Semiconductor process chamber

Abstract

The present invention discloses a semiconductor process chamber comprising a thermocouple. The thermocouple comprises a sleeve enclosing an inner core conductor and having a downstream end and an upstream end. The downstream end serves as a temperature-sensing portion and is inserted into a component to which radio frequency (RF) is applied, while the upstream end is electrically connected to a chamber. The chamber is characterized in that the chamber is grounded, allowing current induced by RF on the sleeve surface to flow through the chamber to the ground, shielding the RF within the chamber.

Description

Technical Field

[0001] The present invention relates to a semiconductor device, in particular to a semiconductor process chamber including a thermocouple. Background Art

[0002] In semiconductor manufacturing, plasma evaporation chemical vapor deposition (PECVD) is a process used to deposit or etch thin films. In the semiconductor process chamber that performs the PECVD process, the spray assembly and the wafer support plate serve as the upper and lower electrodes, respectively. The spray assembly is electrically connected to the RF source, while the support plate is grounded. Of course, the opposite configuration also exists. In a batch process with multiple stations, the temperature of the spray assembly needs to be balanced to obtain a consistent deposited film. However, it is actually difficult to maintain consistency from station to station, because the chamber temperature of each station may disrupt the temperature balance in the chamber due to the difference in the temperature of each incoming wafer, resulting in slight differences in the temperature of the spray assembly between stations. Therefore, precise control of the temperature of each spray assembly helps to ensure the consistency of the wafer process.

[0003] US Patent Application Publication No. US2019256977A1 ​​discloses a thermocouple for monitoring the temperature of a showerhead assembly. The thermocouple is connected to an RF filter. The RF filter uses circuit filtering to isolate the RF signal from the thermocouple signal, preventing interference between the two and causing unreliable temperature sensing. The RF filter can be composed of a high-frequency filter (e.g., 13.56 MHz) and a low-frequency filter (e.g., 400 kHz).

[0004] Although circuitry can accurately monitor the actual temperature of thermocouples, ensuring the consistency of electronic components in the circuitry remains challenging for multiple stations processing wafers in the same process. Therefore, it is necessary to develop a simplified method for thermocouples that is easier than maintaining circuitry. Summary of the Invention

[0005] The object of the present invention is to provide a semiconductor process chamber to shield radio frequency signals within the chamber.

[0006] The semiconductor process chamber provided by the present invention includes: a thermocouple having a sleeve, the sleeve being coated with an inner core wire and having a downstream end and an upstream end, the downstream end serving as a temperature sensing portion and being inserted into a component to which radio frequency is applied, and the upstream end being electrically connected to a chamber, characterized in that: the chamber is grounded, so that the current flowing on the surface of the sleeve caused by the radio frequency can flow through the chamber to the ground, so that the radio frequency is shielded within the chamber.

[0007] The semiconductor process chamber provided by the present invention has the beneficial effect that the upstream end of the thermocouple is connected to the chamber. Since the sleeve and the chamber are conductive, the chamber is grounded, and the flowing current caused by the radio frequency signal is sequentially transmitted from the surface of the sleeve and the chamber to the ground end. Therefore, the radio frequency signal is shielded in the closed chamber and will not interfere with the inner core wire.

[0008] Optionally, the cavity is a closed metal cover.

[0009] Optionally, the thermocouple includes a first insulating sleeve covering the downstream end and a second insulating sleeve partially covering the first insulating sleeve, with a portion of the first insulating sleeve exposed.

[0010] Optionally, the first insulating sleeve and the second insulating sleeve are made of ceramic.

[0011] Optionally, the thermocouple is inserted into the component at a depth that is less than twice the diameter of the sleeve, and the signal processing unit is configured to execute a compensation algorithm to obtain accurate temperature data.

[0012] Optionally, the thermocouple is inserted into the component at a depth greater than twice the diameter of the sleeve, and the sleeve is electrically coupled to a pair of resistors to reduce radio frequency energy in the radio frequency loop.

[0013] Optionally, the semiconductor process chamber further includes a chamber top, the component is a spray assembly fixed to the chamber top, wherein the thermocouple is partially inserted into the spray assembly to sense the temperature of the spray assembly, and a pressing assembly is provided at the chamber top, the pressing assembly is configured to connect the thermocouple and provide a pressing force along the insertion direction of the thermocouple, so that the downstream end of the thermocouple is in close contact with the temperature measuring point in the spray assembly.

[0014] Optionally, the pressing assembly includes a clamping seat fixed above the top of the cavity, a jacket located below the top of the cavity, and a spring located between the clamping seat and the jacket, the clamping seat and the jacket respectively clamp the pipe sleeve of the thermocouple, and the spring provides the pressing force to the jacket, forcing the downstream end of the thermocouple to be in close contact with the temperature measuring point in the spray assembly.

[0015] Optionally, the clamping seat has a clamp and a shielding ring, the clamp clamps the tube sleeve of the thermocouple, and the shielding ring is connected to the periphery of the clamping seat, so that the clamping seat is fixed to the upper surface of the top of the cavity through the shielding ring without the clamping seat contacting the top of the cavity.

[0016] Optionally, the jacket has an inner sleeve and an outer sleeve, the inner sleeve covers the sleeve of the thermocouple, and the outer sleeve is tightly fitted with the inner sleeve to clamp the sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure shows the thermocouple (a component inserted into a cavity) of the present invention having the ability to shield radio frequency signals.

[0018] Figure 2 The figure is a cross-sectional view of a thermocouple with radio frequency signal shielding capability inserted into a spray assembly according to the present invention.

[0019] Figure 3 This is a cross-sectional view of an embodiment of the thermocouple configuration of the present invention.

[0020] Figure 4 This is an enlarged view of the local section of the chuck.

[0021] Figure 5 A three-dimensional diagram of the chuck. DETAILED DESCRIPTION

[0022] 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.

[0023] 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.

[0024] Figure 1 The present invention illustrates a thermocouple 1 with radio frequency shielding capabilities. It comprises a sheath 11 and an inner conductor 12. Sheath 11 is made of a metal with good thermal conductivity, such as stainless steel, and has a downstream end 13 and an upstream end 14. Downstream end 13 primarily serves as the temperature measurement unit, while upstream end 14 is connected to a signal processing unit (not shown) that receives and processes the signal from the inner conductor.

[0025] Figure 1Also shown are a component 2 and a cavity 3. The cavity 3 depicted in the figure can actually be a structure in a semiconductor process cavity, in particular, a structure in a plasma process cavity. Specifically, the cavity 3 can be understood as a closed metal cover. If the structure in the cavity is metal, it will be affected by the radio frequency signal and generate a current flowing on the surface of the structure, which is the skin effect, as shown in the direction of the arrow in the figure. Component 2 refers to the target to which the radio frequency signal is mainly applied, such as the upper electrode or lower electrode well known in the field of plasma process, and the upper electrode and the lower electrode can be a spray assembly and a wafer support plate, respectively. Component 2 is also usually made of metal, such as a layer of metal plate in a spray assembly. Component 2 can be electrically connected to the radio frequency source via a cable, so a current will also flow on the surface of component 2, as shown by the arrow in the figure.

[0026] The downstream end 13 of the thermocouple 1 of the present invention is inserted into the component 2 through a first insulating sleeve 15 to a depth D. The first insulating sleeve 15 has an outer side and an inner side. The downstream portion 13 of the sleeve 11 contacts the inner side of the first insulating sleeve 15, while the outer side of the first insulating sleeve 15 contacts the component 2. Thus, the first insulating sleeve 15 isolates the sleeve 11 from the component 2. In other embodiments, the length of the first insulating sleeve 15 may be adjusted or even omitted depending on the component 2 into which the thermocouple 1 is inserted.

[0027] The upstream end 14 of the thermocouple 1 is connected to the cavity 3. Because the sheath 11 and cavity 3 are conductive, grounding the cavity 3 allows the RF signal-induced current to flow sequentially from the surface of the sheath 11 and cavity 3 to the ground terminal. This shields the RF signal within the enclosed metal housing and prevents it from interfering with the temperature-measuring core wire 12.

[0028] In one specific configuration, if the insertion depth D is less than twice the diameter d of the sleeve 11 (i.e., 2d), the signal processing unit executes a compensation algorithm to obtain accurate temperature data. This is because a shallow insertion depth can easily lead to inaccurate measurement results, necessitating an additional compensation mechanism. The detailed implementation of this mechanism is not essential to the present invention and is therefore not detailed here.

[0029] In another specific configuration, if the insertion depth D is greater than twice the diameter d of the sleeve 11, a high resistance resistor (e.g., 10M ohms) is electrically coupled to the sleeve 11 to prevent excessive RF current from flowing along the sleeve 11. This is because a large insertion depth will generate corresponding parasitic capacitance. Figure 1 The surface current indicated by the arrow is larger, while the current flowing into the discharge plasma region is smaller, requiring the connection of a high-resistance resistor to compensate. As shown in the figure, the configuration is to electrically connect a pair of resistors 31 between the cavity 3 and the sleeve 11 to reduce the current indicated by the arrow in the figure, but the present invention is not limited to this.

[0030] Furthermore, in other embodiments, if the component 2 is grounded and the process requires a low-frequency RF voltage (within 10V), the first insulating sleeve 15 and the resistor 31 may be omitted.

[0031] Figure 2 This is a cross-sectional view of the thermocouple 1' of the present invention inserted into a spray assembly. The spray assembly is mainly composed of metal parts, including a spray plate 21 closest to the chamber processing area, a plate 22 stacked on the spray plate 21, and a cover 23 pushed on the plate 22, but the present invention is not limited to this. The thermocouple 1' is inserted into the spray assembly to a certain depth, specifically, through the cover 23 and extending to the plate 22, but does not contact the spray plate 21, but the present invention is not limited to this. Figure 1 The length of the first insulating sleeve 15 shown in FIG should be at least sufficient to isolate the downstream end of the thermocouple 1 ′ from the isolation plate 22 and / or cover 23 to avoid interference with radio frequency signals.

[0032] Figure 3 This is a cross-sectional view of an embodiment of the thermocouple configuration of the present invention. Figure 1 Similarly, a sleeve 11 and a first insulating sleeve 15 are provided. Figure 3 and Figure 1 The main difference is the inclusion of a second insulating sleeve 16 and a pressing assembly 4. As shown, the inner side of the second insulating sleeve 16 partially contacts the outer side of the first insulating sleeve 15, partially covering the first insulating sleeve 15 and leaving the end of the first insulating sleeve 15 exposed to contact the plate 22. The second insulating sleeve 16 has a length such that, in addition to covering the open end of the first insulating sleeve 15, it also partially covers the downstream end of the pipe sleeve 11, with air between the second insulating sleeve 16 and the pipe sleeve 11. A portion of the outer side of the second insulating sleeve 16 contacts the cover 23, isolating the pipe sleeve 11 from the cover 23.

[0033] The first insulating sleeve 15 and the second insulating sleeve 16 are made of a material with high thermal conductivity but low electrical conductivity, such as alumina (ceramic), but the present invention is not limited thereto. Therefore, the thermocouple can shield radio frequency signals and obtain temperature data at the component without the need for an additional RF filter.

[0034] Furthermore, the upstream end of the pipe sleeve 11 is coupled to the chamber top 3' via a pressing assembly 4. The chamber top 3' herein refers to a portion of the chamber top structure. As shown in the figure, the chamber top 3' is a plate above the spray assembly, but the present invention is not limited to this. The pressing assembly 4 is primarily configured to secure the pipe sleeve 11 in position and provide a downward pressing force, forcing the downstream end of the pipe sleeve 11 to contact the first insulating sleeve 15, and the first insulating sleeve 15 to contact the plate 22.

[0035] The pressing assembly 4 includes a clamping seat 41, a sleeve 42 and a spring 43. The clamping seat 41 is located above the cavity top 3' and has a channel for the sleeve 11 to pass through. The bottom of the clamping seat 41 is connected to the upper surface of the cavity top 3' via a shielding ring 411, so that the clamping seat 41 and the cavity top 3' are not in contact. Since there may still be radio frequency current in the cavity top 3', this configuration can prevent the radio frequency signal from being coupled to the sleeve 11 through the clamping seat 41. Figure 4 and Figure 5 A collet chuck (412) is provided on the top of the clamping seat 41, which cooperates with the clamping seat 41 to clamp the pipe sleeve 11, thereby fixing the pipe sleeve 11 and preventing it from moving vertically easily.

[0036] The jacket 42 is located below the cavity top 3' and above the second insulating sleeve 16. The jacket 42 is composed of an inner sleeve and an outer sleeve. The inner sleeve covers the outer side of the sleeve 11, and the outer sleeve is tightly connected to the outer side of the inner sleeve to firmly secure the jacket 42 to the sleeve 11.

[0037] The ends of spring 43 contact the bottom of clamping seat 41 and the top of jacket 42, respectively, exerting a spring force on both sides. Specifically, spring 43 contacts clamping seat 41 through the opening in cavity top 3', so spring 43 does not contact cavity top 3'. Because clamping seat 41 is secured to cavity top 3' via shielding ring 411, the spring force forces sleeve 11 downward, thereby bringing the downstream end of sleeve 11 into close contact with first insulating sleeve 15, which in turn brings the first insulating sleeve 15 into close contact with second insulating sleeve 16.

[0038] The thermocouple of the present invention can be widely used in plasma process chambers and can measure the temperature of components carrying radio frequency signals, eliminating the additional installation cost of RF filters. The pressed assembly ensures close contact between the thermocouple and the temperature measurement point. Components carrying radio frequency signals include, but are not limited to, 27 MHz, 13.56 MHz, and 400 kHz components.

Claims

1. A semiconductor process chamber, comprising: A thermocouple having an inner core wire for measuring temperature and a sleeve, wherein: The sleeve covers the inner core wire and has a downstream end and an upstream end. The downstream end is inserted into a spray assembly to which radio frequency is applied as a temperature sensing portion to sense the temperature of the spray assembly. The upstream end is electrically connected to a cavity top. The spray assembly is fixed to the top of the cavity, and a pressing assembly is provided, wherein the pressing assembly includes a clamping seat fixed above the top of the cavity, a sleeve located below the top of the cavity, and a spring located between the clamping seat and the sleeve, wherein the top of the cavity is grounded, so that the flow current caused by the radio frequency on the surface of the sleeve flows to the ground through the top of the cavity, so that the radio frequency is shielded in the cavity without interfering with the inner core wire, the pressing assembly is connected to the thermocouple and provides a pressing force along the insertion direction of the thermocouple, the clamping seat and the sleeve respectively clamp the sleeve of the thermocouple, and the spring provides the pressing force to the sleeve so that the downstream end of the thermocouple is in close contact with the temperature measuring point in the spray assembly, the clamping seat has a clamp and a shielding ring, the clamp clamps the sleeve of the thermocouple, and the shielding ring is connected to the outer periphery of the clamping seat, so that the clamping seat is fixed to the upper surface of the top of the cavity through the shielding ring without making the clamping seat contact the top of the cavity.

2. The semiconductor process chamber according to claim 1, wherein: The cavity is a closed metal cover.

3. The semiconductor process chamber according to claim 1, wherein: The thermocouple includes a first insulating sleeve covering the downstream end and a second insulating sleeve partially covering the first insulating sleeve and exposing a portion of the first insulating sleeve.

4. The semiconductor process chamber according to claim 3, wherein: The first insulating sleeve and the second insulating sleeve are made of ceramic.

5. The semiconductor process chamber according to claim 1, wherein: The thermocouple is inserted into the spray assembly at a depth that is less than twice the diameter of the pipe sleeve, and a signal processing unit is configured to execute a compensation algorithm to obtain accurate temperature data.

6. The semiconductor process chamber according to claim 1, wherein: The thermocouple is inserted into the spray assembly at a depth greater than twice the diameter of the sleeve, and the sleeve is electrically coupled to a pair of resistors to reduce radio frequency energy looping through the sleeve to ground.

7. The semiconductor process chamber according to claim 1, wherein: The jacket comprises an inner sleeve and an outer sleeve, wherein the inner sleeve covers the pipe sleeve of the thermocouple, and the outer sleeve is tightly fitted with the inner sleeve to clamp the pipe sleeve.

Images