JP2740709B2 - Method for detecting stacking deviation of multilayer printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting stacking misalignment of a multilayer printed wiring board, and more particularly, to detecting stacking misalignment of a power supply layer or an earth layer of a multilayer printed wiring board having a power supply layer or an earth layer having a clearance in an inner layer. On how to do it.

2. Description of the Related Art Multilayer printed wiring boards are often used to increase the density of printed wiring boards. However, in order to secure electrical characteristics, detection of stacking deviation is performed. There is a need to accurately detect this stacking deviation accurately in a short time.

[0003]

2. Description of the Related Art FIG. 10A is a plan view showing signal lands and signal patterns of a multilayer printed wiring board 51, and FIG.
10A is a cross-sectional view taken along the line hh in FIG. Also,
FIG. 11 is an enlarged view of a portion surrounded by a circle a in FIG. As shown in FIG. 10B, the multilayer printed wiring board 51 has independent power supply layers 40 and ground layers 41 as inner layers, and the signal lands 34 escape by clearances 42.

[0004] The characteristic impedance of a signal pattern is determined by the geometric distance of the signal pattern to a ground layer or a power supply layer, and there are various empirical formulas, theoretical formulas using a Green's function, and the like. When the characteristic impedance of the signal pattern is set to a predetermined value, the pattern design of the printed wiring board is performed using the above empirical formula, theoretical formula, and the like.

A signal pattern in which the area of a portion overlapping with the ground layer or the power supply layer facing through the layers of the multilayer printed wiring board is reduced due to misalignment during the manufacturing of the multilayer printed wiring board 51, the characteristic impedance is not passed. It increases with the number of clearances to be made.

When the power supply layer 40 is displaced as shown in FIG.
b is such that the area of the portion overlapping the opposing power supply layer 40 is reduced, and the characteristic impedance is passed through the clearance 42a.
Rise with the number of.

Therefore, when the characteristic impedance of the signal pattern 35b passing between the signal lands 34 is designed to have a predetermined value, the actual characteristic impedance changes if there is a lamination shift, which is a problem.

Further, even in a multilayer printed wiring board 51 in which the characteristic impedance of the signal pattern 35b does not matter, if there is a misalignment, the signal land 34, the power supply layer 40, and the ground layer 41
In some cases, the withstand voltage cannot be satisfied.

In order to detect a multilayer printed wiring board that does not satisfy the standard of electrical characteristics due to the above-described lamination misalignment, and to obtain data for reducing a defective rate during manufacturing, lamination misalignment is detected.

FIG. 13 is a plan view of a multilayer printed wiring board to which a conventional method for detecting a stacking deviation is applied, and FIG. 14 is an explanatory view of a clearance 71 disposed in the X direction of the detection coupon of FIG. . FIG. 14A is a plan view of a portion of the clearance 71, and FIG.
FIG. 2A is a cross-sectional view taken along the line ii.

[0013] As shown in FIG. 13, a substrate 53 (hereinafter, referred to as a detection coupon) 53 for detecting misalignment is provided around a product substrate 52.

The lamination displacement detection coupon 53 is a part that is manufactured integrally with the product substrate 52 when the multilayer printed wiring board 51 is produced, and a lamination displacement corresponding to the lamination displacement of the product substrate 52 appears. The coupon 53 is cut and removed after manufacturing.

A product substrate 52 is provided on the inner layer of the detection coupon 53.
Power supply layer 61 (see FIG. 10B).
Is formed, and the ground layer 41 of the product substrate 52 (FIG. 10B)
) Is formed integrally with the ground layer 62. This power supply layer 6
1. The ground layer 62 is provided with a plurality of clearances 71 in a direction along the sides of the detection coupon 53. In the surface layer of the detection coupon 53, a land 54 having a through hole 54a disposed inside the clearance 71 is formed.

As shown in FIG. 13, a clearance 71 and a land 5 are detected in order to detect a stacking deviation in the X and Y directions.
No. 4 is formed in two types, one arranged in the X direction and one arranged in the Y direction.

Conventionally, first, after lamination of a printed wiring board, a plane a-a passing through the center of the clearance 71 and bb
The coupon 53 for detection is cut out to the surface of, and then the power supply layer 61 of the inner layer in the cross section passing through the center of the clearance 71,
The position of the earth layer 62 was checked using a microscope or the like, and the misalignment was detected. FIG. 14 shows a case where the power supply layer 61 causes a stacking shift in the −X direction and the clearance 71a shifts in the −X direction.

[0016]

However, in the conventional method of providing a detection coupon and checking the cross section at the clearance after lamination of the printed wiring board to detect lamination displacement, a printed wiring by a skilled worker is required. The plate had to be cut, which required a lot of work. Also, it took time to train workers.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a method for detecting a multilayer misalignment in a multilayer printed wiring board, which can easily detect a misalignment in the production of the multilayer printed wiring board in a short time. And

[0018]

According to the first aspect of the present invention, the power supply layer 21 and / or the ground layer 2 in the inner layer of the multilayer printed wiring board are provided.
2 and 23 have a clearance 18 in which a plurality of pairs are arranged in a part thereof, and a power supply layer 21 and / or an earth layer 22 are provided on a surface layer or an inner layer of the multilayer printed wiring board.
The detection patterns 15a to 15h are formed so as to extend in the area between the clearances 18 of each pair of 23, and the characteristic impedance of the detection patterns 15a to 15h is measured. To detect.

According to the second aspect of the present invention, the patterns 15a, 15b; 15c, 15d;
f; 15g and 15h are two patterns arranged in parallel.

According to the third aspect of the present invention, a plurality of pairs of the clearances 18 are formed in two orthogonal directions and the detection patterns 15a to 15h are formed in two orthogonal directions.

[0021]

According to the first aspect of the present invention, the stacking misalignment can be detected by measuring the characteristic impedance of the detection pattern, so that the shaving operation is not required, the stacking misalignment can be easily detected, and the detection can be performed. It is possible to save time.

According to the second aspect of the present invention, in order to form two parallel detection patterns in a region between the clearances, the characteristic impedance of the two detection patterns is compared with a standard value, thereby making the detection patterns and the detection patterns compatible. It is possible to detect the stacking deviation in the orthogonal direction including the direction.

According to the third aspect of the present invention, since the detection patterns are arranged in two orthogonal directions, it is possible to detect the direction of the misalignment in the plane.

[0024]

FIG. 1 is a plan view of a multilayer printed wiring board 11 to which one embodiment of the present invention is applied, and FIG. 2 is an explanatory view of a detection pattern 15 and a clearance 18 of FIG. FIG.
3A is an enlarged view of a part of the detection pattern 15 and the clearance 18, and FIG. 3B is a cross-sectional view taken along a plane JJ in FIG. 3A.

In FIG. 1, reference numeral 12 denotes a product substrate, and reference numeral 13 denotes a coupon for detecting misalignment. The lamination displacement detection coupon 13 is a part that is manufactured integrally with the product substrate 12 when the multilayer printed wiring board 11 is produced, and a lamination displacement corresponding to the lamination displacement of the product substrate 12 appears. The coupon 13 is cut and removed after manufacturing.

As shown in FIG. 10, the multilayer printed wiring board 11 shown in FIG. 1 has a four-layer board in which a signal pattern is formed on the front and back surfaces of a product board 12, and a power supply layer and an earth layer are formed in an inner layer. It is.

As shown in FIG. 3B, the detection coupon 13 has an inner power supply layer 21 formed integrally with the power supply layer of the product substrate 12, and an inner layer formed integrally with the ground layer of the product substrate 12. Is formed.

The detection coupon 13 is formed with a plurality of pairs of lands 14 having through holes 14a, and the power supply layer 21 and the ground layer 22 are provided with clearances 18 for escaping the lands 14. The upper surface of the detection coupon 13 has an area 19 between the plurality of pairs of the clearances 18.
, Two parallel detection patterns 15a and 15b are formed. On the lower surface of the detection coupon 13, two parallel detection patterns 15c and 15d are formed in a region 19 between the plural pairs of clearances 18.

As shown in FIG. 3, the detection pattern 15 is arranged at a position where the edge on the land 14 side contacts the edge of the clearance 18 in a plan view.

As shown in FIG. 1, the pair of clearances 18 and the detection patterns 15 extend along two adjacent sides of the multilayer printed wiring board 11 in the X direction and in the Y direction in the drawing. Two types are formed.

In the combination of the detection pattern 15 and the clearance 18 extending in the Y direction, as shown in FIG. 1, a plurality of pairs of the clearances 18 arranged at a predetermined interval in the X direction are arranged at predetermined equal intervals in the Y direction. The two parallel detection patterns 15a and 15b are arranged in pairs, and are formed so as to extend in the Y direction in a region 19 (see FIG. 3) between each pair of the clearances 18.

In the combination of the detection patterns 15 and the clearances 18 extending in the X direction, as shown in FIG. 1, a plurality of pairs of the clearances 18 arranged at predetermined intervals in the Y direction are arranged at predetermined equal intervals in the X direction. The two parallel detection patterns 15a and 15b are arranged in pairs, and are formed so as to extend in the X direction in a region 19 (see FIG. 3) between each pair of the clearances 18.

FIG. 2 is an explanatory view of a combination of the detection pattern 15 and the clearance 18 extending in the Y direction in FIG.
The two detection patterns 15a and 15b have the clearance 1
8 are passed through n pairs (10 pairs in the example of FIG. 2). One end is connected to lands P1 and P3 for measurement, and the other end is connected to P2 and P4. The pitch between the pair of clearances 18 arranged in the X direction and the pitch in the Y direction between each pair of the clearances 18 are a predetermined constant value, for example, 2.54 mm.

Next, the procedure of the method for detecting a stack displacement in this embodiment will be described. In the manufacturing process of the multilayer printed wiring board 11, first, the inner power supply layer 21 having the clearance 18 is formed integrally with the power supply layer 40 of the product substrate 12 in the portion of the detection coupon 13 and the inner ground having the clearance 18 is grounded. The layer 22 is formed integrally with the ground layer 41 of the product substrate 12.

Next, a land 14 having a surface detection pattern 15 and a through hole 14a is formed. After the formation of the multilayer printed wiring board 11 as described above, the characteristic impedance of the detection pattern 15 is measured, and the misalignment is detected from the measured value.

The measurement of the characteristic impedance of the detection pattern 15 and the detection of the stacking deviation will be described below. As described above, the detection pattern 15 has the clearance 18.
Through a predetermined number n. here,
As shown in FIG. 3, a case will be described in which the detection patterns 15 are arranged in the Y direction and a stacking deviation in the X direction is detected.

In the measurement of the characteristic impedance, the characteristic impedance of the detection pattern 15 is measured when the power supply layer 21 or the earth layer 22 opposed to the detection pattern 15 via the layer of the multilayer printed wiring board 11 is grounded. .

A terminal having a predetermined characteristic impedance value is connected between one end of the detection pattern 15 and the power supply layer 21 or the earth layer 22. Connect the signal side of the output terminal of the characteristic impedance measuring instrument to the other end of the detection pattern 15, and
The side is connected to the power supply layer 21 or the earth layer 22, and the characteristic impedance of the detection pattern 15 is measured.

For example, when measuring the characteristic impedance of the detection pattern 15a shown in FIG.
1, a signal side of an output terminal of the characteristic impedance measuring instrument is connected to a terminal P1, and a GND side is a power supply layer 2.
1 and measure the characteristic impedance.

FIG. 5 shows the relationship between the number of passing clearances and the characteristic impedance of the detection pattern 15. FIG.
FIG. 4 is a diagram when a predetermined characteristic impedance value is set to 50Ω.

When there is no misalignment as shown in FIG.
The characteristic impedance of the detection pattern 15 falls within a predetermined standard range irrespective of the number of the clearances 18 passing therethrough as shown by I in FIG. On the other hand, when the power supply layer 21 has a stacking deviation in the −X direction as shown in FIG.
As shown in FIG. 5II, the value of the characteristic impedance of the detection pattern 15b affected by the stacking deviation increases as the number of the clearances 18a passing therethrough increases.

Therefore, by measuring the characteristic impedance of the detection pattern 15 passing through the predetermined number n of the clearances 18, it is possible to detect the stacking deviation in the X direction from the measured value.

FIG. 6 shows a case where the detection patterns are arranged so as to pass through the forty clearances 18, and FIG.
4 shows an example of measured values of characteristic impedance when there is a stacking deviation as shown in FIG.

In the case of FIG. 4, the power supply layer 21 is displaced in the −X direction substantially by the pattern width of the detection pattern 15.
For this reason, the characteristic impedance of the detection pattern 15b deviates from the standard value (for example, 50Ω ± 10%), and is 75.7Ω, which is much larger than 50Ω. On the other hand, since the other detection patterns 15a, 15c, and 15d are not affected by the shift of the power supply layer 21, the characteristic impedance is within the standard value.

Therefore, the detection patterns 15a, 15b,
When measuring the characteristic impedance of 15c and 15d, 1
Since only the characteristic impedance 5b has a value larger than the standard value, it can be detected that the power supply layer 21 has a stacking deviation in the −X direction.

FIG. 7 is a cross-sectional view when the power supply layer 21 has a stacking shift in the + X direction, and FIG. 8 shows a case where the stacking shift detection pattern is arranged so as to pass through 40 clearances 18. 7 shows an example of measured values of characteristic impedance when there is a stacking deviation as shown in FIG.

In the case of FIG. 7, the power supply layer 21 is shifted in the + X direction substantially by the pattern width of the detection pattern 15.
For this reason, the characteristic impedance of the detection pattern 15a deviates from the standard value (for example, 50Ω ± 10%), and is 75.7Ω which is much larger than 50Ω. On the other hand, since the other detection patterns 15b, 15c, and 15d are not affected by the displacement of the power supply layer 21, the characteristic impedance is within the standard value.

Therefore, the detection patterns 15a, 15b,
When measuring the characteristic impedance of 15c and 15d, 1
Since only the characteristic impedance 5a has a value larger than the standard value, it can be detected that the power supply layer 21 has a stacking deviation in the + X direction.

As described above, the detection patterns 15a, 1
By measuring each of the characteristic impedances 5b, 15c, and 15d and comparing them with the standard values, it is possible to detect the stacking deviation of the inner power supply layer 21 and the earth layer 22 in the X direction, including the direction. Therefore, the power supply layer 40 and the ground layer 4 of the product substrate 12
It is possible to detect the stacking deviation in the X direction including the direction.

The detection coupon 13 includes the above Y
Since the detection pattern 15 arranged in the X direction is also formed in addition to the detection pattern 15 arranged in the direction, the characteristic impedance of the detection pattern 15 is measured.
The stacking deviation in the Y direction can be detected in the same manner as described above. Therefore, in this embodiment, the stacking shift in the X direction and the stacking shift in the Y direction can be detected including the direction.

In this embodiment, the land 14 having the through hole 14a is formed. However, the land 14 having the through hole 14a is not necessarily required. Is formed, the stacking deviation can be similarly detected without the land 14.

In this embodiment, the detection pattern is formed on the surface layer using a four-layer printed wiring board. However, the present invention is not limited to this. The detection pattern is formed on the inner layer and the inner power supply layer or the ground is formed. It is also possible to detect a layer misalignment.

FIG. 9 is a sectional view showing an example of a seven-layer printed wiring board. As shown in FIG. 9, when the detection patterns 15e, 15f, 15g, and 15h are also formed in the inner layer,
Surface layer detection patterns 15a, 15b, 15c, 15
By measuring the characteristic impedance of the inner layer detection patterns 15e, 15f, 15g, and 15h together with the characteristic impedance of d, the misalignment of the inner layer earth layers 22, 23 and the power supply layer 21 can be detected.

[0054]

According to the first aspect of the present invention, the stacking misalignment can be detected by measuring the characteristic impedance of the detection pattern. It has features such as easy detection.

According to the second aspect of the present invention, since the direction of the stacking shift can be detected, the stacking shift can be detected more accurately.

According to the third aspect of the present invention, since the direction of the lamination misalignment can be detected in the plane, the lamination misalignment can be detected more accurately.

[Brief description of the drawings]

FIG. 1 is a plan view of a multilayer printed wiring board to which an embodiment of the present invention has been applied.

FIG. 2 is an explanatory diagram of a detection pattern and a clearance.

FIG. 3 is an explanatory diagram of a detection pattern and a clearance.

FIG. 4 is an explanatory diagram in the case where there is a stacking deviation in the −X direction.

FIG. 5 is a diagram showing the relationship between the number of passage clearances and characteristic impedance.

FIG. 6 is a diagram illustrating an example of measured values of characteristic impedance in the case of FIG. 4;

FIG. 7 is a cross-sectional view when there is a stacking deviation in the + X direction.

8 is a diagram showing an example of measured values of characteristic impedance in the case of FIG. 7;

FIG. 9 is a diagram illustrating an example of a case where a detection pattern is formed in an inner layer.

FIG. 10 is an explanatory diagram of a multilayer printed wiring board.

FIG. 11 is an enlarged view of a portion surrounded by a circle a in FIG.

FIG. 12 is an enlarged view of the same portion as in FIG. 11 when a stacking error has occurred.

FIG. 13 is a plan view of a multilayer printed wiring board to which a conventional stacking deviation detecting method is applied.

FIG. 14 is an explanatory diagram of a clearance portion of the detection coupon.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Multilayer printed wiring board 12 Product board 13 Coupon for detection 14 Land 14a Through hole 15a-15h Pattern for detection 18 Clearance 21 Power supply layer 22 Earth layer

Claims (3)

(57) [Claims] An internal power supply layer of a multilayer printed wiring board (21).
And / or a ground layer (22, 23) having a clearance (18) in which a plurality of pairs are arranged in a part thereof, and a power supply layer (21) and a power layer (21) on a surface layer or an inner layer of the multilayer printed wiring board. And / or forming the detection patterns (15a to 15h) so as to extend between the clearances (18) of each pair of the ground layers (22, 23), and characteristics of the detection patterns (15a to 15h). A method for detecting a stacking shift of a multilayer printed wiring board, comprising detecting a stacking shift of the multilayer printed wiring board by measuring impedance. 2. The detection pattern (15a, 15b;
2. The method according to claim 1, wherein 15c, 15d; 15e, 15f; 15g, 15h) are two patterns arranged in parallel. 3. The apparatus according to claim 1, wherein the plurality of pairs of clearances are formed in two orthogonal directions and the detection patterns are formed in two orthogonal directions. The method for detecting a stacking deviation of a multilayer printed wiring board according to the above.