Baking equipment and clamp for improving baking time efficiency of photomask
By using a clamping fixture with a hollowed-out central area and peek material pin pillars for support, the problem of inconsistent temperature during photomask baking was solved, resulting in uniformity of photoresist and chromium layer adhesion and improved production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHENGDU ROADWAY OPTOELECTRONICS CO LTD
- Filing Date
- 2025-05-20
- Publication Date
- 2026-04-21
AI Technical Summary
In the existing technology, there is a problem of inconsistent temperature during the baking process of photomasks, which leads to uneven adhesion between the photoresist and the chromium layer, requiring two baking processes, which affects production efficiency and product quality.
A clamping fixture with almost the entire middle area is used to support the photomask by suspending it in the air, so that there is no clamp obstruction during baking, achieving uniform heating and eliminating the second Hard Bake baking process. Pin pillars made of peek material are used to support the edges of the photomask.
This method achieves uniform heating of the photomask, ensures uniform adhesion between the photoresist and the chromium layer, eliminates the need for a second baking process, and improves production efficiency and product quality.
Smart Images
Figure CN224152844U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of photomask preparation technology, specifically to a baking device and a fixture for improving the baking efficiency of photomasks. Background Technology
[0002] A photomask, also known as a photomask or photomask, uses quartz glass as a substrate. First, a layer of chromium metal is deposited on the quartz glass substrate. Then, photoresist is coated on the chromium layer to make it a photosensitive material. The designed circuit pattern is exposed to light by an electronic laser device. The exposed area is developed and etched onto the chromium metal to form a circuit pattern, which becomes a photomask master similar to an exposed film.
[0003] The traditional production process in photomask manufacturing is roughly as follows: Figure 1 As shown; Figure 1 This is a flowchart of the MASK production process.
[0004] exist Figure 1 In the current production process, the entire process requires two baking steps, each of which takes about 2 to 3 hours (including material handling and mounting / unmounting). This is generally used in panel manufacturing because of the large size of the mask and the large area occupied by the equipment. The baking equipment is integrated into the gluing equipment, and gluing cannot be carried out at the same time during the baking process.
[0005] The soft bake process is performed immediately after the photoresist is applied. The soft bake temperature and baking time are 95℃ / 1H. Its main function in the process is to remove the solvent in the photoresist, so that the applied photoresist can dry quickly and increase the adhesion between the photoresist and the substrate.
[0006] The Hard Bake (PDB) process is performed after photolithography and development. The PDB temperature and baking time are 110℃ / 2H. Its main functions in the process are: 1. To further eliminate solvents and water in the photoresist, increasing the adhesion between the photoresist and the substrate; 2. To eliminate the standing wave effect caused by laser reflection from the chromium layer back into the photoresist during photolithography. While the standing wave effect may affect the CD accuracy and resolution of the pattern, for micron-level design dimensions in the panel industry, the impact of the standing wave effect on non-critical layers is negligible.
[0007] Photoresist is a highly sensitive chemical material, generally composed of phenolic resin, photosensitive material, solvent (butyl acetate + xylene + cellulose acetate), and additives. After photoresist is coated onto the surface of the mask material, it has a certain tolerance range for baking temperature and time. Exceeding the maximum temperature and time limits may cause changes in the chemical properties of the photoresist, resulting in discoloration, peeling, and other phenomena after development. Insufficient baking temperature and time will lead to insufficient adhesion between the photoresist and the chromium layer, resulting in side etching during etching (the etching solution laterally erodes the chromium layer along the gap between the photoresist and the chromium layer).
[0008] For the baking process, masks of sizes below G6 require a fixture for both photoresist application and baking. Sizes below G6 include several dimensions such as 8096 / 80945 / 8092 / 7080 / 5280. Conventional fixture designs typically include openings in multiple areas for mounting positioning blocks and a central open section for easy loading and unloading. Therefore, baking the material on the fixture results in varying temperatures due to different areas being shielded by the fixture, typically around the four central rectangular openings and the 16 circular holes. This makes it impossible to achieve a uniform temperature across the entire sheet. Consequently, after baking, the photoresist solvent evaporates at different rates in different areas of the same material, leading to varying adhesion between the photoresist and the chromium layer.
[0009] In summary, the first soft bake cannot simultaneously ensure temperature uniformity between the fixture-shielded area and the cut-out area. Therefore, the temperature cannot be set too high, and the baking time cannot be too long; otherwise, the photoresist in the unshielded area will undergo chemical changes due to over-baking. Thus, the background process requires a second baking step after development. However, two baking steps result in a long baking time, consuming coating machine capacity and affecting raw material supply. Furthermore, baking after coating cannot ensure uniform heating of the entire substrate, leading to differences in adhesion between the photoresist and the chromium layer in different areas, and increasing delivery time and the number of defects. Utility Model Content
[0010] To address the shortcomings of existing technologies, this invention aims to provide a baking device and a fixture for improving the baking efficiency of photomasks. This solution utilizes a clamp with a nearly entirely open central area to suspend and support the photomask, ensuring that the effective area of the mask is baked without obstruction by the clamp, resulting in uniform heating. This ensures that the adhesion of the photoresist and chromium layer is essentially consistent across different areas of the same material. Furthermore, by setting a higher temperature, the second Hard Bake (PDB) baking process can be eliminated.
[0011] This utility model is achieved through the following technical solution:
[0012] A fixture for improving the baking time of photomasks, comprising:
[0013] The clamping plate is hollow and frame-shaped;
[0014] The clamping plate has a number of pin pillars evenly distributed along its circumferential direction, and the pin pillars are used to support the circumferential edge of the photomask.
[0015] Compared to existing technologies, conventional photomask baking using mounting fixtures results in inconsistent temperatures across the entire photomask due to varying fixture coverage. This leads to uneven evaporation of photoresist solvent and varying adhesion between the photoresist and chromium layer in different areas of the same material after baking, necessitating a second baking process after development. This invention provides a fixture for improving the baking efficiency of photomasks. This solution uses a clamp with a nearly entirely open central section to suspend and support the photomask, ensuring unobstructed heating of the effective mask area during baking. This results in consistent heat distribution and uniform adhesion between the photoresist and chromium layer in different areas of the same material. Furthermore, by setting a higher temperature, the second Hard Bake (PDB) baking process can be eliminated. This fixture is primarily used for masks of sizes G6 and below. The specific design includes a plate-shaped clamp fixed in the first Soft Bake process. The clamp is frame-shaped and hollow in the center, with nearly 70% of its area open to minimize shading in the central area. Several pin pillars are evenly distributed around the circumference of the clamp, supporting the circumferential edges of the photomask, making it almost suspended. Therefore, during baking, because the clamp is hollow and the pin pillars only support the edges of the photomask, the photomask is almost completely unblocked, resulting in uniform heating. This ensures consistent adhesion of the photoresist and chromium layer across different areas of the same material, and allows for the elimination of the second Hard Bake (PDB) baking process by setting a higher temperature. Furthermore, the pin pillars are made of Peek material.
[0016] To further optimize the design and facilitate support for the photomask while limiting its displacement, the pin post has a stepped section on the side facing the hollow direction of the clamping plate. The edge of the photomask is positioned on the lower step of this stepped section. In this design, the edge of the pin post can be supported by placing it on the lower step of the stepped section, while the upper structure of the stepped section restricts the pin post to prevent the photomask from shifting.
[0017] To further optimize the design and facilitate adaptation to the size of the photomask, achieving an unobstructed effect, the clamping plate is rectangular; pin posts are provided at both ends of each of the four sides of the clamping plate. Since the pin posts are located at the ends of the four sides of the clamping plate, i.e., at the four corners, only the four corners of the photomask need to be supported, thus achieving stable support while exposing most of the baking area.
[0018] Further optimization, as another specific structure of the Pin post, the Pin post includes a large-diameter section and a small-diameter section arranged coaxially from bottom to top.
[0019] To further optimize the design, since the clamping plate is narrow on its long side, the pin on the long side of the clamping plate is made into a semi-cylinder to prevent the pin from protruding from the clamping plate.
[0020] To further optimize the process and facilitate the handling of the photomask during manual lifting, several rectangular slots are spaced apart along the circumferential direction on the inner side of the clamping plate. Additionally, stepped slots are provided at the four corners of the back of the clamping plate for secure connection with the lifting mechanism of the coating machine.
[0021] To further optimize the process and facilitate quick assembly and disassembly of the pin, the clamping plate has several threaded holes, through which the pin is threadedly connected to the clamping plate.
[0022] To further optimize the design and facilitate adjustment of the pin height, at least one shim is provided between the upper side of the clamping plate and the pin. In this design, one or more shims are provided between the pin and the clamping plate, thus allowing for adjustable pin step height by adding or removing shims, optimizing the levelness during adhesive application.
[0023] Further optimized for ease of handling, the clamping plate is made of aluminum alloy and features a surface treated with electroplating. The clamping plate can be made of high-strength aluminum alloy, achieving a clamp deformation of no more than 1mm even with a nearly 70% hollow area in the center. A clamping plate with dimensions of 1200*850*10mm (length*width*thickness) and a weight of less than 10Kg (approximately 70% hollow area) can be selected, facilitating personnel handling. Additionally, the electroplating treatment on the clamping plate surface protects against long-term corrosion from photoresist and chemicals such as acetone.
[0024] Further solutions:
[0025] This invention also provides a baking device, which includes a fixture for supporting the photomask during the baking process. In this solution, the baking device is primarily used in the first soft bake process; and the fixture is mainly used for masks of G6 size and below.
[0026] Compared with the prior art, this utility model has the following advantages and beneficial effects:
[0027] This invention provides a baking device and a fixture for improving the baking efficiency of photomasks. By using this solution, the photomask is suspended and supported by a clamp plate with almost all of its middle area hollowed out, so that the effective area of the mask is not blocked by the clamp during baking, and the heating is uniform. This makes the adhesion of photoresist and chromium layer in different areas of the same raw material basically consistent, and the second Hard Bake (PDB) baking process can be eliminated by setting a higher temperature. Attached Figure Description
[0028] To more clearly illustrate the technical solutions of the exemplary embodiments of this utility model, the drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this utility model and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:
[0029] Figure 1 A schematic diagram of the front structure of the clamping plate provided by this utility model;
[0030] Figure 2 A schematic diagram of the back structure of the clamping plate provided by this utility model;
[0031] Figure 3 Top view of the clamp provided by this utility model;
[0032] Figure 4 A bottom view of the clamp provided for this utility model.
[0033] The attached diagram shows the markings and corresponding component names:
[0034] 1-Clamping plate, 101-Rectangular through groove, 2-Pin post. Detailed Implementation
[0035] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.
[0036] Example 1:
[0037] This embodiment 1 provides a fixture for improving the baking time of photomasks, such as... Figures 1-4 As shown, it includes:
[0038] Clamping plate 1, which is hollow and frame-shaped;
[0039] A plurality of pin pillars 2 are evenly distributed along the circumferential direction of the clamping plate 1, and the plurality of pin pillars 2 are used to support the circumferential edge of the photomask.
[0040] Compared to existing technologies where conventional photomask baking using fixtures results in uneven temperatures in different areas due to fixture obstruction, this invention provides a fixture for improving the baking efficiency of photomasks. This fixture, with its nearly entirely open central section supporting the photomask, ensures consistent heating of the effective mask area during baking. This allows for a higher temperature setting, eliminating the need for a second Hard Bake (PDB) baking step. This fixture is primarily used for masks of sizes G6 and below. The specific design includes a plate-shaped clamp 1, which is fixed in the first Soft Bake process. The clamp 1 is frame-shaped and hollow in the center, with nearly 70% of its area open to minimize shading in the central area. Several pin pillars 2 are evenly distributed around the circumference of the clamp 1. These pin pillars support the circumferential edges of the photomask, making it almost suspended. Therefore, during baking, because the clamp 1 is hollow and the pin pillars 2 only support the edges of the photomask, the photomask is almost completely unblocked, resulting in uniform heating. This ensures consistent adhesion of the photoresist and chromium layer across different areas of the same material, and allows for the elimination of the second Hard Bake (PDB) baking process by setting a higher temperature. Furthermore, the pin pillars 2 are made of Peek material.
[0041] In some embodiments, to facilitate support of the photomask while limiting its displacement, the pin post 2 has a stepped section on the side facing the hollow direction of the clamping plate 1, and the edge of the photomask is used to rest on the lower step of the stepped section. In this embodiment, the edge of the pin post 2 can be placed on the lower step of the stepped section for support, while the upper structure of the stepped section can restrict the pin post 2 to prevent the photomask from shifting.
[0042] In some embodiments, to facilitate adaptation to the size of the photomask and achieve an unobstructed effect, the clamping plate 1 is rectangular; pin posts 2 are provided at both ends of the four sides of the clamping plate 1. Since the pin posts 2 are located at the ends of the four sides of the clamping plate 1, i.e., at the four corners of the clamping plate 1, only the four corners of the photomask need to be supported, thus achieving stable support while exposing most of the baking area.
[0043] In some embodiments, as another specific structure of the Pin post 2, the Pin post 2 includes a large-diameter section and a small-diameter section arranged coaxially from bottom to top.
[0044] In some embodiments, since the width of the clamping plate 1 on its long side is relatively narrow, the pin 2 located on the long side of the clamping plate 1 is in the form of a semi-cylinder to prevent the pin 2 from extending out of the clamping plate 1.
[0045] In some embodiments, to facilitate the handling of the photomask during manual lifting, a plurality of rectangular through slots 101 are sequentially spaced at intervals along the circumferential position on the inner side of the clamping plate 1. In addition, stepped slots are provided at the four corners of the back side of the clamping plate 1 for fixed connection with the lifting mechanism of the glue coating machine.
[0046] In some embodiments, to facilitate quick assembly and disassembly of the Pin post 2, the clamping plate 1 has several threaded holes, and the Pin post 2 is threadedly connected to the clamping plate 1 through the threaded holes.
[0047] In some embodiments, at least one shim is provided between the upper side of the clamping plate 1 and the pin 2 to facilitate adjustment of the height of the pin 2. In this solution, one or more shims are provided between the pin 2 and the clamping plate 1, so the height of the pin 2 step can be adjusted by increasing or decreasing the shims, thus optimizing the level during adhesive application.
[0048] In some embodiments, for ease of handling, the clamping plate 1 is made of aluminum alloy, and the clamping plate 1 has a surface treated by an electroplating process. The clamping plate 1 can be made of high-strength aluminum alloy, achieving a clamp deformation of no more than 1 mm even with a central hollow area of nearly 70%. A clamping plate 1 with dimensions of 1200*850*10 mm and a weight of less than 10 kg (with approximately 70% central hollow area) can be selected, thus facilitating personnel handling. Furthermore, the electroplating process on the surface of the clamping plate 1 protects against long-term corrosion from photoresist and chemicals such as acetone.
[0049] Example 2:
[0050] Based on Example 1, Example 2 also provides a baking device.
[0051] The baking equipment is equipped with a fixture for supporting the photomask during the baking process. In this solution, the baking equipment is mainly used in the first soft bake process; and the fixture is mainly used for masks of size G6 and below.
[0052] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A jig for enabling photo mask baking age-up, characterized by, include: The clamping plate (1) is hollow and frame-shaped; A plurality of pin pillars (2) are evenly distributed along the circumferential direction of the clamping plate (1), and the plurality of pin pillars (2) are used to support the circumferential edge of the photomask.
2. The fixture for implementing light mask baking aging promotion according to claim 1, wherein, The pin (2) has a stepped section on the side facing the hollow direction of the clamp (1), and the edge of the photomask is used to place on the lower step of the stepped section.
3. The fixture for implementing light mask baking age-uplift according to claim 1, wherein, The clamp (1) is square; pin posts (2) are provided at both ends of the four sides of the clamp (1).
4. The fixture for implementing light mask baking age-uplift according to claim 3, wherein, The pin column (2) includes a large-diameter section and a small-diameter section arranged coaxially from bottom to top.
5. The fixture for enabling photo mask bake age enhancement of claim 3, wherein, The pin post (2) located on the long side of the clamp (1) is a semi-cylinder.
6. The fixture for enabling photo mask bake age enhancement of claim 3, wherein, Several rectangular through slots (101) are spaced apart in sequence on the inner circumferential position of the clamp (1).
7. The fixture for improving the baking of a photomask according to any one of claims 1 to 6, wherein The clamping plate (1) has several threaded holes, and the pin (2) is threadedly connected to the clamping plate (1) through the threaded holes.
8. The fixture for improving the baking of a photomask according to any one of claims 1 to 6, wherein At least one gasket is provided between the upper side of the clamp (1) and the pin (2).
9. The fixture for improving the baking of a photomask according to any one of claims 1 to 6, wherein The clamp (1) is made of aluminum alloy and has a surface treated by electroplating.
10. A toasting apparatus characterised in that, The baking equipment is provided with a fixture for supporting the photomask during the baking process, and the fixture is the fixture described in any one of claims 1 to 6.