Wafer preheating loading chamber and preheating method thereof

Abstract

The present invention discloses a wafer preheating loading chamber and a method for preheating the chamber. The chamber comprises an upper chamber for receiving processed wafers and a lower chamber for preheating wafers to be processed. The bottom of the lower chamber comprises a heat radiating plate and a heating plate. The heating plate is positioned above the heat radiating plate and is movable within the lower chamber, allowing the wafers carried by the heating plate to be moved between a preheating position and a receiving position.

Description

Technical Field

[0001] The present invention relates to a wafer loading chamber located before a wafer reaction chamber, in particular to a wafer loading chamber with preheating treatment and a preheating method thereof. Background Art

[0002] Semiconductor coating equipment requires the wafer to reach a certain temperature during the deposition reaction to deposit a film of satisfactory quality. To increase production capacity, existing semiconductor coating equipment places the wafer in a preheating loading chamber for preheating before it enters the reaction chamber for the deposition reaction.

[0003] Furthermore, to obtain thin films of various materials, the source involved in the deposition reaction is sometimes a liquid source, which can assume a gaseous state at specific temperatures and pressures. The loading chamber typically operates at ambient temperature and pressure, and some unreacted liquid source can diffuse into the chamber, releasing a small amount onto the surface of the deposited film. The residual liquid source, at ambient temperature and pressure, condenses on the inner walls of the chamber. This accumulated condensation can fall onto the surface of the processed wafer, causing defects.

[0004] Patent publication number CN104269369A discloses a wafer preheating device that uses two vacuum preheating chambers mounted on either side of a transfer chamber to preheat wafers before entering the processing chamber. Furthermore, preheating chambers with different structures are mounted at different locations according to different process flows to achieve wafer preheating.

[0005] Patent document publication number CN109786304A discloses a loading chamber in a wafer processing device, located between an atmospheric conveyor and a vacuum conveyor, and comprising two upper chambers (for receiving wafers after reaction processing) and two lower chambers (for preheating wafers before entering the reaction chamber). The upper and lower chambers each have a mechanism for heating the wafers. The lower chamber uses a heating plate and air flow to preheat the wafers, while the upper chamber uses chamber wall heating to maintain the wafer temperature.

[0006] In terms of preheating, the heating and insulation methods of the preheating loading chamber are one of the key factors affecting the wafer preheating efficiency. Therefore, there is a need to optimize the heating and insulation methods of such preheating loading chambers. Summary of the Invention

[0007] The present invention aims to provide a wafer preheating loading chamber and a preheating method thereof, so as to improve wafer preheating efficiency.

[0008] The wafer preheating loading chamber provided by the present invention comprises: an upper chamber, configured to receive a wafer after reaction processing, and formed by a top, a side wall, and a bottom; and a lower chamber, independent of the upper chamber and configured to preheat a wafer awaiting reaction processing, and formed by a top, a side wall, and a bottom. The bottom of the lower chamber comprises: a heat radiation plate; and a heating plate for heating the lower chamber, located above the heat radiation plate and capable of being raised and lowered within the lower chamber to move the wafer carried by the heating plate between a preheating position and a receiving position. The heating plate also comprises at least one gas channel for providing heated inert gas.

[0009] The beneficial effect of the wafer preheating loading of the present invention is that the heating plate has at least one gas channel for providing heated inert gas. During the wafer preheating process, the heated inert gas can heat the wafer quickly and evenly, and the setting of the heat radiation plate can reduce heat loss and reduce the chance of heat being transferred to the outside of the cavity.

[0010] Optionally, the top of the upper chamber has: a heating top plate, a peripheral portion of the heating top plate is connected to the side wall of the upper chamber; and a heat insulation plate located above the heating top plate to prevent heat from the upper chamber from being lost through the top.

[0011] Optionally, the surrounding portion of the heating top plate has a flange, and the side wall of the upper chamber has a shoulder. When the heating top plate is connected to the side wall of the upper chamber, a downward surface of the flange and an upward surface of the shoulder form an annular space, and the annular space accommodates a stainless steel ring and a polytetrafluoroethylene ring to block lateral heat loss of the upper chamber.

[0012] Optionally, the bottom of the lower chamber further includes: a base connected to the side wall of the lower chamber and such that the radiation plate is interposed between the heating plate and the base.

[0013] Optionally, the heating plate has an upper surface and a lower surface facing the heat radiation plate, and a plurality of bosses are formed on the upper surface of the heating plate for supporting the bottom of a wafer, and the height of the bosses is between 0.01 mm and 1.00 mm.

[0014] Optionally, the heating plate has an upper surface and a lower surface facing the heat radiation plate, and a plurality of gas outlets are formed on the upper surface of the heating plate for supplying the heated inert gas.

[0015] Optionally, the heating plate has an upper surface and a lower surface facing the heat radiation plate, and the upper surface of the heating plate is coated with aluminum nitride, silicon carbide or diamond carbon.

[0016] Optionally, the bottom of the lower chamber also includes a plurality of columns, and when the heating plate is located at the receiving position, the plurality of columns protrude from the heating plate to contact the bottom of the wafer, and when the heating plate is located at the preheating position, the plurality of columns retract into the heating plate to place the wafer on the heating plate.

[0017] In addition, the present invention also provides a preheating method for the wafer preheating loading chamber, comprising: using a robot to place the wafer to be reacted before entering a reaction chamber in the lower chamber; using a heating plate in the lower chamber to preheat the wafer to a target temperature; and using a robot to transfer the preheated wafer from the lower chamber to the reaction chamber.

[0018] Since the preheating method of the present invention adopts the wafer preheating loading chamber, its beneficial effects are not described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A cross section of the wafer preheating loading chamber of the present invention is shown.

[0020] Figure 2 for Figure 1 A partial enlargement of the image shows the structure of the upper chamber.

[0021] Figure 3 Schematic diagram of the boss on the upper surface of the heating plate.

[0022] Figure 4A and Figure 4B They are respectively a three-dimensional view and a cross-sectional view of the bottom of the lower chamber (the heating plate is in the access position).

[0023] Figure 5A and Figure 5B They are respectively a three-dimensional view and a cross-sectional view of the bottom of the lower chamber (the heating plate is in the preheating position).

[0024] Figure 6 A partial top view of the upper chamber is shown. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] The wafer preheating loading chamber described herein is a preheating chamber within a semiconductor processing apparatus. It can be a preheating chamber connected to a wafer transfer chamber, as disclosed in Patent Publication No. CN104269369A, or a preheating chamber connected between an atmospheric transfer device and a vacuum transfer device, similar to a load-lock chamber, as disclosed in Patent Publication No. CN109786304A. The preheating loading chamber of the present invention loads wafers about to enter a reaction chamber, as well as wafers after processing in the reaction chamber.

[0028] Figure 1 A cross-section of the wafer preheating loading chamber of the present invention is shown, primarily comprising an upper chamber 1 and a lower chamber 2, each operating independently of the other. Although not shown, each chamber has corresponding valves for wafer transfer and independent gas passages. The number of upper chambers 1 and lower chambers 2 is not limited to one; a pair of upper chambers 1 or a pair of lower chambers 2 is also feasible.

[0029] The upper chamber 1 is formed by a top, a sidewall, and a bottom. The top of the upper chamber 1 has a heat shield 11 and a heated top plate 12, while the sidewall and bottom of the upper chamber 1 are formed as an integral block 13. The upper chamber 1 also has a tray 14 for supporting wafers.

[0030] The heating plate 12 can be a roughly circular plate, with its lower surface serving as the top boundary of the space within the upper chamber 1. The heating plate 12 includes a heating coil, which heats the wafer W on the bracket 14 at the top of the upper chamber 1. A thermal insulation plate 11 covers the top of the heating plate 12 to prevent heat dissipation from above. The thermal insulation plate 11 can be made of polymer materials with low thermal conductivity and good mechanical properties, such as PEEK, THERMOBARRIER 200HP, or Vespel SP. The primary material for the heating plate 12 can be selected from metals with good weldability and good resistance to deformation, such as aluminum, nickel-chromium alloys, Hastelloy, and stainless steel.

[0031] Figure 2 for Figure 1A partial enlargement of the top structure of the upper chamber is shown. A peripheral portion of the heating top plate 12 has a flange 121, which extends radially outward from an outer vertical surface of the heating top plate 12. The flange 121 has a downward surface that is different from the lower surface of the heating top plate 12. The side wall of the upper chamber 1 is formed with a shoulder 131, which has an upward surface perpendicular to the inner surface of the side wall. When the heating top plate 12 is connected to the side wall of the upper chamber 1, the flange 121 of the heating top plate 12 corresponds to the position of the shoulder 131, so that the downward surface and the upward surface form an annular space.

[0032] As thermal resistors, a stainless steel ring 31 and a polytetrafluoroethylene ring 32 (hereinafter referred to as the PTFE ring) are placed within the annular space to prevent heat from the top heater plate 12 from dissipating laterally through the connection between the top heater plate 12 and the sidewall of the upper chamber 1, ensuring a sufficiently high temperature within the upper chamber 1. Consequently, when the high-temperature wafers after reaction are moved to the upper chamber 1, the sidewall temperature of the upper chamber 1 is maintained at an ideal level, preventing condensation on the inner sidewall surfaces due to the sidewall temperature falling below the wafer temperature. Furthermore, the combination of the stainless steel ring 31 and the polytetrafluoroethylene ring 32 reduces the amount of heat transferred from the top heater plate 12 to the sidewall of the upper chamber 1, thereby extending the service life of the sidewall connection components.

[0033] Return Figure 1 The lower chamber 2 is formed by a top, a sidewall, and a bottom, wherein the top and sidewall of the lower chamber 2 are integrally formed as a block 13. Specifically, the block 13 has a partition that serves as both the top of the lower chamber 2 and the bottom of the upper chamber 1. The block 13 has walls extending vertically upward and downward from the periphery of the partition, serving as the sidewalls of the upper chamber 1 and the lower chamber 2, respectively.

[0034] The bottom of the lower chamber 2 comprises a base 21, a heat radiating plate 22, and a heating plate 23. The base 21 is a plate connected to the sidewalls of the lower chamber 2, with the block 13 and the base 21 forming a space within the lower chamber 2. One or more seals may be inserted between the base 21 and the block 13 to seal the lower chamber 2. In one embodiment, a coolant delivery line may be formed within the base 21, providing cooling capabilities. In certain embodiments, a stainless steel ring 31 and a PTFE ring 32, as described above, may be placed between the base 21 and the sidewalls of the lower chamber 2 to prevent lateral heat loss.

[0035] The heat radiating plate 22 is disposed on the upper surface of the base 21. The upper surface of the heat radiating plate 22 forms the lower boundary of the lower chamber 2. The heat radiating plate 22 described herein is not intended to generate heat radiation, but rather is made of a material with a high emissivity, such as oxidized stainless steel or copper. In other embodiments, a thermal insulation plate may be placed between the heat radiating plate 22 and the base 21 to enhance temperature maintenance within the chamber.

[0036] Heating plate 23 is positioned above heat radiating plate 22. The bottom of heating plate 23 is connected to a transmission device 4 through holes in heat radiating plate 22 and base 21, allowing heating plate 23 to move vertically and rotate within lower chamber 2. Transmission device 4 includes electrical wiring and gas lines to provide control signals and heated gas to heating plate 23.

[0037] The heating plate 23 is essentially a nickel alloy disk, with an upper surface for supporting the wafer W and a lower surface facing the heat radiating plate 22. A heating coil is embedded within the heating plate 23 and operates in response to a control signal. A temperature sensor can be located within the heating plate 23 to read the plate's temperature. Figure 3 An embodiment of the top surface of the heating plate 23 is shown, showing a plurality of raised platforms 231 formed on the top surface for contacting the bottom of the wafer, creating a gap G between the wafer and the plate surface. There are at least three raised platforms 231. In one specific embodiment, there are 183 raised platforms 231, and the height H of the raised platforms 231 ranges from 0.01 mm to 1.00 mm.

[0038] Return Figure 1 The heating plate 23 also includes multiple gas channels 232 extending from the bottom of the heating plate 23 to its upper surface and connected to an external gas source. Specifically, the upper surface of the heating plate 23 includes gas outlets 233 connected to the gas channels 232, positioned relatively outside the wafer perimeter. In a practical application, the gas channels 232 deliver heated inert gas (e.g., helium) to the surface of the heating plate 23 to fill the lower chamber 2, improving wafer preheating efficiency.

[0039] Furthermore, the bottom of the lower chamber 2 is provided with a plurality of posts P, which extend upward from the base 21 and pass through the heating plate 23. When the heating plate 23 is in a relatively low position, the posts P are exposed on the upper surface of the heating plate 23 for receiving wafers. When the heating plate 23 is in a relatively high position, the posts P retreat into the heating plate 23 and are hidden.

[0040] Figure 4 and Figure 4B The heating plate 23 is shown in a receiving position. The heating plate 23 is lowered and positioned close to the heat radiating plate 22, with the pillars P exposed through the plate. This position allows the robot to bring wafers into the lower chamber 2 and place them on the pillars P. Similarly, this position allows the robot to enter the lower chamber 2 and remove preheated wafers from the pillars P.

[0041] Figure 5A and Figure 5BThe state of the heating plate 23 in a preheating position is shown. The preheating position is at a high position relative to the receiving position. The heating plate 23 rises until the boss on the upper surface is higher than the column P, allowing the wafer to be transferred to the heating plate 23. Then, the temperature of the heating plate 23 rises, and heat is transferred through the contact between the wafer and the boss. At the same time, the heat radiation plate 22 transmits radiation upward, and the gas channel 232 supplies heated inert gas. Accordingly, during the preheating treatment of the wafer in the lower chamber, the preheating efficiency is optimized due to the effects of contact heat transfer, radiation heat transfer, and convection heat transfer.

[0042] Figure 6 A partial top view of the upper chamber is shown. Wafers after deposition are transferred into the upper chamber of the preheating loading chamber and placed on a carrier 14. A heating plate 12, equipped with heating coils, maintains the temperature within the upper chamber. An observation window 132 is formed on the sidewall of the upper chamber, which in this embodiment represents the wall of the block 13, for operators to monitor the wafer status.

[0043] In summary, the upper chamber and the lower chamber of the wafer preheating loading chamber of the present invention are further optimized, wherein the lateral heat transfer of the upper chamber is suppressed to optimize the thermal insulation effect, and the lower chamber utilizes contact, radiation and convection heat conduction to improve the wafer preheating efficiency, thereby helping to improve the production capacity of semiconductor processing equipment.

Claims

1. A wafer preheating loading chamber, characterized in that: include: An upper chamber, configured to receive a wafer after reaction processing, and formed by a top, a side wall, and a bottom; and a lower chamber, independent of the upper chamber and configured to preheat a wafer awaiting reaction processing, and formed by a top, a side wall, and a bottom, wherein the bottom of the lower chamber comprises: a heat radiation plate; and a heating plate for heating the lower chamber, located above the heat radiation plate and capable of being raised and lowered in the lower chamber to move the wafer carried by the heating plate between a preheating position and a receiving position, the heating plate further comprising at least one gas channel for providing heated inert gas; The top of the upper chamber is provided with a heating top plate, the surrounding portion of the heating top plate is provided with a flange, and the side wall of the upper chamber is provided with a shoulder. When the heating top plate is connected to the side wall of the upper chamber, a downward surface of the flange and an upward surface of the shoulder form an annular space. The annular space accommodates a stainless steel ring and a polytetrafluoroethylene ring for blocking lateral heat loss of the upper chamber.

2. The wafer preheating loading chamber according to claim 1, characterized in that: A peripheral portion of the heating top plate is connected to the side wall of the upper chamber; the upper chamber also has a heat insulation plate located above the heating top plate to prevent heat from being lost from the upper chamber.

3. The wafer preheating loading chamber according to claim 1, characterized in that: The bottom of the lower chamber further includes: a base connected to the side wall of the lower chamber and so that the heat radiation plate is interposed between the heating tray and the base.

4. The wafer preheating loading chamber according to claim 1, characterized in that: The heating plate has an upper surface and a lower surface facing the heat radiation plate. A plurality of bosses are formed on the upper surface of the heating plate for supporting the bottom of a wafer. The height of the bosses is between 0.01 mm and 1.00 mm.

5. The wafer preheating loading chamber according to claim 1, characterized in that: The heating plate has an upper surface and a lower surface facing the heat radiation plate. The upper surface of the heating plate is formed with a plurality of gas outlets for supplying heated inert gas.

6. The wafer preheating loading chamber according to claim 1, characterized in that: The heating plate has an upper surface and a lower surface facing the heat radiation plate. The upper surface of the heating plate is coated with aluminum nitride, silicon carbide or diamond carbon.

7. The wafer preheating loading chamber according to claim 1, characterized in that: The bottom of the lower chamber also includes a plurality of columns. When the heating plate is located at the receiving position, the plurality of columns protrude from the heating plate to contact the bottom of the wafer. When the heating plate is located at the preheating position, the plurality of columns retract into the heating plate to place the wafer on the heating plate.

8. A preheating method for a wafer preheating loading chamber according to claim 1, characterized in that: include: The robot places the wafer to be reacted before entering a reaction chamber into the lower chamber; The heating plate in the lower chamber preheats the wafer to a target temperature; and the robot transfers the preheated wafer from the lower chamber to the reaction chamber.

9. The preheating method for a wafer preheating loading chamber according to claim 6, characterized in that: Placing the wafer in the lower chamber by the robot includes: lowering the heating plate to the receiving position so that the bottom of the lower chamber exposes multiple pillars on an upper surface of the heating plate; and placing the wafer on the multiple pillars by the robot.

10. The preheating method for a wafer preheating loading chamber according to claim 7, characterized in that: The preheating treatment of the wafer includes: raising the heating plate to the preheating position to transfer the wafer from the multiple columns to the heating plate; increasing the temperature of the heating plate; and introducing heated inert gas through multiple air outlets on the heating plate until the lower chamber reaches a target pressure.

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