TWM644795U - Device for being used in semiconductor processing chamber - Google Patents

Abstract

A multi-zone heater with a plurality of thermocouples such that different heater zones can be monitored for temperature independently. The independent thermocouples may have their leads routed out from the shaft of the heater in a channel that is closed with a joining process that results in hermetic seal adapted to withstand both the interior atmosphere of the shaft and the process chemicals in the process chamber. The thermocouple and its leads may be enclosed with a joining process in which a channel cover is brazed to the heater plate with aluminum.

Description

Devices used in semiconductor processing chambers

The present invention relates to heaters for use in semiconductor processing, and more specifically, to heaters and thermocouples having multiple heater blocks to monitor those blocks.

In semiconductor manufacturing, silicon substrates (wafers) are processed at elevated temperatures for the deposition of many different materials. The temperature range is typically in the range of 300-550°C, but occasionally can be as high as 750°C or even higher. The deposited materials "grow" in layers on the surface of the wafer. Many of these materials have very temperature-sensitive growth rates, so changes in temperature across the wafer can affect the local growth rate of the film, causing changes in the thickness of the film as it grows across the wafer.

What is desired is to control variations in the thickness of the deposited film. What it sometimes wants is to make the film thicker in the center of the wafer (like a dome). What one sometimes wants is to have a thicker film on that edge (like a notch or micro pits). What is sometimes desired is to have a film thickness as uniform as possible (within tens of angstroms).

One of the most direct methods for controlling the wafer temperature, and thereby the thickness profile of the unheated film, is to place the wafer on a heater. The desired film thickness profile can be produced by designing a heater with a specific watt-density "map" that produces the desired temperature profile on the wafer. The watt-density of the heater increases in the location(s) where higher temperatures on the wafer are desired, and decreases in locations where lower wafer temperatures are desired. Watt-density of heater.

What is wanted by the chip fab is the ability to run different processes in the same process chamber. Capital equipment used to grow thin films is expensive (typically over a million dollars per process chamber), so the desire is to maximize the utilization of the required process chambers and reduce the number of required process chambers to Minimum. Different temperature processes with different chemistries and phenomena are run in the same chamber to produce different films. These different films can also have different growth rate versus temperature characteristics. This results in the chip fabs wanting the ability to "fluff" the watt-density map of a heater in a given process chamber to achieve the desired film thickness profile.

Additionally, what wafer fabs want is the ability to run the same "recipe" correctly in multiple process chambers, and produce films with matching film thickness profiles (as well as other properties that can be affected by temperature, Such as film stress, refractive index, and others). Therefore, what is desired is the ability to produce a heater that can have unit-to-unit Very repeatable watts-density map.

By using multiple independent heater circuits within the heater, the heater can be made with the ability to change the watt-density map. By varying the voltage and current applied to these different circuits, you can change the power levels in the locations of these individual circuits. The locations of these specific circuits are called "blocks." By increasing the voltage (and thereby the current, when the heater elements are resistive heaters) for a given block, you increase the temperature in that block. Conversely, when you reduce the voltage of a zone, you reduce the temperature in that zone. In this way, different watt-density maps can be produced by the same heater by varying the power to the individual blocks.

At least two limitations have affected chip fabs' ability to effectively use multi-block heaters. The first limitation is that these current state-of-the-art heaters have only one control thermocouple. Only one control thermocouple can be used because the plate and shaft designs currently used for heaters only allow one thermocouple at the center of the heater plate, or within a radius of approximately one inch from the center of the heater. Occasionally the location. Thermocouples are made of metals that are incompatible with the wafer processing environment and therefore must be isolated from the environment. Additionally, for the fastest response of a thermocouple (TC), it is best to operate it in an atmospheric pressure environment rather than the vacuum environment of a typical process chamber. Therefore, the TCs may simply be located in the central hollow area of the heater shaft, which is not connected to the process environment. If there is a heater block located outside the 2 inches diameter of the heater shaft, no TC can be installed there to monitor and help control the temperature of that block.

This limitation has been addressed by using a "driven" power ratio to Controls the heater block located outside the central area of the heater. The power ratio is established from the power to be applied to each of the center block and the other blocks to produce the desired watt-density map. The center control TC monitors the temperature of the center block, and the power applied to the center block (which is based on feedback from the center control TC) is then applied to all blocks, as adjusted by the pre-established ratio . For example, with a two-zone heater, let us assume that a power ratio of 1.2 to 1.0 applied to the outer and inner zones produces the desired temperature profile. By reading the temperature data provided by the central control TC, let us assume that the heater control system determines that 100VAC is required to achieve the appropriate temperature. With the driven ratio control methodology, a voltage of 120VAC will thereby be applied to the external heater block, and a voltage of 100VAC will be applied to the internal block. By changing the driven ratio, the watts-density map can be adjusted.

This leads us to this second limitation. Today's latest technology heaters have inherent variations in the resistance of the embedded heater. Due to the high temperatures and pressures required in the current manufacturing process of ceramic heaters, the resistance tolerance that can be achieved can be close to 50%. In other words, the typical resistance for a semiconductor grade ceramic heater element is in the range of 1.8-3.0 ohms (at room temperature - the heater element material is typically molybdenum and its resistance increases as the operating temperature increases) .

This variation creates a problem with maintaining a repeatable watt-density map from unit to unit with multi-zone heaters controlled by this driven ratio method. With a single block heater, this resistance variation may This is not a problem because the control TC is utilized to monitor the actual operating temperature and adjust the power level fed to the heater accordingly. But if you have a multi-zone heater and the heater element resistance can vary close to 50%, the slave ratio control methodology will not produce a repeatable watt-density map from unit to unit.

What was requested was to create a heater design that would allow the installation of multiple control TCs that could be located entirely within the individual heater blocks to directly allow for feedback and control while still maintaining the TCs are isolated by the processing environment within the process chamber.

100: Plate and shaft device

101:Shaft

102:Plate

103:Top surface

190: (aluminum) joint

191:First Ceramic Semiconductor Processing Equipment Parts (Shaft)

192: Second ceramic semiconductor processing equipment parts (plates)

193:First interface area

194: Second interface area

195: concave part

200:Processing room

201:Environment

202:Atmosphere

203:Plate

204:Shaft

205:Heater

206:Substrate

207:Surface

208:Surface

300:Heater

310:Antenna

320: Heater element

330:Shaft

340:Plate

350:Flange

401: Shaft

500: heater

501:Cover

502:Heater plate

503: concave part

504: Center hole

505: First temperature sensor

506: Second temperature sensor

507: Third temperature sensor

508: Thermowell

509: Thermowell

510: Thermowell

516:Shaft

517:End

518:End

519:Axis

520:Coupling piece

521:Plate

522:Part

526: Center heater block

527:Intermediate heater block

528: Edge heater block

530:Cover

531:Wire

532:Wire

533:Wire

545: Groove

546:Connector

550:Heater

551:Cover

552:Ring piece

556:Plate and shaft device

557:Plate

558:Shaft

561:Layer

562:Layer

563:Layer

564:Electrode layer

565:Heater layer

567:Joint layer

568:Jointing layer

571:Top panel layer

572: Lower panel layer

573: Bottom panel layer

574:Heater

575:Jointing layer

576:Joint layer

577:Border

578: Legs

579: Legs

580: concave part

600:Heater

601:Plate

602:Shaft

603: Internal

604: Center hub

605:Part

610: Bottom panel layer

611: Intermediate panel layer

612:Top panel layer

613:Metal layer

614:Joint layer

615:Jointing layer

616:Jointing layer

620:Trench

621: Heater element

622:Compound

641: Heater block

641a: half block

641b: half block

642:Second end

642a: half block

642b: half block

643: Edge heater block

643a: half block

643b: half block

644:Axis

645: first end

646:Power cord

651: First temperature sensor

652: Second temperature sensor

653: Third temperature sensor

661:Wire

662: Groove

Figure 1 is a view of a plate and shaft assembly used in semiconductor processing in accordance with some embodiments of the present invention.

Figure 2 is a cross-sectional view of the joint between the plate and the shaft according to some embodiments of the present invention.

Figure 3 is a view of a plate and shaft assembly in a process chamber according to some embodiments of the present invention.

Figure 4 is a view of a heater device according to some embodiments of the present invention.

Figure 5 is an illustrative cross-sectional view of a multi-zone heater according to some embodiments of the present invention.

Figure 6 is an illustration of a multi-zone heater according to some embodiments of the present invention. Bright bottom view.

Figure 7 is an illustrative view of a joint cover according to some embodiments of the present invention.

Figure 8 is an illustrative view of a cover plate according to some embodiments of the present invention.

Figure 9 is a perspective view of a heater according to some embodiments of the present invention.

Figure 10 is an exploded perspective view of a heater according to some embodiments of the present invention.

Figure 11 is an illustrative cross-sectional view of a heater having multi-layer panels in accordance with some embodiments of the present invention.

Figure 12 is a close-up partial cross-sectional view of a multi-layer panel according to some embodiments of the present invention.

Figure 13 is an illustrative cross-sectional view of a heater with a plurality of heater blocks and thermocouples in accordance with some embodiments of the present invention.

Figure 14 is a close-up cross-sectional view of the plate and shaft joint area in accordance with some embodiments of the present invention.

Figure 15 is a top view of a central hub according to some embodiments of the present invention.

Figure 16 is a partial cross-sectional view illustrating the appearance of the central hub according to some embodiments of the present invention.

Figure 17 is a mapping illustration of multiple heater blocks according to some embodiments of the present invention.

In an embodiment of the present invention, a multi-block processing device with multiple thermocouples Heaters are provided so that the temperatures of the different heater blocks can be monitored independently. The individual thermocouples can have their wires routed off the heater shaft in channels or recesses that can be closed with a bonding process that results in a gas-tight seal designed to fit To withstand both the internal atmosphere of the shaft and the process chemicals in the process chamber. In the spaces, recesses, or cavities between the plate layers, the individual thermocouples can have their wires routed away from the heater shaft, and the plate layers can be joined in a bonding process that The bonding process results in a gas-tight seal designed to withstand both the internal atmosphere of the shaft and the process chemicals in the process chamber. The thermocouple and its leads may be surrounded by a bonding process in which a first plate layer, which may be the bottom plate layer, or a channel cover is brazed to a second plate layer using any suitable bonding material such as aluminum. or heater plate.

Figure 1 illustrates an exemplary plate and shaft assembly 100, such as a heater used in semiconductor processing. In some aspects, the plate and shaft assembly 100 is constructed of ceramic, such as aluminum nitride. The heater has a shaft 101 which in turn supports a plate 102 . The panel 102 has a top surface 103 . The shaft 101 can be a hollow cylinder. The plate 102 can be a flat disk. Other subcomponents may be present. In some processes, the panels 102 may be individually fabricated in an initial process involving a process furnace in which the ceramic panels are formed. In some embodiments, the plate may be joined to the shaft using a cryogenic hermetic joining process, as described below.

Figure 2 shows a cross-section in which a first ceramic, which may be a ceramic shaft, for example Semiconductor processing equipment piece 191 may be bonded to a second ceramic semiconductor processing equipment piece 192 , which may be made of the same or a different material, and may be, for example, a ceramic plate. Joining materials such as braze may be included, which can be selected from a combination of braze materials described herein, and may be delivered to the (aluminum) joint 190 according to the methods described herein. In some aspects, the plate can be aluminum nitride and the shaft can be aluminum nitride, zirconia, alumina, or another ceramic. In some aspects, it may be desirable to use a shaft material with a lower thermal conductivity in some embodiments.

With regard to the joint depicted in Figure 2, the first ceramic semiconductor processing equipment piece (shank) 191 can be positioned so that it is against the plate with only the brazing layer interposed between the surfaces to be joined, For example, between the first interface area 193 of the shaft and the second interface area 194 of the plate. The second interface region 194 of the second ceramic semiconductor processing equipment component 192 may reside in a recess 195 in the plate. The thickness of this joint is exaggerated for clarity of illustration. In an exemplary embodiment, both the plate and the shaft may be aluminum nitride and have been separately formed in advance using a liquid phase sintering process. In some embodiments, the plate may be approximately 9-13 inches in diameter and 0.5 to 0.75 inches thick. The shaft can be a hollow cylinder that is 5-10 inches long, with a wall thickness in the 0.1-inch range and an outer diameter in the range 1-3 inches. The plate may have a recess designed to receive the outer surface of the first end of the shaft.

As seen in Figure 3, the brazing material used in joints on heaters, or other devices can bridge the gap between two different atmospheres. Significant problems can arise with previously brazed materials. On the exterior surface 207 of the semiconductor processing equipment, such as the heater 205 of the semiconductor wafer chuck, the brazing material must be compatible with the processes occurring in the semiconductor processing chamber 200, and the environment existing in the semiconductor processing chamber 200. 201, and the heater 205 will be used in the semiconductor processing chamber 200. The environment 201 present in the semiconductor processing chamber 200 may contain fluorine chemical compositions. The heater 205 may have a base plate 206 fixed to the top surface of the plate 203, with the heater being supported by a shaft 204. On the interior surface 208 of the heater 205, the brazing layer material must be compatible with a different atmosphere 202, which may be an oxygen-containing atmosphere. Previous brazing materials used with ceramics have not been able to meet either of these criteria. For example, brazing components containing copper, silver, or gold can interfere with the lattice structure of the silicon wafer being processed and are inappropriate. However, in the case of a braze joint joining the heater plate to the heater shaft, the interior of the shaft typically sees high temperatures and has an oxygen-containing atmosphere within the center of the hollow shaft. The portion of the brazed joint that will be exposed to the atmosphere will oxidize, and oxidation can enter the joint, causing a failure in the sealing of the joint. In addition to structural attachments, in many, if not all, applications, the joints between the shafts and plates of these devices used in semiconductor manufacturing must be sealed.

Figure 4 shows a schematic illustration of one embodiment of a heater cylinder for use in a semiconductor processing chamber. Heater 300, which may be a ceramic heater, can include radio frequency antenna 310, heater element 320, shaft 330, plate 340, and mounting flange 350.

In some embodiments of the present invention, as shown in Figure 5, it is provided for use in half Equipment in the conductor fabrication process, such as a wafer chuck or heater 500, can be provided. The device may include an elongated shaft 516, which may be cylindrical in shape and provided with first and second opposite ends 517, 518 and a central, longitudinal axis 519 extending between the ends 517, 518. A passage or central bore 504 extends through the shaft 516 from a first end 517 to a second end 518 . The plate 521 can be joined to the first end 517 of the shaft 516 . The plate 521 can be of any suitable shape, such as cylindrical, and can be centered on the axis 519 . In one embodiment, the radius of the plate 521 is larger than the radius of the shaft 516 . In one embodiment, the plate 521 has a portion 522 , such as an annular portion, extending radially outward from the axis 519 beyond the shaft 516 . The shaft 516 and the plate 521 may each be made of any suitable material, such as a ceramic material, and in one embodiment, the shaft 516 and the plate 521 are each made of aluminum nitride. made. The plate 521 may be provided with a plurality of heater blocks, each heater block having at least one heater therein. In one embodiment, the plate 521 has a first or center heater block 526 , a second or middle heater block 527 , and a third or edge heater block that may be centrally positioned on axis 519 , for example. 528. Each of the heater blocks can be of any suitable shape when viewed in a plane, and in one embodiment, the center heater block 526 is circular in the plane, and the intermediate heater block 526 is circular in plane. Each of heater block 527 and edge heater block 528 is annular in plane. The heater blocks can, for example, overlap, as shown in Figure 5, or not overlap and be radially spaced apart from each other.

The device 500 may be provided with a plurality of temperature sensors, for example, for each At least one temperature sensor of the heater block. In one embodiment, the first temperature sensor 505 is disposed in the plate 521 near the central heater block 526 or adjacent to the intermediate heater block 527 . In the middle heater block, a second temperature sensor 506 is disposed in the plate, and in the vicinity of or adjacent to the edge heater block 528, a third temperature sensor 507 is disposed. in this panel. In one embodiment, each of the temperature sensors is disposed in the radial center of the individual heater block, although other positioning of the temperature sensors relative to the individual heater block is subject to the invention. within the range. In one embodiment, each of the second and third temperature sensors 506, 507 are disposed in portion 522 of the plate 521. In one embodiment, the temperature sensors 505, 506, 507 are radially spaced apart from each other, and in one embodiment, the second temperature sensor 506 is radially spaced from the first temperature sensor 505. The third temperature sensor 507 is spaced radially outward from the second temperature sensor 506 . Each of the temperature sensors may be of any suitable type, and in one embodiment, each of the temperature sensors is a thermocouple.

Electrical wires extend from each of the temperature sensors to the first end 517 of the shaft 516 and through the central hole 504 to the second end 518 of the shaft. In this regard, first electrical lead 531 is electrically coupled or bonded to first sensor 505 at one end, second electrical lead 532 is electrically coupled or bonded to second sensor 506 at one end, and third electrical lead 531 is electrically coupled or bonded to first sensor 505 at one end. Wire 533 is electrically coupled or bonded to third sensor 507 at one end. Each of the wires extends through the shaft 516 so as to be accessible at the second end 518 of the shaft, and allows independent monitoring of the temperature of the panel 521, more specifically in the vicinity of the individual temperature sensors and thus in the vicinity of the individual heater blocks 526, 527, 528.

Plate 516 can be formed in any suitable manner, and in one embodiment is made from multiple layers, such as multi-planar layers. In one embodiment, the first plate layer or cover 501 of the device 500 may be bonded to the second plate layer or the back of the heater plate 502 of the device 500, covering a hollow area or recess 503, which The hollow area or recess may be continuous with the heater shaft hollow hole 504 or communicate with the hollow hole 504 . The recesses can function as conduits for temperature sensor wires 531-533, and one or more of the wires 531-533 can be disposed in each of the recesses or channels. The use of radial feeds, recesses or channels, such as covered hollow areas, allows individually controlled thermocouples to be used directly in each heater zone of multi-zone heater 500, such as heater zones 526-528. Monitor this local temperature. The thermocouples 505, 506, 507 may be installed within individual thermowells 508, 509, 510 located in each individual heater block. The thermocouples can be installed into the sleeves, which are located within the covered hollow area, or channel 503. In some embodiments, machining of the plate may be performed in the channel 503 to allow deeper mounting for the temperature sensors or thermocouples 505-507. The thermocouples may then be covered with a ceramic cover plate 501 positioned on the back of the heater plate between the heater plate and the shaft. The heater plate 502, hollow area cover 501, and heater shaft 516 can then be joined together. This isolates the thermocouples from the process environment, and for traditional The control provides direct feedback of the temperature of each heater block. In some heater designs, the heater is fully embedded within the panel during the panel's manufacturing process. This process can result in high temperatures and high pressure contact forces during the formation of the panel, which can be in the range of 1700°C. Although the heater element itself may be designed to withstand this treatment, the thermocouples 505-507 and the wires 531-533 to the thermocouples, which may be made of Inconel, are not able to withstand this treatment. . With the thermocouples 531-533 installed after the final sintering and pressing of the ceramic plate 521, the thermocouples must then be protected from the process chemicals to which the heater 500 will be exposed during its use. Process chemistry. The use of multiple thermocouples with separate heaters monitoring the temperature of various areas of the panel 521 allows for temperature control of these areas of the panel based on actual temperature readings.

The thermowells can reach a level entering the plate 521 to the heater element. In some embodiments, the heater element may have an open area so that the thermowell does not fall into the heater element, but to the same depth in a region where there is a gap or space. In some embodiments, after the heater plate is fabricated, the hollow area 503 and the thermowells may be machined into the heater plate with the thermowells within the heater plate. Multi-block heater element. The multi-zone heater elements may be in the ceramic heater plate when the plate is manufactured. Using a low temperature bonding process as described herein, the hollow area cover 502 can be bonded to the heater plate 501 and, in some aspects, to a portion or end 517 of the shaft 516 .

6 is a bottom view illustration of a plate member, such as plate member 521, of a semiconductor processing wafer chuck 500, with a shaft, such as shaft 516, attached thereto. A recess, groove or hollow channel area 503 extends radially outward from the portion of the plate residing in the center of the hollow shaft 516 . One or more thermowells may be within this hollow channel area 503 that allow for the insertion of temperature sensors or thermocouples into individual heater blocks, such as intermediate heater block 527 and individual heater elements provided in edge heater block 528 that cannot otherwise be directly monitored.

Figure 7 illustrates a cross-sectional view of a portion of a heater plate 502 and a cover plate 501 having a recess, space or hollow area 503 such as to be contained for use, in accordance with some embodiments of the present invention. Part of the heater or wafer chuck used in semiconductor manufacturing processes. The cover plate 501 may be designed to fit within a groove, recess or opening provided in the bottom of the heater plate. Grooves, channels, recesses or grooves are provided in at least one of the heater plate 502 and the cover plate 503 . In one embodiment, a recess or channel 503 shown in cross-section in Figure 7 may exist beneath the groove and be designed to be adapted for routing an electrical lead or coupling from a temperature sensor or thermocouple 520 to the center of the shaft. A particularly suitable temperature sensor or thermocouple is one that is arranged radially in the plate beyond the outer radius of the shaft, and thus does not overlap the shaft. For example, a suitable joint 521 of any of the bonding layers disclosed herein may attach the cover 501 to the heater plate 502 and bridge the different atmospheres when the atmosphere in the center of the shaft is visible to the channel 503 , the atmosphere will probably be oxygen-containing. for For thermowells in the region of the channel, the atmosphere within the channel may allow for significantly better thermocouple function. The other side of the connector will see the atmosphere inside the process chamber, which can contain corrosive process gases such as fluorine chemicals. Proper joining methods result in a joint, such as the type of hermetic joint disclosed herein, that is compatible with these various atmospheres. The electrical conductors 520 of the device or heater illustrated in Figure 7 extend through the heater plate 502 in a recess, channel, or passage that is airtightly sealed to the environment of the semiconductor processing chamber. separate from the environment in which this equipment is used.

8 illustrates a cross-sectional view of a portion of a first plate layer or heater plate 502 that is included, for example, as part of a heater or wafer chuck for use in a semiconductor manufacturing process and has A second plate layer or hollow cover 530 is designed to be bonded to the bottom of the heater plate 502 . The heater plate 502 and cover plate 530 can form a plate of the heater, such as plate 521 . The hollow cover 530 may cover the electrical conductors or thermocouple coupling wires 520 and thermowells in the bottom of the heater plate. At least one of the opposing surfaces of the heater plate 502 and the cover plate 530 is provided with grooves, channels, recesses or recesses for forming an airtight seal from the environment of the semiconductor processing chamber and is suitable for use as a A groove, channel, recess or recess 545 of a conduit for coupling to a temperature sensor disposed in a portion of the heater plate extending radially outwardly from the heater shaft, or Thermowell electrical conductor or wire 520. A suitable bonding layer or joint 546, such as any of those disclosed herein, can attach the cover 530 to the heater plate 502 and form an airtight seal therebetween. seal up. In the embodiment illustrated in Figure 8, the channel 545 is within or extends through the cover 530, such as within or extending through the heater plate or structure 502. Structure 502 is the opposite.

Figures 9 and 10 illustrate a heater 550 according to some embodiments of the present invention in a perspective view and a partially exploded perspective view respectively. Heater 550 is similar to the heater described above, and like reference numerals have been used to describe like components of such heaters and heater 550 . A hollow cover plate 551 is provided and may have a continuous annular member or ring 552 designed to reside between the shaft 516 and the bottom of the heater plate 502 . In one embodiment, the cover plate 551 and the annular component or ring 552 are integrally formed from the same material and are not dissimilar parts. At least one of the opposing surfaces of the heater plate 502 and the cover plate 551 is provided with grooves, channels, recesses or grooves for forming an airtight seal from the environment of the semiconductor processing chamber and is suitable for use as a A groove, channel, recess or recess of a conduit for coupling to a temperature sensor disposed in a portion of the plate 521 extending radially outward from the shaft 516 of the heater 550 or Thermocouple electrical conductors 532, 533. In heater 550, grooves, channels, recesses, or grooves for the temperature sensor wires are tied into or extend through cover 551, such as on the heater plate or Within or extending across the heater plate or structure 502 is opposite. Outside the perimeter of the shaft 516, the hollow cover plate 551 allows for thermocouple wires or wires 532, 533 to be routed from the bottom of the plate 521 to the center of the shaft. The heater plate 502, the hollow cover plate 551 with the annular member 552, and the shaft 516 can be joined together simultaneously in a single heating operation. In some practical applications In one embodiment, the heating operation brazes the components together. In this regard, any of the bonding processes and layers disclosed herein may be used.

In some embodiments of the present invention, as seen in the enlarged view of Figure 11, a plate and shaft assembly 556, such as a heater or wafer chuck, is seen having a plate assembly or plate 557 and shaft. Rod 558. The plate assembly 557 has layers 561, 562, 563, which may be fully fired ceramic layers before they are assembled into the plate assembly 557. The first or top plate layer 561 overlaps the second or middle layer 562 with an electrode layer 564 residing between the top plate layer 561 and the middle layer 562 . The middle layer 562 overlaps the bottom layer 563 with a heater layer 565 residing between the middle layer 562 and the bottom layer 563 .

In some embodiments, thermocouples may be installed between the panel layers to monitor temperature at different locations. Multilayer plate assemblies may allow access to areas on one or more surfaces of one or more of the plates so that surface machining can be done after final firing of the ceramic plate layers. Furthermore, this proximity to the surface may also allow components to be assembled into the surface of the panel layers and assembled into the spaces between the panel layers.

The layers 561, 562, 563 of the plate assembly 557 may be ceramic, such as aluminum nitride in the case of a heater, or may include aluminum oxide, doped aluminum oxide, AIN, doped AIN, beryllium oxide, doped Other materials of beryllium oxide and others in the case of electrostatic chucks. The layers 561, 562, 563 of the plate assembly that make up the substrate support may be fully fired ceramics before they are introduced into the plate assembly 557. For example, the layers 561, 562, 563 can be fully fired as a high temperature high contact pressure special furnace, or The plate is strip cast, or spark plasma sintering, or another method, and then machined to final dimensions as required by its use and position in the stack of the plate assembly. The panel layers 561, 562, 563 may then be joined together using a brazing process with bonding layers 567 that allow the final assembly of the panel assembly 557 to be made without the need for equipment for high-end applications. Special high-temperature furnace for contact stress press.

In embodiments in which the shaft is also part of the final assembly, such as in the case of a plate and shaft assembly, the plate assembly 557 to shaft 558 joining process step may also use a different process. The brazing process requires a special high-temperature furnace equipped with a press for high contact stress. In some embodiments, the plate layers and the bonding of the plate assembly to the shaft can be made in one simultaneous process step. The shaft 558 may be joined to the plate assembly 557 with a joining layer 568 . In some embodiments, the bonding layer 568 can be a brazing component that is identical to the bonding layers 567 .

Improved methods for manufacturing panels, or panel assemblies, may involve joining the various layers of the panel assembly into the final panel assembly without the time-consuming and expensive steps of additional processing with high temperatures and high contact pressures, This has been described above and in more detail below. According to embodiments of the present invention, the plate layers may be joined using a brazing method for joining ceramics. An example of a brazing method for joining the first and second ceramic objects together may include the step of bringing the first and second objects together with a brazing layer selected from a group disposed on the first ceramic object. A group of aluminum and aluminum alloys between a first and a second ceramic object, and heating the brazing layer to a temperature of at least 800°C and cooling the brazing layer to a temperature below its melting point, resulting in The brazing layer hardens and establishing an airtight seal for joining the first member to the second member. Various geometries of brazed joints can be implemented according to the methods described herein.

In some embodiments of the invention, a panel assembly with layers may be presented such that legs are present between the layers of the panel such that when the joint layers are heated and slight pressure is applied axially When reaching the panels, there is slight axial compression, causing the joint layer to become moderately thinner until the legs on one panel contact the adjacent panel. In some aspects, this allows for not only control of the joint thickness, but also dimensional and tolerance control of the panel assembly. For example, the parallelism of the components of the various panels can be set by machine tolerances on the panel layers, and this can be maintained through the use of feet during the joining process. In some embodiments, control of the rear joint size may be achieved using a circumferential outer ring on one plate layer that overlaps an inner ring on an adjacent layer to provide axial consistency. In some embodiments, one of the outer ring member or the inner ring member may also contact the adjacent plate member in an axial direction perpendicular to the plate member, so that the position control is also in the axial direction. achieved. The axial position control can also determine the final thickness of the bonding layer between the two adjacent panels.

In some embodiments of the present invention, the electrodes between each layer can be made of the same material as the bonding layer, and can function in the dual capabilities of both the bonding layer and the electrode. For example, the area previously occupied by electrodes in an electrostatic chuck could instead be occupied by a bonding layer that has a dual function: acting as electrodes, for example to provide electrostatic clamping force, and performing as bonding. layer to join the two plates, and the joining layer resides between the two plates between. In such embodiments, the labyrinth seal may be formed around the periphery of the two joining plates so that the line of sight and access to the charging electrode from substantially the outside of the plates is minimized.

Figure 12 illustrates a partial cross-sectional view of a panel assembly in accordance with some embodiments of the present invention. The plate assembly is a multi-layer plate assembly having both a heater and electrodes residing between different layers. The layers are joined to brazed elements and the final positions of the panels in a direction perpendicular to the planes perpendicular to the main planes of the panels are indicated by the feet 578, 579 on the panels.

The first or top panel layer 571 overlaps the second or lower panel layer 572 . This lower panel layer 572 overlaps a third or bottom panel layer 573 . Although illustrated with three plate layers in Figure 12, a different number of plate layers may be used depending on the needs of the particular application. The top panel layer 571 is bonded to the lower panel layer 572 using a multifunctional bonding layer 576 . The multifunctional bonding layer 576 is designed to provide bonding of the top plate layer 571 to the lower plate layer 572 and will be an electrode. This electrode may be a bonding layer of a generally circular disk, where the bonding material also serves as an electrode. As seen in Figure 12, the feet 578 are designed to provide positional control of the top panel layer 571 to the lower panel layer 572 in an upright direction perpendicular to the principal planes of the panel layers. The edge of the top panel layer 571 is designed to remove sight at its periphery along the boundary 577 between the two panels. The thickness of the bonding layer 576 may be dimensioned such that the bonding layer 576 is in contact with the top panel layer 571 and the lower panel layer 572 prior to the steps of heating and bonding the panel assembly.

The lower panel layer 572 overlaps the bottom panel layer 573 . Heater 574 Residing between the lower plate layer 572 and the bottom plate layer 573 . In this regard, a recess, cavity or high pressure chamber is provided in at least one of the opposite surfaces of the lower plate layer 572 and the bottom plate layer 573 for forming a recess (cavity) for receiving the heater 574 or high voltage room)580. In one embodiment, illustrated in FIG. 12 , a recess (or cavity) 580 is formed in the upper surface of the bottom plate layer 573 for receiving the heater 574 . The recess 580 may be of any suitable size and shape, and may, for example, be circular when viewed in a plane, so as to be a cylindrical recess. A bonding layer 575 bonds the lower panel layer 572 to the bottom panel layer 573 . The bonding layer 575 may be an annular ring within the perimeter of the plate layers. The feet 579 are designed to provide positional control of the lower panel layer 572 to the bottom panel layer 573 in an upright direction perpendicular to the principal planes of the panel layers. During the joining step of the panel assembly, the components as seen in Figure 12 can be pre-assembled, and then the panel pre-assembly can be joined using the process described herein to form a completed panel assembly. In some embodiments, this panel pre-assembly can be further pre-assembled with the shaft and shaft joint layer so that a completed panel and shaft assembly can be joined in a single heating process. These single heating processes may not require a high temperature furnace, or a high temperature furnace with a press bed designed to provide high contact stresses. In addition, in some embodiments, the completed plate and shaft assembly may not require any post-joint cutting processing, while still meeting the tolerance requirements of this device during actual use in semiconductor manufacturing.

In some embodiments, the top plate layer and the bottom plate layer are aluminum nitride. In some embodiments, the bonding layer is aluminum. The joining process and materials Examples of materials are discussed below.

13 is an illustrative cross-sectional view of a plate and shaft assembly such as heater 600 having multiple heater blocks and multiple thermocouples using multilayer plate 601 in accordance with some embodiments of the present invention. An elongated shaft having a first end 645 and an opposite second end 642, and a longitudinal axis 644 extending between the ends 645, 642 is provided. The first end 645 of the shaft 602 can be coupled to the bottom center of the plate 601 by any suitable method, including as disclosed herein. In these embodiments, the use of a hermetic bonding layer that is also designed to withstand the chemical composition of the corrosive treatment may be used to join adjacent panels together to allow for the insertion of the temperature sensor 605 therein. The portion of plate 601 that extends radially outside the area circumscribed by interior 603 of shaft 602 is also protected from corrosive process gases to which the heater may be exposed.

In some embodiments, the use of multi-layer panels allows access to the spaces between layers where thermocouples can be placed into areas that otherwise cannot be monitored. For example, in a heater (plate and shaft assembly) 600 such as that seen in Figure 13, all power and monitoring is typically routed through the hollow center or central passage 603 of the shaft 602 and fed into the assembly via a chamber Leave the treatment room. In prior art devices, in which the entire ceramic plate and shaft assembly were thermally sintered together, the only available area was the area within the center of the hollow shaft in which a thermocouple was embedded and the telemetry device Loop downward past the hollow shaft. For example, a hole can be drilled in the bottom of the plate using a long drill bit designed to fit down to the center of the hollow shaft. A thermocouple can then be inserted into the hole hole and is used to monitor the temperature of the panel only in this central area. This limitation in where thermocouples can be mounted prevents the monitoring of temperatures at locations outside the interior of the hollow shaft.

In some embodiments of the present invention, a central hub 604 may be used to help facilitate sealing of the space between the plate layers from the atmosphere that may be present within the shaft. In such embodiments, the central hub 604 may serve as a feed from the central portion of the shaft 602 and the layer space between the panel layers.

In some embodiments, the plate 601 of the heater 600 may be assembled from three plate layers. Each of the plate layers may be a fully fired ceramic, such as aluminum nitride. Each of the panel layers may be pre-cut to final, or near final, dimensions before being assembled into the multi-layer panel assembly. A first or top panel layer 612 may overlap a second or middle panel layer 611 , which in turn may overlap a third or bottom panel layer 610 . The shape of each of the plate layers may be cylindrical, and in one embodiment, each of the plates has the same lateral size or diameter, which is equal to the lateral size of the plate 601 or diameter. The middle panel layer may be bonded to the bottom panel layer 610 with a bonding layer 614 around its perimeter. The metal layer 613 between the top plate layer 612 and the middle plate layer 611 can be used as an RF layer and as a bonding layer between these plate layers. The plate 601 has a portion 605 extending radially outward from the axis 644 beyond the shaft 602 .

There may be one or more heater elements between the middle plate layer 611 and the lower plate layer 610 . The middle plate layer 611 may be designed to receive the heater elements such that the heater elements 621 reside on the middle plate In the trench 620 in the bottom of layer 611. An example of a multi-zone heater element design is seen in Figure 17. The heater element is divided into three radial sections, each of which has two halves, for a total of six sections. In this regard, the plate 602 includes a central heater block 641, which may be annular in shape and divided into first and second central half-blocks 641a, 641b; an intermediate heater block 642, which may be in the shape of Ring-shaped and divided into first and second middle half-blocks 642a, 642b; and edge heater block 643, which may be ring-shaped and divided into first and second edge half-blocks 643a, 643b. Each of the half-blocks may be shaped like a semi-ring. The center heater block 641 can be centrally positioned on axis 644, the intermediate heater block can be spaced radially outwardly from axis 644, and the center heater block 641 and the edge heater blocks can be The axis is spaced radially outward from the intermediate heater block. In the schematic illustration of the heater 600 in FIG. 13, only the center heater block 641 and the edge heater block 643 are shown. Two of the radial blocks, namely the middle heater block 642 and the edge heater block 643, are tied in part 605 of the plate 601 and completely outside the perimeter of the interior of the hollow shaft. . The heater elements 621 may be molybdenum and may be loaded into the trenches with the AIN loading compound 622 . Power cords 646 for the heater elements 621 may extend from the central hub to route power to the individual heater circuits.

In one embodiment, at least one first temperature sensor 651 is disposed in the plate 601 near or adjacent to the central heater block 641, and at least one second temperature sensor 652 is disposed in the plate 601. intermediate heating The central heater block 642 is disposed in the plate near or adjacent to the middle heater block 642, and at least one third temperature sensor 653 is disposed near the edge heater block 643 or adjacent to the edge heater block 643. set in this panel. Any suitable positioning of temperature sensors relative to the individual heater blocks is within the scope of the present invention. In one embodiment, each of the second and third temperature sensors 652, 653 are disposed in the portion 605 of the plate 601. Thus, temperature sensors located in heater blocks 642, 643 designed to provide temperature monitoring are placed in the plate at a radial distance greater than the inner radius of the shaft 602. In one embodiment, the temperature sensors 651, 652, 653 are radially spaced apart from each other, and in one embodiment, each second temperature sensor 652 is formed by the at least one first temperature sensor. 651 are radially spaced outwardly, and each third temperature sensor 653 is radially spaced outwardly from the at least one second temperature sensor 652 . Each of the temperature sensors may be of any suitable type, and in one embodiment, each of the temperature sensors is a thermocouple.

Electrical wires 661 extend from each of the temperature sensors 651 - 653 to the first end 645 of the shaft 601 and pass through the central hole 603 of the second end 642 of the shaft. Each of the wires 661 extends through the shaft 601 to provide access to the second end 642 of the shaft and to allow independent monitoring of the temperature of the plate 601 , and more specifically at the individual heater zones. The temperature of the plate is monitored near blocks 641, 642, and 643.

In embodiments such as those shown in Figures 13-16, the bottom surface of the middle plate layer 611 can be seen mounting various components. In some aspects, one or more recesses, channels, grooves or grooves 662 may be machined to create the surface. surface for the installation of heater element 621 and electrical conductors 661. The one or more recesses can contain a single cavity, which may be, for example, cylindrical in shape and, in one embodiment, centered on axis 644. Holes can be drilled into this surface to serve as thermowells for mounting thermocouples 651-653. After this cutting process, the heater elements 621 can be installed and planted. In some embodiments, the heater elements may be molybdenum wires placed in the trenches. In some embodiments, the heater elements may be deposited into the trenches using thick film deposition techniques. The thermocouples 651-653 can also be installed and planted. The heater elements can be attached to the power cord 646, which can be a bus bar. In embodiments in which a central hub is used, power wire 646 and thermocouple wire 661 may be routed through the central hub. The multi-layer plate stack 601 may be assembled, such as in a tip-down manner, with all components including braze layers assembled into a pre-assembly that will then be processed into a final, completed heater assembly. Brazing steps as described herein will join all such components with a gas-tight seal designed to withstand the atmosphere that the heater will see while supporting semiconductor manufacturing, which atmosphere may contain oxygen. atmosphere, and fluorine chemical composition.

By routing wires through the central hub 604, such as thermocouple wires 661 with Inconel exteriors, these wires can be routed through the central hub and also sealed with brazed elements. For example, a wire can be routed through a hole in the central hub, which has an enlarged hole, and a cylindrical brazing element can be placed around the wire prior to the brazing step. The central hub 604 also allows communication between the middle panel layer 611 and the bottom panel layer 610 The inter-plate space is airtightly sealed by the inner space of the shaft. As seen in Figure 14, a bonding layer 615 can be used to seal the shaft from the bottom of the bottom plate layer 610, and another bonding layer 616 can be used to seal the shaft from the upper surface of the bottom plate layer 610. Center hub 604. In some embodiments, when the entire heater assembly is heated in vacuum during the brazing step to join all of the various surfaces attached by the various bonding layers, the inter-plate spaces will Sealed with a gas-tight seal under vacuum conditions. In some aspects, having the inter-board space in which the thermocouples are mounted will better thermally isolate the thermocouples from temperatures different than those seen in the area where they are mounted.

Figures 15 and 16 illustrate the central hub 604 in top view and partial cross-sectional view respectively. The central hub can be used as a closed feed device, which isolates the central area of the shaft by the inter-plate space between the middle plate layer 611 and the bottom plate layer 610 . The power wire 646 powering the heaters, and the thermocouple wires 661 can be routed through the central hub and sealed with the brazing material in the same brazing process step, joining and sealing to each other. Such other components.

Figure 17 illustrates a multi-zone heater element, such as heater 600, as viewed in some embodiments of the present invention. The heater element is divided into three radial sections 641, 642, 643, each of which has two halves, for a total of six heater sections 641a, 641b, 642a, 642b, 643a, 643b. Both of the radial blocks, such as the center heater block 642 and the edge heater block 643 , are tied in the plate portion 605 well outside the perimeter of the interior of the hollow shaft 602 .

Bonding methods according to some embodiments of the present invention depend on the control of wetting and flow of the bonding material relative to the ceramic parts to be bonded. In some embodiments, the lack of oxygen allows for proper wetting during the joining process without changing the reaction of the materials in the joint area. With proper wetting and flow of the joining material, airtightly sealed joints can be obtained at considerably lower temperatures. In some embodiments of the present invention, pre-metalization of the ceramic in the area of the joint is performed prior to the bonding process.

In some applications where ceramic-jointed end products are used, the strength of the joint cannot be a primary design factor. In some applications, tightness of the joint may be required to allow separation of the atmosphere for either side of the joint. The composition of the joining material may also be important so that it is resistant to chemicals to which the end product of the ceramic assembly may be exposed. The joining material may need to be resistant to chemicals that can otherwise cause degradation of the joint and loss of the airtight seal. The bonding material may also need to be a material that does not negatively hinder the later processing supported by the completed ceramic device.

In some embodiments of the present invention, the bonded ceramic assembly is composed of ceramic, such as aluminum nitride. Other materials such as aluminum oxide, silicon nitride, silicon carbide or beryllium oxide can be used. In some aspects, the first ceramic piece can be aluminum nitride, and the second ceramic piece can be aluminum nitride, zirconia, alumina, or another ceramic. In some processes, the joined ceramic assembly components may first be fabricated individually in an initial process involving a process furnace in which the first and second pieces are formed. In some embodiments, a recess may be included in one of the snap members allowing the Another snap member resides in the recess.

In some embodiments, the joint may include legs designed to maintain a minimum brazing layer thickness. In some embodiments, one of the ceramic pieces, such as the The shaft can use multiple support bases. The mesa can be part of the same structure as the ceramic piece, and can be formed by cutting away the structure from the mesa, leaving the mesa. The tabletops can abut the ends of the ceramic piece after the bonding process. In some embodiments, the mesas may be used to establish a minimum brazing layer thickness for the joint. In some embodiments, prior to brazing, the brazing layer material will be thicker than the distance maintained by the table or powder particles between the shaft end and the plate. In some embodiments, other methods may be used to establish a minimum braze layer thickness. In some embodiments, ceramic spheres may be used to establish a minimum brazing layer thickness. In some aspects, the joint thickness may be slightly thicker than the dimensions of the legs, or another minimum thickness determining device, since not all of the brazing material may be formed between the legs and the adjacent interface surface. time was squeezed out. In some aspects, part of the aluminum braze layer may be found between the leg and the adjacent interface surface. In some embodiments, the brazing material may be 0.006 inches thick before brazing to a minimum thickness of 0.004 inches to complete the joint. The brazing material may be aluminum with 0.4 Wt.% Fe. In some embodiments, the legs are not used.

The atmosphere-compatible brazing material for both types is aluminum when they are seen on both sides across a joint in this device. Aluminum has the property of forming a self-limiting layer of oxidized aluminum. This layer is generally homogeneous and, once formed, prevent or significantly limit the penetration of additional oxygen or other oxidizing chemicals (such as fluorine chemicals) into the base aluminum and continue the oxidation process. Thus, there is an initial brief period of oxidation or corrosion of the aluminum, which is then essentially stopped or slowed down by the oxide (fluoride) layer that has formed on the aluminum surface. The brazing material may be in the form of flakes, powders, films, or any other form factor suitable for use in the brazing processes described herein. For example, the braze layer may be a sheet having a thickness ranging from 0.00019 inches to 0.011 inches or more. In some embodiments, the brazing material may be a sheet having a thickness of approximately 0.0012 inches. In some embodiments, the brazing material can be a sheet having a thickness of approximately 0.006 inches. Typically, alloying components in aluminum (such as magnesium, for example) are formed as precipitates between the grain boundaries of the aluminum. Although they can reduce the oxidation resistance of the aluminum joint layer, these precipitates typically do not form a continuous path through the aluminum, and thereby do not allow the oxidant to penetrate through the entire aluminum layer, and thus leave the aluminum intact. Self-confining oxide layer characteristics provide corrosion resistance. In embodiments using aluminum alloys containing components capable of forming precipitates, process parameters including cooling protocols will be designed to minimize precipitates in the grain boundaries. For example, in one embodiment, the brazing material may be aluminum having a purity of at least 99.5%. In some embodiments, commercially available aluminum foil, which may have a purity greater than 92%, may be used. In some embodiments, alloys are used. These alloys may include Al-5w%Zr, Al-5w%Ti, commercial alloys #7005, #5083, and #7075. In some embodiments, these alloys may be used with bonding temperatures of 1100°C. In some embodiments, these alloys can be used with 800°C and Temperatures between 1200°C are used. In some embodiments, these alloys may be used with lower or higher temperatures.

Under process conditions according to embodiments of the present invention, in the manufacture of the plate and shaft assembly, the insensitivity of AlN to the diffusion of aluminum after the brazing step results in material properties of the ceramic, and Preservation of material identity.

In some embodiments, the bonding process is performed in a process chamber designed to provide very low pressure. The joining process according to embodiments of the present invention may require oxygen-free in order to achieve an airtight and sealed joint. In some embodiments, the process is performed at a pressure below 1x10E-4 Torr. In some embodiments, the process is performed at a pressure below 1x10E-5 Torr. In some embodiments, further oxygen removal is achieved with zirconium or titanium disposed in the process chamber. For example, a zirconium inner chamber may be placed around the components to be joined.

In some embodiments, an atmosphere other than a vacuum may be used to achieve an airtight seal. In some embodiments, an argon (Ar) atmosphere may be used to achieve a sealed joint. In some embodiments, other inert gases may be used to achieve a sealed joint. In some embodiments, a hydrogen (H ₂ ) atmosphere may be used to achieve a sealed joint.

The wetting and flow of the braze layer can be sensitive to various factors. Relevant factors include the brazing material composition, the ceramic composition, the chemical composition of the atmosphere in the process chamber, especially the level of oxygen in the chamber during the bonding process, the temperature, the time at the temperature, the hardening The thickness of the welding material, the surface characteristics of the materials to be joined, the geometry of the components to be joined, the physical pressure applied across the joint during the joining process, and/or the The joint clearance maintained during the closing process.

In some embodiments, the surface of the ceramic may be metallized before the ceramic piece is placed in a chamber for bonding. In some embodiments, the metallization can be a friction metallization. The friction metallization may include the use of aluminum rods. When the elements are joined, a rotary tool can be used to pivot the aluminum rod over the area that will adjoin the brazing layer. This friction metallization step can leave some aluminum in the surface of the ceramic piece. The friction metallization step may modify the ceramic surface somewhat, such as by removing some oxides so that the surface is better designed for wetting of the brazing material. In some embodiments, the metallization step may be a thin film sputtering.

An example of a brazing method for joining the first and second ceramic objects together may include the step of bringing the first and second objects together with a brazing layer selected from a ceramic material disposed on the third ceramic object. A group of aluminum and aluminum alloys between the first and second ceramic objects, heating the brazing layer to a temperature of at least 800°C, and cooling the brazing layer to a temperature below its melting point, such that the brazing layer The layer hardens and creates a hermetic seal for joining the first component to the second component. Various geometries of brazed joints can be implemented according to the methods described herein.

Bonding processes according to some embodiments of the present invention may include some or all of the following steps. Two or more ceramic pieces are selected for joining. In some embodiments, multiple devices may be bonded in the same set of process steps using multiple bonding layers, but for clarity of discussion, two ceramic devices bonded with a single bonding layer will be discussed herein. The ceramic piece may be aluminum nitride. The ceramic piece can be single crystal or polycrystalline aluminum nitride. Each part of each component has been The area of each element is recognized as being joined to another element. In one illustrative example, a portion of the bottom of the ceramic plate structure will be bonded to the top of the ceramic hollow cylindrical structure. The joining material may be a brazing layer including aluminum. In some embodiments, the brazing layer can be a commercially available aluminum foil with >99% aluminum content. In some embodiments, the brazing layer may include foil layers.

In some embodiments, specific surface areas to be bonded will be subjected to a pre-metallization step. This pre-metalization step can be achieved in various ways. In one method, a friction pre-metallization process is employed, using a rod of material, which may be 6061 aluminum alloy, that can be spun with a rotating tool and pressed against the ceramic in the joint area, allowing some aluminum to be deposited to each of the two ceramic pieces in the area of the joint. In another method, PVD, CVD, electroplating, plasma spraying, or other methods can be used to apply the pre-metallization.

Prior to joining, the two components may be secured relative to each other to maintain some positional control while in the process chamber. The fastening may also facilitate the application of an externally applied load to establish contact pressure between the two elements and across the joint during the application of temperature. A weight can be placed on top of the fixation element so that contact pressure is exerted across the joint. The weight may be proportional to the area of the braze layer. In some embodiments, the contact pressure applied across the joint to the joint contact area may be in the range of approximately 2-500 psi. In some embodiments, the contact pressure may be in the range of 2-40 psi, and in some embodiments, a minimum pressure may be used. The contact pressure used in this step is significantly lower than that seen in the bonding step using hot pressing/sintering, which, as seen in the previous process, allows Used for pressures in the range of 2000-3000psi.

In embodiments that use a table as a foot, or use other methods of joint thickness control such as ceramic spheres, the original thickness of the braze layer before the application of heat can be greater than the height of the table. When the temperature of the brazing layer reaches and exceeds the liquidus temperature, the pressure across the brazing layer between the components to be joined will cause relative movement between the components until the mesa on the first component contacts the surface on the second component the interface surface. At that point, contact pressure across the joint will no longer be supplied by the external force (other than resistance to the repulsive forces within the braze layer, if any). The mesas prevent the brazing layer from being forced away from the joint area prior to complete wetting of the ceramic parts, and thus allow for better and/or complete wetting during the joining process. In some embodiments, the countertop is not used.

The fixed assembly can be placed in a process furnace. The furnace can be evacuated to a pressure of less than 5 x 10E-5 Torr. In some aspects, a vacuum removes the remaining oxygen. In some embodiments, vacuum below 1×10E-5 Torr is used. In some embodiments, the fixture assembly is placed within a zirconium chamber, and the zirconium acts as an oxygen attractant, further reducing the remaining oxygen that may find its way toward the joint during processing. In some embodiments, the process furnace is flushed and refilled with pure, dehydrated pure inert gas, such as argon, to remove the oxygen. In some embodiments, the process furnace is flushed and refilled with purified hydrogen to remove the oxygen.

The fixed assembly is then subjected to an increase in temperature and remains at the joining temperature. At the beginning of the heating cycle, the temperature can be increased slowly, such as 15°C to 200°C per minute, then 20°C per minute, and thereafter to Standardize temperatures, such as 600°C and the joining temperature, and hold each temperature for a fixed dwell time to allow the vacuum to recover after heating, to minimize gradients and/or for other reasons. When the brazing temperature has been reached, the temperature can be maintained for a period of time to perform the brazing reaction. In an exemplary embodiment, the residence temperature can be 800°C, and the residence time can be 2 hours. In another exemplary embodiment, the residence temperature may be 1000°C, and the residence time may be 15 minutes. In another exemplary embodiment, the residence temperature may be 1150°C, and the residence time may be 30-45 minutes. In some embodiments, the dwell temperature does not exceed a maximum value of 1200°C. In some embodiments, the dwell temperature does not exceed a maximum value of 1300°C. When sufficient brazing dwell time is achieved, the furnace may be cooled to room temperature at a rate of 20°C per minute, or when the inherent furnace cooling rate is less, the furnace may be cooled to room temperature at a rate lower than 20°C per minute. was cooled to room temperature at a rate. The furnace can be brought to atmospheric pressure, opened, and the brazed assembly removed for inspection, characterization, and/or evaluation.

Use of too high a temperature can cause voids to form in the bonding layer as a result of significant aluminum evaporation for too long a period of time. As voids form in the bonding layer, the sealing of the joint may be lost. The process temperature and the duration of the process temperature can be controlled so that the aluminum layer does not evaporate and a sealed joint is achieved. With appropriate temperature and process duration control, in addition to the other process parameters mentioned above, continuous joints can be formed. Continuous joints achieved consistent with embodiments as described herein will result in a gas-tight seal of the parts, as well as a structural attachment.

The brazing material will flow and allow for wetting of the surfaces of the ceramic materials to be joined. When ceramics such as aluminum nitride are joined using an aluminum braze layer and a sufficiently low oxygen content is present as described herein, the joint is a closed braze joint. This contrasts with diffusion welding as seen in some previous ceramic joining processes.

In some embodiments, the components to be joined may be constructed so that no pressure is placed across the brazing layer during brazing. For example, the struts or shafts may be placed into countersunk holes or recesses in the engagement elements. The counterbore can be larger than the outer dimensions of the strut or shaft, which can create an area surrounding the strut or shaft, which can then be filled with aluminum, or an aluminum alloy. In this approach, the pressure placed between the two components to hold them during bonding cannot cause any pressure across the brazing layer. It may also be possible to use fixtures to hold each element in the preferred end position so that little or no pressure is placed between the elements.

A joint assembly joined as described above results in elements having air-tight seals between the joined elements. The assemblies can then be used, where atmospheric isolation is an important aspect in the use of the assemblies. Furthermore, for example, when the bonding assembly is later used in semiconductor processing, the portion of the joint that is exposed to various atmospheres will not degrade in such atmospheres and will not contaminate the portion. Post-semiconductor processing.

Both hermetically sealed and non-hermetic joints can strongly join components where considerable force is required to separate the components. However, the fact that a joint is strong does not depend on whether the joint provides an airtight seal. The ability to obtain a sealed joint may be related to the wetting of the joint. moisten Describes the ability or tendency of a liquid to spread over the surface of another material. If there is insufficient wetting in a brazed joint, there will be areas where there is no bond. If there is sufficient non-wetted area, gas can pass through the joint, causing a leak. During the melting of the brazing material, wetting can be affected at different stages by pressure across the joint. The use of countertop feet, or the insertion of another foot device, such as ceramic spheres of appropriate diameter or powder particles, to limit compression of the braze layer beyond a certain minimum distance can enhance wetting of the area of the joint. During the joining process, wetting of the area of the joint can be enhanced by careful control of the atmosphere seen by the brazed components. In bonding, careful control of the thickness of the joint, and careful control of the atmosphere used during the process, can result in complete wetting of the joint interface area that cannot be achieved with other processes. Furthermore, the use of a brazing layer of appropriate thickness, which may be thicker than the height of the countertop legs, along with other considerations can result in a well-wetted, airtight joint. While various joint layer thicknesses may be successful, increased thickness of the joint layer may enhance the success rate of a sealed version of the joint.

During the brazing process, the presence of significant amounts of oxygen or nitrogen can set up reactions that prevent complete wetting of the joint interface area and, in turn, can cause a joint to be non-hermetic. In the interface area of the joint, there is no complete wetting, and a non-wetted area is introduced into the final joint. When a sufficiently continuous non-wetted area is introduced, the tightness of the joint is lost.

The presence of nitrogen can cause the nitrogen to react with the molten aluminum to form aluminum nitride, and this reaction formation can prevent wetting of the joint interface region. Similarly, the presence of oxygen can cause the oxygen to react with the molten aluminum to form aluminum oxide, and this reaction formation can prevent wetting of the joint interface region. The use of a vacuum atmosphere with pressures below 5 x 10 ^-5 Torr has been shown to remove sufficient oxygen and nitrogen to allow for complete robust wetting of the joint interface area, and hermetic joints. In some embodiments, such as in the process chamber during the brazing step, the use of higher pressures, including atmospheric pressure, but the use of non-oxidizing gases such as hydrogen or pure inert gases such as argon has also resulted in the joint interface Robust wetting of areas, and sealed joints. In order to avoid the oxygen reactions mentioned above, the amount of oxygen present in the process chamber during the brazing step must be low enough so that complete wetting of the joint interface area is not adversely affected. In order to avoid the nitrogen reaction mentioned above, the amount of nitrogen present in the process chamber during the brazing process must be low enough so that complete wetting of the joint interface area is not adversely affected.

The selection of the appropriate atmosphere may allow for complete wetting of the joint during the brazing process, along with maintaining a minimum joint thickness. Conversely, improper atmosphere selection can lead to poor wetting, voids, and lead to non-hermetic joints. During brazing, along with appropriate material selection and temperature, the appropriate combination of a controlled atmosphere and controlled joint thickness allows for the joining of materials with sealed joints.

In some embodiments of the present invention, in which one or both of the ceramic surfaces are pre-metallized prior to brazing, such as with aluminum thin film sputtering, this joining process step may use a bonding process that is held for a shorter duration. lower temperature. At the beginning of the heating cycle, the temperature may be slowly increased, such as 15°C per minute to 200°C, and then 20°C per minute thereafter, to a normalized temperature of, for example, 600°C and the joining temperature, and held at each a temperature A fixed dwell time is provided to allow the vacuum to recover after heating, to minimize gradients and/or for other reasons. When the brazing temperature has been reached, the temperature can be held for a period of time to achieve the brazing reaction. In some embodiments using pre-metallization of one or more of the interface surfaces, the brazing temperature may be in the range of 600°C to 850°C. In an exemplary embodiment, the residence temperature may be 700°C, and the residence time may be 1 minute. In another exemplary embodiment, the residence temperature may be 750°C, and the residence time may be 1 minute. When sufficient brazing dwell time is achieved, the furnace can be cooled to room temperature at a rate of 20°C per minute, or less, when the inherent furnace cooling rate is less. The furnace can be brought to atmospheric pressure, opened, and the brazed assembly removed for inspection, characterization and/or evaluation.

In contrast to an aluminum brazing process in which no aluminum layer is deposited on the interface area of the joint, a process in which the ceramic has a thin layer of aluminum deposited thereon, such as by thin film sputtering techniques, produces a hermetically sealed joint at low temperatures and in the brazing Temperature has a very short residence time. The application of an aluminum layer deposited on the interface surface results in wetting of the surface more easily and requires less energy, allowing for lower temperature use and reduced residence time to achieve a seal. type connector.

A process summary for this brazing process is seen below: The joint is between two components of polycrystalline aluminum nitride. The brazing layer material was 0.003" thick 99.8% aluminum foil. The joint interface area of the ring was metallized using 2 micron aluminum film deposition. The joint temperature was maintained at 780°C for 10 minutes. The The joints were made in a process chamber maintained at a pressure below 6×10E-5 Torr. The joint thickness was maintained using 0.004” diameter _ZrO2 spheres. The first element (ring) is subjected to an etching process before depositing the thin layer of aluminum. Sonic imaging of the joint integrity shows a solid dark color in locations where there is good wetting to the ceramic. The good and full integrity of the joint is seen. This joint is sealed. Tightness is demonstrated by having a vacuum leak rate of <1×10E-9 sccm He/sec; as demonstrated by a standard commercially available mass spectrometer helium leak detector.

According to embodiments of the present invention, thermocouples are used to monitor sections of the heater, and the manufacture of a multi-section heater assembly allows for the insertion of thermocouples after the final firing of the ceramic parts of the heater. The thermocouples are also protected from the external environment to which the heater will be exposed during semiconductor processing, which may include corrosive gases, by a gas-impermeable seal designed to withstand Live in very high temperatures and corrosive gases. Additionally, the hermetic seals are also structural joints, and the multi-component assembly can be structurally connected and airtightly sealed in a single brazing step.

Another advantage of joining methods as described herein is that joints made in accordance with some embodiments of the present invention may allow for component disassembly to repair or replace one of the two components, if desired. By. Because the bonding process does not modify the ceramic parts by diffusing the bonding layer into the ceramic, the ceramic parts can thus be reused.

In some embodiments, the alignment and position of the shaft and plate are maintained by part geometry, eliminating fastening and post-weld machining. Weighing can be used to ensure that there is no movement during the welding process, unlike a axial movement as the brazing material melts. The panel can be placed from top to bottom with an engaging element in a recess in the rear surface of the panel. The shaft can be inserted vertically downward into the recess in the plate. A weight can be placed on the shaft 401 to provide some contact pressure during the joining process.

In some embodiments, the position and verticality of the shaft/plate are maintained by fastening. Due to thermal expansion and machining tolerances, the fastening effect cannot be exact - therefore, post-weld machining may be required. The shaft diameter can be increased to accommodate the required material to be removed to meet final size requirements. Furthermore, weighing can be used to ensure that there is no movement during the welding process other than some axial movement as the brazing material melts. The panel can be placed from top to bottom with an engagement element above the rear surface of the panel. The shaft can be placed on the plate to create a plate and shaft assembly. A fastener is designed to support and position the shaft. The fastener can be locked to the panel to provide positional integrity. A weight can be placed on the shaft to provide some contact pressure during the joining process.

One aspect of the invention is that the maximum operating temperature of the welded shaft-plate members is defined by the tensile strength with decreasing temperature of the aluminum or aluminum alloy selected for the joint. For example, if pure aluminum is used as the joining material, when the temperature of the joint is close to the melting temperature of the aluminum, which is roughly considered to be 660°C, the structural strength of the welding between the shaft and the plate becomes very low. . In fact, when using 99.5% or relatively pure aluminum, the spindle-plate assembly will withstand all normal and expected conditions encountered in a typical wafer processing tool. The stress is expected to reach a temperature of 600℃. However, some semiconductor device manufacturing processes require temperatures greater than 600°C.

A repair procedure for disengagement of an assembly that has been joined according to embodiments of the present invention may be performed as follows. The assembly may be placed in the process oven using a fastener designed to provide tension across the joint. The tightening action places approximately 2-30 psi of tensile stress on the joint contact area. In some embodiments, the tightening action may place greater stresses across the joint. The fastened assembly can then be placed in the process oven. The furnace can be evacuated, although it may not be needed during these steps. The temperature may be raised slowly, for example from 15°C to 200°C per minute, and thereafter by 20°C per minute, to a normalized temperature of, for example, 400°C and then to the separation temperature. Upon reaching the separation temperature, the elements may begin to separate from each other. The separation temperature may be specific to the material used in the brazing layer. In some embodiments, the separation temperature may be in the range of 600-800°C. In some embodiments, the separation temperature may be in the range of 800-1000°C. The fastening may be designed to allow a limited amount of movement between the two elements so that the elements are not damaged when separated. The separation temperature can be a material-specific temperature. For aluminum, the separation temperature may be in the range of 450°C to 660°C.

Before reusing a previously used component, such as a ceramic shaft, the component can be prepared for reuse by machining the joint area so that the irregular surfaces are removed. In some embodiments, it may be desirable that all of the remaining brazing material be removed so that when the component is joined to a new snap-in part, the total amount of brazing material in the joint is controlled.

In contrast to bonding methods that create a diffusion layer within the ceramic, bonding processes according to some embodiments of the present invention do not result in such a diffusion layer. In this way, the ceramic and the brazing material retain the same material properties after the brazing step that they had before the brazing step. Thus, should the component be intended to be reused after separation, the same materials and the same material properties will be present in the component, allowing for reuse with conventional compositions and properties.

In one embodiment, a wafer chuck for use in a semiconductor manufacturing process is provided and can include a shaft having an axis and an end; a plate joined to the end of the shaft and having a the axis extends radially outward beyond the portion of the shaft; a temperature sensor is disposed in the portion of the plate; and electrical conductors extend from the temperature sensor through the shaft for The temperature of the board is measured near the temperature sensor during the semiconductor manufacturing process.

The plate may be a ceramic plate. The wafer chuck may further include an additional temperature sensor disposed in the portion of the plate a radial distance from the first named temperature sensor; and an additional electrical lead. , which extends from the additional temperature sensor through the shaft and is used to measure the temperature of the plate near the additional temperature sensor. The wafer chuck may further include a first heater for heating the plate near the first named temperature sensor and a second heater for heating the plate near the additional temperature sensor. heater, the second heater is independent of the first heater. The panel is formed from at least a first panel layer and an adjacent second panel layer airtightly bonded to the first panel layer, the first panel layer having a first surface, and the second panel The component layer has a second surface opposite to the first surface, and the third At least one of the first and second surfaces has a recess therein to form a recess between the first and second plate layers extending between the temperature sensor and the shaft for supporting Accept the electrical conductors. The recess may include a first channel for receiving the first named electrical conductor and a second channel for receiving the additional electrical conductor. The recess may include a cylindrical cavity centered on the axis. The wafer chuck may further include a bonding layer disposed between the first plate layer and the second plate layer for air-tightly bonding the plate layers together. The temperature sensor can be a thermocouple.

In one embodiment, a multi-zone heater is provided and can include a heater plate including a first heater at a first radial distance from the center of the heater plate; a thermowell within the first radial distance; a first thermocouple within the first thermowell; a second heater at a second radial distance from the center of the heater plate a range, wherein the second radial distance range is further away from the center of the heater plate than the first radial distance range; and a second thermowell, within the second radial distance range; a second thermocouple , within the second thermowell; a channel between the heater plate and the cover; and a cover over the channel, wherein the second thermocouple includes a telemetry wire circulating through the channel .

The multi-zone heater may further include a hollow heater shaft attached to the heater plate, the hollow heater shaft including an inner surface and an outer surface. The second thermowell is located in the heater plate outside the area circumscribed by the interior of the hollow heater shaft. The telemetry wire of the second thermocouple can be routed through the channel into the interior of the hollow heater shaft. The cover may be airtightly bonded to the first bonding layer. Heater plate. The heater plate may contain aluminum nitride. The hollow heater shaft may contain aluminum nitride. The first bonding layer may include aluminum. The multi-zone heater may further include a second bonding layer disposed between the heater plate and the hollow heater shaft, wherein the second bonding layer passes through the second bonding layer from the outside of the shaft. The interior space of the shaft is airtightly sealed. The second bonding layer can comprise aluminum.

In one embodiment, a multi-zone heater is provided and can include multiple layers of heater plates, which may include a top plate layer; one or more intermediate plate layers; a bottom plate layer; and A plurality of plate joint layers are disposed between the plate layers, wherein the joint layers join the plate layers; a plurality of heater element blocks are disposed between the plate layers, and the heating elements are blocks of components designed to be individually controlled; and a plurality of thermocouples mounted between the two of the plate layers.

The thermocouples are located a plurality of distances from the center of the multilayer heater plate. The multi-zone heater may further include a hollow heater shaft attached to the bottom surface of the multi-layer heater plate. The thermocouples include thermocouple wires, and the thermocouple wires can be routed through the interior of the hollow heater shaft. One or more of the thermocouples may be located outside an area circumscribed by a shaft attached to the multilayer plate. The multi-zone heater may further include a bonding layer between the hollow heater shaft and the multi-layer plate. The plurality of panel bonding layers may include aluminum. The bonding layer between the hollow heater shaft and the multi-layer plate may include aluminum. The top plate layer and the bottom plate layer may comprise ceramic. The hollow heater shaft may comprise aluminum. The plurality of panel bonding layers may include aluminum. The hollow heater shaft and the The bonding layer between multi-layer panels may contain aluminum. The multi-zone heater may further include a central hub disposed between the hollow heater shaft and the multi-layer plate.

As will become apparent from the above description, widely varying embodiments may be constructed from the description given herein, and additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, deviations from these details may be made without departing from the spirit or scope of the applicant's general model.

350:Flange

500: heater

501:Cover

502:Heater plate

503: concave part

504: Center hole

505: First temperature sensor

506: Second temperature sensor

507: Third temperature sensor

508: Thermowell

510: Thermowell

516:Shaft

517:End

518:End

519:Axis

521:Plate

522:Part

526: Center heater block

527:Intermediate heater block

528: Edge heater block

531:Wire

532:Wire

533:Wire

Claims (7)

A device used in a semiconductor processing chamber, including: a first ceramic semiconductor processing equipment component having a first interface area and a first ceramic material; a second ceramic semiconductor processing equipment component having a second interface area and a second ceramic material ; A gas-impermeable sealed aluminum joint between the first ceramic semiconductor processing equipment component and the second ceramic semiconductor processing equipment component and by having more than 92 % aluminum by weight; the gas-tight sealed aluminum joint has a thickness greater than zero; and the first ceramic semiconductor processing equipment component and the second ceramic semiconductor processing equipment component are free of diffusion of the aluminum brazing component. The apparatus of claim 1, wherein one or both of the first ceramic semiconductor processing equipment component and the second ceramic semiconductor processing equipment component include aluminum nitride. As claimed in claim 1, the device is used in a semiconductor processing chamber, wherein the brazed component is more than 99% aluminum by weight. The device used in a semiconductor processing chamber according to any one of claims 1 to 3, wherein the first ceramic semiconductor processing equipment component is a plate, and the second ceramic semiconductor processing equipment component is a shaft, and the plate and the The shaft forms the wafer chuck. If any of the requirements 1 to 3 is used in semiconductors An apparatus in a processing chamber, wherein the first ceramic semiconductor processing equipment component is a first plate layer, and the second ceramic semiconductor processing equipment component is a second plate layer, the first plate layer and the second plate layer is part of the heater plate and/or wafer chuck. The device of claim 5 for use in a semiconductor processing chamber includes a heater located between the first plate layer and the second plate layer, wherein the aluminum joint includes a ring surrounding the outside of the heater. As claimed in claim 5, the device used in a semiconductor processing chamber, wherein the heater plate has a diameter, and the diameter of the first plate layer is equal to the diameter of the heater plate.

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