CN114740691A - Processing method adopting lens group - Google Patents

Abstract

The invention provides a processing method using a lens group. According to the magnification of each lens in the lens group, the minimum lens magnification is obtained; the width of the projection strip is obtained with the minimum lens magnification; Projection pattern of each strip; configure each pixel of the spatial light modulation element according to the projection pattern of each strip and the corresponding lens magnification. It effectively solves the problem that the graphics stitching is prone to deviation and the effect is not good when the lens magnification is inconsistent, and avoids the complex debugging of the lens magnification.

Description

A processing method using a lens group

technical field

The invention relates to a processing method using a lens group, in particular to a processing method with different lens magnifications in the lens group.

Background technique

In the semiconductor and PCB industries, the light emitted by the light source can be used to realize various processing procedures such as exposure of substrate circuit patterns, exposure of solder mask ink, punching, and etching. The lens is a commonly used optical element, which performs optical processing on the light emitted by the light source, and enlarges or reduces the light spot projected by the light source through different lens magnifications.

In the exposure process, multiple lenses are usually used to expose the substrate at the same time, which reduces the number of movements of the substrate or the lens and effectively improves the exposure efficiency. However, when multiple lenses are used for exposure, the lens magnification of each lens needs to be consistent to obtain a good stitching effect. The high requirements for the lens magnification virtually increase the production cost. At the same time, in the process of use, if the magnification of each lens is inconsistent, it needs a tedious adjustment and correction process, or even needs to disassemble the lens to realize it, which has low flexibility and cumbersome operation, which increases the time cost and labor cost.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides a processing method with different lens magnifications in a lens group.

The technical solution is as follows: a processing method using a lens group, obtaining the minimum lens magnification according to the magnification of each lens in the lens group; obtaining the width of the projection strip with the smallest lens magnification; according to the projection strip The width of each stripe is obtained to obtain the projection pattern of each strip; each pixel of the spatial light modulation element is configured according to the projection figure of each stripe and the corresponding lens magnification.

Further, the configuration of each pixel of the spatial light modulation element according to the projection pattern and the lens magnification is realized by selecting a configuration area of the projection pattern in the process of rasterizing the projection pattern.

Further, the configuration area of the projection pattern is obtained by the ratio of the width of the projection strip and the magnification of the lens.

Further, the method for measuring the magnification of each lens of the lens group is to measure the initial magnification first, and obtain a plurality of similar test magnifications based on the initial magnification; project the test pattern to the carrier with the initial magnification and the test magnification respectively; The test pattern, the corresponding magnification is the measurement magnification of the lens.

Further, the test magnification increases or decreases by a certain magnification step value from the initial magnification.

Further, the initial magnification and the test magnification are sequentially projected onto the photosensitive substrate in an order from small to large or from large to small.

Further, the test patterns are lines with different widths.

Further, the width of the line is set according to the resolution capability of the lens.

Further, the test pattern is a straight line arranged in parallel.

Further, the test pattern is a horizontal straight line and a vertical straight line.

Further, when multiple lens magnifications are measured at the same time, the initial magnification and measurement magnification of each lens are obtained, and a span covering the test magnifications of all lenses is selected; The test pattern is obtained by projecting the material, or according to the order of the test magnifications of each lens, the multiple lenses simultaneously select their respective test magnifications according to the order to project the photosensitive substrate to obtain the test pattern.

An exposure method of a projection exposure system using the above processing method, the projection exposure system includes an exposure lens system, a motion platform system and a control system, the control system controls the exposure lens system and the motion platform system, the The moving platform system is used for placing the carrier and driving the carrier to move. The exposure lens system includes a plurality of exposure lenses for projecting exposure patterns to the carrier. The exposure lens system uses the above processing method to expose the carrier.

The above method can effectively solve the problem that when the lens magnification is inconsistent, the graphics stitching is prone to deviation and the effect is not good, and the complex debugging of the lens magnification is avoided.

Description of drawings

Figure 1 is a schematic diagram of the lens group.

FIG. 2 is a flow chart of a processing method using a lens group.

FIG. 3 is a schematic diagram of a spatial light modulation element.

FIG. 4 is a schematic diagram of a projection exposure system.

Figure 5 is a schematic diagram of initial magnification measurement.

FIG. 6 is a schematic diagram of exposure patterns corresponding to each lens magnification.

FIG. 7 is a schematic diagram of the completion of exposure at multiple magnifications for each lens.

FIG. 8 is a schematic diagram of simultaneous exposure of multiple lenses.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

Figure 1 shows a lens group, the lens group includes multiple lenses, the number of lenses in the lens group is not limited, set according to needs, when the lens is projected, it is expected that the magnification of each lens is consistent, so that The same strip width can be obtained, which is convenient for matching with the moving device of the carrier 2, and it is beneficial for the strips between adjacent lenses to be well spliced. The following is a detailed description of the processing method when the lens magnifications in the lens group are inconsistent.

Now, the lens group includes four lenses as an example for description, namely the first lens 11, the second lens 12, the third lens 13 and the fourth lens 14. Each lens in the lens group includes a light source, a space A light modulation element and a projection lens, the light emitted by the light source forms different projection graphics through the spatial light modulation element, the projection graphics are projected to the carrier through the projection lens, and the projection graphics are adjusted according to the magnification of the projection lens. For magnification adjustment (enlargement or reduction), the spatial light modulation element may be a digital micromirror array (DMD) or a liquid crystal display, etc., and the carrier is a PCB board, a wafer, or the like.

As shown in Figure 2, when projecting graphics on the carrier, the graphics to be projected onto the carrier are divided according to the number of lenses and the area covered by the lenses, the width of the strip is determined according to the minimum lens magnification, and the corresponding strips of each lens are obtained. graphics. According to the magnification of each lens, the utilization area of the spatial light modulation element is obtained, and the graphics corresponding to each lens corresponds to each pixel of the spatial light modulation element, and is projected to the carrier.

Before performing the graphic projection on the carrier, first obtain the lens magnification of each lens in the lens group, the lens magnification has been marked, or the lens magnification of each lens needs to be obtained by measurement. In this embodiment, the magnification of the first lens is r0, the magnification of the second lens is r1, the magnification of the third lens is r2, and the magnification of the fourth lens is r3. The magnifications of the four lenses are all different or some of the lenses have the same magnification, find the lens magnification with the smallest value of the four lens magnifications, and obtain the width of the projection strips of each lens.

In this embodiment, the magnification r1 of the second lens is the lens magnification with the smallest value among the four lens magnifications, and the minimum lens magnification r1 is used to calculate the stripe width W projected by the second lens, and the stripe width is based on The width W0 of the projected pattern of the spatial light modulation element and the magnification of the lens are obtained, W=WO*r1.

The remaining three lenses adjust the width of the projected graphics according to their respective lens magnifications, so that the width of the strip projected by the lens is the same as the strip width W of the second lens. For the first lens, according to the lens magnification r0 of the first lens, the width W1=W/r0 of the projection image corresponding to the first lens is obtained; for the third lens, according to the Lens magnification r2, the width W3=W/r2 of the projection image corresponding to the third lens is obtained; for the fourth lens, the projection image corresponding to the fourth lens is obtained according to the lens magnification r3 of the fourth lens The width of W4=W/r3.

As shown in FIG. 3 , the area of the spatial light modulation element is cut according to the width of the four projection patterns. Preferably, the middle area is selected as the projection pattern forming area 100 . In the rasterizing process of the projection pattern, each pixel 101 of the spatial light modulation element is configured according to the projection pattern forming area.

The following describes the application of the above-mentioned processing method of the lens group to a projection exposure system. As shown in FIG. 4 , the projection exposure system includes an exposure lens system 200 , an alignment system 300 , a motion platform system 400 and a control system. The control system Control the exposure lens system 200, the alignment system 300 and the motion platform system 400, the motion platform system 400 is used to place the carrier 2 and drive the carrier 2 to move, and the alignment system 300 grabs the The alignment point of the carrier 2 aligns the carrier 2, and after alignment, according to the alignment information, the exposure pattern is obtained by performing operations such as expanding, shrinking, and shifting the pattern to be exposed. The exposure lens system 200 includes a plurality of exposure lenses 1, Used to project the exposure pattern to carrier 2. The exposure lens system 200 and the motion platform system 400 cooperate with each other, so that all the graphics to be exposed to the carrier 2 are projected onto the carrier 2, that is, the exposure lens system 200 according to the position of the motion platform system 400 corresponds to the The exposure pattern is projected on the carrier 2 of the moving platform. If the exposure lens system 200 cannot be moved in the scanning direction by the moving platform system 400 to achieve complete exposure of the pattern in a strip, it needs to pass through the horizontal direction (X direction) Move the motion platform or the exposure lens 1 up. The complete exposure of the graphic is achieved by stitching of strips projected by different lenses and/or by stitching of different strips projected by the same lens.

By applying the processing method of the above-mentioned lens group, when there is a difference between the exposure lens magnifications in the exposure lens system, the minimum lens magnification is obtained, the exposure strip is obtained according to the minimum lens magnification, and the graphics to be exposed correspond to the exposure The lens is divided into each strip, and the corresponding area of the spatial light modulation element is intercepted according to the magnification of the exposure lens corresponding to each strip. pixel. By adjusting the area of the spatial light modulation element corresponding to the graphic data, each pixel of the spatial light modulation element is adjusted to obtain strips of equal width, which solves the problem of different strip widths caused by inconsistent lens magnifications and avoids complex adjustments. Operation of lens magnification.

By calibrating the exposure lens regularly or irregularly, when the lens magnification is deviated, it can also be adjusted quickly without affecting the production progress.

In addition to the above processing methods, the accurate measurement of the lens magnification is also critical to avoid the deviation of the graphics caused by the wrong measurement of the lens magnification. The following describes how to improve the measurement accuracy of the lens magnification.

As shown in Fig. 5, the initial magnification of lens 1 is obtained first. Two marking points 10 are set in the digital graphic file, the first distance S between the two marking points 10 is obtained, and the two marking points are exposed to the photosensitive substrate 2 through the lens 1 to form two recording points 21, and the first distance S between the two marking points 10 is obtained. For the second distance S' between the recording points 21, the initial magnification r0 of the lens magnification is obtained by the ratio between the second distance S' and the first distance S. The method of obtaining the initial magnification of the lens is not limited to this, and other measurement methods may also be used to obtain the initial magnification of the lens, such as optical measurement methods.

A plurality of test magnifications are obtained on the basis of the initial magnification, and the test magnifications are incremented or decremented by a certain magnification step value based on the initial magnification. Specifically, set the magnification step value s, and determine multiple test magnifications r0±Ns, where N is a positive integer, and s is set according to the accuracy of the lens magnification, such as: the accuracy of the lens magnification reaches 10,000ths, and the s is 0.0001 Or a value such as 0.0002.

A photosensitive substrate is placed under the lens, the photosensitive substrate is placed on a stage, the stage can drive the photosensitive substrate to move along the scanning direction, and the photosensitive substrate can cover the exposure range of the lens. According to the test magnification and the initial magnification from large to small or from small to large, the lens sequentially exposes the pattern to the photosensitive substrate, exposes a test pattern 30 with a magnification, and the stage drives the photosensitive substrate The material moves a certain distance along the scanning direction to expose the test patterns 30 at the next magnification. There is an interval between adjacent test patterns 30, and there are intervals between the test patterns obtained according to different test magnifications.

The test patterns 30 are lines with different widths. The widths of the lines are designed according to the resolution capability of the lens, and a line width matching the resolution capability of the lens and a similar line width are selected. Preferably, at least one line width smaller than the resolution capability of the lens is included, which is beneficial to distinguish the quality of exposure effects under different magnifications.

The test pattern 30 can be any pattern including lines, such as concentric circles, nested square boxes, and irregular patterns. In the embodiment of FIG. 6 , the test pattern includes vertical parallel lines and Of course, the horizontally parallel lines may only include vertically parallel graphics, or only include horizontally parallel graphics. The above graphics are simple and easy to judge the splicing effect.

As shown in Fig. 7, 19 test patterns 30 were obtained with s=0.0001, N=9. By detecting the 19 test patterns, find the pattern with the best stitching effect, and the corresponding lens magnification is the measurement magnification. The splicing effect is judged by the uniformity of lines and line widths. The better the uniformity, the better the splicing effect. The detection method can be manual detection through microscope magnification, or automatic detection through machine vision.

As shown in Figure 8, measurement can be performed with a single lens or with multiple lenses at the same time. When multiple lenses are measured at the same time, each lens obtains the same number of test magnifications through the initial magnification. The maximum and minimum test magnifications corresponding to each lens are not the same. The maximum and minimum test magnifications corresponding to all lenses are selected as the test magnification span, that is, the test magnification span covering all lenses. The magnification is exposed at the same time, and the lens magnification of each lens is obtained by analyzing the test pattern of each lens of the photosensitive substrate.

In addition to the above method of measuring multiple lenses at the same time, it is also possible to obtain the same number of test magnifications for each lens through the initial magnification, and perform simultaneous exposure one by one according to the order of the test magnifications corresponding to each lens. Therefore, when the photosensitive substrate is exposed at the same time, the test magnification used by each lens is different. Finally, the lens magnification of each lens is obtained by analyzing the test pattern of each lens of the photosensitive substrate.

The above method can effectively improve the measurement accuracy of the lens magnification, and obtain the best exposure effect.

Claims (12)

1. a processing method using a lens group is characterized in that: according to the magnification of each lens in the lens group, obtain the minimum lens magnification; obtain the width of the projection strip with the minimum lens magnification; The width of the projection pattern of each strip is obtained; each pixel of the spatial light modulation element is configured according to the projection pattern of each strip and the corresponding lens magnification. 2. The processing method according to claim 1, characterized in that: configuring each pixel of the spatial light modulation element according to each stripe projection pattern and the corresponding lens magnification is in the process of rasterizing the projection pattern, through Select the configuration area implementation of the projected graphics. 3 . The processing method according to claim 2 , wherein the configuration area of the projection pattern is obtained by the ratio of the width of the projection strip and the magnification of the lens. 4 . 4. The processing method according to claim 1, wherein: the measuring method of each lens magnification of the lens group is to measure the initial magnification first, and take the initial magnification as a benchmark to obtain a plurality of similar test magnifications; The magnification is to project the test pattern to the carrier respectively; find the test pattern with good splicing effect, and the corresponding magnification is the measurement magnification of the lens. 5 . The processing method according to claim 4 , wherein the test magnification increases or decreases by a certain magnification step value from the initial magnification. 6 . 6 . The processing method according to claim 4 , wherein the initial magnification and the test magnification are sequentially projected onto the photosensitive substrate in an order from small to large or from large to small. 7 . 7 . The processing method according to claim 4 , wherein the test patterns are lines with different widths. 8 . 8 . The processing method according to claim 7 , wherein the width of the line is set according to the resolution capability of the lens. 9 . 9 . The processing method according to claim 4 , wherein the test pattern is a straight line arranged in parallel. 10 . 10. The processing method according to claim 4, wherein the test pattern is a horizontal straight line and a vertical straight line. 11. processing method according to claim 4 is characterized in that: when a plurality of lens magnifications are measured simultaneously, obtain the initial magnification and measurement magnification of each lens, select the span that covers all lens test magnifications; The multiple lenses simultaneously project the photosensitive substrate with the selected test magnification to obtain the test pattern, or according to the order of the test magnifications of each lens, the multiple lenses simultaneously select the respective test magnifications according to the sequence to project the photosensitive substrate to obtain the test pattern. . 12. An exposure method for a projection exposure system, characterized in that: the projection exposure system comprises an exposure lens system, a motion platform system and a control system, the control system controls the exposure lens system and the motion platform system, and the The motion platform system is used to place the carrier and drive the carrier to move. The exposure lens system includes a plurality of exposure lenses for projecting exposure graphics to the carrier. The exposure lens system adopts any one of claims 1 to 11. The described processing method exposes the carrier.

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