JP3607069B2 - Method for manufacturing printed wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention has a conductor circuit constructed from the signal line and the land, a process for producing a print circuit board which is disposed in the solder resist on the surface layer.
[0002]
[Prior art]
In BGA (Ball Grid Array) and LGA (Land Grid Array) substrates, etc., a solder resist is provided on the surface layer to protect the substrates. A plan view of the substrate formed by subtransactions active shown in FIG. 17 (A), shown in FIG. 17 (B) a B-B sectional view of FIG 17 (A). Lands 130 and signal lines 120 are disposed on the upper surface of the substrate 160, and a solder resist 150 is disposed on the surface layer of the substrate 160. In the solder resist 150, an opening 150 a is formed around the land 130. A cross section of the substrate formed by built-up is shown in FIG. This substrate is provided with a permanent record di strike 153.
[0003]
[Problems to be solved by the invention]
However, in the subtractive prior art shown in FIGS. 17A and 17B, thermal contraction occurs at the connection portion X1 between the land 130 and the signal line 120 and the contact portion X2 between the signal line 120 and the opening end. In some cases, the stress due to the stress is concentrated and the signal line (conductor circuit) 120 is broken at X1 and X2. Moreover, in the built-up printed wiring board shown in FIG. 17D, not only disconnection but also a crack K may occur in the insulating layer.
[0004]
For this reason, the present inventor has devised adding a teardrop to the land. However, as shown in FIG. 17C, when the tear drop 140 added to the land 130 does not extend to the contact portion X2 with the opening 150a of the signal line 120, the signal line at the contact portion X2 The stress applied to 120 did not change, and it was expected that disconnection and cracks would also occur.
[0005]
The present invention has been made to solve the above problems, and an object is to provide a method for producing a print wiring board causing no cracks at the opening end of the solder resist.
[0008]
[Means for Solving the Problems]
Claim 1 is a method for manufacturing a printed wiring board in which a signal line and a land are disposed on a substrate and a solder resist is disposed on a surface layer.
Determining whether the land is smaller than the opening of the solder resist disposed corresponding to the land;
When the land is larger than the opening, the teardrop is disposed at an angle so as to maintain an insulation distance from the surrounding conductor circuit with respect to the signal line extending from the land; and
Disposing a tear drop over the edge of the opening of the solder resist with respect to the signal line extending from the land when the land is smaller than or the same as the opening. Technical features.
[0009]
In the method of manufacturing a printed wiring board according to claim 2, in the step of disposing the tear drop so as to cover the end of the opening of the solder resist with respect to the signal line extending from the land in claim 1 . Technically, the gap between the land and the opening is set as a clearance where the opening is the most deviated , and the tear drop is disposed so as to cover the end of the opening of the solder resist even if the tear drop deviates by the clearance. Features.
[0011]
In the method for manufacturing a printed wiring board according to claim 1 , it is determined whether the land is smaller than an opening of a solder resist provided corresponding to the land, and the land is smaller than or the same as the opening. In addition, the width of the signal line is widened at a position intersecting with the end of the opening by arranging the tear drop so as to cover the end of the opening of the solder resist with respect to the signal line extending from the land. Therefore, stress is difficult to concentrate, and wiring and cracks are not generated at the end of the opening.
[0012]
In the printed wiring board according to the second aspect , in consideration of the formation deviation between the land and the opening, the printed wiring board is disposed so as to cover the end of the opening of the solder resist. For this reason, even when the opening of the solder resist is formed with respect to the land, even if the position of the opening is shifted, the width of the signal line is widened at the position intersecting with the end of the opening, so that stress is difficult to concentrate. , No disconnection or cracks occur at the end of the opening.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a printed wiring board and a method of manufacturing the printed wiring board according to the first embodiment of the present invention will be described with reference to the drawings.
FIG. 13 is a plan view showing a part of the printed wiring board of the present embodiment. In the printed wiring board 10, a matrix 30α of lands 30 is disposed, and connection with electronic components (not shown) placed on the matrix 30α is established.
[0014]
FIG. 14A is an enlarged view of the land 30 indicated by J in the figure included in the matrix 30α. A solder resist 50 (not shown in FIG. 13) is disposed on the surface layer of the printed wiring board 10, and the solder resist 50 has openings 50 a corresponding to the lands 30. Here, the diameter of the opening 50 a is formed to be larger than the diameter of the land 30. The land 30 is connected to a land 32 disposed in the via hole 25 through the signal line 20. That is, the connection from the lower layer (rear surface) side is routed to the via hole 25-land 32-signal line 20-land 30, and connection to an electronic component (not shown) is made through the land 30.
[0015]
Here, in the land 30 disposed in the opening 50 a of the solder resist 50, a tear drop 40 is added to the connection portion with the signal line 20. That is, by arranging the tear drop 40 at the connection portion between the land 30 and the signal line 20, the stress is not concentrated at the connection portion. Here, the tear drop 40 is disposed so as to cover the end of the opening 50a. For this reason, unlike the printed wiring board 160 of the prior art described above with reference to FIG. 17B, the width of the signal line 20 becomes wide at the position intersecting with the end of the opening. There is no disconnection or crack at the end of the opening. Similarly, a tear drop 40 is disposed on the land 32 where the via hole 25 is formed, and is configured so that stress is not concentrated at the connection portion between the land 25 and the signal line 20.
[0016]
On the other hand, in the printed wiring board 10 shown in FIG. 13, a land 30β is connected via a signal line 24 to a conductor portion 27 for placing an electronic component (not shown). The land 30β is enlarged and shown in FIG. The opening 50b of the solder resist formed corresponding to the land 30β is formed smaller than the diameter of the land 30β. A tear drop 40 is disposed at a connection portion between the land 30β and the signal line 24. That is, by arranging the tear drop 40 at the connecting portion between the land 30β and the signal line 24, stress is concentrated at the connecting portion so that cracks are not generated.
[0017]
Continuing, referring to the flowcharts of FIGS. 1 to 4 and the explanatory diagrams of FIGS. 5 to 12 for the data generation processing for forming the conductor circuit for adding tear drops to the lands 30 and 30β of the printed wiring board shown in FIG. To explain. Here, the data for providing the land and the signal line (collectively referred to as the conductor pattern) and the data for providing the opening of the solder resist formed on the conductor pattern are already obtained by the conventional method. A process for adding a tear drop to the created land and signal line as formed will be described.
[0018]
First, an opening is extracted from data for forming a solder resist (S14). For example, as shown in FIG. 5A, the opening 50a formed in the solder resist 50 is extracted. Then, the center of the opening is obtained (S16). That is, the center X of the opening 50a is obtained as shown in FIG. Subsequently, as shown in FIG. 5C, N (eight in this case) arrows AR1 to AR8 are arranged from the center X to the end of the land 30 or the signal line 20 (S18). Here, 8 is set as the number N of arrows, but by setting N to 16 or 32, it is also possible to search by arbitrarily setting 16 or 32 directions.
[0019]
Subsequently, the drawing direction of the signal line is obtained (S20). Here, the direction of the longest arrow is detected as the signal line drawing direction, that is, the tear drop adding direction. For the land 30 shown in FIG. 5C, the arrow AR7 provided along the signal line 20 is the longest arrow, and the direction of the arrow AR7 is specified as the drawing direction of the signal line 20.
[0020]
Next, it is determined whether the diameter of the opening is smaller than the diameter of the land (S22). Here, when the diameter of the opening 50a is larger than the diameter of the land 30 (No in S22) as shown in FIG. 5A, the process proceeds to step 26, and on the other hand, as shown in FIG. When the diameter of 50b is smaller than the diameter of the land 30 (Yes in S22), the process proceeds to a tear drop addition process (S24). As will be described later with reference to FIGS. 15 and 16, when the shape of the land and the opening is square or rectangular, the size of the land and the opening is compared, and the subsequent processing proceeds.
[0021]
Here, the tear drop addition process 1 (S24) will be described with reference to the flowchart of FIG. 2 showing the subroutine of the process and the explanatory diagrams of FIGS.
First, for the land 30, as shown in FIG. 7A, the tangent lines 42 a and 42 b are drawn to add the tear drop 40 A so that the tear drop angle is set to the left and right of the signal line 20 (D). (S40). Thereafter, the added tear drop 40 is examined to determine whether a predetermined insulation interval d (eg, 100 μ) can be maintained from the surrounding conductor circuit (eg, signal line 22) (S42). Here, when the predetermined insulation interval can be maintained (S44 is Yes), the process is terminated. As a result, the tear drop 40A is added to the lower side of the solder resist 50 as shown in FIG.
[0022]
On the other hand, when the D ° tear drop is added and the insulation distance d from other conductor circuits cannot be maintained (No in S44), the left and right sides of the signal line 20 as shown in FIG. The teardrop 40B is added so that the teardrop angle becomes an angle (D + γ) obtained by adding a preset step angle (γ) to a preset angle (D) (S46). Thereafter, it is checked whether or not the added tear drop 40B can maintain a predetermined insulation distance d from the surrounding conductor circuit (S48). Here, when the predetermined insulation interval can be maintained (Yes in S50), the process is terminated. As a result, a tear drop 40B is added to the lower side of the solder resist 50 as shown in FIG.
[0023]
On the other hand, if the insulation interval from another conductor circuit (for example, the signal line 22) cannot be maintained even with the tear drop of the angle D + γ (S50 is No), the set maximum angle (the amount of deviation of the solder resist) Is reached (S51). Until the maximum angle is reached (S51 is No), the process returns to step 46 to try to add a teardrop with an angle of D + 2γ. When the angle D + nγ exceeds the maximum angle (Yes in S51), the addition of the teardrop is abandoned as shown in FIG. 7C (S52). Thereby, the tear drop is not added to the land 30 as shown in FIG. 8C through the manufacturing process described later based on the created data.
[0024]
Next, the process when the opening diameter in step 22 described above with reference to FIG. 1 is larger than the land (S22 is No) will be described. Here, first, it is determined whether or not the signal line is bent in the opening (S26). This determination is made based on whether the longest arrow exceeds the opening of the solder resist. That is, as shown in FIG. 5C, when the arrow AR7 provided along the signal line 20 exceeds the opening 50a, it is determined that there is no bending (No in S26), and the tear drop addition in step 28 is performed. Proceed to processing 2. On the other hand, as shown in FIG. 6G, when the arrow AR7 provided along the signal line 20 does not exceed the opening 50a, it is determined that the signal line is bent (S26 is Yes), and a teardrop is added. The process proceeds to process 3 (S30).
[0025]
Here, the tear drop addition process 2 when the signal line is not bent will be described with reference to the flowchart of FIG. 3 and the explanatory diagrams of FIGS. 6, 9, and 10 showing the subroutine of the process.
First, as shown in FIG. 6E, the intersection X2 between the signal line 20 and the opening 50a is obtained for the land 30 (S60 shown in FIG. 3). Then, as shown in FIG. 9A, a tear drop 40C is added by drawing tangents 42a and 42b to the land 30 from the point where the clearance C is provided from the intersection X2 (S62). Thereafter, it is checked whether or not the added tear drop 40C can maintain a predetermined insulation interval from the surrounding conductor circuit (S64). Here, when the predetermined insulation interval can be maintained (Yes in S66), the process is terminated. As a result, the tear drop 40C is added to the lower side of the solder resist 50 as shown in FIG.
[0026]
The clearance C means a positional shift when the opening 50a is formed with respect to the land 30 as shown in FIGS. 6 (E) and 6 (F). That is, as shown in FIG. 6E, even if the position of the tear drop 40 is determined so as to cover the intersection X2 with the design dimension as shown by a one-dot broken line in FIG. 6E, in the actual manufacturing process, as shown in FIG. When the arrangement position of the opening 50a is deviated, the tear drop may not be applied to the intersection point X2. Therefore, the value when the opening 50a is most deviated is set as the clearance C. The tear drop 40 is placed on the intersection X2 even if it deviates.
[0027]
On the other hand, when the tear drop is added, if the insulation interval from another conductor circuit (for example, the signal line 22) cannot be maintained (No in S66), as shown in FIG. The tear drop 40B is added from the point S (L-1) obtained by subtracting the set step distance from the initially obtained distance (S68). Thereafter, it is checked whether or not the added tear drop 40B can maintain a predetermined insulation interval from the surrounding conductor circuit (S70). Here, when the predetermined insulation interval can be maintained (S72 is Yes), the process is terminated. As a result, the tear drop 40B is added to the lower side of the solder resist 50 as shown in FIG.
[0028]
On the other hand, when a teardrop is added at a set distance (L-1), if the insulation interval from other conductor circuits cannot be maintained (No in S72), the set distance (L-1) is set in advance. It is determined whether the distance is less than the set shortest distance (S73). When the distance is equal to or greater than the shortest distance (S73: No), the process returns to step 68 and tries to add a teardrop (L-2l). Here, when the set distance (L-nl) is equal to or less than the preset shortest distance (Yes in S73), the addition of the teardrop is abandoned as shown in FIG. 9C (S74). As a result, the tear drop is not added to the land 30 as shown in FIG. 10C through the manufacturing process described later based on the created data.
[0029]
Subsequently, in the determination of step 30 shown in FIG. 1, when the signal line is bent (S26 is Yes), the teardrop adding process 3 (S30) is a flowchart of FIG. 11 and FIG. 12 for explanation.
First, for the land 30, as shown in FIG. 11A, the teardrop 40 </ b> A is added to the left and right of the signal line 20 so that the teardrop angle is set in advance (S <b> 80). Thereafter, it is checked whether or not a tear drop of the set angle can be added (S82). Here, when the tear drop of the set angle degree can be added, the routine proceeds to step 86. On the other hand, as shown in FIG. 11B, when the bent portion of the signal line is too close to the land 30 to add the tear drop 40A having the set angle (No in S82), the process proceeds to step 84, and FIG. As shown in (2), a tear drop 40D is added from the bent portion. Thereafter, it is checked whether or not the added tear drop 40 can maintain a predetermined insulation interval from the surrounding conductor circuit (S82). If the predetermined insulation interval can be maintained (Yes in S82), the process is terminated. Thereby, the tear drop 40A or the tear drop 40D is added as shown in FIG. 12 (A) or FIG. 12 (C) through the manufacturing process described later based on the created data.
[0030]
On the other hand, when the teardrop is added and the insulation interval from other conductor circuits cannot be maintained (No in S88), the addition of the teardrop is abandoned (S90).
[0031]
The tear drop is added to the land arranged in each opening by the above-described tear drop addition processing 1, 2, and 3. Then, it is determined whether or not there is a next opening (S32 shown in FIG. 1), and when there is a next opening (S32 is Yes), the process returns to step 14 and the above-described processing is repeated. When the processing for all the solder resist openings is completed (No in S32), the teardrop addition processing is completed.
[0032]
Conductor circuit (land, signal line, teardrop) pattern formation data is completed by the above processing, and a mask film is completed by forming a pattern corresponding to the conductive circuit on the resin film using the data. To do. Here, a conductive circuit of a printed wiring board is formed using the mask film, and a solder resist is applied to the conductor circuit. Since this process is the same as that used conventionally, description is abbreviate | omitted.
[0033]
Here, as described above with reference to FIGS. 6 (E) and 6 (F), when the solder resist opening 50a is formed, even if the maximum position error, that is, the clearance C shifts, A tear drop 40C shown in FIG. 10A is applied to the end of the opening 50a, and widens the width of the signal line 20 at the end. For this reason, even if there is an error in the position of the opening of the solder resist with respect to the land, the signal line becomes wider at the position intersecting the edge of the opening. It is difficult to cause disconnection or cracks at the end of the opening.
[0034]
In the above-described embodiment, the process of adding tear drops to the circular land of the circular opening of the solder resist has been described. When the square land 30c is disposed in the square opening 50c of the solder resist 50 as shown in FIG. 15A by the same process, the tear drop addition process 2 described above with reference to FIG. Thus, the teardrop 40C can be added to the drawing side of the signal line 20 so that the end of the opening 50c is applied. Further, as shown in FIG. 15B, even when the signal line is bent in the opening 50c, the tear drop 40D can be added by the tear drop addition process 3 described above with reference to FIG. Further, when the side of the opening 50d is smaller than the side of the land 30c, the tear drop 40A is added to a predetermined tear angle by the tear drop addition process 1 described above with reference to FIG. can do.
[0035]
Similarly, when the rectangular land 30d is disposed in the rectangular opening 50e of the solder resist 50 as shown in FIG. 16A, the tear drop adding process 2 described above with reference to FIG. The tear drop 40C can be added to the lead-out side of the signal line 20 so that the end of the opening 50e is applied. As shown in FIG. 16B, the teardrop 40D can be added by the teardrop addition process 3 described above with reference to FIG. 4 even when the signal line is bent in the opening 50e. Further, when the short side of the opening 50f is smaller than the short side of the land 30d, the tear drop is performed so that the predetermined tear drop angle is obtained by the tear drop addition process 1 described above with reference to FIG. 40A can be added.
[0036]
As described above with reference to FIG. 12C, when the signal line 20 led out from the land 30 disposed in the opening 50a of the solder resist 50 is bent in the opening 50a. In addition, a tear drop 40D is added in the opening, but as shown in FIG. 12D, the tear drop is started from a predetermined position on the signal line 30 outside the opening 50a (for example, a position where the clearance C is provided). It is also possible to arrange the tear drop 40E so as to cover the end of the opening 50a.
[0037]
Furthermore, in this embodiment, even when the opening is larger than the land, by adding a tear drop, the land is reinforced, and the adhesion between copper and resin is improved.
[0039]
【The invention's effect】
The printed wiring board manufacturing method according to claim 1 , wherein when the land is smaller than or the same as the opening diameter of the solder resist, the tear drop is attached to the opening of the solder resist with respect to the signal line extending from the land. Since the signal line is widened at the position intersecting with the end of the opening by being arranged so as to cover the end, it is difficult for stress to concentrate, and disconnection and cracks are not generated at the end of the opening. .
[0040]
In the printed wiring board according to the second aspect , in consideration of the formation deviation between the land and the opening, the printed wiring board is disposed so as to cover the end of the opening of the solder resist. For this reason, for example, even if the position of the opening is shifted when the opening of the solder resist is formed with respect to the land, the width of the signal line is widened at the position intersecting with the end of the opening. Disconnection and cracks are not generated at the end of the opening.
[Brief description of the drawings]
FIG. 1 is a flowchart of a teardrop addition process according to an embodiment of the present invention.
FIG. 2 is a flowchart showing the contents of a subroutine of tear drop addition processing 1 in FIG. 1;
FIG. 3 is a flowchart showing the contents of a subroutine of tear drop addition processing 2 in FIG. 1;
FIG. 4 is a flowchart showing the contents of a subroutine of tear drop addition processing 3 in FIG. 1;
FIGS. 5A to 5C are explanatory diagrams showing lands and openings for adding teardrops. FIG.
6E, FIG. 6F, and FIG. 6G are explanatory views showing lands and openings to which tear drops are added.
FIGS. 7A, 7B, and 7C are explanatory diagrams showing teardrop shape determination based on teardrop addition processing 1. FIG.
8A, FIG. 8B, and FIG. 8C are plan views showing the shape of a teardrop added based on the teardrop addition processing 1;
FIGS. 9A, 9B, and 9C are explanatory diagrams showing teardrop shape determination based on the teardrop addition process 2. FIG.
FIGS. 10A, 10B, and 10C are plan views showing the shape of a teardrop added based on the teardrop addition process 2. FIG.
FIGS. 11A, 11B, and 11C are explanatory diagrams illustrating teardrop shape determination based on the teardrop addition process 3. FIG.
FIGS. 12A, 12B, and 12C are plan views showing the shape of a teardrop added based on the teardrop addition processing 3. FIG.
FIG. 13 is a plan view showing a part of a printed wiring board according to an embodiment of the present invention.
14A is an enlarged view of a portion J in FIG. 13, and FIG. 14B is an enlarged view of a portion K in FIG.
FIGS. 15A, 15B, and 15C are plan views showing the shape of a teardrop added to a square land. FIG.
FIGS. 16A, 16B, and 16C are plan views showing the shape of a tear drop added to a rectangular land. FIGS.
17A is a plan view of a printed wiring board according to the prior art, FIG. 17B is a cross-sectional view taken along line BB in FIG. 17A, and FIG. FIG. 17A is a plan view when a tear drop is added to the printed wiring board shown in FIG. 17A, and FIG. 17D is a cross-sectional view of the printed wiring board.
[Explanation of symbols]
10 Printed wiring board 20 Signal line 25 Via hole 30, 30a, 30b Land 32 Land 40, 40A, 40B Tear drop 50 Solder resist 50a, 50b Opening 60 Substrate

Claims (2)

A method for producing a printed wiring board in which a signal line and a land are disposed on a substrate and a solder resist is disposed on a surface layer,
Determining whether the land is smaller than the opening of the solder resist disposed corresponding to the land;
When the land is greater than the opening, and a step of disposing so as to the signal lines extending from the land, become a teardrop from the surrounding conductor circuit and angle so as to maintain the insulation gap,
Disposing a tear drop over the edge of the opening of the solder resist with respect to the signal line extending from the land when the land is smaller than or the same as the opening. A method for producing a printed wiring board. In the step of disposing the tear drop over the signal line extending from the land so as to cover the end of the opening of the solder resist, the formation deviation between the land and the opening is the value at which the opening is most shifted. set as a certain clearance, a method for manufacturing a printed wiring board according to claim 1 wherein said tear drop, characterized in that arranged as according to the opening end of the solder resist may deviate a clearance.

Images