THICKNESS UNIFORMITY IMPROVEMENT KIT FOR THERMALLY SENSITIVE EPITAXIAL PROCESSING

Embodiments described herein relate to a susceptor kit. The susceptor kit includes a susceptor support plate including a plurality of susceptor lift pin holes and a plurality of susceptor support holes, a plurality of susceptor supports recessed within the plurality of susceptor support holes and coupled to the susceptor support plate, and a lift pin assembly. The plurality of susceptor supports receive a plurality of susceptor support pins. The support body supports the support pin link in a spaced apart relation to the susceptor support plate. The lift pin assembly is received in the plurality of susceptor lift pin holes. The lift pin assembly includes a lift pin cap and a susceptor lift pin comprising a susceptor stop plate. The susceptor support plate stop is receivable within the susceptor lift pin holes.

BACKGROUND

Field

Embodiments of the present disclosure generally relates to thermal processing of thin films on substrates, such as silicon wafers. More specifically, the embodiments of the disclosure relates to processing kits for epitaxial deposition.

Description of the Related Art

In solid-state integrated circuit fabrication, epitaxial processing is typically performed in an epitaxial processing chamber. A substrate disposed on a substrate support in the epitaxial processing chamber is typically heated by lamps positioned over and/or under the substrate.

However, during processing, various chamber components can create shadowing on the substrate support. This shadowing obstructs the heat from the lamps used to heat the substrate support and the substrate, causing non-uniform temperature distribution and consequently non-uniform deposition. Therefore, there is a need for an improved hardware for epitaxial deposition.

SUMMARY

The present disclosure generally relates to thermal processing of thin films on substrates, such as silicon wafers. More specifically, the embodiments of the disclosure relates to processing kits for epitaxial deposition.

In one embodiment, a susceptor kit includes a susceptor support plate, a plurality of susceptor supports, and a lift pin assembly. The susceptor support plate includes a plurality of susceptor lift pin holes and a plurality of susceptor support holes. The plurality of susceptor supports are recessed within the plurality of susceptor support holes and coupled to the susceptor support plate. The plurality of susceptor supports each include two or more susceptor support pins to support a substrate support. The susceptor lift pin assembly received in the plurality of susceptor lift pin holes.

In another embodiment, a susceptor kit includes a susceptor support plate, a plurality of susceptor supports, and a lift pin assembly. The susceptor support plate includes a plurality of susceptor lift pin holes and a plurality of susceptor support holes. The plurality of susceptor supports are recessed within the plurality of susceptor support holes and are coupled to the susceptor support plate. Each of the plurality of susceptor supports include two or more susceptor support pins support a substrate support. The lift pin assembly receives in the plurality of susceptor lift pin holes.

In another embodiment, a susceptor kit includes a susceptor support plate including a plurality of susceptor lift pin holes and a plurality of susceptor support holes, a plurality of susceptor supports recessed within the plurality of susceptor support holes and coupled to the susceptor support plate, and a lift pin assembly. The plurality of susceptor supports include a support body and a support pin link. A support connector is received by a support anchor of the susceptor support plate to secure the support body to the susceptor support plate. The support pin link receives a plurality of susceptor support pins. The support body supports the support pin link in a spaced apart relation to the susceptor support plate. The lift pin assembly is received in the plurality of susceptor lift pin holes. The lift pin assembly includes a lift pin cap and a susceptor lift pin comprising a susceptor stop plate. The susceptor support plate stop is receivable within the susceptor lift pin holes.

DETAILED DESCRIPTION

The present disclosure generally relates to thermal processing of thin films on substrates, such as silicon wafers. More specifically, the embodiments of the disclosure relates to susceptor kits for thermally sensitive epitaxial deposition.

FIG.1is a schematic cross-section of an epitaxial system100according to one embodiment of the present disclosure. The epitaxial system100is utilized to grow an epitaxial film on a substrate, such as the substrate102. The epitaxial system100creates a cross-flow of precursors across the top surface150of the substrate102.

The epitaxial system100includes an upper body156, a lower body148disposed below the upper body156, a flow module112disposed between the upper body156and the lower body148. The upper body156, the flow module112, and the lower body148form a chamber body. Disposed within the chamber body is a substrate support106(e.g. a susceptor), an upper window108(e.g., dome), a lower window110(e.g., dome), a plurality of upper lamps141, and a plurality of lower lamps143.

A controller120is in communication with the epitaxial system100and is used to control processes, such as those described herein. The controller120is configured to receive data or input as sensor readings from the epitaxial system100. The controller120is equipped with or in communication with a system model of the epitaxial system100. The system model includes an epitaxial deposition model. The system model is a program configured to monitor the deposition process within the epitaxial system100throughout a deposition process. The epitaxial system100is further configured to store readings and calculations in the memory135.

The readings and calculations include previous sensor readings as well as any other previous sensor readings within the epitaxial system100. The readings and calculations further include the stored calculated values from after the sensor readings are measured by the sensors153within the epitaxial system100and run through the system model. Therefore, the controller120is configured to both retrieve stored readings and calculations as well as save readings and calculations in the memory135for future use. Maintaining previous readings and calculations in the memory135enables the controller120to adjust the system model over time to reflect a more accurate version of the epitaxial system100.

In embodiments described herein, the controller120includes a programmable central processing unit (CPU)155that is operated with the memory135and a display unit (not shown). The controller120monitors the deposition, gas flow, temperature, and actuation of the shaft118within the epitaxial system100. Support circuits158are coupled to the CPU155for supporting the processor in a conventional manner. In some embodiments, the controller120includes multiple controllers120, such that the stored readings and calculations and the system model are stored within a separate controller120from the controller120, which operates the epitaxial system100. In other embodiments, all of the system model and the stored readings and calculations are saved within the controller120.

The controller120is configured to control the deposition, gas flow, temperature, and actuation of the shaft118within the epitaxial system100. The controller120is configured to adjust the aspects of the epitaxial system100based off the sensor readings, the system model, and the stored readings and calculations. The controller120includes embedded software and a compensation algorithm to calibrate deposition, gas flow, temperature, and actuation of the shaft118within the epitaxial system100. The controller120may include a machine-learning algorithm and may use a regression or clustering technique. The algorithm is an unsupervised or a supervised algorithm.

The substrate support106is disposed between the upper window108and the window110. The plurality of upper lamps141are disposed between the upper window108and a lid154. The lid154includes a plurality of sensors153disposed therein for measuring the temperature within the epitaxial system100. The plurality of lower lamps143are disposed between the lower window110and a floor152. The plurality of lower lamps143form a lower lamp assembly145.

A processing volume136is formed between the upper window108and the lower window110. The processing volume136has the substrate support106disposed therein. The substrate support106includes a top surface on which the substrate102is disposed. The substrate support106is attached to a shaft118. The shaft118is connected to a motion assembly121. The motion assembly121includes one or more actuators and/or adjustment devices that provide movement and/or adjustment of the shaft118and/or the substrate support106within the processing volume136. The motion assembly121includes a rotary actuator122that rotates the shaft118and/or the substrate support106about a longitudinal axis A of the epitaxial system100. The motion assembly121further includes a vertical actuator124to lift and lower the substrate support106in the z-direction. The motion assembly121includes a tilt adjustment device126that is used to adjust the planar orientation of the substrate support106and a lateral adjustment device128that is used to adjust the position of the shaft118and the substrate support106side to side within the processing volume136.

The substrate support106may include lift pin holes107disposed therein. The lift pin holes107are sized to accommodate a lift pin132for lifting of the substrate102from the substrate support106either before or after a deposition process is performed. The lift pins132may rest on lift pin stops134when the substrate support106is lowered from a processing position to a transfer position.

The flow module112includes a plurality of process gas inlets114, a plurality of purge gas inlets164, and one or more exhaust gas outlets116. The plurality of process gas inlets114and the plurality of purge gas inlets164are disposed on the opposite side of the flow module112from the one or more exhaust gas outlets116. One or more flow guides146are disposed below the plurality of process gas inlets114and the one or more exhaust gas outlets116. The flow guide146is disposed above the purge gas inlets164. A liner163is disposed on the inner surface of the flow module112and protects the flow module112from reactive gases used during deposition processes. The process gas inlets114and the purge gas inlets164are positioned to flow a gas parallel to the top surface150of a substrate102disposed within the processing volume136. The process gas inlets114are fluidly connected to a process gas source151. The purge gas inlets164are fluidly connected to a purge gas source162. The one or more exhaust gas outlets116are fluidly connected to an exhaust pump157. Each of the process gas source151and the purge gas source162may be configured to supply one or more precursors or process gases into the processing volume136.

FIG.2is a schematic cross-section of a susceptor kit200coupled to the substrate support106. The susceptor kit200includes a susceptor support plate202attaches to the shaft118between the shaft118and the substrate support106. The susceptor support plate202supports the substrate support106within the processing volume136, as shown inFIG.1, of the epitaxial system100. A distance D1from the top surface of the susceptor support plate202to the bottom surface of the substrate support106is between about 20 mm and about 40 mm. The susceptor kit200further includes a plurality of susceptor supports204and a lift pin assembly205. The susceptor supports204are received within a plurality of susceptor support holes208of the susceptor support plate202. The susceptor supports204couple the susceptor support plate202the substrate support106. The lift pin assembly205further includes a susceptor lift pin212including a lift pin cap214and a susceptor support plate stop216. In one embodiment, the lift pin cap214and the susceptor support plate stop216have inverted frustoconical shapes. The lift pin cap214is received within the plurality of susceptor lift pin holes107of the substrate support106and the susceptor support plate stop216is received within a plurality of susceptor lift pin holes206of the susceptor support plate202. The lift pin holes107have a corresponding inverted frustoconical shape to receive the inverted frustroconical shape of the lift pin cap214. The susceptor support plate lift pin holes206have a corresponding inverted frustoconical shape to receive the susceptor lift pins212. The susceptor support plate202has a thickness t of between about 2 mm and about 5 mm. The susceptor support plate202further includes a diameter d1of between about 200 mm and about 500 mm. The diameter d1of the susceptor support plate202is approximately equal to a diameter d2of the substrate support. In one embodiment, the susceptor support plate202include a material with high UV light transmission (T), e.g., a material through which UV light can travel efficiently. In one embodiment, the material has a T>80%. In one embodiment, the material with high UV transmission includes a quarts material.

FIG.3Ais a schematic cross-section of the susceptor kit200at cut line A-A. The susceptor supports204includes a plurality of susceptor support pins302. The susceptor support pins302are positioned radially from the center of the susceptor support plate202(shown inFIGS.3B and3C) about a perimeter of the susceptor support plate202to contact the edge of the substrate support106. In the illustrated embodiment, each susceptor support204(shown inFIG.2) includes two susceptor support pins302, and the susceptor support pins302are positioned radially about every 60°. The six points of contact help to distribute thermal contact with the substrate support106and assist in positioning (e.g., centering) the substrate support106within the processing volume136. In the illustrated embodiment, the lift pin holes107are positioned radially about every 120° such that the lift pin hole107is between every other susceptor support pin302. Other radially spacing, however, are contemplated by this disclosure. The lift pin holes107are a radial distance R1from the center of the substrate support106of between about 100 mm and about 120 mm. The susceptor support pins302include a silicon carbide material, however, other materials are also contemplated.

FIG.3Bis a schematic cross-section of the susceptor kit200at cut line B-B. The susceptor support204further comprises a support pin link304. The support pin link304spans between the two susceptor support pins302per each susceptor support204, as shown inFIG.6A-6C, and receives the susceptor support pins302. The susceptor support204further comprises a support body604, as shown inFIG.6A-6C. The support body604supports the support pin link304in spaced apart relation to the susceptor support plate202.

FIG.3Cis a schematic cross-section of the susceptor support plate202at cut line C-C. The susceptor support plate202further includes susceptor support holes208which receive the susceptor supports204. In the illustrated embodiment, the susceptor support holes208and the susceptor support plate lift pin holes210is are radially aligned and positioned radially about every 120°. Other radially spacing, however, is contemplated by this disclosure. The susceptor support holes208are a radial distance R2from the center of the susceptor support plate202of between about 165 mm and about 185 mm. The susceptor lift pin holes206are a radial distance R3from the center of the susceptor support plate202of between about 100 mm and about 120 mm. The radial distance R1and R3are substantially the same, e.g., +/−about 1 mm.

FIG.4is a schematic cross-section of the lift pin assembly205. The lift pin cap214is an inverted frustoconical body and includes a bottom surface411and a top surface413. The top surface413of the lift pin cap214is substantially flat in order to facilitate even contact with the substrate102. The bottom surface411includes a lift pin alignment hole415to receive the susceptor lift pin212. In one embodiment, the lift pin alignment hole415has a tapered design, with the sidewalls417of the lift pin alignment hole415tapering outward away from the top418of the lift pin alignment hole415toward the bottom surface411of the lift pin alignment hole415. The tapered design of the lift pin alignment hole415allows for the susceptor lift pin212to easily align with the lift pin alignment hole415. The lift pin cap214further includes flared sidewalls419. The flared sidewall419flare outward from the bottom surface411toward the top surface413such that the diameter of the lift pin cap214increases from the bottom surface411to the top surface413. The flared sidewalls419align the lift pin cap214with the lift pin holes107and prevent the lift pin cap214from passing through the lift pin holes107of the substrate support106. In one embodiment, the lift pin cap214includes a material that thermally matches the material of the substrate support106, e.g., the material of the lift pin cap214includes silicon carbide or silicon carbide coated graphite.

A first end420of the susceptor lift pin212is received within the lift pin alignment hole415. A second end422of the susceptor lift pin212is opposite the first end420of the susceptor lift pin212. The susceptor support plate stop216is configured between the first end420and second end422of the susceptor lift pin212. The susceptor support plate stop216further includes a flared portion424and a stop portion426. The flared portion424is oriented toward the second end422of the susceptor lift pin212, while the stop portion426is oriented toward the first end420of the susceptor lift pin212. The flared portion424flares outwards toward the stop portion426of the susceptor lift pin212. The flared portion424of the susceptor support plate stop216aligns the susceptor support plate stop216with the plurality of susceptor lift pin holes206. The stop portion426of the susceptor support plate stop216prevents the susceptor lift pin212from passing through the plurality of susceptor lift pin holes206.

The second end422of the susceptor lift pin212is engaged by the lift pin stops134when the susceptor support plate202is lowered from a processing position to a transfer position within the processing volume136. As the susceptor support plate continues to be lowered in the processing volume, the first end420of the susceptor lift pin212is received in the lift pin alignment hole415and engages the top418of the lift pin alignment hole415. The susceptor lift pin212forces the top surface413of the lift pin cap214to engage the substrate102, moving the substrate102off the substrate support106. The lift pin cap214, when engaged by the susceptor lift pins212, may lift the substrate102from the substrate support106before a deposition process in order to facilitate alignment of the substrate102by a robot arm on the substrate support106. The lift pin cap214, when engaged by the susceptor lift pins212, may also lift the substrate102from the substrate support106after a deposition process to position the processed substrate102to be removed from the processing volume136by the robot and replaced by a substrate102that is to be processed within the processing volume136. The susceptor lift pins212may rest on lift pin stops134when the substrate support106is lowered from the processing position to the transfer position. While in the processing position, the susceptor lift pin212is not engaged with the lift pin cap214. The lift pin cap214is recessed within the lift pin holes107while in the processing position, such that the lift pin cap214is not in contact with the substrate102.

In one embodiment, the susceptor lift pins212and the lift pin stops134include a material with high UV light transmission (T), e.g., a material through which UV light can travel efficiently. In one embodiment, the material has a T>80%. In one embodiment, the material with high UV transmission includes a quarts material.

FIG.5is a schematic cross-section of an alternative lift pin cap514and alternative susceptor lift pin512. The lift pin cap514may be used in place of lift pin cap214, and susceptor lift pin512may be used in place of susceptor lift pin212. The lift pin cap514includes sidewalls519, top surface513, and bottom surface511. The bottom surface511has a lift pin alignment hole515to receive the susceptor lift pins512. The lift pin alignment hole is defined by a top518of the lift pin alignment hole515, sidewalls517of the lift pin alignment hole515, and bottom lip527of the lift pin alignment hole515. The sidewalls517, top518, and bottom lip527form a generally circular cavity. The susceptor lift pin512further includes a first end cap528at a first end520of the susceptor lift pin512. The first end cap528is received in the lift pin alignment hole515in order to engage the top518of the lift pin cap514. The diameter d3of the first end cap528is substantially the same as the diameter d4of the lift pin alignment hole515, e.g., +/−0.1 mm. The first end cap528is capable of being inserted into the lift pin alignment hole515when the two are aligned. If the first end cap528and lift pin alignment hole515are not aligned, the first end cap528will not fit into the lift pin alignment hole515. When the alternative susceptor lift pin512is in the processing position, e.g., when the lift pin cap514is recessed in the lift pin holes107, the susceptor lift pin is held within the lift pin cap514by the first end cap528. In this embodiment, the susceptor support plate stops216are not used.

The first end cap528of susceptor lift pin512forces the top surface513of the lift pin cap514to engaged the substrate102, moving the substrate102off the substrate support106. The susceptor lift pins512may lift the substrate102from the substrate support106before a deposition process in order to align the substrate102on the substrate support106. The susceptor lift pins512may also lift the substrate102from the substrate support106after a deposition process to position the processed substrate102to be removed from the processing volume136by a robot and replaced by a substrate that is to be processed within the processing volume136.

In one embodiment, the susceptor lift pins512include a material with high UV light transmission (T), e.g., a material through which UV light can travel efficiently. In one embodiment, the material has a T>80%. In one embodiment, the material with high UV transmission includes a quarts material. In one embodiment, the lift pin cap514includes a material that thermally matches the material of the substrate support106, e.g., the material of the lift pin cap514includes silicon carbide or silicon carbide coated graphite.

FIG.6Ais a schematic cross-section of the susceptor support204.FIG.6Bis a schematic cross-section of the susceptor support204at a cutline D-D.FIG.6Cis a schematic cross-section of the susceptor support204at cutline E-E. The susceptor support204includes the susceptor support pins302, the support pin link304, a support connector602, and a support body604. The support body604is partially recessed in the susceptor support holes208and secured to the susceptor support plate202with the support connector602(i.e., a pin). The support connector602passes through the support body604above the susceptor support hole208. The susceptor support plate202further includes a plurality of support anchors606on an inner side and an outer side of the susceptor support holes208. The inner side of the susceptor support hole208is the side of the susceptor support hole208nearest the center of the susceptor support plate202, while the outer side of the susceptor support hole208is the side of the susceptor support hole208that is furthest from the center of the susceptor support plate202. The support anchors606receive the exposed ends of the support connector602in a pivot connection in order to secure the susceptor supports204to the susceptor support plate202. The support anchors606include a cavity to receive the support connector602. The support body604is sized relative to the susceptor support hole208in order to allow the susceptor support204to pivot within the susceptor support hole208. The susceptor support204pivots about an axis A between about +/−5°. The ability of the susceptor support204to pivot allows for the susceptor support pins302to maintain six-point contact with the substrate support106. The width W1of the support body604(shown inFIG.6C) is between about 10 mm and about 30 mm. The width W2of the susceptor support holes208is between about 12 mm and about 32 mm. The difference between the width W2and the width W1should be about +/−2 mm.

The support body604extends away from the susceptor support plate202and toward the substrate support106. support The support pin link304further includes a pin flange608. The pin flange608extends orthogonally from the support pin link304and support body604toward the center of the susceptor support plate202. The pin flange608further has a support pin hole610for receiving the susceptor support pins302(as shown inFIG.6B). A distance D2from the top surface of the susceptor support plate202to the top of the pin flange608(as shown inFIG.6B) is between about 20 mm and about 40 mm. A distance D3between the support body604and a midpoint of the support pin hole610(as shown inFIG.6A) is between about 10 mm and about 15 mm.

In one embodiment, the components of the susceptor support204and support anchors606include a material with high UV light transmission (T), e.g., a material through which UV light can travel efficiently. In one embodiment, the material has a T>80%. In one embodiment, the material with high UV transmission includes a quarts material.

The use of material with high UV transmission for the components of the susceptor kit200helps to eliminate the shadowing effect of the components on the substrate support106. More uniform heating of the substrate support106leads to more uniform heating of the substrate102, allowing for more uniform deposition over the substrate, i.e., a thickness uniformity range of less than 1%.

In summary, a susceptor kit includes a susceptor support plate, a plurality of susceptor supports, and a lift pin assembly. The susceptor support plate includes a plurality of susceptor lift pin holes and a plurality of susceptor support holes. The plurality of susceptor supports are recessed within the plurality of susceptor support holes and coupled to the susceptor support plate. The plurality of susceptor supports each include two or more susceptor support pins to support a substrate support. The susceptor lift pin assembly received in the plurality of susceptor lift pin holes.

In another embodiment, a susceptor kit includes a susceptor support plate, a plurality of susceptor supports, and a lift pin assembly. The susceptor support plate includes a plurality of susceptor lift pin holes and a plurality of susceptor support holes. The plurality of susceptor supports are recessed within the plurality of susceptor support holes and are coupled to the susceptor support plate. Each of the plurality of susceptor supports include two or more susceptor support pins support a substrate support. The lift pin assembly receives in the plurality of susceptor lift pin holes.

In another embodiment, a susceptor kit includes a susceptor support plate including a plurality of susceptor lift pin holes and a plurality of susceptor support holes, a plurality of susceptor supports recessed within the plurality of susceptor support holes and coupled to the susceptor support plate, and a lift pin assembly. The plurality of susceptor supports include a support body and a support pin link. A support connector is received by a support anchor of the susceptor support plate to secure the support body to the susceptor support plate. The support pin link receives a plurality of susceptor support pins. The support body supports the support pin link in a spaced apart relation to the susceptor support plate. The lift pin assembly is received in the plurality of susceptor lift pin holes. The lift pin assembly includes a lift pin cap and a susceptor lift pin comprising a susceptor stop plate. The susceptor support plate stop is receivable within the susceptor lift pin holes.