Wafer support device and method of using the same

Abstract

The present invention discloses a wafer support device comprising a support plate and a shield ring. The support plate is characterized by having a plurality of air holes formed therein. When the shield ring is coupled to the support plate, an exhaust passage is formed between the support plate and the shield ring. When the plurality of air holes supply air to the exhaust passage, a flowing air cushion is formed between the wafer and the support surface, thereby reducing friction between the wafer and the support surface. Furthermore, the present invention provides a method for using the wafer support device.

Description

Technical Field

[0001] The present invention relates to a wafer support device for use in a semiconductor manufacturing process, in particular to a wafer support device for use in a process chamber, and a method for using the wafer support device. Background Art

[0002] In certain semiconductor processes, such as chemical vapor deposition (CVD) or plasma-enhanced chemical vapor deposition (PECVD), a wafer is placed on a support plate in a semiconductor processing chamber and sequentially undergoes pre-treatment and deposition.

[0003] Regarding the support plate (i.e., the heating plate), Chinese patent application publication number CN102498558A discloses a support plate technology provided with a correction mechanism, which is equipped with multiple centripetal mechanisms to bring the central axis of the wafer closer to the central axis of the support plate. The centripetal mechanism can support the wafer at a distance above the plate surface, or the centripetal mechanism can place the wafer on the plate surface through appropriate operation. The centripetal mechanism is a movable pivot mechanism, which mainly moves the wafer by pressing the centripetal finger against the edge of the wafer to achieve the purpose of position correction. However, the centripetal mechanism or similar correction mechanisms have disadvantages. When the wafer is pushed, the friction between the bottom of the wafer and the plate surface will generate particles. It should be understood that non-reactive particles generated in the semiconductor processing chamber are harmful to the effect of the process. Although the particles are generated at the bottom of the wafer, the convection in the chamber may still cause the particles to fall on the surface of the wafer or other components, increasing the risk of contamination.

[0004] Therefore, preventing or reducing the friction between the wafer and the disk during the wafer moving process is one of the problems to be solved in the art. Summary of the Invention

[0005] The present invention aims to provide a wafer support device and a method for using the wafer support device to reduce friction between the wafer and the carrying surface.

[0006] The present invention provides a wafer support device comprising: a support plate having a supporting surface and an upward surface, the supporting surface being configured to support a wafer and having a plurality of air holes formed therein, the upward surface surrounding the supporting surface; and a shielding ring coupled to the upward surface of the support plate and having a first downward surface and a covering portion, the covering portion being located at an inner edge of the shielding ring, and the first downward surface surrounding the covering portion. When the shielding ring is coupled to the upward surface of the support plate, an exhaust passage is formed between the upward surface of the support plate and the first downward surface of the shielding ring, such that when the plurality of air holes supply air to the exhaust passage, a flowing air cushion is formed between the wafer and the supporting surface to reduce friction between the wafer and the supporting surface.

[0007] Optionally, the upward surface of the support plate is higher than the bearing surface.

[0008] Optionally, a plurality of protrusions are formed on the carrying surface for supporting the wafer so that the bottom of the wafer does not cover the plurality of air holes.

[0009] Optionally, the wafer support device further includes: a sleeve ring, which is sleeved around the support plate, so that the shielding ring is coupled to the support plate through the sleeve ring and forms the exhaust channel.

[0010] Optionally, the collar has a downward surface and an upward surface. When the collar is sleeved on the support plate, the downward surface of the collar contacts the upward surface of the support plate, and the upward surface of the collar contacts the shielding ring.

[0011] Optionally, the shielding ring has a second downward surface, the second downward surface of the shielding ring surrounds the first downward surface of the shielding ring, and the second downward surface is higher than the first downward surface, so that the upward surface of the ring sleeved on the support plate contacts the second downward surface of the shielding ring.

[0012] Optionally, the collar has a gap, so that when the collar is sleeved on the support plate and contacts the shielding ring, the collar does not shield the exhaust passage due to the gap.

[0013] Optionally, the covering portion of the shielding ring extends downward and inward from the first downwardly facing surface, such that when the shielding ring is coupled to the support plate, the covering portion is sufficient to shield an outer edge of the wafer.

[0014] Optionally, when the shielding ring is coupled to the supporting plate, a gap is formed between the covering portion and the wafer, and the gap is connected to the exhaust channel, so that particles above the wafer can be discharged through the gap and the exhaust channel.

[0015] Optionally, there is an inclined surface between the supporting surface and the upward surface of the support plate, and a gap is formed between the inclined surface and the wafer, and the gap between the covering part and the wafer is smaller than the gap between the inclined surface and the wafer, thereby making the flowing air cushion mainly flow toward the plate air channel rather than flowing above the wafer.

[0016] The present invention also provides a method for using a wafer support device, the wafer support device comprising a support plate having a support surface and a plurality of air holes formed on the support surface. The method comprises: placing a wafer on the support surface of the support plate; moving the wafer using a mechanical alignment mechanism so that the center of the wafer is aligned with the center of the support plate; and supplying air through the plurality of air holes while moving the wafer to form a flowing air cushion between the wafer and the support surface, thereby reducing friction between the wafer and the support surface.

[0017] Optionally, an exhaust channel is provided around the wafer so that the flowing air cushion is exhausted to the periphery of the supporting plate through the exhaust channel, wherein the exhaust channel is formed when a shielding ring is coupled to the supporting plate.

[0018] Optionally, a spray assembly supplies gas downward to above the wafer, so that the particles above the wafer are exhausted to the periphery of the supporting plate through the exhaust channel together with the gas supplied downward.

[0019] Optionally, an annular channel is provided around the exhaust channel and is evacuated synchronously during the formation of the fluid cushion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a partial cross-sectional view showing a semiconductor processing chamber and the wafer support device of the present invention disposed therein.

[0021] Figure 2 It shows that the flowing air cushion provided by the wafer support device of the present invention flows toward the exhaust channel.

[0022] Figure 3 The downward supply gas from the spray assembly is shown flowing toward the exhaust channel. DETAILED DESCRIPTION

[0023] The present invention will be more fully described below with reference to the accompanying drawings, with specific exemplary embodiments shown by way of illustration. However, the claimed subject matter may be embodied in many different forms, and thus the construction of the claimed subject matter is not limited to any exemplary embodiment disclosed herein; the exemplary embodiments are merely illustrative. Similarly, the present invention is intended to provide a reasonably broad scope for the claimed subject matter.

[0024] The use of the phrase "in one embodiment" in this specification does not necessarily refer to the same embodiment, and the use of the phrase "in other (some) embodiments" in this specification does not necessarily refer to different embodiments. For example, the claimed subject matter includes combinations of all or part of the exemplary embodiments.

[0025] Figure 1A partial cross-sectional view of a semiconductor processing chamber and a wafer support apparatus of the present invention is shown. Although the complete cross-section of the processing chamber is not shown, it should be sufficient for those skilled in the art to understand the complete configuration based on symmetry.

[0026] The semiconductor processing chamber includes a cavity consisting of a side wall 1, a bottom 2 and a spray assembly 3 connected to one or more gas sources. A liner 4 is provided on the inner side of the side wall 1, and an annular channel 5 for exhaust is formed between the liner 4 and the side wall 1. The annular channel 5 extends along the side wall 1 and is fluidically connected to an exhaust system (omitted and not shown). The liner 4, the upward surface of the bottom 2 and the bottom of the spray assembly 3 (such as a spray plate) together define a chamber space, which is fluidically connected to the annular channel 5 via a plurality of exhaust holes 41 on the liner 4. Thereby, the gas supplied downward by the spray assembly 3 can be discharged out of the cavity through these exhaust holes 41 and the annular channel 5.

[0027] The wafer support device of the present invention is installed in the chamber space to support the wafers to be processed. It primarily comprises a tray 6 and support columns 7 extending downward from the bottom of the tray. Support columns 7 extend through the bottom 2 and connect to a lifting system (not shown), enabling the wafer support device to move vertically and rotate horizontally.

[0028] The tray 6 has a support surface 61 for placing the wafer W and an upward surface 62 surrounding the support surface 61. In this embodiment, the upward surface 62 is higher than the support surface 61, but the present invention is not limited to this. Furthermore, an inclined surface 63 is provided between the support surface 61 and the upward surface 62 to facilitate the sliding of the wafer.

[0029] A plurality of air holes 64 are formed in the tray body 6 and extend to the supporting surface 61. These air holes 64 are fluidically coupled to an air supply system (not shown) via air inlet channels 71 of the support columns 7. These air holes 64 are evenly distributed across the supporting surface 61 and spaced appropriately apart. The air holes 64 can be of uniform or non-uniform size to optimize the flow rate across the entirety of the air holes 64.

[0030] In this embodiment, a plurality of protrusions 65 are formed on the carrying surface 61 for contacting the bottom of the wafer W, so that a distance is formed between the bottom of the wafer W and the carrying surface 61 .

[0031] The wafer support device of the present invention also includes a shielding ring 8 coupled to the support plate 6. The shielding ring 8 is mainly used to shield the edge area of ​​the wafer W during the process to prevent the formation of a fragile film on the edge of the wafer W and to prevent it from peeling off and contaminating the environment in the cavity. In one embodiment, the shielding ring 8 is a replaceable component to meet the shielding requirements. In a certain embodiment, the shielding ring 8 can be a correction ring for limiting the position of the wafer W without a shielding function. In a possible embodiment, the shielding ring 8 can be combined with the correction mechanism described in the prior art, that is, the shielding ring 8 can have similar centripetal fingers for supporting the edge of the wafer W and moving it to the ideal position.

[0032] However, whether it is a shielding ring 8, a correction ring or a shielding ring 8 combined with a correction mechanism, in order to reduce the friction between the wafer W and the supporting surface 61 or the protrusion 65, the present invention not only proposes a flow air cushion but also includes an exhaust channel for the flow air cushion, thereby maintaining the stability of the flow air cushion.

[0033] The shielding ring 8 is coupled to the upward surface 62 of the support plate 6 via a sleeve ring 9. The sleeve ring 9 has a horizontal extension portion and a vertical extension portion, and is detachably mounted around the support plate 6. As shown in the figure, when the sleeve ring 9 is mounted on the outside of the support plate 6, the horizontal extension portion abuts against the upward surface 62 of the support plate 6, and the vertical extension portion covers the side of the support plate 6. The horizontal extension portion of the sleeve ring 9 provides a contact surface that is higher than the upward surface 62, and the shielding ring 8 is placed on the contact surface of the sleeve ring 9 and coupled to the upward surface 62 of the support plate 6. The contact surface of the sleeve ring 9 can provide a limiting structure to prevent the shielding ring 8 from shifting. When the shielding ring 8 is coupled to the support plate 6, an exhaust channel 81 is formed between the shielding ring 8 and the support plate 6. The sleeve ring 9 is formed with at least one notch 91 at a position corresponding to the exhaust channel 81 so that the exhaust channel 81 is not closed.

[0034] Figure 2 A partial enlarged view of the shield ring 8 and the direction of the air flow cushion are shown. The shield ring 8 is essentially a ring, with a flat top surface and an inner, downwardly sloping surface. Its bottom surface comprises one or more first downwardly facing surfaces 82, a second downwardly facing surface 83, and a covering portion 84. The second downwardly facing surface 83 surrounds and is higher than the first downwardly facing surface 82, while the covering portion 84 extends downwardly from the first downwardly facing surface 82. In other embodiments, the covering portion 84 may be omitted.

[0035] When the shadow ring 8 is coupled to the support plate 6 via the collar 9, the second downward-facing surface 83 abuts the horizontal extension of the collar 9, while the first downward-facing surface 82 is suspended above the upward-facing surface 62 of the support plate 6 due to the thickness of the horizontal extension of the collar 9, thereby forming the exhaust channel 81 between the support plate 6 and the shadow ring 8. The cover portion 84 is located above the edge of the wafer but does not press down on the wafer.

[0036] The exhaust channel 81 is essentially a flat, annular channel, but the present invention is not limited thereto. In other embodiments, the exhaust channel 81 may be composed of multiple independent, flat, arc-shaped channels. The inner end of the exhaust channel 81 is adjacent to the cover portion 84 and fluidically connects the space between the support surface 61 and the wafer. The outer end of the exhaust channel 81 is fluidically connected to the notch 91 of the collar 9.

[0037] like Figure 2 As shown, the fluid cushion P generates an upward support force on the wafer when the gas flow rate supplied by the air hole 64 reaches a certain level, but does not completely separate the wafer from the protrusion 65 or the plate surface. The fluid cushion P is flowing and will dissipate to the exhaust channels 81 on both sides and separate from the support plate 6 and be Figure 1 The exhaust ring 5 is used to exhaust the air out of the chamber. Therefore, those skilled in the art should understand that the fluid cushion P does not have a specific shape, but rather controls the flow rate to create a cushion-like effect. With the help of the fluid cushion P, friction between the wafer and the support surface 61 is reduced. The introduction of a wafer alignment mechanism can prevent particle generation. Even if particles are present at the bottom of the wafer, the fluid cushion P has a chance to remove them through the exhaust channel 81.

[0038] In the illustrated embodiment, the notch 91 of the collar 9 corresponds to the outer end of the exhaust channel 81, indicating a straight-through arrangement. However, the present invention is not limited thereto. In other possible embodiments, the notch 91 and the outer end of the exhaust channel 81 may be offset, meaning that there may be another section of the channel between the notch 91 and the exhaust channel 81.

[0039] In other embodiments where the supporting surface 61 does not have the protrusion 65 , even though the wafer blocks the air holes 64 , a fluid cushion P can be formed under the wafer by supplying gas with an appropriate flow rate.

[0040] The configuration of the present invention supporting the wafer also has further advantages. Figure 3 A partial enlarged view of the support ring 6 and shield plate 8 is shown, along with the downward airflow from the spray assembly (indicated by the arrows). In reality, a gap G1 exists between the cover portion 84 of the shield ring 8 and the wafer edge, allowing the downwardly supplied air to enter the exhaust duct 81 through gap G1. This airflow helps carry particles on the wafer surface to the wafer edge and even out through the exhaust duct 81, maintaining the cleanliness of the wafer surface.

[0041] On the other hand, there is another gap G2 between the wafer edge, the cover portion 84, and the inclined surface 63, but this gap G2 is larger than the aforementioned gap G1. Therefore, the airflow of the fluid cushion P still mainly enters the exhaust channel 81 rather than flowing over the wafer through the gap G1.

[0042] Based on the above configuration, the method for using the wafer support device of the present invention may include multiple steps, especially the process of placing the wafer on the support plate before performing the process. Step one, place a wafer on the supporting surface 61 of the supporting plate 6. Optionally, the wafer is transferred from the front end of the robot to a plurality of vertically movable support pins, and then the support pins are lowered to place the wafer on the supporting surface 61 or the protrusion 65. Step two, a mechanical correction mechanism is used to move the wafer so that the center of the wafer is aligned with the center of the supporting plate. Optionally, the shielding ring 8 is coupled to the supporting plate 6, and the shielding ring 8 may include a correction mechanism (centripetal finger) or other calibration means as in the prior art, so that the covering portion 84 can properly cover the edge of the wafer, but not contact it. Step three, while the wafer is being moved, air is supplied synchronously through the air hole 64 to form an outward flowing air cushion P between the wafer and the supporting surface 61, thereby reducing the friction between the wafer and the supporting surface. It should be understood that the gas holes 64 mainly supply non-reactive gas and the flow rate is selected to prevent the edge of the wafer from rubbing against the cover portion 84 of the shadow ring 8. Therefore, particles on the bottom of the wafer and the supporting surface 61 have the opportunity to be removed by the flowing air cushion P, ensuring the cleanliness of the wafer and the supporting plate 6.

[0043] In addition, during the cleaning step, the spray assembly 3 may supply gas downward to above the wafer, so that particles above the wafer are exhausted through the exhaust channel 81 together with the gas supplied downward.

[0044] Preferably, the annular channel 5 is arranged at the same height as or close to the exhaust channel 81 , and the annular channel 5 is simultaneously exhausted while the air holes 64 are supplying air.

Claims

1. A wafer support device provided with an air cushion, characterized in that: The invention comprises: a supporting plate having a carrying surface and an upward surface, the carrying surface being used to carry a wafer and being formed with a plurality of air holes, the upward surface surrounding the carrying surface; and a shielding ring coupled to the upward surface of the supporting plate and having a first downward surface and a covering portion, the covering portion being located at an inner edge of the shielding ring, and the first downward surface surrounding the covering portion, wherein when the shielding ring is coupled to the upward surface of the supporting plate, an exhaust channel is formed between the upward surface of the supporting plate and the first downward surface of the shielding ring, so that when the plurality of air holes supply air to the exhaust channel, a flowing air cushion is formed between the wafer and the carrying surface to reduce friction between the wafer and the carrying surface; The wafer support device further comprises a sleeve ring which is sleeved around the support plate, so that the shielding ring is coupled to the support plate through the sleeve ring and forms the exhaust channel; The ring has a notch, so that when the ring is placed on the support plate and contacts the shielding ring, the ring does not shield the exhaust channel due to the notch; when the shielding ring is coupled to the support plate, a gap is formed between the covering portion and the wafer, and the gap is connected to the exhaust channel, so that particles above the wafer can be discharged through the gap and the exhaust channel.

2. The wafer support device according to claim 1, wherein: The upward surface of the support plate is higher than the bearing surface.

3. The wafer support device according to claim 1, wherein: The carrying surface is formed with a plurality of protrusions for supporting the wafer so that the bottom of the wafer does not cover the plurality of air holes.

4. The wafer support device according to claim 1, wherein: The collar has a downward surface and an upward surface. When the collar is sleeved on the support plate, the downward surface of the collar contacts the upward surface of the support plate, and the upward surface of the collar contacts the shielding ring.

5. The wafer support device according to claim 4, wherein: The shielding ring has a second downward surface, which surrounds the first downward surface of the shielding ring and is higher than the first downward surface, so that the upward surface of the ring sleeved on the support plate contacts the second downward surface of the shielding ring.

6. The wafer support device according to claim 1, wherein: The covering portion of the shadow ring extends downward and inward from the first downward-facing surface, such that when the shadow ring is coupled to the support plate, the covering portion is sufficient to shield an outer edge of the wafer.

7. The wafer support device according to claim 1, wherein: There is also an inclined surface between the supporting surface and the upward surface of the support plate, and a gap is formed between the inclined surface and the wafer, and the gap between the covering part and the wafer is smaller than the gap between the inclined surface and the wafer, thereby allowing the flowing air cushion to flow mainly toward the exhaust channel rather than flowing above the wafer.

8. A method for using the wafer support device according to claim 1, characterized in that: The method includes: placing a wafer on the supporting surface of the support plate; moving the wafer by a mechanical alignment mechanism so that the center of the wafer is aligned with the center of the supporting plate; and supplying air through the plurality of air holes during the movement of the wafer to form a flowing air cushion between the wafer and the supporting surface, thereby reducing friction between the wafer and the supporting surface; The wafer supporting device further includes a sleeve ring which is sleeved around the supporting plate, so that the shielding ring is coupled to the supporting plate through the sleeve ring and forms the exhaust channel.

9. The method of use according to claim 8, characterized in that: The method further comprises providing an exhaust channel around the wafer so that the flowing air cushion is exhausted to the periphery of the supporting plate through the exhaust channel, wherein the exhaust channel is formed when a shielding ring is coupled to the supporting plate.

10. The method of use according to claim 9, characterized in that: The method further comprises: supplying gas downward to the top of the wafer through a spray assembly, so that the particles above the wafer and the downwardly supplied gas are exhausted to the periphery of the supporting plate through the exhaust channel.

11. The method of use according to claim 9, characterized in that: The method further comprises providing an annular channel around the exhaust channel and synchronously exhausting air during the formation of the fluid air cushion.

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