Wafer supporting structure for baking

Abstract

The utility model relates to the technical field of semiconductor manufacturing, in particular to a wafer supporting structure for baking. The utility model provides a wafer supporting structure for baking, which can enable the side end supporting assembly and the middle supporting assembly to alternately support the lower surface of a wafer through a mode of arranging the side end supporting assembly, the lifting motor and the middle supporting assembly, thereby reducing the influence on the baking effect of the wafer caused by heat transfer blocking due to local shielding, and improving the baking quality of the wafer. The baking difference of the wafer is reduced; and 2, the side end supporting assembly lifts or sinks one side of the wafer, so that the wafer swings up and down during baking, the surface adhesive film flows and is redistributed through external force, the thickness uniformity of the adhesive film is improved, meanwhile, solvent steam is more easily diffused to the surface from the interior of the adhesive film, and the volatilization efficiency of the solvent steam is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor manufacturing, especially to a wafer support structure for baking. BACKGROUND

[0002] In the semiconductor chip manufacturing process, the wafer surface coating photoresist and subsequent baking process occupies a very key position. Among them, when the wafer enters the baking equipment, it needs to be accurately placed on a specific support structure, which is commonly known as a needle structure. This support structure is essential for the smooth development of the entire wafer baking process.

[0003] From the existing technology, there are single-sided or double-sided coating conditions for wafers. The traditional support structure supports the center of the wafer bottom, and at the same time, it uses control movement to achieve the wafer's approach or distance from the baking hot plate. However, since the needle directly contacts the wafer surface, it can damage the photoresist layer at the supported position. Once the photoresist layer is damaged, subsequent key process steps such as lithography and etching cannot be accurately implemented according to design requirements, ultimately affecting the performance and yield of the chip.

[0004] For example, the Chinese utility model patent with patent announcement number CN221486478U and announcement date 2024.08.06 discloses a needle support, wafer lifting mechanism, and process chamber. The structure includes a support, a needle mounting hole, a needle, and a lifting support.

[0005] The needle support, wafer lifting mechanism, and process chamber in the utility model patent have the following general structure and principles: the bottom of the multiple needles is fixedly installed in the corresponding needle mounting hole of the needle support, the top of the needle passes through the heating plate and extends above the heating plate to adjust the height of the wafer carried on the heating plate under the driving of the lifting support; the needle support is fixedly installed to the lifting support, and the installation height of the corresponding needle on the lifting support is adjusted to realize the leveling of the multiple needles, thereby achieving the leveling of the wafer.

[0006] However, the needle support, wafer lifting mechanism, and process chamber have at least the following two deficiencies in actual use, which is the technical problem to be solved by the utility model: 1. The long-term support of the needle on the wafer bottom blocks the heat transfer at the contact point position, affecting the baking effect; 2. When the wafer is baked in a horizontal and stationary state, the photoresist with high surface tension is not easy to spread on the wafer surface, resulting in discontinuous or uneven thickness of the film, affecting the wafer performance.

[0007] Therefore, based on the above, there is an urgent need for a new wafer support structure for wafer baking that can heat the wafer bottom surface support points and make the film more easily spread. UTILITY MODEL CONTENT

[0008] This utility model provides a wafer support structure for baking, which, by setting up a side support component, a lifting motor, and a middle support component, enables: 1. The side support component and the middle support component to alternately support the lower surface of the wafer, thereby reducing the impact of heat transfer obstruction caused by local shading on the wafer baking effect and reducing the baking difference of the wafer; 2. The side support component raises or lowers one side of the wafer, causing the wafer to swing up and down during baking, and the surface film to flow and redistribute through external force, thereby improving the thickness uniformity of the film, and at the same time, the solvent vapor can more easily diffuse from the inside of the film to the surface, improving the evaporation efficiency of the solvent vapor.

[0009] The technical solution adopted by this utility model to solve the above problems is: a wafer support structure for baking, including two side support components that are disposed opposite to each other on the mounting housing and pass through the heating plate on the mounting housing to support both sides of the wafer, a lifting motor disposed at the lower end of the side support components and causing the wafer to swing up and down by lifting / lowering one side of the wafer, and a central support component disposed on the mounting housing and passing through the middle of the heating plate and causing the wafer to move away from the side support components by lifting the wafer.

[0010] A further preferred technical solution is that the side support assembly includes a mounting rod disposed on the heating plate, a support base plate disposed on the mounting rod and used to support the bottom of the wafer, and a vertical plate disposed on the outside of the support base plate and used to limit the outer side of the wafer.

[0011] A further preferred technical solution is that the central support assembly includes a telescopic motor disposed within the mounting housing, a telescopic rod disposed at the output end of the telescopic motor and passing through the heating plate, and a contact portion disposed at the upper end of the telescopic rod and supporting the lower surface of the wafer.

[0012] A further preferred technical solution is that the contact portion includes a support plate disposed at the upper end of the telescopic rod.

[0013] A further preferred technical solution is that: the contact portion includes a plurality of extension arms disposed on the telescopic rod and extending toward a position away from the center of the wafer, a support rod disposed at the end of the extension arm and used to support the lower surface of the wafer, and the spacing between adjacent extension arms is the same.

[0014] A further preferred technical solution is that the contact portion further includes an arc-shaped sleeve disposed on the support rod and used to reduce the contact area with the wafer.

[0015] A further preferred technical solution is that the contact portion further includes a fixing groove disposed on the inner ring of the arc-shaped sleeve, a protruding rod disposed on the support rod and inserted into the arc-shaped sleeve, and an anti-detachment block disposed on the upper end of the protruding rod and used to engage the fixing groove.

[0016] A further preferred technical solution is that the extension arm is set horizontally.

[0017] A further preferred technical solution is that the end of the extension arm closer to the support rod is higher than the end farther from the support rod.

[0018] A further preferred technical solution is that: there are two lifting motors, and the two lifting motors drive the two side support components to lift / lower respectively, and the driving directions of the two lifting motors are opposite.

[0019] The beneficial effects of this utility model are:

[0020] The side support assembly and the middle support assembly alternately support the lower surface of the wafer, thereby reducing the impact of heat transfer obstruction caused by local shading on the wafer baking effect and reducing the temperature difference at the bottom of the wafer.

[0021] The side support component raises or lowers one side of the wafer, causing the wafer to swing up and down during baking. This external force causes the surface resist film to flow and redistribute, thereby improving the uniformity of the resist film thickness. At the same time, solvent vapor can more easily diffuse from the inside of the resist film to the surface, promoting convection inside the photoresist and improving the evaporation efficiency of the solvent vapor.

[0022] The side support assembly provides initial support for the wafer, positioning it in its initial position to facilitate wafer placement and reduce the possibility of wafer tipping. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the position of the present invention from a forward-looking angle.

[0025] Figure 2 This is a top-view diagram showing the position of this utility model.

[0026] Figure 3 This is a schematic diagram of the lifting motor raising one side of the wafer in this utility model.

[0027] Figure 4 This is a schematic diagram of the wafer on the lower side of the lifting motor in this utility model.

[0028] Figure 5 This is a schematic diagram of the central support component lifting the wafer in this utility model.

[0029] Figure 6 This is a schematic diagram showing the horizontal arrangement of the extension arm in this utility model.

[0030] Figure 7 This is a schematic diagram showing the inclined arrangement of the extension arm in this utility model.

[0031] Figure 8 This is a perspective view of the central support component lifting the wafer in this utility model.

[0032] Figure 9 This is a cross-sectional view of the arc-shaped sleeve in this utility model.

[0033] Figure 10 This is a cross-sectional view of the connection of the arc-shaped sleeve in this utility model.

[0034] Mounting housing (a), heating plate (b), wafer (c), ventilation system (d);

[0035] Side support assembly 1, lifting motor 2, middle support assembly 3;

[0036] Mounting rod 11, supporting base plate 12, vertical plate 13, telescopic motor 31, telescopic rod 32, contact part 33;

[0037] Support plate 331, extension arm 332, support rod 333, arc sleeve 334, fixing groove 335, protruding rod 336, anti-detachment block 337. Detailed Implementation

[0038] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

[0039] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc., mentioned or possibly mentioned in this specification are defined relative to the structure shown in the accompanying drawings. The terms "inner" and "outer" refer to the direction toward or away from the geometric center of a specific component, respectively. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0040] As attached Figures 1-10As shown, a wafer support structure for baking includes two side support components 1 that are disposed opposite to each other on a mounting housing a and pass through a heating plate b on the mounting housing a to support both sides of a wafer c; a lifting motor 2 disposed at the lower end of the side support components 1 and causing the wafer c to swing up and down by lifting / lowering one side of the wafer c; and a central support component 3 disposed on the mounting housing a and passing through the middle of the heating plate b and causing the wafer c to move away from the side support components 1 by lifting the wafer c.

[0041] In this embodiment, the baking machine mainly includes the mounting housing a, the heating plate b disposed above the mounting housing a, the exhaust system d covering the mounting housing a and located above the heating plate b, and a temperature control system and other auxiliary modules. The mounting housing a has a hollow shell structure to facilitate the installation of the heating plate b and other structures. The heating plate b is the main heating system, typically using resistance heating or induction heating, and can be made of hard anodized aluminum or micro-polished stainless steel. The heat source can be located inside the mounting housing a. The exhaust system d covers the heating plate b, creating a stable baking space for the wafer c and extracting solvent vapor above the wafer c. When the wafer c enters the baking machine, it needs to be placed on the baking wafer support structure, so that the wafer c is suspended on the heating plate b and does not directly contact the heating plate b.

[0042] Furthermore, two of the side support components 1 are disposed on the heating plate b and are disposed opposite to each other on both sides of the wafer c to support it. The main body material of the side support component 1 can be high-temperature resistant stainless steel or ceramic, and the contact part with the wafer c can be made of polyetheretherketone (PEEK) or ceramic to prevent scratching the back of the wafer c.

[0043] Furthermore, during the initial baking stage of the wafer c, a fluid photoresist is adhered to its surface. The purpose of baking is to remove the solvent from the photoresist, allowing the film to solidify. However, the uneven thickness of the photoresist film on the wafer c surface during static baking is mainly affected by the following factors: First, the inherent characteristics of the photoresist itself. High-viscosity photoresist flows slowly during coating, making it difficult to spread evenly, while low-viscosity photoresist results in a film that is too thin, failing to meet process requirements. Additionally, the surface tension of fluid photoresist makes it difficult to spread on the wafer surface, easily leading to discontinuous or uneven film thickness. Second, the flatness of the wafer surface. Although minor defects on the wafer c surface do not affect wafer performance, these defects are amplified after photoresist coating, resulting in uneven film thickness. The lifting motor 2 can reduce the problem of uneven film baking caused by baking in a static state by driving the wafer c to swing slightly up and down during baking. The advantages of the lifting motor 2 are mainly reflected in the following aspects: First, external force allows the photoresist to flow and redistribute more fully on the wafer surface under the combined action of gravity and centrifugal force, which helps the photoresist flow from thick areas to thin areas, thereby improving the uniformity of the film thickness. However, the amplitude, frequency, or speed must be controlled to avoid photoresist being thrown out or accumulating. Second, the up-and-down swing can increase the contact area and frequency between the wafer b surface and the air. On the one hand, it makes it easier for solvent vapor to diffuse from the inside of the photoresist to the surface and then into the surrounding air. On the other hand, it helps to break the boundary layer of solvent vapor on the wafer surface, allowing fresh air to contact the wafer surface more frequently and carry away the solvent vapor, thereby improving the evaporation efficiency. However, it is necessary to avoid swinging too violently or at too high a frequency, which could lead to an unstable flow state on the photoresist surface or excessively turbulent airflow around the wafer. The lifting motor 2 is disposed inside the mounting housing a, and the output end of the lifting motor 2 passes through the mounting housing a and the heating plate b and is connected to the bottom end of the side support assembly 1, thereby driving the side support assembly 1 to move up and down. The lifting motor 2 mainly operates during the initial baking stage, when the photoresist is in a flowing state. Appropriate oscillation can accelerate its spread. The oscillation duration can be determined according to the baking process, usually accounting for one-third of the total baking time. The oscillation speed should be relatively slow and uniform, and the oscillation amplitude should be controlled between ±0.5° and ±3°. After the photoresist has initially cured and set, oscillation should be minimized to avoid causing minor deformation or displacement of the formed pattern.

[0044] Finally, the central support component 3 is disposed in the middle of the heating plate b, and the central support component 3 is a retractable support structure. (See attached diagram) Figure 1 As shown, during the initial baking stage, the wafer c is horizontally supported by the side support component 1. At this time, the middle support component 3 is not in contact with the wafer c. When it is necessary to swing the wafer c up and down, as shown in the attached diagram... Figure 3 and attached Figure 4As shown, the lifting motor 2 drives the wafer c to swing up and down, so that the photoresist is further spread evenly. After spreading is completed, the wafer c is reset to the attached position. Figure 1 As shown in the diagram, the central support component 3 is then driven, as shown in the attached diagram. Figures 5-8 As shown, the central support component 3 supports the wafer c, ensuring that the wafer c does not contact the side support component 1. After baking, the wafer c falls back onto the side support component 1 for easy handling. The side support component 1 and the central support component 3 alternately support the wafer c, allowing for baking of the area shielded by the side support component 1, improving temperature distribution uniformity and enhancing the overall baking effect of the wafer c.

[0045] The side support assembly 1 includes a mounting rod 11 disposed on the heating plate b, a support base plate 12 disposed on the mounting rod 11 and used to support the bottom of the wafer c, and a vertical plate 13 disposed on the outside of the support base plate 12 and used to limit the outside of the wafer c.

[0046] In this embodiment, the mounting rod 11 is disposed on the heating plate b, the supporting base plate 12 supports the bottom of the wafer c near the side end, and the vertical plate 13 limits the side end of the wafer c. When the wafer c is placed on the supporting base plate 12, it can be positioned by the vertical plate 13. When the lifting motor 2 drives the wafer c to swing up and down, the vertical plate 13 can prevent the wafer c from tipping over to the sides due to gravity.

[0047] The central support assembly 3 includes a telescopic motor 31 disposed within the mounting housing a, a telescopic rod 32 disposed at the output end of the telescopic motor 31 and passing through the heating plate b, and a contact portion 33 disposed at the upper end of the telescopic rod 32 and supporting the lower surface of the wafer c.

[0048] In this embodiment, the telescopic motor 31 is disposed inside the mounting housing a, and the telescopic rod 32 passes through the heating plate b and is connected at both ends to the output end of the telescopic motor 31 and the bottom of the contact part 33, respectively. After the telescopic motor 31 is started, it drives the contact part 33 to approach and support the heating plate b.

[0049] The contact portion 33 includes a support plate 331 disposed at the upper end of the telescopic rod 32.

[0050] In this embodiment, as shown in the appendix Figure 5 As shown, the support disk 331 is a circular or rectangular disk structure that supports the bottom of the wafer c to achieve an alternating support effect.

[0051] The contact portion 33 includes a plurality of extension arms 332 disposed on the telescopic rod 32 and extending toward a position away from the center of the wafer c, and a support rod 333 disposed at the end of the extension arm 332 and used to support the lower surface of the wafer c, and the spacing between adjacent extension arms 332 is the same.

[0052] In this embodiment, the extension arm 332 extends from the center of the wafer c and supports the bottom of the wafer c through the support rod 333 located away from the center. The support rod 333 contacts the wafer c through multi-point support, which not only ensures the stability of the support for the wafer c but also reduces the contact area with the wafer c. The number of extension arms 332 is not less than three, and the support rods 333 are all equidistant from the center of the wafer c. This arrangement can distribute pressure and reduce thermal stress concentration.

[0053] The contact portion 33 also includes an arc-shaped sleeve 334 disposed on the support rod 333 and used to reduce the contact area with the wafer c.

[0054] In this embodiment, as shown in the appendix Figures 9-10 As shown, the upper surface of the arc-shaped sleeve 334 has an arc-shaped structure, which can further reduce the contact area with the wafer c and increase the support stability.

[0055] The contact portion 33 further includes a fixing groove 335 disposed on the inner ring of the arc-shaped sleeve 334, a protruding rod 336 disposed on the support rod 333 and inserted into the arc-shaped sleeve 334, and an anti-detachment block 337 disposed on the upper end of the protruding rod 336 and used to engage the fixing groove 335.

[0056] In this embodiment, the protruding rod 336 and the anti-detachment block 337 are integrally formed, and the arc-shaped sleeve 334 is engaged with the anti-detachment block 337 through the fixing groove 335. Other structures with anti-detachment functions can also be used. The arc-shaped sleeve 334 and the protruding rod 336 can be made of different materials to meet the requirements of the baking process.

[0057] The extension arm 332 is set horizontally.

[0058] In this embodiment, as shown in the appendix Figure 6 As shown, when the extension arm 332 is set horizontally, the reserved space between the wafer c and the heating plate b is less restricted, reducing interference between structures.

[0059] The end of the extension arm 332 closer to the support rod 333 is higher than the end farther away from the support rod 333.

[0060] In this embodiment, as shown in the appendix Figure 7As shown, when the extension arm 332 tilts to support the wafer c, the telescopic rod 32 has a small telescopic distance and better telescopic stability. Furthermore, each of the extension arms 332 lifts the wafer c away from the center in an octopus-like manner, resulting in better support stability.

[0061] There are two lifting motors 2, and the two lifting motors 2 drive the two side support components 1 to lift / lower respectively. The driving directions of the two lifting motors 2 are opposite.

[0062] In this embodiment, the lifting motor 2 can support only one side support component 1. In this case, one side support component 1 is fixedly mounted on the heating plate b, and the other side support component 1 is connected to the output end of the lifting motor 2 and passes through the heating plate b. However, this method lacks the swing stability of the wafer and requires space for the movement of the support base plate 12 during sinking. Preferably, two lifting motors 2 are provided, each connected to one of the two side support components 1. After the two lifting motors 2 are started, the wafer on the side support component 1 swings up and down, reducing the lifting space of the side support component 1. The bidirectional drive makes the swing effect of the wafer c better, which is beneficial for the uniform spread of photoresist.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of this utility model.

Claims

1. A wafer support structure for baking, characterized in that, The device includes two side support assemblies (1) that are mounted on the mounting housing (a) and pass through the mounting housing (a) to support both sides of the wafer (c); a lifting motor (2) that is located at the lower end of the side support assembly (1) and causes the wafer (c) to swing up and down by lifting / lowering one side of the wafer (c); and a central support assembly (3) that is mounted on the mounting housing (a) and passes through the middle of the heating plate (b) and causes the wafer (c) to move away from the side support assembly (1) by lifting the wafer (c).

2. The wafer support structure for baking according to claim 1, characterized in that, The side support assembly (1) includes a mounting rod (11) disposed on the heating plate (b), a support base plate (12) disposed on the mounting rod (11) and used to support the bottom of the wafer (c), and a vertical plate (13) disposed on the outside of the support base plate (12) and used to limit the outside of the wafer (c).

3. The wafer support structure for baking according to claim 1, characterized in that, The central support assembly (3) includes a telescopic motor (31) disposed in the mounting housing (a), a telescopic rod (32) disposed at the output end of the telescopic motor (31) and passing through the heating plate (b), and a contact portion (33) disposed at the upper end of the telescopic rod (32) and supporting the lower surface of the wafer (c).

4. The wafer support structure for baking according to claim 3, characterized in that, The contact part (33) includes a support plate (331) disposed at the upper end of the telescopic rod (32).

5. A wafer support structure for baking according to claim 3, characterized in that, The contact portion (33) includes a plurality of extension arms (332) disposed on the telescopic rod (32) and extending toward a position away from the center of the wafer (c), and a support rod (333) disposed at the end of the extension arm (332) and used to support the lower surface of the wafer (c), with the spacing between adjacent extension arms (332) being the same.

6. The wafer support structure for baking according to claim 5, characterized in that, The contact portion (33) further includes an arc-shaped sleeve (334) disposed on the support rod (333) and used to reduce the contact area with the wafer (c).

7. A wafer support structure for baking according to claim 6, characterized in that, The contact part (33) further includes a fixing groove (335) disposed on the inner ring of the arc sleeve (334), a protruding rod (336) disposed on the support rod (333) and inserted into the arc sleeve (334), and an anti-detachment block (337) disposed on the upper end of the protruding rod (336) and used to engage the fixing groove (335).

8. A wafer support structure for baking according to claim 5, characterized in that, The extension arm (332) is set horizontally.

9. A wafer support structure for baking according to claim 5, characterized in that, The end of the extension arm (332) closer to the support rod (333) is higher than the end farther away from the support rod (333).

10. A wafer support structure for baking according to claim 1, characterized in that, There are two lifting motors (2), and the two lifting motors (2) drive the two side end support components (1) to lift / sink respectively. The driving directions of the two lifting motors (2) are opposite.

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