TW201625093A - Screen-printed correction method for circuit board - Google Patents

Abstract

The invention is a screen-printed correction method for circuit board silk screen. It presets a first shaft design value of silk screen pattern printing, and detects etch measured value of the first shaft of the circuit board, and calculates the first axial length variation around squeegee pressure in screen length along the first axial of the screen, further calculates the correction parameters of the first axis according to the first axial length variation behind, corrects the first axis to the printing pattern on the screen for reformatting screen; and thereby corrects the printing pattern on the screen for reducing offset generated during the manufacture process so as to raise the yield of manufacturing circuit board.

Description

Circuit board screen printing correction method

The invention relates to a printing correction method, in particular to a method for correcting screen printing.

In the prior art, when the circuit board is manufactured, the circuit board is printed to form a wiring pattern on one side of the circuit board, and then the wiring pattern on the circuit board is cured after exposure, development, and aging. Then complete the production of the board. The exposure system irradiates the circuit board with an ultraviolet light source to cause the material on the circuit board to be hardened and hardened, and the ultraviolet light source is shielded by a light-emitting film to illuminate the circuit board in a specific shape so as to be in a specific shape or region on the circuit board. The material deteriorates and hardens. After the exposed circuit board, because the material in a specific shape or region on the circuit board is hardened, it has better etching resistance than the area not irradiated by the ultraviolet light source, and then pickled with an acidic substance. The board is etched and developed, and the difference in etching resistance of the material on the board causes differential erosion to form a specific pattern on the board. Then, after the curing baking, the specific pattern on the circuit board is further hardened to form a finished circuit board.

The method in which the board is printed is performed by screen printing in the prior art. Referring to FIG. 10, the screen printing system is designed on a screen 50, and the graphic can be various patterns. When printing a board by screen printing, the graphic on the screen 50 is a net. Printed graphic 501. Referring to FIG. 11 together, the screen 50 is fixed on a frame 51. When the board 60 is screen-printed, the screen 50 on which the screen printing is designed is placed on the board. 60, and a gap is left between the frame 51 and the circuit board 60, and the top surface of the screen 50 has an ink paint 52, and a scraper 53 is disposed on the top surface of the screen 50. Referring to FIG. 12, when the screen printing is started, the doctor blade 53 is pressed down from the top surface of the screen 50, and the screen 50 is brought into contact with the top surface of the circuit board 60 to start moving. The screen 50 ink coating 52 is applied to the top surface of the screen 50. The screen printing pattern 501 on the screen 50 is formed by perforation, so when the blade 53 uniformly applies the ink coating 52 to the top surface of the screen 50, the ink coating 52 will pass through the perforation of the screen printing pattern. The screen printing pattern on the screen 50 is printed on the top surface of the circuit board 60 to form a wiring pattern of the circuit board 60 to complete the printing process of the circuit board 60.

However, when the circuit board 60 subsequently completes the development process, the wiring pattern on the circuit board 60 is offset after the image etching and the original screen printing pattern on the screen 50 is used because of technical defects. Differently, the actual wiring pattern on the board is different from the design of the original user, and the yield of the board process is reduced.

Therefore, the prior art has a correction formula, which is calculated from an etched measurement value and a screen printing pattern design value through the correction formula, and the etching measurement value is measured by a photosensitive coupling element (CCD). The wiring pattern on the circuit board after the etching is developed, and the size of the wiring pattern is the etching measurement value, and the offset is further corrected by the correction parameter. According to the correction parameter, the screen printing pattern on the screen 50 is re-created, so that after the subsequent image etching is completed, the wiring pattern on the circuit board 60 is more in line with the original design size of the user, so as to reduce the error and thereby improve the production. Board yield. The correction formula is:

Where P represents the correction parameter, A represents the screen printing pattern design value, and B represents the etching measurement value.

However, when the screen 53 presses the screen 50, since the screen 50 is fixed to the frame 51 and the screen 50 has elasticity, the screen 50 is deformed due to the force. The screen printing pattern on the screen 50 is deformed, and the error in the screen printing is generated, so that the wiring pattern printed on the board 60 is offset from the screen printing pattern on the screen 50, and the prior art is corrected. The formula still does not solve the technical problem.

In view of this, the main object of the present invention is to provide an improved method for screen printing correction of a circuit board to improve the fabrication yield of the circuit board.

In order to achieve the above object, the method for correcting the screen printing of the circuit board of the present invention comprises: presetting a first axis design value of a screen printing pattern and a first axis etching measurement value of a circuit board; a first axial direction of the plate, calculating a first axis length change amount of the screen before and after the blade pressing; calculating according to the first axis length variation, the first axis design value, and the first axis etching value a first axis correction parameter; according to the first axis correction parameter, recalculating the corrected first axis size of the screen printing graphic.

The invention detects a first shaft length change amount before and after the blade is pressed by the screen, and further calculates a first axis correction parameter according to the first shaft length variation to correct the net along the first axis. The screen prints the graphic and recreates the screen to modify the screen print of the screen. The invention not only corrects the error caused by the etching process of the circuit board, but also corrects the error caused by the expansion of the screen by the blade pressing when the screen printing is performed, so that the wiring pattern and the user on the circuit board are completed after the circuit board is completed. The original design is consistent, further reducing the error to increase the board's production yield.

The technical means adopted by the present invention for achieving the intended purpose of the invention are further described below in conjunction with the drawings and preferred embodiments of the invention.

Referring to FIG. 1 , the present invention is a circuit board screen printing correction method, and the circuit board screen printing correction method comprises the following steps: Presetting a first screen design value A1 of a screen printing graphic a first axis etching measurement value B1 of a circuit board (S11); along a first axial direction of a screen, calculating a first axis length change amount C1 (S12) of the screen before and after the blade pressing; The first axis length change amount C1, the first axis design value A1, and the first axis etch measurement value B1 calculate a first axis correction parameter P1 (S13); recalculate the network according to the first axis correction parameter P1 The first axis size after the correction of the printed image (S14).

The first axis design value A1 of the screen printing pattern refers to the original size of the screen printing pattern on the screen along the first axis. The first axis time measurement value B1 refers to the actual size of the wiring pattern formed on the circuit board along the first axial direction after the circuit board is etched and developed. The first axis correction parameter P1 is calculated by a first axis correction formula, and the first axis correction formula is:

As shown in FIG. 2 and FIG. 3 , a frame 20 is disposed around the screen 10 for printing a circuit board 30 to print a wiring pattern on the circuit board 30 . 301, and defining a first axial direction and a second axial direction, the first axial direction is an X-axis direction, and the second axial direction is a Y-axis direction. The screen 10 is provided with a screen printing pattern 101 for printing the screen board 30. In the preferred embodiment, the circuit board 30 is also defined as its first axial direction in the X-axis direction and its second axial direction in the Y-axis direction, and the first axial etching measurement value is one. A photosensitive coupling element (CCD) detects four points (A, B, C, D) on the circuit board 30, and detects the length of the line connecting the two points along the first axial direction of the circuit board 30, for example, or length. In the preferred embodiment, the first axial direction of the screen 10 is perpendicular to the second axial direction, and the first axial direction of the circuit board 30 is perpendicular to the second axial direction.

Referring to FIGS. 4 and 5, a side view along the first axial direction of the circuit board 30, a gap H is left between the screen 10 and the circuit board 30, and a doctor blade 40 is disposed on the network. Above version 10. As shown in FIG. 4, the blade 40 is not in contact with the screen 10 before the screen printing has been performed, so the shape of the screen 20 is a plane, and the screen 10 is viewed along the side of the first axis. The shape is a straight line. As shown in FIG. 5, when screen printing is performed, the blade 40 presses the screen 10 so that the bottom surface of the screen 10 is in contact with the circuit board 30, and the position of the frame 20 is not moved. The periphery of the frame 10 is similarly fixed to the frame 20, so that the screen 10 is deformed by being pulled down by the blade 40, and the length of the line segment of the screen 30 along the first axial direction after deformation is also change. In the preferred embodiment, after the screen 30 is deformed, the line of sight of the first axial direction is changed from a straight line to a broken line, and both ends of the line are the same as the ends of the straight line before the deformation, and the net is the same. The plate 10 is fixed on the frame 20, and the principle that the closest distance between the two points is the length of the straight line is that the total length of the deformed line is greater than the length of the line before the deformation.

Therefore, the present invention calculates the length variation of the line segment along the side of the first axial direction before and after the deformation of the screen 10, and calculates the first axis correction parameter through the first axis correction formula to the network on the screen 10 The printing pattern 101 performs the first axis correction to recalculate the corrected first axis size of the screen printing pattern 101, so that the wiring pattern printed on the circuit board of the circuit board can be closer to the original design of the user after the image etching. The process error is reduced, thereby improving the fabrication yield of the circuit board 30.

Referring to FIG. 4 , further, before the scraper 40 is pressed down and viewed along the first axis, the distance between the two ends of the screen and the opposite sides of the screen 10 along the first axis is respectively a first distance X1 and a second distance X2, and a length along the first axial side of the screen 10 is a first length L1, the first length L1 is the scraper 40 along the first axial direction Length X plus the first distance X1 and the second distance X2, ie . The screen 10 has the spacing H between the screen 40 and the circuit board 30 before the doctor 40 is depressed.

Referring to FIG. 5, when the blade 40 presses the screen 10, the screen 10 is deformed by pressure, and the first distance X1 becomes a first extension distance X1', and the second distance becomes one. The second extension distance X2'. The first extension distance X1' can be calculated according to the Bisch's theorem, And calculating the second extension distance X2', . The first extended length L1' after the deformation of the screen 10 along the first axial side is the length X of the scraper 40 along the first axial direction plus the first extended distance X1' and the second Extension distance X2', ie . Further, the first axial length change amount C1 of the screen 10 before and after the blade 40 is pressed along the length of the first axis is calculated as:

Referring to FIG. 6 , for example, the pitch H is 6.5 mm (mm), and the first first axis distance X1 and the second first axis distance X2 are both 150 mm (mm), according to the above. The formula calculates the first axis length variation C1 of the screen 10 along the length of the first axis before and after the blade 40 is depressed:

And the first axis correction parameter P1 is:

Wherein P1 is the first axis correction parameter, B1 is the first axis etching measurement value, A1 is the first axis design value, and C1 is the first axis length variation amount.

Then, the first axis size corrected by the screen printing pattern can be recalculated according to the first axis correction parameter. The first axis size corrected by the screen printing pattern is calculated by the following formula:

Wherein P1 is the first axis correction parameter, α1 is the first axis size before the screen printing pattern 101 is corrected, and β1 is the first axis size after the screen printing pattern 101 is corrected.

For example, the first axis design value A1 is 700 mm (mm), that is, the first axis size α1 before the screen printing pattern 101 is corrected, and the first axis measurement value B1 is 699 mm (mm). The first axial length change amount C1 was found to be 0.28 mm (mm) based on the above calculation. The first axis correction parameter P1 is calculated based on the first axis correction formula as ((699-700-0.28)/700)*100%=-0.18%. Then, according to the first axis correction parameter P1, the screen printing pattern on the screen 10 is corrected along the first axis. The original first axis design value of the screen printing pattern of the screen 10 is 700. After the correction, the screen is corrected. The corrected first axis design value of the 10 screen printing pattern is 700*(100%-0.18%)=698.72 mm (mm), that is, the first axis size β1 after the screen printing pattern 101 is corrected. In other words, the screen printing pattern of the screen 10 is reduced by 0.18% along the first axial direction to further correct the offset caused by the deformation of the screen 10 after the blade 40 is pressed down.

Referring to FIG. 7, the board screen printing correction method further performs the following steps: Presetting one of the screen printing patterns, the second axis design value A2, and one of the second axis etching values of the board. B2 (S21); calculating a second axial length change amount C2 of the screen before and after the blade pressing along the second axial direction of the screen (S22); according to the second shaft length variation C2, the second The second axis correction parameter P2 is calculated by the axis design value A2 and the second axis etching measurement value B2 (S23); and the second axis size corrected by the screen printing pattern is recalculated according to the second axis correction parameter P2 ( S24).

The second axis correction parameter P2 is calculated by a second axis correction formula, and the second axis correction formula is:

Referring to Figures 2 and 3, the second axis design value A2 of the screen printing pattern refers to the original size of the screen printing pattern 101 on the screen 10 along the second axis. The second axis time measurement value B2 is the actual size of the wiring pattern 301 formed on the circuit board 30 along the second axial direction after the circuit board 30 is etched and developed. In the preferred embodiment, four points (A, B, C, D) on the circuit board 30 are detected by a photosensitive coupling element (CCD), and the second axis time measurement value A2 is coupled by the photosensitive coupling. The length of the dimension of the two points of the component detection along the second axis, for example, or length.

With the above principle of calculating the first axis correction parameter and performing the first axis correction, the present invention further corrects the second axis to correct the first axis and the second axis of the screen printing pattern 101 of the screen 10 The screen printing pattern 101 on the screen 10 is re-created to further improve the production yield of the board 30.

Referring to FIG. 8 , one end of the scraper 40 is in contact with the screen 10 before the scraper 40 is pressed down and along the second axial side, and one end of the scraper 40 and the screen 10 are The distance from the contact point to the opposite sides of the screen 10 along the second axis is a third distance Y1 and a fourth distance Y2, respectively. The screen 10 has a second length L2 depending on the length of the screen 10 in the second axis direction.

Referring to FIG. 9, when the doctor blade 40 presses the screen 10 to make the screen 10 contact the circuit board 40, the shape of the screen 10 along the second axis is a straight line segment. A fold line is formed, and the bend of the fold line is the contact point of the screen 10 with the circuit board 40. The lengths of the straight lines projected on the circuit board 40 are respectively the third distance Y1 and the fourth distance Y2, and the third distance Y1 plus the fourth distance Y2 is the The second axis is viewed from the side and the second length L2 before the blade 40 is not depressed, ie . The screen 10 has the spacing H between the screen 40 and the circuit board 30 before the doctor 40 is depressed. After the scraper 40 is pressed, the lengths of the two straight segments of the fold line are respectively a third extension distance Y1' and a fourth extension distance Y2'.

In summary, before the blade 40 is pressed, the second length L2 of the screen 10 along the second axis side is the third distance Y1 plus the fourth distance Y2. When the blade 40 is pressed down, the length of the screen 10 along the side of the second axis becomes a second extension length L2', and the third extension distance Y1' is added to the fourth extension distance Y2'. , which is . And the third extension distance Y1' can be calculated according to the Bisch's theorem, And calculating the fourth extension distance Y2', . Further, the second axis length variation C2 of the screen 10 along the length of the second axis before and after the blade 40 is pressed is calculated as:

For example, the spacing H is 6.5 mm (mm), the third distance Y1 and the fourth distance Y2 are both 350 mm (mm), and the length of the screen 10 along the second axis is calculated according to the above formula. The second shaft length change amount C1 before and after the blade 40 is pressed is:

The second axis correction parameter P2 is:

Wherein P2 is the second axis correction parameter, B2 is the second axis etching measurement value, A2 is the second axis design value, and C2 is the second axis length variation amount.

Then, the second axis correction of the screen printing pattern 101 of the screen 10 can be performed according to the calculated second axis correction parameter P2 to recalculate the corrected second axis size of the screen printing pattern 101. The second axis size corrected by the screen printing pattern 101 is calculated by the following formula:

Wherein P2 is the second axis correction parameter, α2 is the second axis size before the screen printing pattern 101 is corrected, and β2 is the second axis size after the screen printing pattern 101 is corrected.

For example, the second axis design value A2 is 700 mm (mm), that is, the second axis size α2 before the screen printing pattern 101 is corrected, and the second axis measurement value B2 is 699 mm (mm). The second axial length change amount C2 was found to be 0.12 mm (mm) based on the above calculation. The second axis correction parameter P2 is calculated according to the second axis correction formula as ((699-700-0.12)/700)*100%=-0.16%. Then, according to the second axis correction parameter P2, the screen printing pattern on the screen 10 is corrected along the second axis. The original second axis design value of the screen printing pattern of the screen 10 is 700. After the correction, the screen is corrected. The second axis design value after correction of the screen printing pattern 101 is 700*(100%-0.16%)=698.88 mm (mm), that is, the second axis size β2 after the screen printing pattern 101 is corrected, in other words, That is, the screen printing pattern of the screen 10 is reduced by 0.16% along the second axial direction to further correct the offset caused by the deformation of the screen 10 after the blade 40 is pressed down.

By correcting the first axis and the second axis at the same time, the screen printing pattern 101 on the entire screen 10 plane is corrected, so that the wiring pattern of the circuit board 40 is closer to the design of the original user. Reduce the offset and error generated during the process, and achieve the purpose of effectively improving the board production yield.

The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention. A person skilled in the art can make some modifications or modifications to equivalent embodiments by using the above-disclosed technical contents without departing from the technical scope of the present invention. It is still within the scope of the technical solution of the present invention to make any simple modifications, equivalent changes and modifications to the above embodiments.

10‧‧‧Web Edition
101‧‧‧ Screen printing graphics
20‧‧‧ net frame
30‧‧‧ boards
40‧‧‧ scraper
50‧‧‧Web Edition
51‧‧‧ net frame
52‧‧‧Ink coating
53‧‧‧ scraper
60‧‧‧ boards

1 is a flow chart of a first axis correction method in accordance with a preferred embodiment of the present invention. 2 is a top plan view of a frame of a preferred embodiment of the present invention. 3 is a top plan view of a circuit board according to a preferred embodiment of the present invention. Figure 4 is a schematic view of the preferred embodiment of the present invention before the doctor blade is pressed down. Figure 5 is a side elevational view of the preferred embodiment of the present invention with the doctor blade depressed. Figure 6 is a partial side elevational view of the preferred embodiment of the present invention with the doctor blade depressed. Figure 7 is a flow chart of a second axis correction method in accordance with a preferred embodiment of the present invention. Figure 8 is a side elevational view of another perspective view of the preferred embodiment of the present invention before the blade is depressed. Figure 9 is a side elevational view of another perspective view of the preferred embodiment of the present invention with the doctor blade depressed. Figure 10 is a top plan view of an existing screen printing technique. Figure 11 is a side elevational view of the prior art screen printing technique before the blade is depressed. Figure 12 is a side elevational view of the conventional screen printing technique after the blade is depressed.

Claims (11)

A method for correcting a screen printing method of a circuit board comprises: presetting a first axis design value of a screen printing pattern and a first axis etching measurement value of a circuit board; Calculating a first axis length change amount of the screen before and after being pressed by a blade; calculating a first axis according to the first axis length variation, the first axis design value, and the first axis etching measurement value Correcting the parameter; recalculating the first axis size after the screen printing pattern is corrected according to the first axis correction parameter. The circuit board screen printing correction method according to claim 1, wherein the first axis correction parameter is calculated by a first axis correction formula, and the first axis correction formula is: Where P1 is the first axis correction parameter, B1 is the first axis etching measurement value, A1 is the first axis design value, and C1 is the first axis length variation amount. The method for correcting a screen printing method according to claim 1, wherein: before the blade is not pressed, the screen is spaced apart from the circuit board by a distance along the first axial direction of the blade. The distance between the opposite sides of the screen is a first distance and a second distance; the first shaft length variation is: Where X1 is the first distance, X2 is the second distance, and H is the spacing. The method for correcting a screen printing method according to claim 2, wherein: before the blade is not pressed, the screen has a spacing between the screen and the blade along the first axial side. The distance between the two ends and the opposite sides of the screen along the first axis is a first distance and a second distance; the first shaft length variation is: Where X1 is the first distance, X2 is the second distance, and H is the spacing. The method for correcting a screen printing method according to any one of claims 1 to 4, wherein before the step of remaking the screen, the following steps are further performed: preset one of the screen printing patterns of the screen a shaft design value and a second axis etching measurement value of the circuit board; calculating, along a second axial direction of the screen plate, a second axis length change amount of the screen plate before and after the blade pressing; according to the second axis The second axis correction parameter is calculated by the length change amount, the second axis design value, and the second axis etch measurement value; and the second axis correction is performed on the screen printing pattern of the screen according to the second axis correction parameter. The circuit board screen printing correction method according to claim 5, wherein the second axis correction parameter is calculated by a second axis correction formula, and the second axis correction formula is: Where P2 is the second axis correction parameter, B2 is the second axis etching measurement value, A2 is the second axis design value, and C2 is the second axis length variation amount. The method of claim 5, wherein: the screen has a spacing between the screen and the board before the blade is unpressed, and the blade is viewed along the second axis. One end of the blade is in contact with the screen, and the distance between the contact point of the blade and the screen to the opposite sides of the screen along the second axis is a third distance and a fourth distance; The amount of change in the length of the two axes is: Where Y1 is the third distance, Y2 is the fourth distance, and H is the spacing. The method for correcting a screen printing method according to claim 6, wherein: the screen has a spacing between the screen and the board before the blade is not pressed, and the blade is viewed along the second axis side. One end of the blade is in contact with the screen, and the distance between the contact point of the blade and the screen to the opposite sides of the screen along the second axis is a third distance and a fourth distance; The amount of change in the length of the two axes is: Where Y1 is the third distance, Y2 is the fourth distance, and H is the spacing. The board screen printing correction method of claim 5, wherein the first axis is perpendicular to the second axis. The board screen printing correction method according to any one of claims 1 to 4, wherein the first axis size after the screen printing pattern is corrected is calculated by the following formula: Where P1 is the first axis correction parameter, α1 is the first axis size before the screen printing pattern is corrected, and β1 is the first axis size after the screen printing pattern is corrected. The circuit board screen printing correction method according to claim 5, wherein the second axis size after the screen printing pattern is corrected is calculated by the following formula: Where P2 is the second axis correction parameter, α2 is the second axis size before the screen printing pattern is corrected, and β2 is the second axis size after the screen printing pattern is corrected.