Upper electrode assembly for semiconductor process chamber and semiconductor process chamber

Abstract

The present application relates to an upper electrode assembly for a semiconductor process chamber and the semiconductor process chamber. The top of the semiconductor process chamber has a ceramic upper cover, and the upper electrode assembly is placed above the ceramic upper cover. The upper electrode assembly includes an adsorption power supply and a temperature control layer, a radio frequency feed layer, and a uniform heat adsorption layer arranged in sequence from top to bottom, wherein the uniform heat adsorption layer includes an electrode layer and a first uniform heat layer placed below the electrode layer, the first uniform heat layer transfers heat evenly, the electrode layer is provided with a positive electrode and a negative electrode, and the adsorption power supply is used to apply positive voltage and negative voltage to the positive electrode and the negative electrode respectively, so as to form an electrostatic attraction between the electrode and the ceramic upper cover, and the first uniform heat layer can fit tightly with the ceramic upper cover. According to the technical solution of the present application, the entire contact surface between the upper electrode assembly and the ceramic upper cover can be pressed tightly, which improves the efficiency and uniformity of heat transfer and is easy to disassemble and maintain.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to an upper electrode assembly for a semiconductor process chamber and the semiconductor process chamber. Background Art

[0002] In some semiconductor processes, controlling the temperature within the process chamber is crucial. For example, HDPCVD (High-Density Plasma Chemical Vapor Deposition) is a key hole-filling process in IC manufacturing. Its key feature is the generation of a plasma within the CVD reactor. This plasma contains oxygen and silane, which are used to deposit silicon dioxide. It also contains high-energy argon ions, which directly impact the wafer surface, causing a sputtering reaction. The implementation of processes such as HDPCVD places high demands on the stability of the process chamber environment. Temperature control of the ceramic cover at the top of the process chamber is particularly critical, as it largely determines whether the final process results meet the process requirements. Therefore, the temperature control device for this ceramic cover is crucial.

[0003] One method for temperature control of a ceramic cover is to configure the cover as a flat surface and place a temperature control device above it for temperature control. Currently, a loose fit between the cover and the temperature control device can lead to poor heat transfer stability and uneven temperature distribution. Therefore, optimizing the temperature control structure of the cover is urgently needed to improve the performance of semiconductor process equipment such as HDPCVD machines.

[0004] How to improve the temperature control efficiency of the ceramic cover on top of the process chamber is a technical issue that the industry is very concerned about. Summary of the Invention

[0005] The purpose of the present application is to provide an upper electrode assembly for a semiconductor process chamber, which can be evenly pressed against the entire contact surface of a ceramic upper cover to improve thermal conductivity uniformity and thermal conductivity efficiency.

[0006] According to one aspect of the present application, an upper electrode assembly for a semiconductor process chamber is provided. The top of the semiconductor process chamber has a ceramic upper cover. The upper electrode assembly is placed above the ceramic upper cover. The upper electrode assembly includes an adsorption power supply and a temperature control layer, a radio frequency feed layer, and a uniform heat adsorption layer arranged in sequence from top to bottom, wherein:

[0007] The temperature control layer is used to control the temperature of the ceramic upper cover;

[0008] The radio frequency feeding layer is electrically connected to a radio frequency source to ionize the gas in the semiconductor process chamber;

[0009] The uniform heat adsorption layer includes an electrode layer and a first uniform heat layer located below the electrode layer. The first uniform heat layer is used to uniformly transfer heat. The electrode layer is provided with a positive electrode and a negative electrode. The adsorption power supply is used to apply a positive voltage and a negative voltage to the positive electrode and the negative electrode, respectively, to form an electrostatic attraction between the positive electrode and the negative electrode and the ceramic upper cover.

[0010] In some possible implementations, the uniform heat adsorption layer further includes a second uniform heat layer, which is placed above the electrode layer and configured to uniformly transfer heat.

[0011] In some possible implementations, the temperature control layer includes a cooling layer and a heating layer. A cooling medium flows through the cooling layer to provide cooling, and the heating layer is arranged below the cooling layer to provide heating.

[0012] In some possible implementations, the RF feeding layer is provided with a RF coil, and the RF coil is electrically connected to the RF source to ionize the gas in the process chamber.

[0013] In some possible embodiments, the device further includes an air inlet channel, which passes through the temperature control layer, the RF feed layer, the uniform heat adsorption layer and the ceramic upper cover from top to bottom, and is used to introduce gas into the semiconductor process chamber.

[0014] In some possible implementations, the device further includes an annular seal, which is disposed at the junction of the air inlet channel and the upper surface of the ceramic upper cover to seal a gap between the air inlet channel and the upper surface of the ceramic upper cover.

[0015] In some possible implementations, the voltage applied by the adsorption power supply to the positive electrode and the negative electrode is 1500V to 2500V.

[0016] In some possible implementations, the material filled in the first uniform heat layer is a mixed material containing asbestos.

[0017] In some possible implementations, the electrode layer and the first heat-distributing layer are fixed by bonding with thermal grease.

[0018] In some possible implementations, the material filled in the second heat-leveling layer is a mixed material containing asbestos, and the second heat-leveling layer and the electrode layer are fixed by bonding with thermal grease.

[0019] According to another aspect of the present application, a semiconductor process chamber is also provided, which includes a chamber body and an upper electrode assembly as described above, wherein the top of the chamber body has a ceramic upper cover, the upper surface of the ceramic upper cover is a planar structure, and the upper electrode assembly is placed above the ceramic upper cover.

[0020] The technical solution of the present application is to provide an adsorption power supply and an electrode layer in the upper electrode assembly, and the electrode layer is located above the first uniform heating layer. When the adsorption power supply applies positive voltage and negative voltage to the positive electrode and the negative electrode, the surface of the ceramic upper cover in contact with the first uniform heating layer generates a charge with opposite polarity to the positive electrode and the negative electrode, so that the positive electrode and the negative electrode respectively form an electrostatic attraction with the ceramic upper cover, which can press the first uniform heating layer onto the ceramic upper cover. Since the electrostatic attraction is evenly distributed over the entire surface in contact with the first uniform heating layer, the central area and edge area of ​​the contact surface between the first uniform heating layer and the ceramic upper cover have a good compression effect, which improves the efficiency and uniformity of heat transfer, avoids local fragmentation of the ceramic upper cover due to excessive temperature difference, and significantly improves the reliability of the upper electrode assembly. In addition, according to the above technical solution, when it is necessary to disassemble the upper electrode assembly, the upper electrode assembly can be easily removed by stopping the adsorption power supply from applying voltage to the electrode layer, which significantly improves the maintainability of the upper electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0022] Figure 1 The figure shows a schematic structural diagram of an upper electrode assembly used in a semiconductor process chamber in the prior art.

[0023] Figure 2 A schematic structural diagram of an upper electrode assembly for a semiconductor process chamber according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0024] The present application will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0025] In the related art, the existing upper electrode assembly for semiconductor process chamber is as follows Figure 1As shown, from top to bottom, it can be divided into a temperature control layer 101, an RF feed layer 102, and a uniform heating layer 103. The temperature control layer 101 is used for temperature control, including heating and cooling. The RF feed layer 102 is electrically connected to the RF source to ionize the gas in the semiconductor process chamber. The uniform heating layer 103 is located at the bottom of the upper electrode assembly. It needs to take into account both thermal conductivity and uniform heating characteristics. It can not only efficiently transfer heat between the ceramic cover 104 and the temperature control layer 101 to ensure that the temperature of the ceramic cover is appropriate, but also ensure that heat is evenly distributed in the uniform heating layer 103 to ensure that the surface temperature of the ceramic cover 104 is uniform, thereby preventing the ceramic cover 104 from breaking due to excessive surface temperature difference. The temperature control device also includes an air inlet channel 105 arranged in the central area. The air inlet channel 105 passes through the entire temperature control device and the ceramic cover 104 longitudinally to inject gas into the process chamber. During actual use, the entire upper electrode assembly is naturally placed above the ceramic upper cover 104. There is inevitably a gap between the heat-uniform layer 103 and the ceramic upper cover 104, which affects the heat transfer between the upper electrode assembly and the ceramic upper cover 104. In order to alleviate this problem, the existing technical solution provides a hollow area 106 surrounding the air inlet channel 105, and a cover plate 107 is provided above the hollow area 106. The vacuum tube 108 draws a vacuum from the hollow area 106, so that a pressure difference is formed between the upper and lower surfaces of the cover plate 107. With the help of atmospheric pressure, the cover plate 107 presses the entire upper electrode assembly tightly against the ceramic upper cover 104, thereby achieving the purpose of reducing the gap between the upper electrode assembly and the ceramic upper cover 104. In order to form a vacuum in the hollow area 106, strict sealing treatment must be performed. Therefore, an annular seal 109 needs to be provided at the gap between the air inlet channel and the ceramic upper cover to prevent the gas in the process chamber from overflowing through the gap and affecting the vacuum extraction effect.

[0026] The existing technical solution uses a cover plate to compress the upper electrode assembly. Although it can achieve the purpose of reducing the gap between the upper electrode assembly and the ceramic upper cover to a certain extent, it also has the following two problems:

[0027] On the one hand, the force application area of ​​the cover is very limited. Only the central area below the cover is under force on the entire upper electrode assembly. The edges will be slightly stretched, and it cannot fit tightly with the ceramic cover, seriously affecting the compaction effect.

[0028] On the other hand, the annular seal will be corroded by the process gas and needs to be replaced frequently. To remove the annular seal, it is necessary to inflate the hollow area to destroy its vacuum environment and balance the pressure difference between the upper and lower parts of the cover. Only then can the temperature control device be removed to replace the annular seal, which brings a lot of trouble to maintenance personnel.

[0029] According to one embodiment of the present application, an upper electrode assembly for a semiconductor process chamber is provided. The top of the semiconductor process chamber has a ceramic upper cover. The upper electrode assembly is placed above the ceramic upper cover. The upper electrode assembly includes an adsorption power supply and a temperature control layer, a radio frequency feed layer, and a uniform heat adsorption layer arranged in sequence from top to bottom, wherein:

[0030] The temperature control layer is used to control the temperature of the ceramic upper cover;

[0031] The radio frequency feeding layer is electrically connected to a radio frequency source to ionize the gas in the semiconductor process chamber;

[0032] The uniform heat adsorption layer includes an electrode layer and a first uniform heat layer placed below the electrode layer, the first uniform heat layer is used to uniformly transfer heat, the electrode layer is provided with a positive electrode and a negative electrode, and the adsorption power supply is used to load positive voltage and negative voltage to the positive electrode and the negative electrode respectively, so as to form an electrostatic attraction between the electrode layer and the ceramic upper cover.

[0033] According to this embodiment, the surface of the ceramic cover in contact with the first uniform heating layer generates a uniformly distributed charge, creating an electrostatic attraction between the positive electrode and the negative electrode, respectively, and the ceramic cover. This compresses the first uniform heating layer against the ceramic cover. The electrostatic attraction is evenly distributed across the ceramic cover, resulting in a good compression effect in both the central and edge areas of the contact surface between the first uniform heating layer and the ceramic cover. This improves the efficiency and uniformity of heat transfer, avoids localized cracking of the ceramic cover due to excessive temperature differences, and significantly enhances the reliability of the upper electrode assembly. Furthermore, according to this embodiment, by disconnecting the power to the electrode layer, the entire upper electrode assembly can be removed for repair or replacement, significantly improving the maintainability of the device.

[0034] Please refer to Figure 2 . Figure 2 A schematic diagram illustrates a schematic diagram of an upper electrode assembly for a semiconductor process chamber according to an exemplary embodiment of the present invention. The upper electrode assembly is used to control the temperature of a process chamber of an HDPCVD (high-density plasma chemical vapor deposition) device and to ionize gases in the process chamber.

[0035] As shown in the figure, the temperature control device includes a temperature control layer 201, a radio frequency feeding layer 202 and a uniform heat adsorption layer 203 arranged in sequence from top to bottom.

[0036] The temperature control layer includes a cooling layer 2011 located above and a heating layer 2012 located below. The cooling layer 2011 and the heating layer 2012 are fixedly connected. The cooling layer 2011 can be connected to an external chiller. When the temperature of the ceramic cover 204 exceeds a certain value, the cold water circulation system can be activated to remove heat in a timely manner. The heating layer 2012 can be provided with a high-power heating core 20121. When the temperature of the ceramic cover 204 is detected to be below a certain value (for example, 120 degrees Celsius), heating is activated to keep the ceramic cover warm. The dual-layer temperature control layer with separate hot and cold zones facilitates faster response to temperature control needs and more convenient and flexible temperature control.

[0037] The RF feed layer 202 and the temperature control layer 201 can be fastened and compressed using bolts. An RF coil 2021 is distributed within the RF feed layer 202. The RF coil 2021 can be electrically connected to an RF source (not shown) to generate a magnetic field that ionizes the gas in the HDPCVD process chamber and generates plasma. All components of the RF feed layer 202, except the RF coil 2021, can be made of ceramic.

[0038] The uniform heat adsorption layer 203 and the RF feed layer 202 can be fixed and pressed by bolts. In this example, the uniform heat adsorption layer 203 includes a second uniform heat layer 2031, an electrode layer 2032 and a first uniform heat layer 2033 arranged in sequence from top to bottom. The second uniform heat layer 2031 and the first uniform heat layer 2033 both have good thermal conductivity and uniform heat performance. The double-layer uniform heat layer is more conducive to the efficient and uniform transfer of heat between the temperature control layer 201 and the ceramic cover 204, and physically isolates the electrode layer 2032 from the RF feed layer 202 and the ceramic cover 204. In this example, the materials filled in the first uniform heat layer 2033 and the second uniform heat layer 2031 are both mixed materials containing asbestos, which take into account both thermal conductivity and uniform heat performance, can efficiently conduct heat and distribute heat evenly,

[0039] Electrode layer 2032 is provided with a positive electrode and a negative electrode. An adsorption power supply (not shown) applies corresponding positive and negative voltages to the positive and negative electrodes, respectively. When voltage is applied, the surface of the ceramic upper cover 204 in contact with the first uniform heat layer 2033 generates a charge of opposite polarity to the positive and negative electrodes. This creates an electrostatic attraction between the electrodes and the ceramic upper cover, pressing the first uniform heat layer 2033 against the ceramic upper cover 204. After in-depth research and extensive experiments, the inventors have discovered that applying a voltage of 1500-2500V between the positive and negative electrodes of electrode layer 2032 achieves excellent electrostatic adsorption. To ensure consistent and uniform heat transfer, the positive and negative electrodes are preferably applied with the same voltage.

[0040] In this example, the electrode layer 2032 may be a metal electrode, such as a tungsten electrode.

[0041] In this example, thermal grease is used to secure the first heat-leveling layer 2033 to the electrode layer 2032, and the electrode layer 2032 to the second heat-leveling layer 2031. Thermal grease has excellent thermal conductivity, further improving the thermal conductivity between the temperature-control layer 201 and the ceramic cover 204.

[0042] Because this process chamber is used for HDPCVD processing, the upper electrode assembly also includes an inlet channel 205. This channel runs from top to bottom through the temperature control layer 201, the RF feed layer 202, the uniform heat adsorption layer 203, and the ceramic upper cover 204, allowing gas to enter the HDPCVD process chamber. The portion of the inlet channel 205 that extends upward from the upper electrode assembly is fixed to the upper electrode assembly via a cover plate 206.

[0043] In order to prevent the gas in the HDPCVD process chamber from leaking through the gap between the outer wall of the air inlet channel and other parts and causing pollution, in this example, an annular seal can be set at the junction of the air inlet channel 205 and the upper surface of the ceramic upper cover 204 to seal the gap between the air inlet channel 205 and the upper surface of the ceramic upper cover 204, prevent gas leakage, avoid polluting the environment, and improve reaction efficiency.

[0044] When the annular seal needs to be replaced, the adsorption power supply can be stopped from applying voltage to the electrode layer 2032, and the electrostatic effect between the upper electrode assembly and the ceramic upper cover 204 will disappear immediately, so that the temperature control device can be easily removed and the annular seal corroded by the process gas can be replaced.

[0045] Some or all of the above solutions have at least the following advantages:

[0046] 1. The uniform electrostatic attraction between the electrode and the ceramic cover makes the center and edge areas of the contact surface of the first uniform heat layer and the ceramic cover fit tightly, improving the efficiency and uniformity of heat transfer, avoiding local cracking of the ceramic cover due to excessive temperature difference, and improving the reliability of the upper electrode assembly;

[0047] 2. The entire upper electrode assembly is easy to disassemble and maintain, and the annular seal is easy to replace, which significantly improves the maintainability of the equipment;

[0048] 3. Two layers of uniform heat dissipation layers are used to further improve the stability and uniformity of heat conduction between the upper electrode assembly and the ceramic upper cover;

[0049] 4. The uniform heat adsorption layer includes two uniform heat layers and one electrode layer. Its occupied space is significantly larger than the single uniform heat layer in the existing technology, so that there is a larger heat dissipation space between the RF feed layer and the ceramic cover, which can better adapt to the high-power working mode of the RF feed layer.

[0050] According to one embodiment of the present application, a semiconductor process chamber is also provided, which includes a chamber body and an upper electrode assembly as described above, wherein the top of the chamber body has a ceramic upper cover, the upper surface of the ceramic upper cover is a planar structure, and the upper electrode assembly is placed above the ceramic upper cover to control the temperature of the ceramic upper cover and ionize the gas in the chamber.

[0051] The semiconductor process chamber can be used to perform HDPCVD (high-density plasma chemical vapor deposition) reactions.

[0052] For other aspects and advantages of this embodiment, please refer to the above.

[0053] While various embodiments of the present application have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. An upper electrode assembly for a semiconductor process chamber, wherein the top of the semiconductor process chamber has a ceramic upper cover, and the upper electrode assembly is placed above the ceramic upper cover, characterized in that: The upper electrode assembly includes an adsorption power supply and a temperature control layer, a radio frequency feed layer and a uniform heat adsorption layer arranged in sequence from top to bottom, wherein: The temperature control layer is used to control the temperature of the ceramic upper cover; The radio frequency feeding layer is electrically connected to a radio frequency source to ionize the gas in the semiconductor process chamber; The uniform heat adsorption layer includes an electrode layer and a first uniform heat layer located below the electrode layer, the first uniform heat layer is used to uniformly transfer heat, the electrode layer is provided with a positive electrode and a negative electrode, and the adsorption power supply is used to apply a positive voltage and a negative voltage to the positive electrode and the negative electrode, respectively, so that the positive electrode and the negative electrode respectively form an electrostatic attraction with the ceramic upper cover; The uniform heat adsorption layer further includes a second uniform heat layer, which is placed above the electrode layer and is used for uniformly transferring heat.

2. The upper electrode assembly according to claim 1, wherein: The temperature control layer includes a cooling layer and a heating layer. A cooling medium flows through the cooling layer for providing cooling. The heating layer is arranged below the cooling layer for providing heating.

3. The upper electrode assembly according to claim 1, wherein: The RF feeding layer is provided with a RF coil, and the RF coil is electrically connected to the RF source to ionize the gas in the process chamber.

4. The upper electrode assembly according to claim 1, wherein: The upper electrode assembly also includes an air inlet channel, which runs through the temperature control layer, the RF feed layer, the uniform heat adsorption layer and the ceramic upper cover from top to bottom and is used to introduce gas into the semiconductor process chamber.

5. The upper electrode assembly according to claim 4, characterized in that The upper electrode assembly further includes an annular seal, which is disposed at the junction of the air inlet channel and the upper surface of the ceramic upper cover to seal the gap between the air inlet channel and the upper surface of the ceramic upper cover.

6. The upper electrode assembly according to claim 1, wherein: The voltage applied by the adsorption power supply to the positive electrode and the negative electrode is 1500V~2500V.

7. The upper electrode assembly according to claim 1, wherein: The material filled in the first heat-leveling layer is a mixed material containing asbestos; and / or the electrode layer and the first heat-leveling layer are fixed by bonding with thermal grease.

8. The upper electrode assembly according to claim 2, wherein: The material filled in the second heat-leveling layer is a mixed material containing asbestos, and / or the second heat-leveling layer and the electrode layer are fixed by bonding with thermal grease.

9. A semiconductor process chamber, characterized in that: The semiconductor process chamber includes a chamber body and an upper electrode assembly as described in any one of claims 1-8, the top of the chamber body has a ceramic cover, the upper surface of the ceramic cover is a planar structure, and the upper electrode assembly is placed above the ceramic cover.

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