Device for increasing thickness uniformity of photoresist coating
By using a temperature detection module in conjunction with a heating module in photomask processing, the photoresist is detected and heated in real time, which solves the problem of uneven photoresist thickness and improves the uniformity of mask layer thickness and process accuracy.
Patent Information
- Application Number
- CN202511401784.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-28
- Publication Date
- 2026-01-27
AI Technical Summary
In existing technologies, the thickness of photoresist varies significantly in different regions of the substrate, affecting the precision of the process.
A temperature detection module and a heating module are used together to detect the photoresist temperature in real time and perform precise heating to ensure uniform photoresist flow and thus control the uniformity of mask layer thickness.
By precisely controlling the photoresist temperature, the thickness uniformity and process accuracy of the mask layer were improved.
Smart Images
Figure CN121411071A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photomask processing technology, and specifically provides a device for increasing the uniformity of photoresist coating thickness. Background Technology
[0002] Photoresist coating is a crucial step in photomask production, aiming to form a temporary mask of uniform thickness on the substrate surface. Current technologies primarily rely on spin coating, which uses centrifugal force generated by rotation to spread the photoresist liquid onto the substrate surface. However, this method faces a significant challenge: during radial flow, the viscosity of the photoresist increases at its leading edge due to temperature decrease, and the liquid film thins accordingly. This combination results in substantial thickness variations in the mask layer across different areas of the substrate, affecting process accuracy. Summary of the Invention
[0003] This invention provides a device for increasing the uniformity of photoresist coating thickness, which solves the problem of large thickness deviations of the mask layer in different areas of the substrate, affecting the process accuracy.
[0004] The technical solution of the present invention is as follows:
[0005] An apparatus for increasing the uniformity of photoresist coating thickness includes a turntable, a temperature detection module, a controller, and several heating modules. The temperature detection module and the heating modules are respectively disposed on the upper side of the turntable. The turntable is used to fix a substrate and drive the substrate to rotate. The temperature detection module is used to detect the temperature of the photoresist at various points on the substrate. The temperature detection module and the heating modules are electrically connected to the controller. The heating modules are used to heat the photoresist at various points on the substrate according to the temperature signal detected by the temperature detection module.
[0006] In this design, a temperature detection module monitors the temperature of the photoresist on the substrate in real time, while a heating module heats the photoresist. The temperature detection and heating modules work together to achieve precise temperature control of the photoresist. Furthermore, both modules are positioned on the upper side of the turntable, ensuring the highest temperature at the top of the photoresist during heating, thus guaranteeing good flowability. Precise temperature control of the photoresist allows for control over the thickness of the mask layer formed on the substrate, resulting in a more uniform thickness and improved mask layer accuracy.
[0007] Preferably, the temperature detection module includes an infrared thermometer or an infrared thermal imager.
[0008] In this solution, an infrared thermometer or infrared thermal imager can detect the temperature of the photoresist in a non-contact manner, directly measuring the temperature of the top of the photoresist from above. This works in conjunction with the top-heating method of the heating module to improve the sensitivity of heating control.
[0009] Preferably, the heating module includes an infrared laser heater.
[0010] In this solution, an infrared laser heater is used for heating. Its advantages include the ability to heat a small area without causing the entire substrate to heat up, facilitating precise temperature control. For example, during heating, the infrared laser heater irradiates a fixed circular area. As the turntable rotates, only a ring-shaped area on the substrate is ultimately heated, preventing the entire substrate from being heated. Furthermore, because this solution heats from above, the direct target of heating is the photoresist, not the substrate itself, thus avoiding an overall temperature rise in the substrate.
[0011] Preferably, each heating module is distributed along the radial direction of the turntable, forming several concentric ring-shaped heating areas on the substrate.
[0012] In this solution, because the substrate rotates with the turntable, only radially distributed heating modules are needed to achieve full coverage of the substrate. This also allows for a wider range of heating modules, thus reducing costs. Therefore, this solution is the preferred option for cost control.
[0013] Preferably, a plurality of heating modules are arranged in a ring above the turntable, each heating module forming at least two rings of different diameters, and the center of each ring coincides with the axis of the turntable.
[0014] In this scheme, several heating modules arranged in a ring are provided above the turntable, and each heating module forms at least two heating rings of different diameters, with the center of each heating ring coinciding with the axis of the turntable.
[0015] Preferably, each heating ring includes the same number of heating modules, or each heating ring includes a different number of heating modules.
[0016] In this design, because the heating rings are coaxially arranged, the increasing spacing between heating elements on the same heating ring along the radial direction may affect the heating effect. Therefore, the number of heating modules on each heating ring can be reasonably set according to the actual heating conditions. For example, the third and fourth heating rings can have the same number of heating modules along the radial direction, while the fifth heating ring can have one more heating module to ensure heating effect.
[0017] Preferably, the heating temperature of each heating module in the same heating ring is the same.
[0018] In this solution, the heating modules in a heating ring all have the same heating temperature, thus ensuring that the heating effect of the heating area corresponding to the heating ring is uniform and controllable.
[0019] Preferably, the heating temperature of each heating module increases outward along the radial direction of the turntable.
[0020] In this scheme, as the photoresist spreads under the action of centrifugal force, the temperature of the photoresist will gradually decrease. Therefore, the heating temperature of the heating module increases outward along the radial direction of the turntable, which can ensure the temperature of the photoresist, thereby ensuring the flow of the photoresist and ensuring the uniform thickness of the mask layer.
[0021] Preferably, each heating module is arranged in an array on the upper side of the turntable.
[0022] The beneficial effects of this invention are:
[0023] This invention uses the combination of a temperature detection module and a heating module to precisely control the temperature of the photoresist, thereby controlling the flowability of the photoresist and making the mask layer formed by the photoresist more uniform in thickness. Attached Figure Description
[0024] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a schematic diagram of the structure of Embodiment 1;
[0026] Figure 2 This is a top view of the turntable and substrate in Embodiment 3;
[0027] Figure 3 This is a diagram showing the thickness distribution of the mask layer in traditional techniques.
[0028] Figure 4 This is a thickness distribution diagram of the mask layer obtained by the present invention.
[0029] The reference numerals in the above figures are as follows;
[0030] 1. Turntable; 2. Substrate; 3. Heating module; 4. Temperature detection module. Detailed Implementation
[0031] The technical solution of the present invention will be clearly and completely described in conjunction with the accompanying drawings and through specific embodiments of the present invention.
[0032] Example 1:
[0033] like Figure 1As shown in the figure, this embodiment provides a device for increasing the uniformity of photoresist coating thickness, including a turntable, a temperature detection module, a controller, and a heating module. The turntable is rotatably mounted, similar to existing turntables. A positioning groove for placing a substrate is provided on the top of the turntable. The substrate is placed in the positioning groove and rotates with the turntable. The shape of the positioning groove is the same as the shape of the substrate; for example, if the substrate is circular or square, the positioning groove is a corresponding circular groove or directional groove.
[0034] Both the temperature detection module and the heating module are located on the upper side of the turntable. For example, in existing spin coating processes, the top of the turntable is sealed with a cover. Therefore, the temperature detection module and the heating module can be located at the bottom of the cover.
[0035] The temperature detection module is located on the top of the turntable and can directly detect the temperature of the top of the photoresist. As the photoresist spreads on the top surface of the substrate, the bottom photoresist adheres to the top surface of the substrate, while the top photoresist flows. Therefore, directly monitoring the temperature of the top photoresist allows for a more accurate assessment of its flow properties.
[0036] The temperature detection module and the heating module are electrically connected to the controller, and the heating module can heat the device according to the temperature signal from the temperature detection module.
[0037] To improve temperature control at various points on the photoresist, multiple heating modules are set up. Each heating module heats different areas of the substrate, so that the photoresist in different areas of the substrate is heated differently, achieving the effect of precisely heating the photoresist in a certain area and improving heating accuracy.
[0038] The temperature detection module can use existing infrared thermometers or infrared thermal imagers.
[0039] If an infrared thermometer is used, because the infrared thermometer has a small detection range, multiple temperature detection modules can be set up to detect the temperature of the photoresist at various locations on the top of the substrate.
[0040] If an infrared thermal imager is used, its detection range is larger, and the temperature of the photoresist at various points on the top of the substrate can be detected by a single infrared thermal imager.
[0041] The heating module is located on the top of the turntable. During heating, the photoresist at the top is heated first. Combined with the temperature detection module located on the top, this improves the accuracy of temperature control.
[0042] The heating module is located on the top and heats the photoresist using a non-contact heating method. Existing infrared laser heating devices can be used. Infrared laser heating devices have the advantage of high heating precision.
[0043] When the heating module is heating, the turntable drives the substrate to rotate, so the heating range of the heating module falls on the substrate, forming a ring-shaped heating area as the substrate rotates.
[0044] Optionally, the turntable can be driven by a servo motor, which is electrically connected to the controller. The controller controls the heating module to heat intermittently based on the rotation speed of the servo motor, thus achieving the goal of heating a specified area on the substrate. For example, when the temperature detection module detects a point on the substrate with a low photoresist temperature, the heating module is activated when that point rotates to be directly under the heating module, heating the point. When the point moves away from being directly under the heating area, the controller shuts off the heating module, achieving a precise heating effect.
[0045] Each heating module is arranged along the radial direction of the turntable.
[0046] Along the radial direction of the turntable, the power of each heating module gradually increases to address the issue of photoresist gradually decreasing in temperature over time.
[0047] The controller can be a microcontroller or a PLC.
[0048] Example 2:
[0049] This second embodiment provides a device for increasing the uniformity of photoresist coating thickness. Unlike the first embodiment, the arrangement of the heating modules is different in this second embodiment.
[0050] The heating modules are grouped together, with each group of heating modules arranged in a ring to form a heating ring, and each heating ring includes at least two heating modules.
[0051] It should be noted that the heating ring refers to the arrangement of the heating modules, not a circular heating structure, but rather multiple heating modules arranged in a ring.
[0052] Each heating ring is concentrically arranged, and the center of each heating ring coincides with the rotation axis of the turntable.
[0053] The number of heating modules in two adjacent heating rings can be the same or different. However, the number of heating modules in the heating rings generally increases outwards along the radial direction of the turntable. Increasing the number of heating modules ensures the heating effect of the heating rings.
[0054] Within the same heating ring, all heating modules have the same power, resulting in the same heating temperature and making the heating effect of the heating ring more uniform and reliable.
[0055] When the substrate is circular, an edge heating ring can be installed, positioned corresponding to the edge of the substrate. To ensure the photoresist covers the entire substrate surface, an excessive amount of photoresist is dropped, with the excess flowing along the substrate edge to the turntable. The edge heating ring has a much higher heating power than other heating rings, thus melting the photoresist at the substrate edge and separating the mask layer formed on the substrate from the photoresist solidified on the turntable.
[0056] Example 3:
[0057] This third embodiment provides a device for increasing the uniformity of photoresist coating thickness. Unlike the first embodiment, the arrangement of the heating modules in this second embodiment is different.
[0058] like Figure 2 As shown, the heating modules in this third embodiment are arranged in an array. Figure 2 The circles arranged in the middle array represent the heating range of the heating module.
[0059] The arrangement can be a rectangular column or a circular array.
[0060] By using the technical solutions of Embodiment 1, Embodiment 2 or Embodiment 3 of the present invention to control the temperature of the photoresist, a more uniform thickness of the mask layer is obtained.
[0061] like Figure 3 As shown, Figure 3 The traditional solution shows a large variation in the thickness of the mask layer at different locations.
[0062] Figure 4 The mask layer obtained by temperature control according to this application shows that the thickness difference of the mask layer is smaller and the thickness of the mask layer is more uniform.
[0063] Figure 3 and Figure 4 The vertical axis represents the thickness value, and the horizontal axis represents the position coordinates corresponding to the substrate.
Claims
1. An apparatus for increasing the uniformity of photoresist coating thickness, characterized in that, The device includes a turntable (1), a temperature detection module (4), a controller, and several heating modules (3). The temperature detection module (4) and the heating modules (3) are respectively located on the upper side of the turntable (1). The turntable (1) is used to fix the substrate (2) and drive the substrate (2) to rotate. The temperature detection module (4) is used to detect the temperature of the photoresist at various points on the substrate (2). The temperature detection module (4) and the heating modules (3) are respectively electrically connected to the controller. The heating modules (3) are used to heat the photoresist at various points on the substrate (2) according to the temperature signal detected by the temperature detection module (4).
2. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 1, characterized in that, The temperature detection module (4) includes an infrared thermometer or an infrared thermal imager.
3. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 1, characterized in that, The heating module (3) includes an infrared laser heater.
4. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 1, characterized in that, Each heating module (3) is distributed along the radial direction of the turntable (1), forming several concentric ring-shaped heating areas on the substrate (2).
5. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 1, characterized in that, Several heating modules (3) arranged in a ring are provided above the turntable (1). Each heating module (3) forms at least two heating rings of different diameters, and the center of each heating ring coincides with the axis of the turntable (1).
6. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 5, characterized in that, Each heating ring includes the same number of heating modules (3), or each heating ring includes a different number of heating modules (3).
7. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 5, characterized in that, The heating temperature of each heating module (3) in the same heating ring is the same.
8. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 1, characterized in that, The heating temperature of each heating module (3) increases outward along the radial direction of the turntable (1).
9. The apparatus for increasing the uniformity of photoresist coating thickness according to claim 1, characterized in that, Each heating module (3) is arranged in an array on the upper side of the turntable (1).