KR102374534B1 - Integrated two-axis lift-rotation motor center pedestal in multi-wafer carousel ald - Google Patents

Abstract

Apparatus and methods for processing a semiconductor wafer comprising a two-axis lift-rotating motor central pedestal with vacuum capabilities are disclosed. The wafers are subjected to a differential pressure between the top surface and the bottom surface such that sufficient force prevents the wafer from moving during processing, the differential pressure being achieved by applying reduced pressure to the back side of the wafer through an interface with a motor assembly. occurs

Description

INTEGRATED TWO-AXIS LIFT-ROTATION MOTOR CENTER PEDESTAL IN MULTI-WAFER CAROUSEL ALD}

[0001] Embodiments of the present disclosure generally relate to apparatus and methods for supporting a substrate during processing. Specifically, embodiments of the present disclosure relate to apparatus and methods that use differential pressure to support substrates on a susceptor under large acceleration forces.

[0002] In some CVD and ALD processing chambers, substrates, also referred to herein as wafers, are moved relative to a precursor injector and/or heater assembly. If this movement creates acceleration forces that are greater than the acceleration forces of the friction force, the wafer may displace causing damage or related problems. Wafers placed off-axis can slide with high acceleration/deceleration on a moving/rotating susceptor. Friction from the weight of the wafer itself may be insufficient to support the wafer on tools where higher throughput is required.

Additional hardware may be used to clamp or chuck the wafer in place to prevent rotational forces from dislodging the wafer during the process. Additional hardware may be expensive, difficult to install, difficult to use, and/or may cause damage to wafers during use.

[0004] Accordingly, there is a need in the art for methods and apparatus capable of holding a wafer in place during processing to prevent accidental damage to the wafer and hardware.

One or more embodiments of the present disclosure relate to a motor assembly including a motor housing having a top portion and a bottom portion. A drive shaft extends a distance from a top portion of the motor housing and has a cavity therein. A first motor is in the motor housing to rotate a drive shaft in the motor housing about a central axis. Adjacent to the bottom portion of the motor housing is a second motor in communication with at least one rail within the motor housing to move the first motor and the hollow shaft along a central axis.

Additional embodiments of the present disclosure relate to a motor assembly including a motor housing, a drive shaft, a first motor, a second motor, a seal housing, and a water jacket. The motor housing has a top portion and a bottom portion. The drive shaft extends a distance from the top portion of the motor housing. The drive shaft has a cavity therein, and at least one channel forms a fluid connection to the cavity. A first motor is within the motor housing for rotating a drive shaft within the motor housing about a central axis. A second motor is adjacent a bottom portion of the motor housing and communicates with at least one rail in the motor housing to move the first motor and the hollow shaft along a central axis. The seal housing is within the motor housing and has a gas volume therein. A seal housing is positioned around a portion of the drive shaft. The gas volume is in fluid communication with a cavity in the drive shaft through at least one channel. The water jacket contacts a lower portion of the drive shaft that is partially surrounded by the seal housing.

[0007] Further embodiments of the present disclosure relate to processing chambers, including at least one gas distribution assembly within the processing chamber. A susceptor assembly is below the at least one gas distribution assembly and includes a top surface, a bottom surface, and at least one recess in the top surface for supporting a wafer. The motor assembly includes a motor housing, a drive shaft, a first motor, and a second motor. The motor housing has a top portion and a bottom portion. The drive shaft extends a distance from a top portion of the motor housing and has a cavity therein. A first motor is within the motor housing for rotating a drive shaft within the motor housing about a central axis. A second motor is adjacent the bottom portion of the motor housing. A second motor communicates with at least one rail in the motor housing to move the hollow shaft and the first motor along a central axis to move the susceptor assembly closer to and away from the at least one gas distribution assembly. . At least one passageway extends between a cavity in the drive shaft and a bottom surface of at least one recess in the susceptor assembly, wherein a vacuum formed in the cavity of the drive shaft is in fluid communication with the recess in the susceptor assembly through the at least one passageway do.

[0008] In such a way that the above-listed features of the present disclosure may be obtained and understood in detail, a more specific description of the present disclosure, briefly summarized above, may be made with reference to embodiments of the present disclosure, which embodiments include shown in the drawings. The accompanying drawings illustrate only typical embodiments of the present disclosure and are not to be considered limiting of the scope of the present disclosure, as the present disclosure may admit to other equally effective embodiments.
1 shows a partial cross-sectional view of a processing chamber, in accordance with one or more embodiments of the present disclosure; And
2 shows a view of a portion of a gas distribution assembly, in accordance with one or more embodiments of the present disclosure;
3 shows a partial cross-sectional view of a processing chamber, in accordance with one or more embodiments of the present disclosure;
4 shows a partial cross-sectional view of a processing chamber, in accordance with one or more embodiments of the present disclosure;
5 shows a perspective view of a recess in a susceptor assembly with visible vacuum passages, in accordance with one or more embodiments of the present disclosure;
[0014] FIG. 6 shows a cross-sectional perspective view of a susceptor assembly, in accordance with one or more embodiments of the present disclosure;
7 shows a partial cross-sectional view of a susceptor assembly having vacuum passages, in accordance with one or more embodiments of the present disclosure;
8 shows a partial cross-sectional view of a susceptor assembly having vacuum passages, in accordance with one or more embodiments of the present disclosure;
9 shows a partial cross-sectional view of a susceptor assembly, in accordance with one or more embodiments of the present disclosure; And
10 shows a cross-sectional view of a motor assembly, in accordance with one or more embodiments of the present disclosure;
To facilitate understanding, like reference numerals have been used, where possible, to indicate like elements that are common to the drawings. It is contemplated that elements and features of one embodiment may be advantageously utilized in other embodiments without further recitation.

Embodiments of the present disclosure provide methods and apparatus that can hold a wafer in place during processing to prevent or minimize accidental damage to the wafer and hardware. Certain embodiments of the present disclosure provide an apparatus for generating differential pressure developed from a unique precursor injector design, having a size sufficient to hold wafers in place at high rotational speeds. and methods. As used in this specification and the appended claims, the terms “wafer,” “substrate,” and the like are used interchangeably. In some embodiments, the wafer is a rigid, discrete substrate.

[0021] In some spatial ALD chambers, the precursors used for deposition are injected very close to the wafer surface. To generate gas dynamics, the injector channels are independently controlled to a higher pressure than the surrounding chamber. By creating a differential pressure between the back side of the wafer and the front side of the wafer, a positive pressure force suitable to hold the wafer against a relatively greater acceleration force can be generated.

Embodiments of the present disclosure relate to the use of differential pressure to support substrates (wafers) on a susceptor under high acceleration forces. High acceleration forces, as a result of the high rotational speeds that can be experienced in carousel-type processing chambers, include larger batch sizes and processing speeds or higher reciprocating for higher wafer throughput. ) from action.

In some embodiments, the wafers are placed in shallow pockets on the susceptor below the injector assembly. The susceptor may provide heat transfer, improved gas dynamics, and/or may act as a carrier vehicle for substrates.

Embodiments of the present disclosure relate to susceptors having an angled hole for vacuum, from the inside diameter of the susceptor-bottom to the wafer pocket. The susceptor may be connected to a vacuum source via a rotating shaft and a rotating motor below the shaft. If the susceptor is made of silicon carbide coated (SiC) graphite, for example, every three times hole diameter, additional holes spaced apart are added to the susceptor for better penetration of the SiC coating. It may be provided from the top or from the bottom. Redundant holes are plugged for vacuum. The graphite plugs can be press-fitted prior to SiC coating, after which the susceptor is SiC coated. In some embodiments, threaded SiC coated plugs and a second SiC coating on the SiC coated susceptor may be applied for better sealing of the graphite by SiC for more corrosive applications. .

1 shows a portion of a processing chamber 100 in accordance with one or more embodiments of the present disclosure. The processing chamber 100 includes at least one gas distribution assembly 110 for dispensing reactive gases to the chamber. 1 has a single gas distribution assembly 110, those skilled in the art will appreciate that there may be any suitable number of gas distribution assemblies. There may be a plurality of assemblies with spaces between each assembly, or virtually no space therebetween. For example, in some embodiments, there is a plurality of gas distribution assemblies 110 positioned next to each other such that the wafer 120 effectively sees consistent repetition of the gas streams.

Although various types of gas distribution assemblies 110 may be used (eg, showerheads), for ease of illustration, the embodiment shown in FIG. 1 is a plurality of substantially parallel gas channels. 111 are shown. As used herein and in the appended claims, the term “substantially parallel” means that the elongate axes of the gas channels 111 extend in the same general direction. There may be some imperfections in the parallelism of the gas channels 111 . However, those skilled in the art will appreciate that a carousel-type processing chamber can rotate wafers about a central axis that is offset from the central axis of the wafer. In such a configuration, substantially non-parallel gas channels 111 may be useful. Referring to FIG. 2 , the gas distribution assembly 110 may be a pie-shaped segment in which gas channels 111 form a pie-shaped outer edge 116 from a pie-shaped inner edge 115 . extend towards The shape of the gas channels 111 may also vary. In some embodiments, the gas channels 111 have a substantially uniform width along the length of the channel extending from the inner edge 115 to the outer edge 116 . In some embodiments, the width W of the gas channel 111 increases along the length L of the channel extending from the inner edge 115 to the outer edge 116 . This is shown in FIG. 2 , where the gas channels 111 have a smaller width near the inner edge 115 and a wider width near the outer edge 116 . According to some embodiments, the aspect ratio of the change in width may be equal to the radial difference in position, such that the edges of each channel extend from the same point. This can result in all points of the wafer having approximately the same dwell time under the gas channel. In other words, each channel width can vary with distance from the center of rotation of the susceptor.

Referring back to FIG. 1 , the plurality of gas channels 111 include at least one first reactive gas (A) channel, at least one second reactive gas (B) channel, and at least one purge gas (P). ) channels and/or at least one vacuum (V) channel. Gases flowing from the first reactant gas (A) channel(s), the second reactant gas (B) channel(s), and the purge gas (P) channel(s) pass through the top surface 121 of the wafer 120 . oriented towards The gas flow is shown by arrows 112 . A portion of the gas flow horizontally traverses the surface 121 of the wafer 120 , as shown by arrows 113 , through the vacuum (V) channel(s) up and out of the processing region. Move. A substrate moving from left to right will in turn be exposed to the respective process gases, forming a layer on the substrate surface. The substrate may be in a single wafer processing system in which the substrate is moved in a reciprocating motion under a gas distribution assembly, or on a carousel-type system in which one or more substrates are rotated about a central axis as they pass under gas channels. can be in 2 illustrates a portion of a carousel-type system in accordance with one or more embodiments of the present disclosure. In the orientation of Figure 2, the process gases can be considered to flow out of the plane of the drawing sheet. The substrate along path 127 will be exposed to the respective process gases in turn. Path 127 is shown as an arc encircling about 90°, however, those skilled in the art will appreciate that path 127 can be any length and any portion of an arcuate path.

3 shows a cross-sectional view of one or more embodiments of the present disclosure; A cross-sectional portion of the gas distribution assembly 110 may be considered, for example, taken along the length of the purge gas port of FIG. 2 . A susceptor assembly 130 may be positioned below the gas distribution assembly 110 . The susceptor assembly 130 includes a top surface 131 , a bottom surface 132 , and at least one recess 133 in the top surface 131 . The recess 133 may be of any suitable shape and size depending on the shape and size of the wafers 120 being processed. In the illustrated embodiment, the recess 133 has two step regions 134 around an outer peripheral edge of the recess 133 . The stepped regions 134 may be sized to support the outer peripheral edge 122 of the wafer 120 . The amount of outer perimeter edge 122 of the wafer 120 , supported by the stepped regions 134 , may vary depending on, for example, the thickness of the wafer and the presence of features already on the back side 123 of the wafer. there is.

In some embodiments, the recess 133 in the top surface 131 of the susceptor assembly 130 is such that the wafer 120 supported in the recess 133 is the top of the susceptor assembly 130 . It is sized to have a top surface 121 that is substantially coplanar with surface 131 . As used herein and in the appended claims, the term “substantially coplanar” means that the top surface of the wafer and the top surface of the susceptor assembly are coplanar to within ±0.2 mm. In some embodiments, the top surfaces are coplanar to within ±0.15 mm, ±0.10 mm, or ±0.05 mm.

The bottom 135 of the recess has at least one passageway 140 extending from the bottom of the recess 133 through the susceptor assembly 130 to the drive shaft 160 of the susceptor assembly 130 . has The passageway(s) 140 may be of any suitable shape and size and may form fluid communication between the recess 133 and the drive shaft 160 . The passageway 140 shown in FIG. 3 is angled with respect to the bottom of the recess. In some embodiments, passageway 140 includes more than one leg forming fluid communication with the recess. For example, a major portion of the passageway 140 may extend parallel to a top or bottom surface of the susceptor and may be connected to a second leg turned relative to the major portion of the passageway. The drive shaft 160 may be connected to a vacuum source 165 that forms a region of reduced pressure (referred to as a vacuum) within the cavity 161 of the drive shaft 160 . As used herein and in the appended claims, the term “vacuum” as used in this context means a region having a pressure lower than that of the processing chamber. In some embodiments, the region of vacuum or reduced pressure is less than about 50 Torr, or less than about 40 Torr, or less than about 30 Torr, or less than about 20 Torr, or less than about 10 Torr, or less than about 5 Torr, or less than about 1 Torr, or less than about 100 mTorr, or less than about 10 mTorr.

[0031] Cavity 161 may act as a vacuum plenum such that, in the event of a loss of external vacuum, the vacuum within cavity 161 may be maintained at a reduced pressure. The passageway 140 is in communication with the cavity 161 such that a vacuum within the cavity 161 can be drawn through the passageway 140 onto the back side 123 of the wafer 120 .

Due to the vacuum or partial vacuum in the recess 133 below the wafer 120 , the pressure in the reaction region 102 above the wafer 120 is greater than the pressure in the recess 133 . This pressure differential provides sufficient force to prevent the wafer 120 from moving during processing. In one or more embodiments, the pressure within the recess 133 below the wafer 120 is lower than the pressure above the wafer 120 and within the processing chamber 100 .

[0033] The pressure applied to the top surface 121 of the wafer 120 from the gas streams emitted by the gas distribution assembly 110, along with the reduced pressure underneath the wafer, helps to hold the wafer in place. . This can be particularly useful in carousel-type processing chambers where wafers are offset from and rotated about a central axis. Centrifugal forces associated with rotation of the susceptor assembly may cause the wafer to slide away from the central axis. The differential pressure on the top side of the wafer relative to the bottom side, due to the gas pressure from the gas distribution assembly relative to the pressure applied to the back side of the wafer by the vacuum, helps prevent movement of the wafer. The gas channels of the gas distribution assembly may be simultaneously (eg, all output channels controlled together—reactant gases and purge channels), in groups (eg, all first reactant gas channels controlled together) or It can be controlled independently (eg, the leftmost channel controlled separately from an adjacent channel, etc.). As used in this specification and the appended claims, the terms "output channels," "gas channels," "gas injectors," etc. refer to a slot, channel, or nozzle through which gas is injected into a processing chamber. Used interchangeably to mean a type opening. In some embodiments, the first reactant gas channel, the second reactant gas channel, and the at least one purge gas channel are independently controlled. Independent control may be useful to provide positive pressure on the top surface of a wafer positioned within a recess of the susceptor assembly. In some embodiments, each individual first reactant gas injector, second reactant gas injector, purge gas injector and pump channel may be individually and independently controlled.

[0034] The differential pressure between the top surface of the wafer and the bottom surface of the wafer is, for example, the pressure of gases from the gas distribution assembly, the flow rate of gases from the gas distribution assembly, and the pressure difference between the gas distribution assembly and the wafer or susceptor surface. It can be adjusted by varying the distance and vacuum pressure. As used herein and in the appended claims, differential pressure is a measure of the pressure above the wafer relative to the pressure below the wafer. The pressure above the wafer is the pressure applied to the wafer surface or the pressure within the reaction region 102 of the processing chamber 100 . The pressure under the wafer is the pressure on the bottom surface of the vacuum pressure in the susceptor assembly 130 , the pressure in the recess. The magnitude of the differential pressure can directly affect the degree to which the wafer is chucked. In some embodiments, the differential pressure between the top surface 121 of the wafer 120 and the bottom surface 123 of the wafer 120 is greater than about 15 torr, or greater than about 10 torr, or greater than about 5 torr. In one or more embodiments, the differential pressure between the top surface 121 of the wafer 120 and the pressure in the recess 133 is 300 mm at a bolt center radius of about 320 mm at a rotational speed of about 200 rpm. equal to a chucking force large enough to hold the wafer.

In some embodiments, as shown in FIG. 3 , the processing chamber 100 includes a heating assembly 150 . The heating assembly may be located at any suitable location within the processing chamber, including, but not limited to, below the susceptor assembly 130 and/or on an opposite side of the susceptor assembly 130 other than the gas distribution assembly 110 . can be located in The heating assembly 150 provides sufficient heat to the processing chamber to raise the temperature of the wafer 120 to temperatures useful in the process. Suitable heating assemblies include, but are not limited to, radiant heaters (eg, a plurality of lamps) and resistive heaters that direct radiant energy toward the bottom surface of the susceptor assembly 130 .

The distance between the gas distribution assembly 110 and the top surface 121 of the wafer 120 can be adjusted and can affect the efficiency and pressure differential of gas flows from the gas distribution assembly. If the distance is too large, the gas flows may diffuse outward before meeting the surface of the wafer, resulting in a lower differential pressure and a less efficient atomic layer deposition reaction. If the distance is too small, gas flows may not be able to flow across the surface to the vacuum ports of the gas distribution assembly, resulting in a large differential pressure. In some embodiments, the gap between the wafer surface and the gas distribution assembly is within a range of about 0.5 mm to about 2.0 mm, or within a range of about 0.7 mm to about 1.5 mm, or within a range of about 0.9 mm to about 1.1 mm. , or about 1.0 mm.

The recess 133 shown in FIG. 3 supports the wafer 120 around the outer peripheral edge 122 of the wafer 120 . Depending on the thickness, stiffness, and/or vacuum pressure of the recess 133 , this arrangement may result in successful chucking of the wafer, preventing or minimizing movement of the wafer during rotation or movement of the susceptor assembly 130 . However, if the wafer is not thick or stiff, or if the vacuum pressure in the recess 133 is too low, however, the central portion of the wafer may be larger than the outer peripheral edge 122 of the wafer 120 in the gas distribution assembly 110 . ), the wafer 120 may be deflected further away from it.

4 shows another embodiment that helps prevent deflection of the wafer by providing a larger support surface area; Here, the wafer 120 is supported by the susceptor assembly 130 over a majority of the back side 123 . This figure shows a cross-section of the susceptor assembly. The central portion 137 of the susceptor assembly 130 is not free floating, but is connected to the remainder of the susceptor in a plane different from the cross-sectional view. The passageway 140 extends from the drive shaft 160 , or from a cavity 161 in the drive shaft 160 towards the recess 133 . The passageway 140 connects to a channel 146 extending towards the top surface 131 of the susceptor assembly 130 . The vacuum chucks the wafer 120 into the susceptor assembly 130 by vacuum through the channels 146 and passageways 140 .

5 shows a perspective view of a susceptor assembly 130 similar to the susceptor assembly of FIG. 4 . The illustrated susceptor assembly 130 has a recess 133 having a relatively large stepped area 134 for supporting an outer peripheral edge 122 (not shown) of a wafer. Recess 133 includes a large passage 140 that connects channel 146 to a vacuum in the drive shaft. The channel shown is shaped like a cap theta to provide a channel ring with a channel portion (or cross groove) extending over the diameter of the ring. The central portion 137 of the susceptor assembly 130 may be approximately coplanar with the stepped region 134 such that the central portion 137 and the stepped region 134 simultaneously support a wafer.

6 shows a perspective view of a susceptor assembly 130 in accordance with one or more embodiments of the present disclosure. Here, passage 140 extends from drive shaft 160 towards recess 133 , connecting cavity 161 , which acts as a vacuum plenum, with channel 146 in the recess. The passageway 140 has a plurality of holes 147 connecting the top surface 131 of the susceptor assembly 130 with the passageway 140 . In some embodiments, there is at least one hole extending into the passageway 140 from one of the top surface 131 of the susceptor assembly 130 and the bottom surface 132 of the susceptor assembly 130 . These holes 147 may be created (eg, drilled) during manufacture of the susceptor assembly to allow the inside of the passageway 140 to be coated. For example, in some embodiments, the susceptor assembly 130 has a silicon carbide coating. The susceptor assembly of some embodiments is silicon carbide coated graphite. Holes 147 allow silicon carbide coating on passage 140 , which is then sealed with plugs 148 . The plugs may be made of any suitable material, including, but not limited to, silicon carbide, silicon carbide coated graphite, a material having a silicon carbide coating, and graphite. After the plugs 148 are inserted into the holes 147 , the susceptor assembly may again be coated with silicon carbide to provide additional sealing of the holes 147 . The plugs 148 may be press fit (eg, friction fit), connected to the holes 147 by threads of a complementary screw, or to some other mechanical connection (eg, epoxy). can be connected by

During preparation of the silicon carbide coated susceptor assembly 130 , the holes 147 provide a useful passage for silicon carbide to coat the passage 140 . The size and spacing of the holes 147 may affect the effectiveness of the coating. The holes 147 may be spaced apart in increments of the hole diameter. For example, if the diameter of the holes is 5 mm, the spacing may be 5x mm, where x is any suitable value. For example, the spacing may be 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 times the diameter of the hole. The holes 147 may be located at any suitable points along the length of the passage 140 , and need not be evenly distributed over the length of the passage 140 . As shown in FIG. 6 , the holes 147 are centered towards the inner portion of the susceptor assembly 130 , where the passage 140 is furthest from the top surface 131 of the susceptor assembly 130 .

The passageways 140 may be used to supply a vacuum to the recess 133 to chuck the wafer 120 . However, as the wafer is processed, the vacuum may be too strong to easily remove the processed wafer from the recess. To facilitate removal of the wafer, passages 140 may also be utilized to provide a flow of gas towards the back side of the wafer 120 . Thus, providing positive pressure on the back side of the wafer allows for easy removal of the wafer from the susceptor assembly.

9 shows a schematic diagram of a susceptor assembly in accordance with one or more embodiments of the present disclosure; Here, a recess 133 is connected to a passage 140 leading to a cavity 161 in the drive shaft. A valve 171 is located in the passage 140 . The valve 171 may allow a fluid connection between the passageway 140 and the cavity 161 via the connector 141 . If a region of vacuum or reduced pressure is formed within cavity 161 , the valve may connect cavity 161 to recess 133 via connector 141 and passageway 140 . The valve 171 may be switched to shut off the fluid connection between the passageway 140 and the cavity 161 . The valve may be set in a closed position that isolates passage 140 , or may be set in a position where a connection is made between passage 140 and dechucking gas plenum 173 via connector 142 . The dechucking gas plenum 173 is shown in fluid communication with a dechucking gas source 175 . The dechucking gas source 175 may include any suitable gas including, but not limited to, nitrogen, argon, helium, or an inert gas.

7 shows another embodiment of a susceptor assembly 130 . Here, passageway 140 extends generally parallel to the bottom of recess 133 from an outer edge of susceptor assembly 130 . A plug 148 blocks the end of the passageway 140 . A first portion 140a of the passage runs towards a second portion 140b and extends into the drive shaft 160 . Channel 146 extends from passage 140 to the bottom of recess 133 at approximately the center of recess 133 . A plurality of standoffs 149 extend from the bottom 135 of the recess 133 to the height of the first step of the stepped area 134 . A plurality of standoffs 149 provide support for the wafer to prevent or minimize bowing. Standoffs 149 are positioned with gaps around the recess to allow vacuum to affect the entire recess.

8 shows another embodiment of a susceptor assembly 130 . Here, the recess includes a plurality of steps that are gradually higher than the height of the initial step area 134 . The first stepped region 134a has a first height. The second stepped region 134b has a second height greater than the first height. The third stepped region 134c has a third height greater than the second height. Although three stepped regions are shown, those skilled in the art will appreciate that any number of stepped regions may be present. In the embodiment shown, the heights of the first, second and third stepped regions increase towards the center of the recess. In some embodiments, the heights of the individual stepped areas may vary so that some areas have a higher height than others, independent of the location of the area relative to the center of the recess.

[0046] The diameter and heights of the individual stepped regions may vary. In some embodiments, the first stepped region 134a has a height in a range of about 10 μm to about 90 μm with respect to the initial stepped region 134 . Because the wafer 120 rests on the initial stepped region 134 , the first height is the initial stepped region 134 , although the initial stepped region 134 is below the level of the top surface 131 of the susceptor assembly 130 . ) is measured for In some embodiments, the first height is in a range from about 20 μm to about 80 μm, or in a range from about 30 μm to about 70 μm, or in a range from about 40 μm to about 60 μm.

In the embodiment shown in FIG. 8 , the second stepped region 134b of some embodiments has a height in the range of about 35 μm to about 115 μm, which is higher than the height of the first stepped region 134a . . In some embodiments, the second stepped region 134b has a height in a range from about 45 μm to about 105 μm, or in a range from about 55 μm to about 95 μm, or in a range from about 65 μm to about 85 μm.

In the embodiment shown in FIG. 8 , the third stepped region 134c has a height in the range of about 60 μm to about 140 μm, and is higher than the height of the second stepped region 134b. In some embodiments, the third stepped region 134c has a height in a range of about 70 μm to about 130 μm, or in a range of about 80 μm to about 120 μm, or in a range of about 90 μm to about 110 μm.

[0049] The height of the standoffs 149 may vary according to the height of a specific stepped area in which the standoff is located. Referring to FIG. 8 , the standoffs in the third stepped area are higher than the standoffs in the first stepped area. The standoffs of some embodiments are of sufficient height to make the top of the standoff substantially flush with the initial stepped area such that the wafer positioned in the recess is substantially flush with the top surface of the susceptor assembly.

The vacuum source 165 may be connected to the cavity 161 via a valve 162 . The valve 162 may be used to isolate the cavity 161 from the vacuum source 165 in the event of a loss of vacuum from the vacuum source 165 . This allows the cavity 161 to act as a vacuum plenum so that the wafers on the susceptor assembly remain chucked until the vacuum source is reconnected or repaired.

Each of the individual recesses 133 in the susceptor assembly 130 may include a separate passageway 140 and a valve 171 . This allows each individual recess 133 to be isolated from the vacuum within cavity 161 . For example, the wafer 120 being processed may be rotated relative to the loading/unloading region of the processing chamber. The valve 171 can be closed or switched to a dechucking gas plenum 173 to cause a positive pressure on the back side of the wafer, allowing the robot to pick up the wafer. After picking up the wafer, the valve may be closed so that the pressure in the recess 133 will equal the pressure in the chamber. A new wafer may be placed in the recess and the valve 171 may be switched back to allow fluid connection with the cavity 161 to chuck the new wafer.

[0052] According to one or more embodiments of the present disclosure, a central pedestal on a carousel style susceptor, driven by integrated two-axis motors for lift and rotation of the susceptor, for example It can also be used to incorporate vacuum or nitrogen to chuck/dechuck wafers. Additionally, some embodiments utilize water or coolant to maintain electrical grounding of the seals and motor magnets and wafers, for example during plasma processing.

Referring to FIG. 10 , a schematic diagram of a motor assembly 200 used with one or more embodiments of the present disclosure is provided. The motor assembly 200 has a motor housing 202 having a top portion 203 and a bottom portion 204 . The illustrated motor assembly 200 includes a bottom 206 that may be integrally formed with the sides 207 of the housing 202 or may be separate components.

The motor assembly 200 includes a drive shaft 210 from a top portion 203 of a motor housing 202 . The drive shaft 210 includes a body 213 and a cavity 212 therein. Cavity 212 may be in flow communication with a gas or vacuum source and may act as a plenum as further described below.

The drive shaft 210 may be made of any suitable material capable of supporting the susceptor assembly during wafer processing while retaining the cavity therein. In some embodiments, the drive shaft 210 is made of a material comprising stainless steel. The dimensions of the drive shaft 210 may vary depending on, for example, the size and weight of the susceptor assembly, or other component supported on the susceptor assembly.

The drive shaft 210 extends a distance D from the motor housing 202 . This distance D may change or be changed before, during and/or after processing. In use, the motor assembly 200 supports and rotates the susceptor assembly. The distance D the drive shaft 210 extends from the motor housing 202 is directly related to the vertical height of the susceptor and any wafers supported thereon.

The drive shaft 210 is in contact with a first motor 220 located within the motor housing 202 . The first motor 220 rotates the drive shaft 210 about a central axis 211 within the motor housing 202 . The drive shaft 210 may be connected to the first motor by contact, friction, or hardware. In the embodiment shown in FIG. 10 , the drive shaft 210 is connected to a motor/shaft interface 222 which is connected to a first motor 220 . Motor/shaft interface 222 may be any suitable material including, but not limited to, stainless steel or aluminum. The motor/shaft interface 222 material may have a coefficient of expansion similar to that of the drive shaft 210 or seal housing 240 described below. The first motor 220 may be any suitable type of motor capable of rotating the drive shaft 210 . In some embodiments, first motor 220 is a direct drive motor coupled directly to hollow drive shaft 210 .

[0058] The direct drive motor can be raised and lowered by a combination of one ball screw motor and two symmetrical machine rails. In some embodiments, the ball screw is positioned as close to center as possible to minimize shaft tilt. A second motor 230 is positioned adjacent the bottom portion 204 of the motor housing 202 . The second motor 230 may be any suitable type of motor including, but not limited to, a ball screw motor. In the embodiment shown in FIG. 10 , the second motor 230 is located outside the motor housing 202 , but may also be disposed within the motor housing. The second motor 230 communicates with at least one rail 232 in the motor housing 202 to move the drive shaft 210 and the first motor 220 along the length of the central axis 211 . . Movement along the length of the central axis 211 changes the distance D the drive shaft 210 extends from the top portion 203 of the motor housing 202 . A nut 234 is positioned along the second motor screw 236 . Rotation of the screw 236 causes the nut 234 to move along the length of the screw 236 .

The second motor 230 may be positioned at any position with respect to the central axis 211 of the assembly 200 . In some embodiments, the second motor 230 is positioned as close as possible to the central axis 211 to minimize racking of the motor assembly during movement. In one or more embodiments, the motor assembly is round and the functional components (eg, screws, nuts and rails) of the second motor 230 are motor measured from the central axis 211 . located within 50% of the radius of 220 .

In some embodiments, there are at least two symmetrical rails 232 within the motor housing 202 . The two rails may be located on either side of the central axis 211 or on either side of the screw 236 . For example, the single rail 232 shown in FIG. 10 may be two pieces with the nut 234 in contact simultaneously.

The motor assembly 200 may also include a seal housing 240 for a combination of dynamic seals for a z-theta motor, the seal housing being mounted to the high speed rotating drive shaft 210 . , provide a vacuum channel with holes on its side. The seal housing 240 may be positioned within the motor housing 202 and around at least a portion of the drive shaft 210 . The seal housing 240 of some embodiments is in fluid communication with one or more of a vacuum source 241 or a gas source (not shown). A vacuum source 241 or a gas source may be connected to the seal housing via port 242 . In some embodiments, the seal housing 240 includes a gas volume 243 for maintaining a gas or vacuum. When the vacuum source 241 is connected to the seal housing 240 , the gas volume 243 is under vacuum. When a gas source (not shown) is connected to the seal housing 240 , the gas volume 243 may hold gas.

As shown in FIG. 10 , the drive shaft 210 has at least one channel 215 forming a fluid connection between the gas volume 243 of the seal housing 240 and the cavity 212 of the drive shaft. may include The seal housing 240 includes at least one o-ring 245 for forming a hermetic seal between the seal housing 240 and the drive shaft 210 . In the embodiment shown in FIG. 10 , there are two o-rings 245 shown positioned above and below the channel 215 . The o-rings 245 help to ensure a hermetic seal, while allowing gases to pass from the cavity 212 through the channel 215 , into the seal housing 240 gas volume 243 and finally into the vacuum source 241 . allow it to move When a gas source is used instead of a vacuum source, the gas flow path is reversed.

In some embodiments, at least one channel 215 in the drive shaft extends substantially perpendicular to the central axis 211 . As used in this specification and the appended claims, the term “substantially perpendicular” as used herein means that the angle of the axis of the channel 215 with respect to the central axis 211 is greater than or equal to about 45 degrees. In some embodiments, the angle of the channel axis relative to the central axis 211 is about 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85 degrees. all big In one or more embodiments, the angle of the channel axis relative to the central axis ranges from about 85 to about 90 degrees, or from about 80 to about 90 degrees.

The number of channels 215 formed in the drive shaft 210 may be any suitable number. In some embodiments, 1, 2, 3, 4, 5, 6, 7, 8, or more separate channels extend through the body 213 of the drive shaft 210 , such that the cavity 212 and gas It forms a fluid connection between the volumes 243 . In some embodiments, there are four cross-drilled channels extending through the body 213 . In one or more embodiments, a single zone 20 mm diameter vacuum is fed to the susceptor and is circular between the shaft lip seal (top o-ring 245) and quad seal (bottom o-ring 245). It is provided in a pocket and then taken up the shaft through the four side holes or channels. In some embodiments, the cavity in drive shaft 210 has a 100 mm diameter and may be used as a vacuum reservoir to keep the remainder of the wafers chucked during wafer replacement.

Vacuum isolation may be assisted or achieved using a combination of stainless steel bellows 260 , and/or dynamic lip seals (o-rings 245 ) housed in seal housing 240 . To further isolate the gas volume 243 of the seal housing 240 from the processing environment, a bellows 260 is positioned between the top 205 of the motor housing 202 and the seal housing. The top 205 of the motor housing 202 may be connected to the motor housing sides 207 by any suitable method. The top 205 may be a separate component that is mechanically attached to the sides 207 , or may be formed integrally with the sides 207 . Bellows 260 expands and contracts during movement of motor 220 , drive shaft 210 and seal housing 240 along the length of central axis 211 .

[0066] The rotor shaft supporting the susceptor may cool to prevent thermal conduction to the direct-drive motor magnets, causing demagnetization. The first motor 220 , which may be a direct drive motor, may be water cooled by flowing water through the seal housing 240 . Additionally, according to an embodiment, since the susceptor is often heated to process temperatures up to 550° C., the bottom end of the drive shaft 210 is designed to prevent damage to the motor magnets and dynamic seals due to overheating. is cooled This involves attaching, contacting or bolting a water rotary union or water jacket 270 under the drive shaft 210 with water flowing through the press-fit connection of the water jacket to the shaft to the seals. can be implemented by In some embodiments, the water jacket 270 contacts the bottom of the drive shaft 210 extending through the motor/shaft interface 222 . A water jacket 270 may be connected to the lower portion of the drive shaft 210 , and a simple contact between the two may be sufficient to cool the drive shaft 210 . During rotation of the drive shaft 210 , the water jacket 270 may also rotate or remain stationary. In some embodiments, the seal housing 240 is positioned around a portion of the water jacket 270 .

[0067] Although referred to as a water jacket, those skilled in the art will understand that any type of coolant may be used. For example, automotive antifreeze can be used instead of water. The water jacket 270 is generally made of a material that is a good conductor of heat. In some embodiments, the water jacket is made of aluminum.

In the embodiment shown in FIG. 10 , the water jacket 270 is connected to the rotatable union 272 via a jacket/union interface 274 . The rotary union 272 can remain stationary during rotation of the drive shaft 210 , while the water jacket 270 rotates with the drive shaft 210 . This may be accomplished by a coolant (gas or liquid) flowing through the inlet tube 275 to the stationary rotating union 272 . The coolant then flows to the jacket/union interface 274 , where the tube connects to a corresponding tube in the water jacket 270 and then out of the outlet tube 276 .

[0069] To lead the electrical wires to the susceptor, an electrical multi-conductor slip ring can be bolted under the male rotatable union. An electrical connection can be made from the susceptor down through the drive shaft 210 by a slip ring mounted to the bottom of the shaft. The slip ring and motor/shaft interface 222 (also referred to as a motor/shaft union) may be the same component or different components. A plurality of wires for grounding the wafers on the susceptor and a plurality of thermocouple wires for checking the susceptor temperatures in the plurality of zones are routed through the drive shaft 210, water jacket 270, electrical It may extend through a feed conduit 277 .

Some embodiments of the present disclosure are directed to susceptor assemblies including a motor assembly 200 , such as the motor assembly of FIG. 10 , and a susceptor in communication with a top portion 217 of a drive shaft 210 . it's about In some embodiments, a torque plate 280 is connected to the top portion 217 of the drive shaft 210 . The torque plate 280 forms an interface between the drive shaft 210 and the susceptor assembly 130 . As shown in FIG. 10 , in some embodiments, a reflector plate 282 is positioned between the torque plate 280 and the susceptor assembly 130 . In some embodiments, heat from the susceptor assembly 130 is progressively reduced by a plurality of stainless steel plates (reflector plates 282 ) stacked in parallel. Heat from the heater around the shaft (see FIG. 3 ) can be reflected back using 17-4 PH steel reflector shields around the drive shaft to keep the shaft cooler. In some embodiments, the remaining heat conducted through the susceptor is reduced by water cooling the shaft using the water jacket described above, with a water rotating union underneath the shaft. Water or coolant can be passed through gun-drill holes in the thickness of the drive shaft or by bolting a male rotary union under a press-fit aluminum water jacket to the motor shaft.

[0071] In some embodiments, angled holes are provided from the inner diameter of the susceptor bottom to respective wafer pockets for chucking/dechucking. The angled holes can be connected to the hollow drive shaft with precision machined flat plates without high temperature face seals to prevent vacuum leaks. The hollow shaft can act as a vacuum plenum in case of an external vacuum loss.

In some embodiments, as can be seen in FIGS. 5 and 6 , the susceptor assembly 130 has a plurality of recesses 133 in the top surface 131 of the susceptor assembly 130 . include 6-8 , a plurality of passageways 140 extend from the cavity 212 of the drive shaft 210 to the recesses 133 of the susceptor assembly 130 . In some embodiments, as shown in FIG. 9 , the passageways 140 may include a valve in fluid communication with the passageway. Multi-zone vacuum chucking allows independent control of each wafer pocket on the carousel, which aids in wafer exchange. Each of the vacuum zones is connected through a rotor shaft that supports the susceptor, and can be a conduit for electrical feeds to the susceptor and various fluids, for example nitrogen gas for wafer dechucking or purging; A multi-zone vacuum may be applied for chucking.

[0073] Substrates for use with embodiments of the present disclosure may be any suitable substrate. In detailed embodiments, the substrate is a rigid discrete, generally planar substrate. As used herein and in the appended claims, the term “discrete” when referred to a substrate means that the substrate has certain dimensions. The substrate of certain embodiments is a semiconductor wafer, such as a 200 mm or 300 mm diameter silicon wafer.

[0074] As used herein and in the appended claims, the terms "reactive gas", "reactive precursor", "first precursor", "second precursor", etc. Available gases and gas species are indicated.

In some embodiments, one or more layers may be formed during a plasma enhanced atomic layer deposition (PEALD) process. In some processes, the use of plasma provides sufficient energy to promote the species to an excited state, for which surface reactions are favorable and likely. The introduction of plasma into the process may be continuous or pulsed. In some embodiments, successive pulses of precursors (or reactant gases) and a plasma are used to process the layer. In some embodiments, reagents may be ionized locally (ie, within the processing region) or remotely (ie, outside the processing region). In some embodiments, remote ionization may occur upstream of the deposition chamber such that ions or other energetic or luminescent species do not come into direct contact with the deposition film. In some PEALD processes, the plasma is generated outside the processing chamber, such as by a remote plasma generator system. The plasma may be generated by any suitable plasma generating process or technique known to those skilled in the art. For example, the plasma may be generated by one or more of a microwave (MW) frequency generator or a radio frequency (RF) generator. The frequency of the plasma can be adjusted depending on the specific reactive species being used. Suitable frequencies include, but are not limited to, 2 MHz, 13.56 MHz, 40 MHz, 60 MHz and 100 MHz. Plasma may be used during the deposition processes disclosed herein, but plasmas may not be necessary. Indeed, other embodiments relate to deposition processes under very mild conditions in the absence of plasma.

According to one or more embodiments, the substrate is subjected to processing prior to and/or after forming the layer. Such processing may be performed in the same chamber or in one or more separate processing chambers. In some embodiments, the substrate is moved from the first chamber to a separate second chamber for further processing. The substrate may be moved directly from the first chamber to the separate processing chamber, or the substrate may be moved from the first chamber to one or more transfer chambers and then into the separate processing chamber. Accordingly, the processing apparatus may include a plurality of chambers in communication with the transfer station. A device of this kind may be referred to as a “cluster tool” or a “clustered system” or the like.

[0077] In general, a cluster tool is a modular system that includes a plurality of chambers that perform various functions including substrate-center finding and orientation, degassing, annealing, deposition and/or etching. According to one or more embodiments, the cluster tool includes at least a first chamber and a central transfer chamber. The central transfer chamber may house a robot capable of reciprocating substrates between processing chambers and load lock chambers. The transfer chamber is typically maintained under vacuum conditions and provides an intermediate stage for reciprocating substrates from one chamber to another and/or to a load lock chamber located at the front end of the cluster tool. Two well-known cluster tools that may be adapted for this disclosure are Centura® and Endura®, both available from Applied Materials, Inc. of Santa Clara, CA. Details of one such staged vacuum substrate processing apparatus can be found in a US patent publication entitled "Staged-Vacuum Wafer Processing Apparatus and Method" to Tepman et al., issued February 16, 1993. 5,186,718. However, the exact arrangement and combination of chambers may be altered for purposes of performing specific steps of a process as described herein. Other processing chambers that may be used include, but are not limited to, periodic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-clean, chemical cleaning. , thermal treatment such as RTP, plasma nitridation, degassing, orientation, hydroxylation and other substrate processes. By running the processes in a chamber on the cluster tool, contamination of the surface of the substrate by atmospheric impurities can be avoided as there is no oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuously under vacuum or “load lock” conditions and is not exposed to ambient air as it is moved from one chamber to the next. Thus, the transfer chambers are under vacuum and are “pumped down” under vacuum pressure. Inert gases may be present in the processing chambers or in the transfer chambers. In some embodiments, an inert gas is used as a purge gas to remove some or all of the reactants after forming the silicon layer on the surface of the substrate. According to one or more embodiments, a purge gas is injected at the outlet of the deposition chamber to prevent reactants from moving from the deposition chamber to the transfer chamber and/or additional processing chamber. Thus, the flow of inert gas forms a curtain at the outlet of the chamber.

[0079] A substrate may be processed in single substrate deposition chambers, in which a single substrate is loaded, processed, and unloaded before another substrate is processed. The substrates may also be processed in a continuous manner, such as a conveyor system in which a plurality of substrates are individually loaded into a first portion of a chamber, moved through the chamber, and unloaded from a second portion of the chamber. . The shape of the chamber and associated conveyor system may form a straight path or a curved path. Additionally, the processing chamber may be a carousel, in which a plurality of substrates are moved about a central axis and exposed to processes such as deposition, etching, annealing, cleaning, etc. throughout the carousel path. .

[0080] During processing, the substrate may be heated or cooled. Such heating or cooling may be accomplished by any suitable means, including, but not limited to, changing the temperature of the substrate support and flowing heated or cooled gases to the substrate surface. In some embodiments, the substrate support includes a heater/cooler that can be controlled to conductively change the substrate temperature. In one or more embodiments, the gases in use (reactive gases or inert gases) are heated or cooled to locally change the substrate temperature. In some embodiments, a heater/cooler is positioned within the chamber adjacent the substrate surface to convectively change the substrate temperature.

[0081] The substrate may also be stationary or rotated during processing. The rotating substrate may be rotated continuously or rotated in individual steps. For example, the substrate may be rotated throughout the process, or the substrate may be rotated by a small amount between exposures to different reaction or purge gases. Rotating the substrate (continuously or stepwise) during processing can help produce a more uniform deposition or etch, for example by minimizing the effect of local variability in gas flow geometries.

[0082] While the disclosure herein has been described with respect to specific embodiments, it should be understood that these embodiments are merely illustrative of applications and principles of the disclosure. It will be apparent to those skilled in the art that various modifications and changes can be made to the method and apparatus of the present disclosure without departing from the spirit and scope of the disclosure. Accordingly, this disclosure is intended to cover modifications and variations that come within the scope of the appended claims and equivalents.

Claims (15)

As a motor assembly:
a motor housing having a top portion and a bottom portion;
a drive shaft extending a distance from the top portion of the motor housing and having a cavity therein;
a first motor in the motor housing for rotating the drive shaft in the motor housing about a central axis;
a second motor adjacent the bottom portion of the motor housing, the second motor communicating with at least one rail in the motor housing to move the first motor and drive shaft along the central axis;
a seal housing within the motor housing, the seal housing positioned around a portion of the drive shaft; and
a water jacket in contact with the lower portion of the drive shaft; and
wherein the seal housing is positioned around a portion of the water jacket;
motor assembly. The method of claim 1,
The seal housing is in fluid communication with a vacuum source.
motor assembly. The method of claim 1,
wherein the drive shaft includes at least one channel forming a fluid connection between the seal housing and the cavity of the drive shaft.
motor assembly. 4. The method of claim 3,
wherein the seal housing includes an o-ring forming a gas-tight seal between the seal housing and the drive shaft.
motor assembly. As a motor assembly:
a motor housing having a top portion and a bottom portion;
a drive shaft extending a distance from the top portion of the motor housing, the drive shaft having a cavity therein, and at least one channel forming a fluid connection to the cavity;
a first motor in the motor housing for rotating the drive shaft in the motor housing about a central axis;
a second motor adjacent the bottom portion of the motor housing, the second motor communicating with at least one rail in the motor housing to move the first motor and drive shaft along the central axis;
a seal housing in the motor housing, the seal housing having a gas volume therein and positioned around a portion of the drive shaft, the gas volume in fluid communication with the cavity in the drive shaft through the at least one channel; ; and
a water jacket in contact with a lower portion of the drive shaft that is partially surrounded by the seal housing;
wherein the seal housing is positioned around a portion of the water jacket;
motor assembly. As a susceptor assembly:
The motor assembly of any one of claims 1 to 5; and
a susceptor in communication with the top portion of the drive shaft; including
susceptor assembly. 7. The method of claim 6,
and a torque plate forming an interface between the drive shaft and the susceptor.
susceptor assembly. 8. The method of claim 7,
further comprising a reflector plate between the torque plate and the susceptor
susceptor assembly. 7. The method of claim 6,
wherein the susceptor includes a plurality of recesses in a top surface of the susceptor.
susceptor assembly. 10. The method of claim 9,
and a plurality of passageways extending from the cavity of the drive shaft to the recesses in the susceptor.
susceptor assembly. 11. The method of claim 10,
and a valve in fluid communication with the passageway.
susceptor assembly. As a processing chamber:
at least one gas distribution assembly within the processing chamber;
a susceptor assembly below the at least one gas distribution assembly, the susceptor assembly including a top surface, a bottom surface, and at least one recess in the top surface for supporting a wafer; and
A motor assembly according to any one of claims 1 to 5; including
processing chamber. delete delete delete

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