A substrate adaptive leveling device for semiconductor lithography production

Abstract

The application discloses a substrate self-adaptive leveling device for semiconductor lithography production and relates to the technical field of semiconductor lithography production.The device can actively and timely measure the gap between upper and lower substrates at different support points and quickly drive the floating platform to adjust the posture, greatly shortening the time consumption of leveling the upper and lower substrates, effectively improving the leveling precision and gap control precision, and automatically adjusting the alignment after leveling the upper and lower substrates, which can not only save the manufacturing cost of the mask plate, but also improve the effective utilization rate of the wafer, and is conducive to reducing the cost of chip production to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of semiconductor photolithography production technology, and in particular to an adaptive leveling device for substrates used in semiconductor photolithography production. Background Technology

[0002] In semiconductor lithography, the leveling of the upper and lower substrates (mask and wafer) and the control of the gap (GAP) are the core links that determine the quality of lithography. At present, most of the industry uses passive lamination to complete the alignment and leveling of the substrate.

[0003] During the lamination and leveling process, the leveling is time-consuming and the overall leveling accuracy is low. This not only increases the processing time for a single batch of products but also directly restricts the overall processing efficiency and forming accuracy of the photolithography process. Furthermore, after the leveling operation is completed using the existing passive lamination and leveling structure, slight misalignment and skewness of the upper and lower substrates are very likely to occur. To compensate for the exposure defects caused by the alignment deviation, the industry's conventional approach is to widen the effective area of ​​the circuit pattern on the mask. The effective area of ​​the circuit pattern on the mask is enlarged by 1-3mm compared to the nominal size of the wafer as a tolerance allowance. At the same time, redundant dummy patterns are arranged over a large area on the outer edge of the wafer. The above redundant design is used to offset the alignment error of the upper and lower substrates, ensuring the complete exposure of the entire wafer and solving the problem of missing etch at the wafer edge. However, this solution will significantly increase the material usage and wafer layout design costs during mask manufacturing. Moreover, the redundant dummy patterns will occupy the effective chip area of ​​the wafer, causing waste of raw materials and a decrease in chip yield, significantly increasing the cost of chip photolithography production.

[0004] To address these issues, an adaptive leveling device for semiconductor lithography production substrates is proposed to solve some of the problems existing in the prior art. Summary of the Invention

[0005] The purpose of this invention is to solve the problems in the prior art of semiconductor photolithography, such as the time-consuming and low-precision leveling and gap control of the upper and lower substrates, and the need for redundant design after leveling to offset the alignment error of the upper and lower substrates, which leads to high production costs. Therefore, an adaptive leveling device for substrates in semiconductor photolithography production is proposed.

[0006] To address the problems existing in the prior art, the present invention adopts the following technical solution: An adaptive leveling device for semiconductor photolithography substrates includes a horizontally mounted base plate. Three Z-axis adjustment components are arranged in a circular pattern on the top of the base plate. A floating platform is mounted on the upper end of the three Z-axis adjustment components, and an adsorption platform is fixedly mounted on top of the floating platform. An upper substrate is positioned above the adsorption platform, and a lower substrate is placed on top of the adsorption platform. Multiple evenly distributed suction holes are formed on the top of the adsorption platform, and air pumps are connected to these holes. Three first laser rangefinders are positioned above the upper substrate, corresponding to the three Z-axis adjustment components. The distance between the first laser rangefinders and the base plate is constant, and each first laser rangefinder measures the distance between itself and the upper substrate. Second laser rangefinders are positioned on the right and rear sides of the adsorption platform, and deflection mechanisms are provided on the outer sides of each second laser rangefinder to control its vertical deflection. Each second laser rangefinder measures the distance between itself and the upper and lower substrates. A horizontal and vertical adjustment mechanism is mounted on the top of the adsorption platform, controlling the horizontal and vertical movement of the lower substrate along the top of the adsorption platform.

[0007] Preferably, the Z-axis adjustment assembly includes a base fixedly installed on the top of the base plate, and a lifting platform is connected to the base for lifting. A vertically arranged lead screw is rotatably installed on the base. A first servo motor for driving the lead screw to rotate is fixedly installed on the base. A nut seat is fixedly installed on the lifting platform and threadedly connected to the lead screw. A ball joint unit is connected between the lifting platform and the floating platform. The ball joint unit includes a ball head fixedly installed on the top of the lifting platform and a ball seat fixedly installed on the bottom of the floating platform. The ball seat is ball-jointed to the outside of the ball head.

[0008] Preferably, a spring is installed on the base to provide elastic support at the bottom of the lifting platform.

[0009] Preferably, a vertically arranged lead screw two is rotatably mounted on the base, and a nut seat two is lifted and connected to the base, with the nut seat two threadedly connected to the outside of the lead screw two. A spring elastically supports the nut seat two and the lifting platform. A second servo motor is fixedly installed in the middle of the base plate, and a belt drive assembly is connected between the drive shaft of the second servo motor and the lead screw two in the three Z-axis adjustment assemblies.

[0010] Preferably, a synchronous moving mechanism is provided above the first laser rangefinder. The center mark of the three Z-axis adjustment components is the origin. The synchronous moving mechanism is used to control the first laser rangefinder to move along the origin and the direction of the corresponding Z-axis adjustment component. The synchronous moving mechanism includes three first lead screw modules distributed in a circle. One end of the first lead screw module points vertically to the vertical line where the origin is located, and the other end of the first lead screw module points vertically to the vertical line where the corresponding ball head is located. A third servo motor for driving the lead screw inside the first lead screw module to rotate is fixedly installed on the outside of the first lead screw module. The three first laser rangefinders are respectively fixedly connected to the nut seats inside the three first lead screw modules.

[0011] Preferably, a first bevel gear is rotatably mounted between the three first lead screw modules, and a second bevel gear that meshes with the first bevel gear is fixedly mounted on the end of the lead screw in each of the three first lead screw modules.

[0012] Preferably, the deflection mechanism includes a bearing seat, and a rotating shaft is rotatably mounted on the bearing seat. A connecting frame is fixedly mounted on one end of the rotating shaft. A second laser rangefinder is fixedly mounted on the connecting frame. A fourth servo motor for driving the rotating shaft to rotate is fixedly mounted on the bearing seat. An angle sensor for detecting the rotation angle of the rotating shaft is fixedly mounted on the bearing seat.

[0013] Preferably, a first gear is fixedly mounted on the rotating shaft, a second gear that meshes with the first gear is rotatably mounted on the shaft seat, a worm gear that is coaxially fixedly connected to the second gear is rotatably mounted inside the shaft seat, and a worm that meshes with the worm gear is fixedly mounted on the drive shaft of the fourth servo motor.

[0014] Preferably, the horizontal and vertical adjustment mechanism includes a cross groove vertically and horizontally intersecting at the top of the adsorption platform. A second lead screw module is fixedly installed horizontally on both sides of the cross groove. A fifth servo motor for driving the lead screw within the second lead screw module is fixedly installed on the outside of the second lead screw module. A first Bernoulli suction cup is fixedly installed on the nut seat within the second lead screw module. A third lead screw module is fixedly installed vertically on both the front and rear sides of the cross groove. A sixth servo motor for driving the lead screw within the third lead screw module is fixedly installed on the outside of the third lead screw module. A second Bernoulli suction cup is fixedly installed on the nut seat within the third lead screw module. The tops of the first and second Bernoulli suction cups are flush with the top of the adsorption platform. Both the first and second Bernoulli suction cups are externally connected to an air pump.

[0015] Preferably, a third bevel gear is rotatably mounted at the center of the cross groove, and a fourth bevel gear that meshes with the third bevel gear is fixedly mounted on the end of the lead screw in each of the two second lead screw modules. A drive shaft is coaxially fixedly connected between the ends of the lead screws in the two third lead screw modules, and the drive shaft is positioned above the third bevel gear.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, by setting three high-precision first laser rangefinders and three independent controllable Z-axis adjustment components, a closed-loop feedback adjustment can be formed, enabling the device to actively and in real time measure the gap between the upper and lower substrates at different support points and quickly drive the floating platform to adjust its attitude. This can greatly shorten the time required for leveling the upper and lower substrates and effectively improve the leveling accuracy and gap control accuracy. At the same time, by setting two mutually perpendicular second laser rangefinders on the side for measurement and embedding the horizontal and vertical adjustment mechanism in the top of the adsorption platform, the device can automatically perform rapid and accurate alignment adjustment after the upper and lower substrates are leveled. This not only saves the manufacturing cost of the mask but also improves the effective utilization rate of the wafer, reducing the chip production cost to a certain extent and laying the foundation for high-quality photolithography. 2. In this invention, by providing spring elastic support at the bottom of the lifting platform, the tooth backlash between the lead screw and the nut seat during the lifting adjustment of the Z-axis adjustment component can be offset, which is beneficial to improving the accuracy of height adjustment. At the same time, by providing a second servo motor to drive multiple lead screws to rotate synchronously, the preload of the springs can be adjusted uniformly by the cooperation of the lead screws and the nut seat. Thus, the elastic support strength of the springs on the lifting platform in this device can be precisely matched according to wafers of different sizes, thicknesses and weights, which is beneficial to further improve the accuracy and stability of the device in leveling the upper and lower substrates and controlling the gap. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a perspective view of the present invention; Figure 2 This is a top view of the present invention; Figure 3 For the present invention Figure 2 Sectional view at point AA; Figure 4 For the present invention Figure 2 Sectional view at point BB; Figure 5 This is a perspective view of the Z-axis adjustment assembly of the present invention installed between the base plate and the floating platform; Figure 6 This is a perspective view of the Z-axis adjustment component of the present invention; Figure 7 This is an exploded view of the Z-axis adjustment component of the present invention; Figure 8 This is a perspective view of the second servo motor and belt drive assembly of the present invention; Figure 9This is a perspective view of the first laser rangefinder and synchronous movement mechanism of the present invention; Figure 10 This is a perspective view of the second laser rangefinder and deflection mechanism of the present invention; Figure 11 This is an exploded view of the second laser rangefinder and deflection mechanism of the present invention; Figure 12 This is a perspective view of the horizontal and vertical adjustment mechanism of the present invention installed on the top of the adsorption platform; Figure 13 For the present invention Figure 12 Enlarged view of point C in the middle; Figure 14 This is a schematic diagram of the first laser rangefinder of the present invention measuring the distance to the top of the upper substrate; Figure 15 This is a schematic diagram of the first laser rangefinder of the present invention measuring the distance to the top of a small-sized upper substrate; Figure 16 This is a schematic diagram of the second laser rangefinder of the present invention measuring the distance between the edges of the upper and lower substrates; Figure 17 This is a schematic diagram showing the precise alignment of the lower substrate with the upper substrate after multiple horizontal and vertical adjustments according to the present invention.

[0018] In the picture: 1. Base plate; 2. Z-axis adjustment assembly; 21. Base; 22. Lifting platform; 23. Lead screw one; 24. First servo motor; 25. Nut seat one; 26. Ball joint unit; 261. Ball head; 262. Ball seat; 27. Spring; 28. Lead screw two; 281. Nut seat two; 282. Second servo motor; 283. Belt drive assembly; 3. Floating platform; 31. Adsorption platform; 32. Suction hole; 4. First laser rangefinder; 5. Synchronous moving mechanism; 51. First lead screw module; 52. Third servo motor; 53. First bevel gear; 531. Second bevel gear; 6. Second laser rangefinder; 7. Deflection mechanism; 71. Shaft seat; 72. Rotating shaft; 73. Connecting frame; 74. Fourth servo motor; 75. First gear; 751. Second gear; 752. Worm gear; 753. Worm; 76. Angle sensor; 8. Horizontal and vertical adjustment mechanism; 81. Cross groove; 82. Second lead screw module; 83. Fifth servo motor; 84. First Bernoulli suction cup; 85. Third bevel gear; 851. Fourth bevel gear; 86. Third lead screw module; 87. Sixth servo motor; 88. Second Bernoulli suction cup; 89. Drive shaft; 9. Upper base plate; 91. Lower base plate. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Example: This example provides an adaptive leveling device for substrates used in semiconductor photolithography production. See [link to example]. Figures 1-17 Specifically, the system includes a horizontally mounted base plate 1, with three Z-axis adjustment assemblies 2 arranged in a ring around the top of the base plate 1. A floating platform 3 is mounted on the upper end of each of the three Z-axis adjustment assemblies 2. Each Z-axis adjustment assembly 2 includes a base 21 fixedly mounted on the top of the base plate 1, and a lifting platform 22 connected to the base 21. A vertically mounted lead screw 23 is rotatably mounted on the base 21. A first servo motor 24 for driving the lead screw 23 to rotate is fixedly mounted on the base 21. A nut seat 25 threadedly connected to the lead screw 23 is fixedly mounted on the lifting platform 22. A ball joint unit 26 connects the lifting platform 22 and the floating platform 3, and the ball joint unit 26 includes components fixedly mounted on the lifting platform 22. The top ball head 261 and the ball seat 262 fixedly installed at the bottom of the floating platform 3 are connected to the outside of the ball head 261 by a ball joint. The top of the floating platform 3 is fixedly installed with an adsorption platform 31. An upper base plate 9 is provided above the adsorption platform 31. A lower base plate 91 is placed on the top of the adsorption platform 31. The top of the adsorption platform 31 has a plurality of evenly distributed suction holes 32, and the suction holes 32 are connected to an air pump. Three first laser rangefinders 4 are provided above the upper base plate 9. The three first laser rangefinders 4 are correspondingly set with three Z-axis adjustment components 2. The distance between the first laser rangefinders 4 and the base plate 1 is constant. The first laser rangefinders 4 are used to measure the distance between themselves and the upper base plate 9.

[0021] In this device, within the Z-axis adjustment assembly 2, the first servo motor 24 drives the lead screw 23 to rotate. Through the threaded connection between the nut seat 25 and the lead screw 23, and the limitation imposed by the lifting platform 22 on the nut seat 25, which can only move up and down, the nut seat 25 can drive the lifting platform 22 to adjust its height, thus flexibly adjusting the support height of the Z-axis adjustment assembly 2. The upper substrate 9 is positioned above the lower substrate 91. The upper substrate 9 is typically a photomask, and the lower substrate 91 is a wafer. The upper substrate 9 is mounted stably on the photolithography equipment. The three first laser rangefinders 4 are initially positioned in an equilateral triangle structure and mounted on the same horizontal plane. The centers of the three first laser rangefinders 4 and the centers of the three Z-axis adjustment assemblies 2 are on the same vertical line. The measurement error of the first laser rangefinders 4 is 0.25 μm. Using the principle of three points determining a plane, the plane containing the upper substrate 9 is positioned and measured. Then, by adjusting the height of the three Z-axis adjustment assemblies 2, the lower substrate 91 is automatically and quickly adjusted to be parallel to the upper substrate 9.

[0022] During this process, the external air pump is powered on and starts to evacuate air from the multiple evenly distributed suction holes 32. Through the principle of negative pressure adsorption, the lower substrate 91 can be stably attached to the top of the adsorption platform 31. Then, the three first laser rangefinders 4 measure the distances between themselves and the top of the upper substrate 9 as H1, H2, and H3, respectively. The real-time support heights of the three Z-axis adjustment components 2 are known and are recorded as Z1, Z2, and Z3. The distances between the three first laser rangefinders 4 and the base plate 1 are also known and are recorded as H. Therefore, by calculation, it can be found that in the real-time state, the distances between the upper substrate 9 and the lower substrate 91 on the vertical lines corresponding to the three Z-axis adjustment components 2 and the three first laser rangefinders 4 are P1, P2, and P3, respectively. (See reference...) Figure 14 As shown, taking the first Z-axis adjustment component 2 and its corresponding first laser rangefinder 4 as an example, the distance between the upper substrate 9 and the lower substrate 91 at this point is P1 = H - H1 - Z1. Similarly, P2 and P3 are calculated in sequence. By adjusting the height of the Z-axis adjustment component 2, the values ​​of P1, P2 and P3 can be adjusted in real time. Then, the average value of P1, P2 and P3 is calculated and recorded as ∆P. By adjusting the target values ​​of P1, P2 and P3 to be the same as ∆P, the lower substrate 91 can be adjusted from the initial state to the state parallel to the upper substrate 9.

[0023] After leveling the lower substrate 91 and the upper substrate 9, the tilt angle of the upper substrate 9 and the lower substrate 91 can be determined by using the principle of three points determining a plane. Then, with ∆P known, the vertical distance P′ between the upper substrate 9 and the lower substrate 91 can be calculated using trigonometric function formulas. Therefore, the gap between the upper substrate 9 and the lower substrate 91 can be fed back in real time by obtaining the value of ∆P. By synchronously adjusting the lifting and lowering of the three Z-axis adjustment components 2, the GAP value between the upper substrate 9 and the lower substrate 91 can be adjusted quickly and accurately. It should be noted that during the measurement and calculation process, the thickness span changes of structures such as the ball joint unit 26, the floating platform 3, the adsorption platform 31, and the upper substrate 9 and the lower substrate 91 in the tilted state in the vertical direction need to be considered. The thickness of these structures and their changes in the tilted state are used as known constants in the calculation, or their influence is incorporated into the system error compensation model through calibration. This can ensure the accuracy of the measurement reference and help guarantee the ultra-high precision of the final leveling and gap control results.

[0024] In the specific implementation process, such as Figure 2 and Figure 10 - Figure 11 As shown, a second laser rangefinder 6 is provided on the right side and rear of the adsorption platform 31, and a deflection mechanism 7 for controlling its up and down deflection is provided on the outside of the second laser rangefinder 6. The deflection mechanism 7 includes a bearing 71, and a rotating shaft 72 is rotatably mounted on the bearing 71. A connecting frame 73 is fixedly mounted on one end of the rotating shaft 72. The second laser rangefinder 6 is fixedly mounted on the connecting frame 73. A fourth servo motor 74 for driving the rotating shaft 72 to rotate is fixedly mounted on the bearing 71. An angle sensor 76 for detecting the rotation angle of the rotating shaft 72 is fixedly mounted on the bearing 71. The second laser rangefinder 6 is used to measure the distance between itself and the upper substrate 9 and the lower substrate 91.

[0025] In this device, after the lower substrate 91 and the upper substrate 9 are leveled, the alignment deviation between the lower substrate 91 and the upper substrate 9 in the right and rear directions can be measured by the corresponding second laser rangefinder 6. (See reference...) Figure 16As shown, taking the second laser rangefinder 6 on the right as an example, after leveling, the deflection mechanism 7 can control the second laser rangefinder 6 to deflect up and down for scanning measurement. During this process, the fourth servo motor 74 is powered on and starts, driving the rotating shaft 72 to rotate, which in turn drives the connecting frame 73 to deflect the second laser rangefinder 6 up and down. First, the second laser rangefinder 6 is used to measure the distance between itself and the edge of the upper substrate 9 in this direction as d1. Then, the second laser rangefinder 6 is used to measure the distance between itself and the edge of the lower substrate 91 in this direction as d2. The angle sensor 76 identifies d1 and d2. The included angle between 2 is ∠β. Then, the distance between the edges of the upper substrate 9 and the lower substrate 91 in this direction is calculated as d3 according to the trigonometric function formula. Again, according to the trigonometric function formula, the alignment distance between the edges of the upper substrate 9 and the lower substrate 91 in this direction is calculated as d. In the above way, the alignment difference between the upper and lower substrates 91 and the edge of the upper substrate 9 in the horizontal and vertical directions is quickly located. These real-time acquired alignment deviation data in the horizontal and vertical directions are transmitted to the control system and can be used as input commands for position compensation when driving the lower substrate 91 to perform horizontal and vertical adjustment.

[0026] In the specific implementation process, such as Figure 1 - Figure 3 and Figure 12 - Figure 13 As shown, a horizontal and vertical adjustment mechanism 8 is installed on the top of the adsorption platform 31. The horizontal and vertical adjustment mechanism 8 includes cross grooves 81 that are opened horizontally and vertically intersecting on the top of the adsorption platform 31. A second lead screw module 82 arranged horizontally is fixedly installed on the left and right sides of the cross groove 81. A fifth servo motor 83 for driving the lead screw in the second lead screw module 82 is fixedly installed on the outside of the second lead screw module 82. A first Bernoulli suction cup 84 is fixedly installed on the nut seat in the second lead screw module 82. A third bevel gear 85 is rotatably installed at the center position in the cross groove 81. A fourth bevel gear 851 that meshes with the third bevel gear 85 is fixedly installed on the end of the lead screw in both second lead screw modules 82. The cross groove 81 is fixed on the front and rear sides. A third lead screw module 86 is fixedly installed vertically. A sixth servo motor 87 for driving the rotation of the lead screw inside the third lead screw module 86 is fixedly installed on the outside of the third lead screw module 86. A second Bernoulli suction cup 88 is fixedly installed on the nut seat inside the third lead screw module 86. A drive shaft 89 is coaxially fixedly connected between the ends of the lead screws inside the two third lead screw modules 86, and the drive shaft 89 is located above the third bevel gear 85. The tops of the first Bernoulli suction cup 84 and the second Bernoulli suction cup 88 are flush with the top of the adsorption platform 31. Both the first Bernoulli suction cup 84 and the second Bernoulli suction cup 88 are externally connected to air pumps. The horizontal and vertical adjustment mechanism 8 is used to control the horizontal and vertical movement adjustment of the lower substrate 91 along the top of the adsorption platform 31.

[0027] In this device, the alignment difference between the lower substrate 91 and the upper substrate 9 in the horizontal and vertical directions is calculated in real time by the second laser rangefinders 6 on the right and rear sides. Then, the device can adjust the horizontal and vertical movement of the lower substrate 91 along the top of the adsorption platform 31 through the horizontal and vertical adjustment mechanism 8 to actively align the lower substrate 91 with the upper substrate 9. During this process, the external air pump is started to supply air to the first Bernoulli suction cup 84 and the second Bernoulli suction cup 88 as needed. The high-speed airflow is ejected through the first Bernoulli suction cup 84 and the second Bernoulli suction cup 88, which can be used to... A high-speed airflow layer is formed at the bottom of the substrate 91. Under the Bernoulli effect, the first Bernoulli suction cup 84 or the second Bernoulli suction cup 88 can grasp the lower substrate 91 without contact. Since the tops of the first Bernoulli suction cup 84 and the second Bernoulli suction cup 88 are flush with the top of the adsorption platform 31, the lower substrate 91 is suspended above the adsorption platform 31 when the first Bernoulli suction cup 84 or the second Bernoulli suction cup 88 performs non-contact grasping of the lower substrate 91. This can avoid the lower substrate 91 from contacting and rubbing against the top of the adsorption platform 31 during the horizontal and vertical movement adjustment process.

[0028] During lateral adjustment, the first Bernoulli suction cup 84 performs non-contact gripping of the lower substrate 91. Then, the fifth servo motor 83 is powered on and starts, driving the second lead screw module 82 to operate. Based on the alignment difference d between the upper and lower substrates 91 and the upper substrate 9, the first Bernoulli suction cup 84 drives the lower substrate 91 to move laterally for adjustment. During longitudinal adjustment, the second Bernoulli suction cup 88 performs non-contact gripping of the lower substrate 91, and the non-contact gripping of the lower substrate 91 by the third lead screw module 86 is stopped. Then, the sixth servo motor 87 is powered on and starts, driving the third lead screw module 86 to operate. Based on the alignment difference d between the upper and lower substrates 91 and the upper substrate 9, the second Bernoulli suction cup 88 drives the lower substrate 91 to move longitudinally for adjustment.

[0029] See Figure 17 As shown, the lower substrate 91 is adjusted repeatedly in both the horizontal and vertical directions. Through this iterative process of "measurement → calculation → horizontal adjustment → measurement → calculation → vertical adjustment", usually only a few cycles are needed to make the edge alignment accuracy between the lower substrate 91 and the upper substrate 9 meet the process requirements. The operation is fast and accurate. After the alignment adjustment is completed, the gripping of the lower substrate 91 by the first Bernoulli chuck 84 and the second Bernoulli chuck 88 is disconnected, and the lower substrate 91 is stably adsorbed on the top of the adsorption platform 31 again using the suction hole 32, in preparation for subsequent photolithography exposure.

[0030] In the specific implementation process, such as Figure 4 - Figure 8As shown, a spring 27 is installed on the base 21, which is elastically supported at the bottom of the lifting platform 22. A vertically arranged lead screw 28 is rotatably installed on the base 21. A nut seat 281 is connected to the base 21 and threaded onto the outside of the lead screw 28. The spring 27 provides elastic support between the nut seat 281 and the lifting platform 22. A second servo motor 282 is fixedly installed in the middle of the base plate 1. The drive shaft of the second servo motor 282 is connected to the lead screw 28 in the three Z-axis adjustment components 2 by a belt drive assembly 283. In this device, the spring 27 provides elastic support for the lifting platform 22, which can offset the tooth backlash between the lead screw 23 and the nut seat 25 when the lifting platform 22 is adjusted, thus improving the accuracy of the Z-axis adjustment components 2 when adjusting the support height.

[0031] Meanwhile, in this device, by controlling the rotation of the second lead screw 28, and utilizing the threaded connection between the second nut seat 281 and the second lead screw 28, as well as the limitation that the second nut seat 281 can only be adjusted up and down, the device can flexibly adjust the preload of the spring 27 by adjusting the position and height of the second nut seat 281. This allows the preload of the spring 27 to be flexibly matched with the weight differences and precision requirements when processing wafers of different sizes. For example, when processing large and heavy wafers, the preload of the spring 27 can be appropriately increased by driving the second nut seat 281 upward, thereby providing more stable support and the ability to suppress minor vibrations. This helps to further ensure the accuracy of the device's height leveling. Furthermore, in this device, the second servo motor 282 synchronously drives the three second lead screws 28 to rotate through the belt drive assembly 283, which can realize the uniform and convenient adjustment of the preload of the spring 27 at the three support points.

[0032] In the specific implementation process, such as Figures 1-4 and Figure 9 As shown, a synchronous moving mechanism 5 is provided above the first laser rangefinder 4. The center mark of the three Z-axis adjustment components 2 is the origin. The synchronous moving mechanism 5 is used to control the first laser rangefinder 4 to move along the origin and the corresponding Z-axis adjustment component 2. The synchronous moving mechanism 5 includes three first lead screw modules 51 distributed in a circle. One end of the first lead screw module 51 points vertically to the vertical line where the origin is located, and the other end of the first lead screw module 51 points vertically to the vertical line where the corresponding ball head 261 is located. A third servo motor 52 for driving the lead screw inside the first lead screw module 51 to rotate is fixedly installed on the outside of the first lead screw module 51. A first bevel gear 53 is rotatably installed between the three first lead screw modules 51. A second bevel gear 531 that meshes with the first bevel gear 53 is fixedly installed on the end of the lead screw in each of the three first lead screw modules 51. The three first laser rangefinders 4 are respectively fixedly connected to the nut seats in the three first lead screw modules 51.

[0033] In this device, after the third servo motor 52 is powered on and started, it can drive the first lead screw module 51 to run, thereby driving the positions of the three first laser rangefinders 4 to be flexibly adjusted. During this process, the three first laser rangefinders 4 are always distributed in an equilateral triangle structure. By moving the first laser rangefinders 4, the device can adapt to leveling operations in cases where the lower substrate 91 is larger than the upper substrate 9.

[0034] See Figure 15 As shown, when the size of the upper substrate 9 is smaller than that of the lower substrate 91, and the projection area of ​​the upper substrate 9 on the horizontal plane does not cover the preset measurement point directly above the Z-axis adjustment component 2, the first laser rangefinder 4, located directly above the Z-axis adjustment component 2, cannot directly measure the distance H1 between the first laser rangefinder 4 and the upper substrate 9 at that point. In this case, the device controls the position of the first laser rangefinder 4 through the synchronous movement mechanism 5, moving the first laser rangefinder 4 to a point above the upper substrate 9. At this point, the point marked on the upper substrate 9 illuminated by the first laser rangefinder 4 is labeled 'a', and the distance between the first laser rangefinder 4 and the upper substrate 9 at this point is measured as h1′. Then, the first laser rangefinder 4 is moved to another point above the upper substrate 9. At this point, the point marked on the upper substrate 9 illuminated by the first laser rangefinder 4 is labeled 'b', and the distance between the first laser rangefinder 4 and the upper substrate 9 at this point is measured as h1″. The distance between the upper substrate 9 and the lower substrate 9 is then calculated. The height difference h between points a and b on plate 9 is h = h1′ - h1″, and the horizontal projection distance between points a and b is recorded as L1′. According to the trigonometric function formula, the local tilt angle ∠α of the surface of the upper plate 9 along the line connecting a and b is calculated. Since the movement of the first laser rangefinder 4 is controlled by the synchronous movement mechanism 5, the horizontal projection distance L1″ between the initial position of the first laser rangefinder 4 directly above the Z-axis adjustment component 2 and the position after the first laser rangefinder 4 has moved is known. Therefore, according to the trigonometric function formula, the height difference h1 between the corresponding position of the upper plate 9 directly above the Z-axis adjustment component 2 and the previously measured position can be calculated. Thus, the vertical distance H1 = h1′ - h1 between the corresponding position of the upper plate 9 directly above the Z-axis adjustment component 2 and the first laser rangefinder 4 can be calculated. With H1, Z1, and H known, P1, as well as the leveled ∆P and P′, can be calculated normally.

[0035] The above-mentioned structural configuration allows the device to flexibly project the measurement point onto the actual area of ​​the upper substrate 9 for sampling through the drive of the synchronous moving mechanism 5. Then, the measurement result is accurately converted back to the original theoretical position corresponding to the Z-axis adjustment component 2 through geometric relationships. This structural configuration can greatly expand the application range of the leveling device, making it compatible with masks and wafers of different sizes, which is beneficial to improving the versatility and efficiency of the device.

[0036] In the specific implementation process, such as Figure 10 and Figure 11 As shown, a first gear 75 is fixedly mounted on the rotating shaft 72, and a second gear 751 meshing with the first gear 75 is rotatably mounted on the shaft seat 71. A worm gear 752 coaxially and fixedly connected to the second gear 751 is rotatably mounted inside the shaft seat 71. A worm 753 meshing with the worm gear 752 is fixedly mounted on the drive shaft of the fourth servo motor 74. In this device, when the fourth servo motor 74 drives the second laser rangefinder 6 to deflect, the fourth servo motor 74 is energized and starts to drive the worm 753 fixedly connected to its drive shaft to rotate. The meshing of the worm 753 and the worm gear 752... The first gear 751 is driven to rotate, and then the meshing of the second gear 751 and the first gear 75 drives the rotating shaft 72 to rotate the connecting frame 73, providing power for the deflection adjustment of the second laser rangefinder 6. Through the meshing of the first gear 75 and the second gear 751, the rotating shaft 72 is not directly coaxially connected to the drive shaft of the fourth servo motor 74, which provides sufficient space for the installation of the angle sensor 76. At the same time, thanks to the self-locking meshing of the worm gear 753 and the worm wheel 752, the weight of the second laser rangefinder 6 can be prevented from interfering with the rotational accuracy of the rotating shaft 72.

[0037] Specifically, the working principle of this invention is as follows: First, the upper substrate 9 (mask) is fixed in the photolithography equipment, and the lower substrate 91 (wafer) is placed on the adsorption platform 31 and fixed by the adsorption hole 32. After the system is started, three first laser rangefinders 4 simultaneously measure the distances H1, H2 and H3 between themselves and three points on the upper surface of the upper substrate 9. Combined with the known laser rangefinder installation height H and the real-time heights Z1, Z2 and Z3 of the Z-axis adjustment components 2, the distances P1, P2 and P3 between the upper substrate 9 and the lower substrate 91 corresponding to the three points are calculated. The control system calculates the average distance ΔP based on the distance values ​​of the three points, and then drives three first servo motors 24 to adjust the heights of the three Z-axis adjustment components 2 respectively until P1=P2=P3=ΔP. At this time, the lower substrate 91 and the upper substrate 9 are parallel, and the gap is precisely controlled at the vertical distance P′ corresponding to ΔP. By synchronously adjusting the lifting and lowering of the three Z-axis adjustment components 2, the GAP value between the upper substrate 9 and the lower substrate 91 can be quickly and accurately adjusted.

[0038] After leveling and gap setting are completed, the second laser rangefinders 6 on the right and rear sides, driven by the deflection mechanism 7, emit lasers sequentially to measure the edges of the upper substrate 9 and the lower substrate 91. Using the triangulation principle, they calculate the lateral and longitudinal edge alignment deviations. The control system then instructs the lateral and longitudinal adjustment mechanisms 8 to operate: first, the first Bernoulli suction cup 84 activates, gripping the lower substrate 91 and slightly lifting it; the fifth servo motor 83 drives its lateral movement to compensate for the lateral alignment deviation. Subsequently, the first Bernoulli suction cup 84 releases, and the second Bernoulli... The suction cup 88 is activated and moves longitudinally to compensate for longitudinal alignment deviation. This process can be iterated rapidly until the alignment accuracy meets the requirements. Finally, all Bernoulli suction cups are closed, and the negative pressure of the suction hole 32 firmly adsorbs the lower substrate 91 again. The entire adaptive leveling and alignment process is completed, and the system is ready for photolithography exposure. Through the above operations, the device can realize a closed-loop control process of "three-point distance measurement - independent drive leveling - side scanning deviation measurement - non-contact horizontal and vertical deviation correction", effectively realizing active, real-time, and adaptive leveling and alignment operations for the upper and lower substrates.

[0039] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A substrate adaptive leveling device for semiconductor photolithography production, comprising a horizontally mounted base plate (1), characterized in that: The top of the base plate (1) is equipped with three Z-axis adjustment components (2) arranged in a ring. The upper ends of the three Z-axis adjustment components (2) are all equipped with a floating platform (3). The top of the floating platform (3) is fixedly equipped with an adsorption platform (31). An upper substrate (9) is provided above the adsorption platform (31). A lower substrate (91) is placed on the top of the adsorption platform (31). The top of the adsorption platform (31) is provided with a plurality of evenly distributed suction holes (32). The suction holes (32) are connected to an air pump. Three first laser rangefinders (4) are provided above the upper substrate (9). The three first laser rangefinders (4) are correspondingly arranged with the three Z-axis adjustment components (2). The distance between the first laser rangefinders (4) and the base plate (1) is constant. The first laser rangefinders (4) are used to measure the distance between them and the upper substrate (9). The Z-axis adjustment assembly (2) includes a base (21) fixedly installed on the top of the base plate (1), and a lifting platform (22) is connected to the base (21) for lifting. A vertically arranged lead screw (23) is rotatably installed on the base (21). A first servo motor (24) for driving the lead screw (23) to rotate is fixedly installed on the base (21). A nut seat (25) threaded to the lead screw (23) is fixedly installed on the lifting platform (22). A ball joint unit (26) is connected between the lifting platform (22) and the floating platform (3). The ball joint unit (26) includes a ball head (261) fixedly installed on the top of the lifting platform (22) and a ball seat (262) fixedly installed on the bottom of the floating platform (3). The ball seat (262) is ball-jointed to the outside of the ball head (261). A spring (27) is installed on the base (21) to provide elastic support to the bottom of the lifting platform (22). A vertically mounted lead screw 2 (28) is rotatably mounted on the base (21). A nut seat 2 (281) is vertically connected to the base (21), and the nut seat 2 (281) is threaded onto the outside of the lead screw 2 (28). The spring (27) provides elastic support between the nut seat 2 (281) and the lifting platform (22). A second servo motor (282) is fixedly mounted in the middle of the base plate (1), and a belt drive assembly (283) is connected between the drive shaft of the second servo motor (282) and the lead screw 2 (28) in the three Z-axis adjustment assemblies (2). By controlling the rotation of the lead screw 2 (28), By means of the threaded connection between the second nut seat (281) and the second lead screw (28), and the limitation that the second nut seat (281) can only be adjusted up and down, the substrate adaptive leveling device can adjust the preload of the spring (27) by adjusting the position height of the second nut seat (281), so that the preload of the spring (27) can be flexibly matched with the weight difference and precision requirements of wafers of different sizes during processing. The second servo motor (282) drives the three lead screws (28) to rotate synchronously through the belt drive assembly (283), so as to realize the uniform and convenient adjustment of the preload of the spring (27) at the three support points. A second laser rangefinder (6) is provided on the right side and rear of the adsorption platform (31), and a deflection mechanism (7) for controlling its up and down deflection is provided on the outside of the second laser rangefinder (6). The second laser rangefinder (6) is used to measure the distance between it and the upper substrate (9) and the lower substrate (91). A horizontal and vertical adjustment mechanism (8) is installed on the top of the adsorption platform (31), and the horizontal and vertical adjustment mechanism (8) is used to control the lower substrate (91) to move horizontally and vertically along the top of the adsorption platform (31). The horizontal and vertical adjustment mechanism (8) includes a cross groove (81) that is horizontally and vertically intersecting on the top of the adsorption platform (31). A second lead screw module (82) is fixedly installed on the left and right sides of the cross groove (81). A fifth servo motor (83) for driving the lead screw inside the second lead screw module (82) is fixedly installed on the outside of the second lead screw module (82). A first Bernoulli suction cup (84) is fixedly installed on the nut seat inside the second lead screw module (82). A third bevel gear (85) is rotatably installed at the center position of the cross groove (81). A fourth bevel gear (851) meshing with the third bevel gear (85) is fixedly installed on the ends of the lead screws in both second lead screw modules (82). 1) A third lead screw module (86) is fixedly installed on the front and rear sides of the inner side. A sixth servo motor (87) for driving the lead screw inside the third lead screw module (86) to rotate is fixedly installed on the outer side of the third lead screw module (86). A second Bernoulli suction cup (88) is fixedly installed on the nut seat inside the third lead screw module (86). A transmission shaft (89) is coaxially fixedly connected between the ends of the lead screws inside the two third lead screw modules (86). The transmission shaft (89) is located above the third bevel gear (85). The tops of the first Bernoulli suction cup (84) and the second Bernoulli suction cup (88) are flush with the top of the adsorption platform (31). Both the first Bernoulli suction cup (84) and the second Bernoulli suction cup (88) are connected to an external air pump.

2. The adaptive leveling device for a substrate used in semiconductor photolithography production according to claim 1, characterized in that: A synchronous moving mechanism (5) is provided above the first laser rangefinder (4). The center mark of the three Z-axis adjustment components (2) is the origin. The synchronous moving mechanism (5) is used to control the first laser rangefinder (4) to move along the origin and the corresponding Z-axis adjustment component (2). The synchronous moving mechanism (5) includes three first lead screw modules (51) distributed around it. One end of the first lead screw module (51) points vertically to the vertical line where the origin is located. The other end of the first lead screw module (51) points vertically to the vertical line where the corresponding ball head (261) is located. A third servo motor (52) for driving the lead screw inside the first lead screw module (51) to rotate is fixedly installed on the outside of the first lead screw module (51). The three first laser rangefinders (4) are respectively fixedly connected to the nut seats inside the three first lead screw modules (51).

3. The adaptive leveling device for a substrate used in semiconductor photolithography production according to claim 2, characterized in that: A first bevel gear (53) is rotatably mounted between the three first lead screw modules (51), and a second bevel gear (531) that meshes with the first bevel gear (53) is fixedly mounted on the end of the lead screw in each of the three first lead screw modules (51).

4. The adaptive leveling device for semiconductor photolithography production substrate according to claim 1, characterized in that: The deflection mechanism (7) includes a bearing seat (71), and a rotating shaft (72) is rotatably mounted on the bearing seat (71). A connecting frame (73) is fixedly mounted on one end of the rotating shaft (72). The second laser rangefinder (6) is fixedly mounted on the connecting frame (73). A fourth servo motor (74) for driving the rotating shaft (72) to rotate is fixedly mounted on the bearing seat (71). An angle sensor (76) for detecting the rotation angle of the rotating shaft (72) is fixedly mounted on the bearing seat (71).

5. The adaptive leveling device for a substrate used in semiconductor photolithography production according to claim 4, characterized in that: A first gear (75) is fixedly installed on the rotating shaft (72), a second gear (751) that meshes with the first gear (75) is rotatably installed on the shaft seat (71), a worm gear (752) that is coaxially fixedly connected to the second gear (751) is rotatably installed inside the shaft seat (71), and a worm (753) that meshes with the worm gear (752) is fixedly installed on the drive shaft of the fourth servo motor (74).

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