Variable temperature hardware and methods for reduction of wafer backside deposition

Abstract

A process tuning kit for use in a chemical vapor deposition apparatus is provided, and the process tuning kit includes a carrier ring, horseshoes, and shims. The horseshoes have identical dimensions, and the shims are provided in sets of different thicknesses to control the height of the horseshoes relative to the upper surface of a pedestal assembly on which the horseshoes and shims are mounted. A semiconductor substrate is transferred into the vacuum chamber of the chemical vapor deposition apparatus by means of a carrier ring positioned on the horseshoes, so that MCA (minimum contact area) supports lift the substrate from the carrier ring and support the substrate at a predetermined offset relative to the upper surface of the pedestal assembly. During the processing of the substrate, back deposition can be reduced by using shims of a target thickness to control the predetermined offset.

Description

Technology Field

[0001] The present invention relates to apparatuses and processes for performing chemical depositions and for use in plasma-enhanced chemical depositions. Background Technology

[0002] Plasma processing devices can be used to process semiconductor substrates by techniques including etching, PVD (physical vapor deposition), CVD (chemical vapor deposition), PECVD (plasma enhanced chemical vapor deposition), ALD (atomic layer deposition), PEALD (plasma enhanced atomic layer deposition), PDL (pulsed deposition layer), PEPDL (plasma enhanced pulsed deposition layer) processing, and resist removal. For example, one type of plasma processing device used for plasma processing includes a reaction or deposition chamber comprising an upper electrode and a lower electrode. RF (radio frequency) power is applied between the electrodes to excite process gases or reactor chemicals into plasma to process semiconductor substrates within the reaction chamber.

[0003] According to one embodiment, a process tuning kit useful for a chemical vapor deposition apparatus comprises a carrier ring, a set of three horseshoes, and a set of three shims, wherein (a) the shims have an upper surface, a lower surface parallel to the upper surface, an end wall, a U-shaped sidewall extending from the end wall, and a bore extending between the upper surface and the lower surface, a first set of three shims having the same thickness, and a second set of three shims having a thickness different from the first set of shims, and (b) the horseshoes have an upper surface, a lower surface parallel to the upper surface, an end wall, a U-shaped sidewall extending from the end wall, and a bore extending between the upper surface and the lower surface, and a slot opening extending within the end wall and over less than 1 / 2 of the upper surface, the bore having the same diameter as the bore of the shims, and / or (c) the carrier ring has an upper surface, a lower surface parallel to the upper surface, an outer sidewall, an inner sidewall, and extending from the lower surface It has 3 alignment pins.

[0004] According to another embodiment, the shim of a process tuning kit useful for a chemical vapor deposition apparatus has an upper surface, a lower surface parallel to the upper surface, an end wall, a U-shaped side wall extending from the end wall, a bore extending between the upper surface and the lower surface, and a bore extending between the upper surface and the lower surface. The shim preferably has a bore having a length of about 0.8 inches, a width of about 0.5 inches, and a diameter of about 0.15 inches, and dimensions of 0.0465 inches, 0.0470 inches, 0.0475 inches, 0.0480 inches, 0.0485 inches, 0.0490 inches, 0.0495 inches, 0.0500 inches, 0.0505 inches, 0.0510 inches, 0.0515 inches, 0.0520 inches, 0.0525 inches, 0.0530 inches, 0.0535 inches, 0.0540 inches, 0.0545 inches, 0.0550 inches, 0.0555 inches, 0.0560 inches, 0.0565 inches, 0.0570 inches, and 0.0575 inches. It has a thickness of 0.0580 inches, 0.0585 inches, 0.0590 inches, 0.0595 inches, 0.0600 inches, 0.0605 inches, 0.0610 inches, or 0.0615 inches.

[0005] According to another embodiment, the horseshoe of a process tuning kit useful for a chemical vapor deposition apparatus has an upper surface, a lower surface parallel to the upper surface, an end wall, a U-shaped side wall extending from the end wall, a bore extending between the upper surface and the lower surface, and a slot opening extending within the end wall and across less than half of the upper surface. The horseshoe preferably has a length of about 0.8 inches, a width of about 0.5 inches, and a thickness of about 0.5 inches, the bore has a diameter of about 0.15 inches, the slot has a width of about 0.19 inches and a height of about 0.25 inches, the bore is aligned with the slot, and the sidewalls have a pair of parallel straight sections connected by a semicircular section having a radius of about 0.26 inches measured from the center of the bore, the bore has a uniform diameter section extending about 0.16 inches from the lower surface and a conical section extending into the upper surface of the horseshoe, the conical section forms a chamfer at an angle of about 80°, and the slot has chamfered edges along the end wall and the upper surface.

[0006] In another embodiment, a method for processing a semiconductor substrate in a chemical deposition apparatus comprises: (a) transferring a substrate on a carrier ring into a vacuum chamber of the chemical deposition apparatus and placing the carrier ring on a pedestal assembly having a set of horseshoes and shims that support the carrier ring, wherein the horseshoes have bores that accommodate alignment pins extending from the lower surface of the carrier ring, and the substrate is lifted from the carrier ring by MCA (minimum contact area) supports on the pedestal assembly such that the lower side of the substrate is located at a predetermined offset distance from the upper surface of the carrier ring; and (b) heating the substrate to minimize back-side deposition on the substrate and depositing a material layer on the substrate while maintaining a predetermined offset distance. Brief explanation of the drawing

[0007] FIG. 1 illustrates a schematic diagram showing a chemical deposition apparatus having a pedestal according to an exemplary embodiment. FIG. 2 is a perspective view of a pedestal assembly supporting a carrier ring on horseshoes and shims positioned around the periphery of the pedestal assembly. FIGS. 3a to 3e are drawings of a carrier ring, FIG. 3a is a top view of the carrier ring, FIG. 3b is a side view of the carrier ring along line AA of FIG. 3a, FIG. 3c is a cross-sectional view of detail B of FIG. 3b, FIG. 3d is a cross-sectional view of detail D of FIG. 3c, and FIG. 3e is a cross-sectional view of detail E of FIG. 3c. FIGS. 4a to 4d are drawings of a horseshoe, FIG. 4a is a perspective view of a horseshoe, FIG. 4b is a top view of a horseshoe, FIG. 4c is a drawing of the end of a horseshoe, and FIG. 4d is a cross-sectional view along line AA of FIG. 4b. FIGS. 5a to 5c are drawings of the core, FIG. 5a is a perspective view of the core, FIG. 5b is a top view of the core, and FIG. 5c is a drawing of the end of the core. FIG. 6 is a perspective view of a pedestal assembly having a horseshoe and a shim mounted on the pedestal assembly using a positioning pin. Specific details for implementing the invention

[0008] Cross-reference of related applications

[0009] This application is a partial continuation of U.S. Patent Application No. 14 / 972,205, filed December 17, 2015, the entire contents of which are incorporated herein by reference.

[0010] In the following detailed disclosure, exemplary embodiments are mentioned to provide an understanding of the apparatuses and methods disclosed herein. However, as will be obvious to those skilled in the art, exemplary embodiments may be practiced without these specific details or by using alternative elements or processes. In other examples, known processes, procedures, and / or components are not described in detail so as not to unnecessarily obscure the aspects of the embodiments disclosed herein.

[0011] According to exemplary embodiments, the apparatuses and associated methods disclosed herein may be used to perform chemical deposition such as PECVD. The apparatuses and methods may be used in conjunction with, but are not limited to, semiconductor fabrication based on dielectric deposition processes that require the separation of self-limiting deposition steps in a multi-step deposition process (e.g., ALD (atomic layer deposition), PEALD (plasma enhanced atomic layer deposition), PDL (pulsed deposition layer), or PEPDL (plasma enhanced pulsed deposition layer) processing).

[0012] As indicated, the embodiments provide apparatus and associated methods for performing chemical deposition such as PECVD. The apparatus and methods are applicable, but not limited to, use in semiconductor manufacturing based on dielectric deposition processes that require the separation of self-limiting deposition steps in multi-step deposition processes (e.g., ALD (atomic layer deposition), PEALD (plasma enhanced atomic layer deposition), PECVD (plasma enhanced chemical vapor deposition), PDL (pulsed deposition layer), or PEPDL (plasma enhanced pulsed deposition layer) processing). The aforementioned processes may suffer from some disadvantages associated with deposition on the back surface of a processed wafer, which can cause wafer curvature as a result of stress on the wafer induced by back film deposition.

[0013] In chemical vapor deposition processes, a semiconductor substrate, such as a wafer, can be held on minimum contact area (MCA) pins positioned on a heated pedestal. The wafer or other substrate can be transferred onto a carrier ring, such as a ceramic carrier ring, which, in addition to holding the wafer, also helps to focus plasma onto a targeted area on the wafer. The pedestal may be made of any material that withstands high temperatures and is inert to chemical environments. Examples of suitable materials include metals such as aluminum or ceramics such as aluminum nitride and boron nitride. To support the wafer and accommodate the carrier ring, the pedestal may have two sections of different diameters, where a mesa-shaped portion supports the wafer and an annular recess at the periphery of the pedestal allows for the placement of the carrier ring used to transfer the wafer into and from the pedestal. While the MCA pins ensure uniform and high-speed heating of the wafer, the front-to-back film deposition ratio can be approximately 1:1 when measured at 3 mm from the bevel edge of the wafer.

[0014] The embodiments disclosed herein are preferably implemented in a deposition apparatus such as a plasma-enhanced chemical vapor deposition apparatus (i.e., a PECVD apparatus, a PEALD apparatus, or a PEPDL apparatus), but are not limited thereto. FIG. 1 provides a simple block diagram illustrating various substrate plasma processing apparatus components configured to implement embodiments as disclosed herein. As illustrated, the substrate plasma processing apparatus (300) includes a vacuum chamber (324) that serves to contain plasma within a processing zone, and the processing zone is created by a capacitor-type system comprising a substrate pedestal assembly (320) having a lower RF electrode (not shown) inside and a showerhead assembly (314) having an upper RF electrode (not shown) that works together with the lower RF electrode (not shown) inside. At least one RF generator is operable to supply RF energy into the processing zone on the upper surface of the substrate (316) within the vacuum chamber (324) so ​​as to energize the gas supplied into the processing zone of the vacuum chamber (324) into plasma so that a plasma deposition process may be performed within the vacuum chamber (324). For example, the HF RF generator (302) and the LF RF generator (304) may each be connected to a matching network (306), and the matching network is connected to the upper RF electrode of the showerhead assembly (314) so ​​that RF energy may be supplied into the processing zone on the substrate (316) within the vacuum chamber (324).

[0015] The power and frequency of the RF energy supplied into the interior of the vacuum chamber (324) by the matching network (306) are sufficient to generate plasma from the gas. In one embodiment, both an HF RF generator (302) and an LF RF generator (304) are used, and in an alternative embodiment, only the HF RF generator (302) is used. In the process, the HF RF generator (302) may be operated at frequencies of about 2 to 100 MHz, in a preferred embodiment, 13.56 MHz or 27 MHz. The LF RF generator (304) may be operated at about 50 kHz to 2 MHz, in a preferred embodiment, about 350 to 600 kHz. Process parameters may be scaled based on the chamber volume, substrate size, and other factors. Similarly, the flow rates of the process gases may depend on the free volume of the vacuum chamber or processing zone.

[0016] The upper surface of the substrate pedestal assembly (320) supports the substrate (316) during processing within the vacuum chamber (324). The substrate pedestal assembly (320) may optionally include a chuck for holding the substrate and / or lift pins for raising and lowering the substrate before, during, and / or after the deposition process and / or plasma treatment process. In an alternative embodiment, the substrate pedestal assembly (320) may include a carrier ring for raising and lowering the substrate before, during, and / or after the deposition process and / or plasma treatment process. The chuck may be an electrostatic chuck, a mechanical chuck, or various other types of chucks available for industrial and / or research use. Details of a lift pin assembly for a substrate pedestal assembly including an electrostatic chuck are known from the jointly assigned U.S. Patent No. 8,840,754, which is incorporated herein by reference in its entirety. Details of the carrier ring for the substrate pedestal assembly are known from the jointly assigned U.S. Patent No. 6,860,965, which is incorporated herein by reference in its entirety. The rear gas supply unit (341) is operable to supply a heat transfer gas or purge gas through the substrate pedestal assembly (320) to an area below the lower surface of the substrate during processing. The substrate pedestal assembly (320) may include a lower RF electrode internally, and the lower RF electrode is preferably grounded during processing, but in an alternative embodiment, the lower RF electrode may be supplied with RF energy during processing.

[0017] To process a substrate within the vacuum chamber (324) of a substrate plasma processing device (300), gases are introduced into the vacuum chamber (324) from a gas source (362) through an inlet (312) and a showerhead assembly (314), and the gases are formed into plasma using RF energy so that a film may be deposited on the upper surface of the substrate. In one embodiment, the gas source (362) may include a plurality of gas lines (310) connected to a heated manifold (308). The gases may be pre-mixed or supplied individually to the chamber. Appropriate valves and mass flow control mechanisms are employed to ensure that the correct gases are delivered through the showerhead assembly (314) during substrate processing. During processing, a back heat transfer gas or a purge gas is selectively supplied to an area below the lower surface of the substrate supported on the substrate pedestal assembly (320). Preferably, the processing is at least one of CVD processing, PECVD processing, ALD processing, PEALD processing, PDL processing, or PEPDL processing.

[0018] In specific embodiments, a system controller (162) is employed to control process conditions during deposition, post-deposition processes and / or other process operations. The system controller (162) will typically include one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc. In specific embodiments, the system controller (162) controls all activities of the device. The system controller (162) executes system control software comprising sets of instructions for controlling the timing of processing operations, the frequency and power of operations of the LF RF generator (304) and HF RF generator (302), the flow rates and temperatures of precursors and inert gases, and their relative mixing, the temperature of the plasma-exposed surface of the substrate (316) and showerhead assembly (314) supported on the upper surface of the substrate pedestal assembly (320), the pressure of the vacuum chamber (324), and other parameters of a specific process. Other computer programs stored on memory devices associated with the controller may be employed in some embodiments. Typically, there will be a user interface associated with the system controller (162). The user interface may include a display screen, a graphical software display of the device and / or a graphical software display of process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, etc. A non-transient computer machine-readable medium may contain instructions for controlling the device. Computer program code for controlling processing operations may be written in any conventional computer-readable programming language: for example, assembly language, C, C++, Pascal, Fortran, etc.Compiled object code or scripts are executed by the processor to perform tasks identified within the program.

[0019] Controller parameters relate to process conditions, such as, for example, the timing of processing steps, the flow rates and temperatures of precursors and inert gases, the temperature of the substrate, the pressure of the chamber, and other parameters of a specific process. These parameters are provided to the user in the form of a recipe and may be entered using a user interface. Signals for monitoring the process may be provided by the analog input connection and / or digital input connection of the system controller. Signals for controlling the process are outputs on the analog output connection and digital output connection of the device. The system software may be designed or configured in numerous different ways. For example, various chamber component subroutines or control objects may be written to control the operation of chamber components necessary to perform deposition processes. Examples of programs or sections of programs for this purpose include codes for substrate timing of processing steps, codes for the flow rates and temperatures of precursors and inert gases, and codes for the pressure of the vacuum chamber (324).

[0020] As mentioned above, it would be desirable to reduce back-side deposition on the processed wafer. In exemplary embodiments, back-side deposition can be significantly reduced. For example, considering a 300 Å film, a process tuning kit (PTK) can be used to reduce back-side deposition to 150 Å or less, preferably 100 Å or less, and more preferably 50 Å or less at 3 mm from the bevel edge. This improved performance is enabled by modifications to the carrier ring and horseshoe set that hold the wafer at a target distance over the carrier ring during processing. However, in one embodiment, the wafer and the carrier ring may come into contact with each other during processing.

[0021] The PTK comprises at least one of a carrier ring, a horseshoe, and a shim of a shim set. In a preferred embodiment, the pedestal comprises three recesses that accommodate three horseshoes whose height can be varied relative to the upper surface of the pedestal by mounting a shim under each horseshoe. The shim set comprises shims of different thicknesses that may range from 0.04 inches to 0.08 inches. For example, the shim set may comprise groups of shims having at least 10, preferably at least 20, and more preferably at least 30 groups of shims having different thicknesses that vary by 0.0005 inches. In an exemplary embodiment, for use with a pedestal, the shim set comprises 0.0465, 0.0470, 0.0475, 0.0480, 0.0485, 0.0490, 0.0495, 0.0500, 0.0505, 0.0510, 0.0515, 0.0520, 0.0525, 0.0530, 0.0535, 0.0540, 0.0545, 0.0550, 0.0555, 0.0560, 0.0565, 0.0570, 0.0575, 0.0580, 0.0585, 0.0590, 0.0595, 0.0600, It may include groups of at least three shims having thicknesses of 0.0605, 0.0610, and 0.0615 inches. Thus, depending on the specific deposition process and the temperature of the pedestal, the set of shims can be used to position the wafer at a predetermined gap (offset distance) between the wafer and the carrier ring by adjusting the height of the horseshoes.

[0022] In a vacuum chamber (324), a pedestal assembly (320) supports a substrate (316) upon which materials may be deposited. The pedestal assembly (320) may be coupled with a heater block for heating the substrate (316) to a target temperature. Generally, the substrate (316) is maintained at a temperature of about 25°C to 500°C depending on the material to be deposited. In a multi-station deposition apparatus, each station may heat the wafer to a different temperature, and shims of different thicknesses may be used to vary the offset distance suitable for processing conditions at each station.

[0023] FIG. 2 is a perspective view of a pedestal assembly (320) in which a carrier ring (400) is placed (sit) within an annular recess (321) that extends into the upper surface (322) of the pedestal assembly (320). In a preferred embodiment, the pedestal assembly (320) includes three rectangular openings (323) that extend into the outer periphery of the side wall (324) of the pedestal assembly (320), and three horseshoes (500) are positioned within the openings (323). Shims (600) are positioned under the horseshoes (500) to adjust the height of the horseshoes relative to the upper surface (322) of the pedestal assembly (320).

[0024] FIGS. 3a through 3d illustrate preferred embodiments of a carrier ring (400). As shown in FIG. 3a, the carrier ring (400) comprises an annular upper surface (401), an outer sidewall (402), and an inner sidewall (403). FIG. 3b illustrates a cross-sectional view of the carrier ring (400) along line AA of FIG. 3a. As shown in FIG. 3b, the carrier ring (400) comprises a lower surface (404), and the lower surface comprises a plurality of alignment pins (405) extending from the lower surface. FIG. 3c is a cross-sectional view of the carrier ring (400) at detail B of FIG. 3b. As shown in FIG. 3c, the alignment pin (405) is positioned inward of the outer sidewall (402), and the annular recess (406) extends into the inner sidewall (403) and into the upper surface (401). FIG. 3d is a cross-sectional view of the carrier ring (400) in detail D of FIG. 3c, and FIG. 3e is a cross-sectional view of the carrier ring (400) in detail E of FIG. 3e. As shown in FIG. 3d, the alignment pin (405) includes a uniform diameter portion (407) near the lower surface (404) and a tapered portion (408) at the free end of the alignment pin (405). As shown in FIG. 3e, the annular recess (406) is formed by a vertical wall (409) and a horizontal wall (410). The carrier ring preferably has an outer diameter of about 15 inches, an inner diameter of about 11.7 inches, a thickness of about 0.1 inches, and three alignment pins, each of which has a length of about 0.2 inches with a uniform diameter portion extending about 0.06 inches from the lower surface and a tapered portion extending to the unblocked end of the alignment pin, and an annular recess extending into the inner wall and the upper surface, having a diameter of about 11.9 inches and formed by a vertical wall extending about 0.03 inches from the upper surface and a horizontal wall extending about 0.08 inches from the inner wall.

[0025] FIGS. 4a through 4d illustrate details of a preferred horseshoe (500). FIG. 4a is a perspective view of a horseshoe (500) having an upper surface (501), an end wall (502), a side wall (503), a lower surface (504), a bore (505), and a slot (506). The side wall (503) has a pair of opposing straight sections connected by a curved portion. The bore (505) extends from the upper surface (501) to the lower surface (504). The slot (506) is open on the end wall (502) and extends along about 1 / 2 of the upper surface (501). The bore (505) is positioned between the slot (506) and the curved portion of the side wall (503). FIG. 4b is a top view of the horseshoe (500), FIG. 4c is a drawing of the end of the horseshoe (500), and FIG. 4d is a cross-sectional view of the horseshoe taken along line AA in FIG. 4b. As can be seen in FIG. 4c, the slot (506) is formed by a vertical wall (507) and a horizontal wall (508), and the vertical wall (507) includes a pair of short curved sections (507a), a pair of straight sections (507b), and a curved section (507). As shown in FIG. 4d, the bore (505) includes a tapered section (505a) and a uniform diameter section (505b). The horseshoe preferably has a length of about 0.8 inches, a width of about 0.5 inches, and a thickness of about 0.5 inches, the bore has a diameter of about 0.15 inches, the slot has a width of about 0.19 inches and a height of about 0.25 inches, the bore is aligned with the slot, and the sidewalls have a pair of parallel straight sections connected by a semicircular section having a radius of about 0.26 inches measured from the center of the bore, the bore has a uniform diameter section extending about 0.16 inches from the lower surface and a conical section extending into the upper surface of the horseshoe, the conical section forms a chamfer at an angle of about 80°, and the slot has chamfered edges along the end wall and the upper surface.

[0026] FIGS. 5A through 5C illustrate details of a shim (600). FIG. 5A is a perspective view of a shim (600) having an upper surface (601), an end wall (602), a side wall (603), a bottom surface (604), and a bore (605) extending between the upper surface (601) and the lower surface (604). The upper surface (601) is parallel to the lower surface (604), and the side wall (603) includes a pair of parallel straight sections (603a) connected by a curved section (603b). The bore (605) has the same diameter as the bore (505) of the horseshoes (500). The shims of the shim set have the same shapes and various thicknesses "t" between the upper surface (601) and the lower surface (604). The shim preferably has a bore having a length of about 0.8 inches, a width of about 0.5 inches, and a diameter of about 0.15 inches, and dimensions of 0.0465 inches, 0.0470 inches, 0.0475 inches, 0.0480 inches, 0.0485 inches, 0.0490 inches, 0.0495 inches, 0.0500 inches, 0.0505 inches, 0.0510 inches, 0.0515 inches, 0.0520 inches, 0.0525 inches, 0.0530 inches, 0.0535 inches, 0.0540 inches, 0.0545 inches, 0.0550 inches, 0.0555 inches, 0.0560 inches, 0.0565 inches, 0.0570 inches, and 0.0575 inches. It has a thickness of 0.0580 inches, 0.0585 inches, 0.0590 inches, 0.0595 inches, 0.0600 inches, 0.0605 inches, 0.0610 inches, or 0.0615 inches.

[0027] FIG. 6 illustrates details of a horseshoe (500) and a shim (600) mounted within a rectangular opening (323) of a pedestal assembly (320). As illustrated, the horseshoe and the shim (600) are held within the opening (323) by a positioning pin (325) that extends through a bore (605) within the shim (600) and into the bore (505) of the horseshoe (500). By using a shim having a targeted thickness "t", it is possible to position an upper surface (501) having a targeted offset relative to the upper surface (322) of the pedestal assembly (320).

[0028] The process tuning kit (PTK) preferably includes a set of shims configured to position the carrier ring (400) at a targeted offset distance with respect to the upper surface (322) of the pedestal assembly (320). In a multi-station processing apparatus, such as a system in which four carrier rings are mounted on four pedestal assemblies positioned inside a vacuum chamber and wafers are processed sequentially at each station, each pedestal assembly may be provided with shims having a predetermined thickness selected to reduce back-side deposition on the substrate. Thus, it is possible to use a set of horseshoes within each pedestal assembly and adjust their height together with the set of shims.

[0029] The carrier ring (400) may have different inner diameters to achieve targeted processing effects. For example, to change the degree of back deposition, it may be targeted to reduce the inner diameter of the inner sidewall (403) to provide a targeted gap between the bottom side of the wafer and the annular recess (406) of the carrier ring (400). Variations in the inner diameter of the carrier ring (400) of approximately a few thousandths of an inch may contribute to a reduction in back deposition.

[0030] The materials used for the carrier rings, horseshoes, and shims are preferably ceramic materials having a suitable purity, such as 99.5% or higher, suitable for semiconductor processing. The carrier rings, horseshoes, and shims are preferably made of high-purity aluminum oxide produced by any suitable technique. For example, as a starting material, high-purity alumina powder and small amounts of MgCO3, CaCO3, and SiO2 powders acting as sintering aids during firing may be mixed to obtain a slurry and subjected to wet grinding, an organic binder may be added to the slurry, mixing is performed, and then spray-dried to form alumina granules.

[0031] To produce a carrier ring, alumina granules can be formed into a molded body having an outer diameter of about 15 inches, an inner diameter of about 11.7 inches, and a thickness of about 0.1 inches using three alignment pins about 0.2 inches long. The resulting molded body can be machined if necessary and fired in air at 1,550 °C to 1,650 °C to form a sintered body. The resulting sintered body can undergo heat treatment by hot isostatic pressing (HIP) in Ar gas at a temperature lower than the firing temperature, ranging from 1,500 °C to 1,600 °C and at 200 MPa. Accordingly, a dense alumina body is formed. The resulting dense alumina body can be annealed in air for at least 5 minutes at a temperature in the range of 1,400 °C to 1,550 °C, which is lower than the heat treatment temperature by HIP. The temperature drop rate from the temperature during HIP to the annealing temperature after HIP is set low to less than 1.0 °C / hour. For example, the temperature drop rate can be set to 0.6 °C / hour. After annealing is performed, both main surfaces can be polished with any suitable equipment, such as diamond-electrodeposited grindstone using a rotary grinder. Accordingly, a carrier ring can be obtained. Using a laser beam machine, the resulting carrier ring can be machined to have precise dimensions and surface roughness.

[0032] To produce a horseshoe, alumina granules may be formed into a molded body approximately 0.825 inches long, 0.525 inches wide, and 0.53 inches thick. The resulting molded body may be machined to form a bore approximately 0.15 inches in diameter with a taper of approximately 80° on the upper surface, and a slot may be formed approximately 0.25 inches deep, 0.2 inches wide, and 0.3 inches long and processed for a carrier ring as described above. After sintering and annealing treatments are performed, the exposed surfaces may be polished using any suitable equipment, such as diamond-electrodeposited grindstone using a rotary grinder. Accordingly, a horseshoe may be obtained. Using a laser beam machine, the resulting horseshoe may be machined to have precise dimensions and surface roughness.

[0033] To produce a shim, alumina granules may be formed into a molded body with a length of 0.825 inches, a width of about 0.525 inches, and a thickness of about 0.05 to 0.06 inches. The resulting molded body may be machined to form a bore having a diameter of about 0.15 inches and processed for a carrier ring as described above. After sintering and annealing treatments are performed, the exposed surfaces may be polished using any suitable equipment, such as a diamond-electrodeposited grindstone using a rotary grinder. Accordingly, a shim may be obtained. Using a laser beam machine, the resulting shim may be machined to have precise dimensions and surface roughness.

[0034] A method for processing a semiconductor substrate within a processing apparatus is also disclosed herein. The method comprises the steps of supplying reactor chemicals from a reactor chemicals source into a deposition chamber, and processing a semiconductor substrate within a plasma processing chamber. The method preferably comprises the step of plasma processing a substrate in which RF energy is applied to the reactor chemicals using an RF generator that generates plasma within the deposition chamber.

[0035] When the word "about" is used with a numerical value in this specification, the associated numerical value is intended to include a tolerance of ±10% with respect to the mentioned numerical value.

[0036] Furthermore, when the words “generally,” “relatively,” and “substantially” are used with geometric shapes, rather than requiring precision of the geometric shapes, the latitude of the shapes is intended to be within the scope of the present disclosure. When used with geometric terms, the words “generally,” “relatively,” and “substantially” are intended to encompass not only features satisfying the strict definitions but also features that are fairly close to the strict definitions.

[0037] Although a plasma processing apparatus including an isothermal deposition chamber has been described with reference to specific embodiments, it will be obvious to those skilled in the art that various changes and modifications may be made and equivalents adopted without departing from the scope of the appended claims.

Claims

Claim 1 A method for processing a semiconductor substrate in a chemical vapor deposition apparatus, comprising the steps of: transferring the substrate on a ceramic carrier ring into a vacuum chamber of the chemical vapor deposition apparatus and placing the carrier ring on a pedestal assembly having a set of ceramic horseshoes and ceramic shims that support the carrier ring, wherein the horseshoes have bores that receive alignment pins extending from the lower surface of the carrier ring, and the substrate is lifted from the carrier ring by MCA (minimum contact area) supports on the pedestal assembly such that the lower surface of the substrate is located at a predetermined offset distance from the upper surface of the carrier ring; and heating the substrate and depositing a layer of material on the substrate while maintaining the predetermined offset distance. Claim 2 A method for processing a semiconductor substrate according to claim 1, wherein the pedestal assembly comprises an annular recess and three rectangular openings extending into the outer periphery of the pedestal assembly and opening into the annular recess, each of the rectangular openings having the shim and the horseshoe mounted internally using a positioning pin on the pedestal assembly extending through the bores of the shims and partially extending through the bores of the horseshoes, and each of the shims having the same thickness and providing the predetermined offset distance that limits back deposition to 50 Å or less at 3 mm from the bevel edge of the substrate.

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