A method for automatic compensation of the height of a stamp in a pad printing process

Abstract

The present application provides a kind of automatic stamp height compensation method in transfer printing process, the method is by using laser ranging device and multi-axis motion displacement table, the height value of different positions of the surface of substrate to be transferred and to be printed is measured in turn and is recorded in turn to form a relative height matrix, the vertical height displacement amount of one position in stamp calibration is combined with the height matrix obtained, so as to obtain the accurate height displacement amount required for stamp to transfer and print objects at different positions in the range of substrate;The present application is mainly used to improve the reliability of automatic transfer printing work, solve the failure problem of stamp pick-up and placement caused by the height fluctuation in the range of large area substrate to be transferred and to be printed.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of stamp height compensation method in automatic transfer printing process, including the design of related device and height compensation method, mainly for the optimization of automatic transfer printing operation process. BACKGROUND

[0002] The transfer printing technology based on polymer stamp is a kind of functional object from the original substrate surface to the target substrate assembly integration technology such as inorganic semiconductor, metal, oxide film or transistor, small size circuit, sensor and the like. With the more diverse types of these functional objects to be transferred printing, the structure is more complex, and the previous manual transfer printing operation is difficult to meet the consistency and efficiency of integration in parallel. Thus, automated transfer printing technology is the development trend of future batch processing transfer printing assembly.

[0003] The existing polymer stamp transfer printing technology is a kind of dry transfer printing technology, which mainly realizes the adhesion regulation between the functional object and the stamp and the substrate based on the rate-dependent theory. Its main principle is to use the viscoelastic properties of the polymer stamp, high-speed transfer (pick up), and low-speed printing (place). However, when using the polymer stamp to perform transfer printing operation on a large area substrate, due to the fact that the substrate is not absolutely flat in a large area, the height fluctuation can reach 10 to 40 microns. When the stamp performs global transfer printing operation on such uneven substrate surface, if the same drop height is used for operation, the stamp cannot form effective contact with the substrate surface in some areas of the substrate surface, so effective transfer and printing operation cannot be formed. SUMMARY

[0004] The present application provides a stamp height compensation method in the process of automatic transfer printing.

[0005] Technical scheme: The present application provides a stamp height compensation method in the process of automatic transfer printing, including the device design of automatic transfer printing equipment and the step design of stamp height compensation method implementation, wherein the device design of automatic transfer printing equipment includes: a first workbench YS with horizontal Y direction displacement, a stamp fixed platform ST provided on the first workbench YS, a first motion platform Z1 in vertical direction, a laser reflection type distance measuring sensor LS fixedly connected opposite to the stamp fixed platform ST, an image observation system VS coaxial with the stamp fixed platform ST and the first motion platform Z1 in vertical direction, a second motion platform Z2 independently moving in Z direction coaxial with the first motion platform Z1, a second workbench XS with horizontal X direction displacement, the second workbench XS is installed on a support SG, and the second workbench XS is provided with a to-be-transferred substrate fixed platform TS and a to-be-printed substrate fixed platform PS;

[0006] The step design of the stamp height compensation method includes:

[0007] Step 1: respectively place the first square substrate T1 and the second square substrate P1 on the substrate fixation platform TS and the substrate fixation platform PS, and invert the high polymer stamp STAMP fixed on the transparent glass surface and attach it on the stamp fixation platform ST;

[0008] Step 2: move the image observation system VS above the first square substrate T1 by displacement operation of the first workbench YS and the second workbench XS;

[0009] Step 3: move the laser reflection range sensor LS above the first square substrate T1 according to the horizontal fixed deviation of the laser reflection range sensor LS and the stamp fixation platform ST;

[0010] Step 4: divide the first square substrate T1 into several equal step regions according to the equal step value in the transfer process, and move the laser reflection range sensor LS to the first region position;

[0011] Step 5: measure the height value between the probe of the laser reflection range sensor LS and the adjacent divided regions of the transfer substrate according to the step value in the transfer process, and record it as H TL1 , H TL2 , …;

[0012] Step 6: move the stamp fixation platform ST to the first region position of the first square substrate T1, record the height value H TL0 of the sensor LS at this time, slowly lower the stamp until the stamp contacts the first square substrate T1, record the height value h TL0 of the sensor LS again, and restore the stamp to the initial height position;

[0013] Step 7: move the image observation system VS above the second square substrate P1 by displacement operation of the first workbench YS and the second workbench XS;

[0014] Step 8: move the laser reflection range sensor LS above the second square substrate P1 according to the horizontal fixed deviation between the laser reflection range sensor LS and the stamp fixation platform ST;

[0015] Step 9: divide the second square substrate P1 into several equal step regions according to the equal step value in the printing process, and move the laser reflection range sensor LS to the first region position of the printing substrate;

[0016] Step 10: According to the step value of the printing process, the laser reflection distance sensor LS is used to measure the height value between the probe of the laser reflection distance sensor LS and the adjacent divided area of the printing substrate and record it as H PL1 , H PL2 , …;

[0017] Step 11: The stamp fixing platform ST is moved to the first area position of the second square substrate P1, and the height value H PL0 of the sensor LS at this time is recorded. The stamp is slowly lowered until the stamp is in contact with the second square substrate P1, and the height value h PL0 of the sensor LS is recorded again. The stamp is restored to the initial height position.

[0018] Step 12: By calculation, the height compensation values of each area on the first square substrate T1 and the second square substrate P1 are H TLn - H TL1 and H PLn - H PL1 , respectively. The required height of the stamp fixing platform ST to be lowered for picking and placing the structure on the first square substrate T1 and the second square substrate P1 is H TL0 - h TL0 + H TLn - H TL1 and H PL0 - h PL0 + H PLn - H PL1 , respectively. When the stamp moves to the corresponding area of the first square substrate T1 or the second square substrate P1, the first motion stage Z1 is directly controlled according to the calculated height value to pick or place the required structure.

[0019] Further, the first workbench YS in the Y direction is driven by a linear motor and is positioned by a grating ruler with a precision better than 1 μm to form a closed loop motion.

[0020] Further, the second motion stage Z2 in the vertical direction is driven by a linear motor with a pulse precision better than 0.5 μm.

[0021] Further, the laser reflection distance sensor LS uses laser reflection distance measurement with a measurement precision better than 1 μm.

[0022] Further, the image observation system VS uses a monochromatic light source for illumination.

[0023] Further, the second motion stage Z2 in the vertical direction is driven by a linear motor with a pulse precision better than 1 μm.

[0024] Further, the second worktable XS with horizontal X direction displacement is driven by a linear motor and is provided with a grating ruler with a positioning precision of 1 μm to form a closed loop motion.

[0025] Further, the support SG is made of super flat material.

[0026] Further, the surfaces of the substrate fixing platform TS to be transferred and the substrate fixing platform PS to be printed are treated by super flat processing.

[0027] Further, in step 1, the total area of the first square substrate T1 and the second square substrate P1 is greater than 10 mm*10 mm.

[0028] Further, in step 1, the transparent glass for curing is made of JSG1 type high-transparency quartz sheet with a thickness of 1-2 mm.

[0029] Further, in step 1, the high-molecular stamp is made of polydimethylsiloxane material and is prepared by normal temperature curing with a thickness of 5-10 mm.

[0030] Further, in step 4 and step 9, the set equidistance step value is greater than 5 mm.

[0031] Further, in step 6 and step 11, the judgment basis for slowly lowering the stamp until the stamp is in contact with the substrate to be transferred is that the image observation system VS observes that the stamp is in contact with the currently underlying substrate to be transferred or printed and then the first motion table Z1 in the vertical direction is lowered by 10 μm.

[0032] Beneficial effects: by using the method of the present application, without changing the mechanism of the transfer printing technology, the surface of the substrate to be transferred and the substrate to be printed is divided into regions by periodic steps, the height fluctuation data of the substrate surface is quickly obtained, and the height drop value of the stamp pickup and placement at each position is compensated, the precision can reach the order of 1 μm, and the success rate of automatic transfer printing can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structural schematic view of the device design of the automatic transfer printing equipment in the stamp height compensation method in the automatic transfer printing process of the present application.

[0034] Figure 2 It is a structural schematic view of the step design of the stamp height compensation method in the stamp height compensation method in the automatic transfer printing process of the present application.

[0035] Figure 3 It is a structural schematic view of step 4 in the step design of the stamp height compensation method.

[0036] Figure 4A schematic diagram of step 6 in the design of the steps for implementing the seal height compensation method;

[0037] Figure 5 A schematic diagram of step 9 in the design of the steps for implementing the seal height compensation method;

[0038] Figure 6 A schematic diagram of step 11 in the design of the steps for implementing the seal height compensation method. Specific Implementation

[0039] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0040] This embodiment provides a method for compensating for stamp height during the automatic transfer printing process, such as... Figure 1 As shown, the various supporting devices are assembled, including:

[0041] The first worktable YS, with horizontal Y-direction displacement, is driven by a linear motor and positioned by a grating ruler with an accuracy of 1μm, forming a closed-loop motion. A stamp fixing platform ST, controlled by a vertical first motion stage Z1, is fixedly mounted on the first worktable YS. The first motion stage Z1 is driven by a linear motor with a single-pulse motion accuracy of 0.5μm. A laser reflective rangefinder LS, with a measurement accuracy of 1μm, is fixedly mounted 3cm offset from the center of the stamp fixing platform ST. An image observation system VS is mounted coaxially and perpendicularly to the stamp fixing platform ST. The illumination system of the image observation system VS uses a red monochromatic light source, and the image observation system VS is controlled by a vertical second motion stage Z2, which is driven by a linear motor with a pulse accuracy of 1μm. A super-flat support SG, made of grade 00 marble, is placed on the horizontal surface below the first worktable YS. A second worktable XS with horizontal X-direction displacement is installed on the support SG. The second worktable XS is driven by a linear motor and equipped with a grating ruler with an accuracy better than 1μm to form a closed-loop motion. The upper end of the second worktable XS is equipped with an ultra-flat substrate fixing platform TS and a substrate fixing platform PS made of 000-grade ultra-flat marble.

[0042] like Figure 2 As shown, the detailed steps for obtaining seal height compensation are as follows:

[0043] Step 1: Place one first square substrate T1 and one second square substrate P1 on the substrate fixation platform TS and the substrate fixation platform PS, respectively, wherein the first square substrate T1 is a silicon material with a size of 30 mm*10 mm, and the second square substrate P1 is a gallium arsenide material with a size of 30 mm*10 mm. Attach the polydimethylsiloxane stamp STAMP with a thickness of 5 mm on the surface of the JSG1 type high-transmittance quartz sheet with a thickness of 1.5 mm on the stamp fixation platform ST in an inverted manner;

[0044] Step 2: Move the image observation system VS to the top of the first square substrate T1 by displacement operation of the first workbench YS and the second workbench XS, and observe the surface of the first square substrate T1 through the image observation system VS;

[0045] Step 3: Move the laser reflection range sensor LS to the top of the first square substrate T1 according to the horizontal fixed deviation value of 30 mm between the laser reflection range sensor LS and the stamp fixation platform ST;

[0046] Step 4: Assuming that the step value of the transfer process is 10 mm, divide the first square substrate T1 into 3 equal step regions in the Y direction according to the step value, and move the laser reflection range sensor LS to the top of the first step region;

[0047] Step 5: According to the step value of 10 mm of the transfer process, use the laser reflection range sensor LS to sequentially measure the height values between the 3 divided regions on the transfer substrate and record them as H TL1 , H TL2 , and H TL3 ;

[0048] Step 6: Move the stamp fixation platform ST to the first region position of the first square substrate T1, record the height value H TL0 of the laser reflection range sensor LS at this time, slowly lower the stamp until the stamp contacts the first square substrate T1, record the height value h TL0 of the sensor LS again, and restore the stamp to the position where the height value of the laser reflection range sensor LS is H TL0 ;

[0049] Step 7: Move the image observation system VS to the top of the second square substrate P1 by displacement operation of the first workbench YS and the second workbench XS, and observe the surface of the first square substrate T1 through the image observation system VS;

[0050] Step 8: Move the laser reflection range sensor LS to the top of the second square substrate P1 according to the horizontal fixed deviation value of 30 mm between the laser reflection range sensor LS and the stamp fixation platform ST.

[0051] Step 9: Assuming the step value of the printing process is 15mm, the second square substrate P1 is divided into 2 equal step areas in Y direction according to the step value, and the laser reflection ranging sensor LS is moved to the top of the first equal step area;

[0052] Step 10: According to the step value of the transfer process, 10mm, the height values between the 2 divided areas on the printing substrate are measured in sequence using the laser reflection ranging sensor LS and recorded as H PL1 and H PL2 ;

[0053] Step 11: The stamp fixing platform ST is moved to the first area position of the substrate to be printed, and the height value H PL0 of the laser reflection ranging sensor LS at this time is recorded. The stamp is slowly lowered until the stamp is in contact with the substrate to be printed, and the height value h PL0 of the laser reflection ranging sensor LS is recorded again. The stamp is restored to the position where the height value of the laser reflection ranging sensor LS is H PL0 ;

[0054] Step 12: According to the height values above, the height compensation values of the 3 areas on the first square substrate T1 are calculated as 0, H TL2 - H TL1 and H TL3 - H TL1 , respectively. The height compensation values of the 2 areas on the second square substrate P1 are 0 and H PL2 -H PL1 , respectively. When the stamp picks up the required structure on the 3 different areas of the first square substrate T1, the accurate height that the stamp fixing platform ST needs to drop is H TL0 - h TL0 , H TL0 - h TL0 +H TL2 - H TL1 and H TL0 - h TL0 +H TL3 - H TL1 , respectively. When the stamp places the required structure on the 2 different areas of the second square substrate P1, the accurate height that the stamp fixing platform ST needs to drop is H PL0 - h PL0 and H PL0 - h PL0 +H PL2 - H TPL1 , respectively. When the stamp moves to the corresponding area of the first square substrate T1 or the second square substrate P1, the first motion platform Z1 directly controls the picking up or placing of the required structure according to the calculated height value.

[0055] The embodiments of the present application are described in detail above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

1. A method for compensating for stamp height during an automatic transfer printing process, characterized in that, This includes the design of the automatic transfer printing equipment and the design of the steps for implementing the stamp height compensation method. The device design of the automatic transfer printing equipment includes: A first worktable YS capable of horizontal Y-direction displacement and a second worktable XS capable of horizontal X-direction displacement are provided on the first worktable YS. The first worktable YS is provided with a stamp fixing platform ST, a first vertical motion stage Z1, a laser reflection range sensor LS opposite to and fixedly connected to the stamp fixing platform ST, an image observation system VS vertically coaxial with the stamp fixing platform ST and the first motion stage Z1, and a second motion stage Z2 that independently performs Z-direction coaxial movement with the first motion stage Z1. The second worktable XS is mounted on a support SG. The second worktable XS is provided with a substrate to be transferred fixing platform TS and a substrate to be printed fixing platform PS. The first square substrate T1 is configured as the substrate to be transferred, and the second square substrate P1 is configured as the substrate to be printed. The steps for implementing the seal height compensation method include: Step 1: Place the first square substrate T1 and the second square substrate P1 on the substrate to be transferred fixing platform TS and the substrate to be printed fixing platform PS respectively, and attach the polymer stamp STMP, which is cured on the transparent glass surface, upside down to the stamp fixing platform ST. Step 2: By displacing the first stage YS and the second stage XS, the image observation system VS is moved to directly above the first square substrate T1; Step 3: Based on the horizontal fixed deviation between the laser reflection range sensor LS and the stamp fixing platform ST, move the laser reflection range sensor LS to directly above the first square substrate T1; Step 4: Based on the equidistant step value during the transfer process, divide the first square substrate T1 into several equidistant step regions, and move the laser reflection ranging sensor LS to the first region position; Step 5: According to the step value of the transfer process, use the laser reflection range sensor LS to sequentially measure and record the height value between the probe of the laser reflection range sensor LS and the adjacent divided areas of the first square substrate T1. Step 6: Move the stamp fixing platform ST to the first area of ​​the first square substrate T1, record the height value of the laser reflection range sensor LS at this time, slowly lower the stamp until the stamp contacts the substrate to be transferred, record the height value of the laser reflection range sensor LS again, and restore the stamp to the initial height position. Step 7: By displacing the first stage YS and the second stage XS, the image observation system VS is moved directly above the second square substrate P1; Step 8: Based on the horizontal fixed deviation between the laser reflection range sensor LS and the stamp fixing platform ST, move the laser reflection range sensor LS to directly above the second square substrate P1; Step 9: Based on the equidistant step value during the printing process, divide the second square substrate P1 into several equidistant step regions, and move the laser reflection ranging sensor LS to the first region position of the second square substrate P1. Step 10: According to the step value of the printing process, use the laser reflection range sensor LS to measure and record the height value between the probe of the laser reflection range sensor LS and the adjacent divided areas of the second square substrate P1. Step 11: Move the stamp fixing platform ST to the first area of ​​the second square substrate P1, record the height value of the sensor LS at this time, slowly lower the stamp until the stamp contacts the second square substrate P1, record the height value of the laser reflection ranging sensor LS again, and restore the stamp to the initial height position. Step 12: Calculate the height compensation values ​​for each region on the substrate to be transferred and printed. When the stamp picks up the required structure on each region of the first square substrate T1, the precise height at which the stamp fixing platform ST needs to descend is based on the height compensation value of the corresponding region. When the stamp places the required structure on each region of the second square substrate P1, the precise height at which the stamp fixing platform ST needs to descend is based on the height compensation value of the corresponding region. When the stamp moves to the corresponding region of the first square substrate T1 or the second square substrate P1, control the first motion stage Z1 to pick up or place the required structure according to the precise height of the corresponding region.

2. The method for compensating for stamp height in the automatic transfer printing process according to claim 1, characterized in that, The first worktable YS with Y-direction displacement is driven by a linear motor and equipped with a grating ruler with an accuracy better than 1μm for positioning to form a closed-loop motion; The first motion stage Z1 in the vertical direction is driven by a linear motor with a pulse accuracy better than 0.5μm; The laser reflection ranging sensor LS uses reflective laser ranging, and its measurement accuracy is better than 1μm; The image observation system VS is illuminated by a monochromatic light source; The second motion stage Z2 is driven by a linear motor with a pulse accuracy better than 1μm; The second worktable XS, which has horizontal X-direction displacement, is driven by a linear motor and equipped with a grating ruler with an accuracy better than 1μm for positioning to form a closed-loop motion; The support SG is made of ultra-flat material; The surfaces of both the substrate-to-be-transfer-mounted platform TS and the substrate-to-be-printed-mounted platform PS are treated with an ultra-flat surface.

3. The method for compensating for stamp height in the automatic transfer printing process according to claim 1, characterized in that, In step 1, the total area of ​​the first square substrate T1 and the second square substrate P1 is greater than 10mm*10mm; The transparent glass used for curing is a JSG1 type high-transparency quartz sheet with a thickness of 1-2 mm; The polymer stamp STAMP is prepared by curing polydimethylsiloxane at room temperature, with a thickness of 5-10 mm.

4. The method for compensating for stamp height in the automatic transfer printing process according to claim 1, characterized in that, In steps 4 and 9, the set equidistant step values ​​are both greater than 5 mm.

5. The method for compensating for stamp height in the automatic transfer printing process according to claim 1, characterized in that, In steps 6 and 11, the basis for slowly lowering the stamp until it contacts the substrate to be printed or transferred is that the first motion stage Z1 in the vertical direction descends another 10 μm after the stamp contacts the substrate to be transferred or printed below, as observed by the image observation system VS.

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