substrate;
A lower insulating layer formed to cover the conductor pattern and having an opening partly exposing the conductor pattern;
A conductive paste layer formed on the lower insulating layer and connected to the conductor pattern exposed in the opening;
A circuit board having an upper insulating layer formed to cover the conductive paste layer,
A circuit board, wherein a characteristic evaluation site for the conductive paste layer is provided on the circuit board. The conductive paste layer is a jumper wiring for wiring connecting conductor patterns exposed in the opening,
The circuit board according to claim 1, wherein the characteristic evaluation site is a resistance measurement terminal that measures a resistance value of the jumper wiring. The opening includes a first opening where a jumper wiring is connected to the exposed conductor pattern, and a second opening where the conductive paste layer is exposed to the surface of the circuit board without being connected to the conductive paste layer. Become
The resistance measurement terminal is a conductor pattern that is connected to a conductor pattern exposed in the first opening and exposed in the second opening disposed near the first opening. 2. The circuit board according to 2.   The characteristic evaluation site is a layer thickness measurement test coupon for measuring each layer thickness of any one of the lower insulating layer, the conductive paste layer, the upper insulating layer, or a combination thereof. The circuit board according to 1.   The circuit board according to claim 4, wherein the layer thickness measurement test coupon has a portion for measuring a step between the insulating base material exposed on the surface of the circuit board and the lower insulating layer.   6. The circuit board according to claim 4, wherein the layer thickness measurement test coupon has a portion for measuring a step between the conductor pattern exposed on the surface of the circuit board and the lower insulating layer.   The circuit according to any one of claims 4 to 6, wherein the layer thickness measurement test coupon has a portion for measuring a step between the lower insulating layer and the conductive paste layer exposed on the surface of the circuit board. substrate.   The circuit according to any one of claims 4 to 7, wherein the layer thickness measurement test coupon has a part for measuring a step between the conductive paste layer exposed on the surface of the circuit board and the upper insulating layer. substrate.   9. The circuit board according to claim 4, wherein the layer thickness measurement test coupon has a portion for measuring a step between the conductor pattern exposed on the surface of the circuit board and the upper insulating layer. 10. .   The circuit board according to any one of claims 5 to 9, wherein the layer thickness measurement test coupon has an insulating base material exposed on a surface of the circuit board at both ends.   The circuit board according to any one of claims 5 to 9, wherein the layer thickness measurement test coupon has a conductor pattern exposed on a surface of the circuit board at both ends. The circuit board consists of a product part that is cut out to become a product, and a frame part for holding the product part,
The circuit board according to claim 4, wherein the layer thickness measurement test coupon is formed on the frame portion.   The circuit board according to claim 1, wherein the characteristic evaluation site is an adhesion measurement test coupon for measuring adhesion of the conductive paste layer to the conductor pattern.   The circuit board according to claim 13, wherein the adhesion measurement test coupon is formed of a conductive paste layer formed on a conductor pattern exposed in the opening and exposed on a surface of the circuit board. The circuit board consists of a product part that is cut out to become a product, and a frame part for holding the product part,
The circuit board according to claim 13 or 14, wherein the adhesion measurement test coupon is formed on the frame portion.   The circuit board according to claim 1, wherein the characteristic evaluation site is an insulation resistance measurement test coupon for measuring an insulation characteristic of the lower insulating layer. The insulation resistance measurement test coupon is
A pair of conductor patterns formed in a comb-like shape and arranged such that the side surfaces of the comb teeth face each other; and the lower insulating layer formed to cover the comb-tooth portions facing each other of the pair of conductor patterns; ,
The circuit board according to claim 16, comprising the opening. The lower insulating layer is formed of three layers laminated in order of the first lower insulating layer, the second lower insulating layer and the third lower insulating layer from the insulating base material side,
The circuit board according to claim 17, wherein the lower insulating layer covering the comb-tooth portion includes the second lower insulating layer and the third lower insulating layer. The lower insulating layer is formed of three layers laminated in order of the first lower insulating layer, the second lower insulating layer and the third lower insulating layer from the insulating base material side,
18. The circuit board according to claim 17, wherein the lower insulating layer covering the comb-tooth portion is composed of only the third lower insulating layer. The circuit board consists of a product part that is cut out to become a product, and a frame part for holding the product part,
The circuit board according to claim 16, wherein the insulation resistance measurement test coupon is formed on the frame portion.

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