TWI703671B - Bolted wafer chuck thermal management systems and methods for wafer processing systems - Google Patents

Abstract

A workpiece holder includes a puck, first and second heating devices in thermal communication with respective inner and outer portions of the puck, and a thermal sink in thermal communication with the puck.  The first and second heating devices are independently controllable, and the first and second heating devices are in greater thermal communication with the puck, than thermal communication of the thermal sink with the puck.  A method of controlling temperature distribution of a workpiece includes flowing a heat exchange fluid through a thermal sink to establish a reference temperature to a puck, raising temperatures of radially inner and outer portions of the puck to first and second temperatures greater than the reference temperature, by activating respective first and second heating devices disposed in thermal communication with the radially inner and outer portions of the puck, and placing the workpiece on the puck.

Description

Screw-on wafer clamp thermal management system and method for wafer processing system

Cross-reference to related applications: This disclosure relates to the subject matter of the jointly-owned U.S. patent application No. 14/820,365 (Attorney No. A23061/K947524). The U.S. application and this application were issued on August 2015. It was filed on the 6th, and the entire US application is incorporated herein by reference for all purposes.

This disclosure is widely used in the field of processing equipment. More specifically, a system and method for providing spatially tailored processing on a workpiece are disclosed.

Integrated circuits and other semiconductor products are usually manufactured on the surface of a substrate called a "wafer." Sometimes, processing is performed on a group of wafers held in a carrier, and at other times, processing and testing are performed on one wafer at a time. When performing a single wafer process or test, the wafer can be positioned on the wafer fixture. Other workpieces can also be processed on similar fixtures. The fixture can be temperature controlled to control the temperature of the workpiece for processing.

In one embodiment, a workpiece holder positions a workpiece for processing. The workpiece holder includes: a substantially cylindrical positioning plate; a first heating device arranged to be in thermal communication with a radially inner portion of the positioning plate; and a second heating device arranged to be connected to a diameter of the positioning plate The outer part is in thermal communication; and a cold source is arranged in thermal communication with the positioning plate. The first and second heating devices are independently controllable with respect to each other, and the first and second heating devices are significantly different from the positioning disk compared to the degree of thermal communication between the cold source and the positioning disk Degree of thermal communication.

In one embodiment, a method for controlling the spatial temperature distribution of a workpiece includes the following steps: by flowing a heat exchange fluid at a controlled temperature through a channel in a cold source that is in thermal communication with the positioning plate toward a substantial cylinder The locating disk provides a reference temperature, and by activating a first heating device arranged in thermal communication with a radially inner portion of the locating disk, a temperature of the radially inner portion of the locating disk is raised to be greater than the A first temperature of the reference temperature, by activating a second heating device arranged in thermal communication with a radially outer part of the positioning plate, raises a temperature of the radially outer part of the positioning plate to be greater than the A second temperature of the reference temperature, and placing the workpiece on the positioning plate.

In one embodiment, a workpiece holder for positioning a workpiece for processing includes: a substantially cylindrical positioning disk characterized by a cylindrical shaft and a substantially flat top surface. The positioning plate defines two radial heat interrupters. The first heat interrupter is characterized as a radial notch that intersects a bottom surface of the positioning disk with a first radius and extends from the bottom surface through at least one thickness of the positioning disk half. The second heat interrupter is characterized as a radial notch that intersects the top surface of the positioning plate with a second radius greater than the first radius and extends through the top surface At least half the thickness of one of the positioning plates. The first and second heat interrupters define a boundary between a radially inner portion of the positioning disk and a radially outer portion of the positioning disk. The positioning disk includes a first heating device embedded in the radially inner portion of the positioning disk and a second heating device embedded in the radially outer portion of the positioning disk. The workpiece holder also includes a cold source extending substantially below the bottom surface of the positioning plate. The cold source includes a metal plate that flows a heat exchange fluid through a channel defined therein, To maintain a reference temperature for the positioning plate. The cold source is mechanically and thermally coupled with the positioning plate at the attachment point, and the attachment points provide a degree of thermal communication between the cold source and the positioning plate, and the degree of thermal communication is less than the first and second heating A degree of thermal communication between each of the devices and the positioning plate.

The present disclosure can be understood by referring to the following detailed description by combining the drawings described below, where similar reference numerals are used throughout the drawings to refer to similar elements. Note that for the purpose of clarity, some components in the drawing may not be drawn to scale. A number with a dash (for example, heater 220-1, 220-2) can be used to indicate a specific instance of an item, and a number without brackets refers to any such item (for example, heater 220). For clear description, in the example showing multiple project examples, only certain parts of the examples can be marked.

FIG. 1 schematically shows the main components of a wafer processing system 100. The system 100 is depicted as a single wafer, semiconductor wafer plasma processing system, but it will be clear to those skilled in the art that the techniques and principles herein can be applied to any type of wafer processing system (for example, and Not necessarily processing wafers or semiconductors and not necessarily processing systems that use plasma). The processing system 100 includes a housing 110 for a wafer interface 115, a user interface 120, a plasma processing unit 130, a controller 140, and one or more power supplies 150. The processing system 100 is supported by various facilities, which may include gas (or multiple) 155, external power source 170, vacuum 160, and optional other things. For clarity, the internal pipes and electrical connections in the processing system 100 are not shown.

The processing system 100 is illustrated as a so-called indirect plasma processing system, which generates plasma at a first location and directs the plasma and/or plasma products (such as ions, molecular fragments, excited species, and the like) To the second position where the processing step occurs. Therefore, in FIG. 1, the plasma processing unit 130 includes a plasma source 132 that supplies plasma and/or plasma products of the processing chamber 134. The processing chamber 134 includes one or more workpiece holders 135, and the wafer interface 115 places workpieces 50 (such as semiconductor wafers, but can be different types of workpieces) to be held for processing in the workpiece holders器135上. When the workpiece 50 is a semiconductor wafer, the workpiece holder 135 is generally called a wafer holder. In operation, the gas (or multiple types) 155 is introduced into the plasma source 132, and a radio frequency generator (RF Gen) 165 supplies power to ignite the plasma in the plasma source 132. The plasma and/or plasma products pass through the diffusion plate 137 from the plasma source 132 to the processing chamber 134 where the workpiece 50 is processed. Instead of or in addition to the plasma from the plasma source 132, the plasma may also be ignited in the processing chamber 134 for direct plasma processing of the workpiece 50.

The embodiments herein provide new and useful functions for plasma processing systems. Significantly in recent years, the size of semiconductor wafers has increased while the feature size has been reduced, so that each wafer processed can harvest more integrated circuits with better performance. The processing of smaller features while the wafer grows larger requires significant improvements in processing uniformity. Because the chemical reaction rate is usually temperature-sensitive, temperature control across the wafer during processing is usually critical for uniform processing.

Also, certain types of processing can have radial effects (for example, processing that varies from the center to the edge of the wafer). Certain types of processing equipment control these effects better than other types of processing equipment. The embodiments herein recognize that it is best to control radial effects, and it would be further advantageous to be able to provide radial processing that can be tailored to compensate for the inability to achieve such controlled processing. For example, consider the situation where a layer is deposited on a wafer and then selectively etched away, as is common in semiconductor processing. If the deposition step is known to deposit a thicker layer at the edge of the wafer than at the center of the wafer, the compensating etching step will advantageously be at the edge of the wafer compared to the center of the wafer Provides a higher etching rate so that the deposited layer will be etched completely at all parts of the wafer at the same time. Similarly, if the etching process is known to have a center-to-edge variation, the compensation deposition before the etching process can be adjusted to provide the corresponding variation.

In the case of many processes with radial effects, the compensation process can be provided by providing a clear center-to-edge temperature change, because temperature usually substantially affects the reaction rate of the process.

FIG. 2 is a schematic cross-section showing an exemplary configuration detail of the workpiece holder 135 of FIG. 1. As shown in FIG. 2, the workpiece holder 135 includes a substantially cylindrical positioning disk 200 and has a feature in the sense that it has a positioning disk radius r1 in the radial direction R from the cylindrical axis Z. In use, the workpiece 50 (for example, a wafer) can be placed on the positioning plate 200 for processing. The bottom surface 204 of the positioning disk 200 is taken as the height of the center bottom surface of the positioning disk 200; that is, the features that the positioning disk 200 may be formed as attachment points for other hardware (such as edge rings or other protrusions 206, or indents 208) are not included. ) A plane defining the height of the general bottom surface of the positioning plate 200 in the direction of the axis Z. Similarly, the top surface 202 is taken as a flat surface configured to accommodate the workpiece 50, regardless of grooves (for example, vacuum channels, refer to FIG. 4) that may be formed in the flat surface and/or other features that secure the workpiece 50. All such protrusions, dimples, grooves, rings, etc. do not detract from the "substantially cylindrical" feature of the positioning plate 200 in the context of this specification. The positioning plate 200 may also have a feature in the sense that there is a thickness t between the bottom surface 204 and the top surface 202, as shown. In some embodiments, the radius r1 of the positioning disk is at least four times the thickness t of the positioning disk, but this is not a requirement.

The positioning disc 200 defines one or more radial heat interrupters 210, as shown. The heat interrupter 210 is a radial notch defined in the positioning disk 200, and the notch intersects at least one of the top surface 202 or the bottom surface 204 of the positioning disk 200. The heat interrupters 210 function as the name suggests, that is, they provide thermal resistance between the radially inner portion 212 and the radially outer portion 214 of the positioning disk 200. This promotes clear radial (eg center to edge) thermal control of the radially inner and outer portions of the positioning disk 200, which is useful in providing accurate thermal matching of the inner and outer portions or providing deliberate temperature changes across the inner and outer portions. It is advantageous in the sense. The heat interrupter 210 may have characteristics in the sense of the depth and radius of the heat interrupter. The depth of the heat insulator 210 can vary among embodiments, but the depth of the heat insulator generally exceeds half of the thickness t. The radial positioning of the heat insulator 210 can also be changed among the embodiments, but the radius of the heat insulator r2 is usually at least one half of the radius of the positioning disk r1, and in other embodiments, r2 may be the radius of the positioning disk r1 Three-quarters, four-fifths, five-sixths or more of Some embodiments may use a single heat interrupter 210, while other embodiments may use two heat interrupters 210 (as shown in FIG. 2) or more. The difference between the radially inner portion 212 and the radially outer portion 214 is shown as the radial average position between the two heat interrupters 210, but in an embodiment with a single heat interrupter 210, such differences The point can be regarded as the radial midpoint of the single heat interrupter 210.

One way in which a heat interrupter (as shown in FIG. 2) can be advantageously used is to provide radially applied heating and/or cooling to the inner portion 212 and outer portion 214 of the positioning disk 200. FIG. 3 is a schematic cross-sectional view showing the integration of the heater and the cold source with the inner and outer parts of the positioning plate 200. For clarity of illustration, some mechanical details of the positioning plate 200 are not shown in FIG. 3. FIG. 3 shows the central channel 201 defined by the positioning plate 200 and the optional cold source 230. The central channel 201 is described in conjunction with FIG. 4. The inner heater 220-1 and the outer heater 220-2 are placed in thermal communication with the positioning plate 200; the heater 220 is illustrated as embedded in the positioning plate 200, although this is not required. It may be advantageous for the heater 220 to be placed across most of the positioning plate 200, but the distribution of the heater 220 across the surface 204 may vary in embodiments. The heat provided by the heater 220 will substantially control the temperature of the inner part 212 and the outer part 214 of the positioning plate 200; the heat interrupter 210 helps the parts 212 and 214 to be thermally isolated from each other to improve the accuracy of heat control. The heater 220 is generally a resistance heater, but other types of heaters (for example, using forced gas or liquid) can be used.

An optional cold source 230 can also be provided. The cold source 230 can be controlled to exhibit a lower temperature than the general operating temperature, for example, by flowing a heat exchange liquid at a controlled temperature through the cold source 230, or by using a cooling device (such as Peltier (Peltier cooler). When present, the cold source 230 provides several advantages. One such advantage is to provide a reference temperature, without the heat provided by the heater 220, all parts of the positioning plate 200 tend to have the reference temperature. That is, although the heater 220 can provide heat, such heat will generally propagate through the positioning plate 200 in all directions. The cold source 230 provides the ability to drive all parts of the positioning plate 200 to a lower temperature, so that if the heater 220 is located in a specific part of the positioning plate 200, the heat generated by the heater is not only on the positioning plate 200 in every direction. It spreads everywhere and heats a part of the positioning plate 200 where the heat from the heater 200 locally exceeds the tendency of the cold source 230 to remove heat. When present, the cold source 230 may be connected at a plurality of attachment points 222 (schematically illustrated in FIG. 3, although the attachment points 222 may not resemble those shown in FIG. 3; refer to FIGS. 6A, 6B, and 6C). The positioning plate 200 is thermally and/or mechanically coupled. The attachment points 222 are preferably numerous and evenly distributed around the surface 204 of the positioning plate 200. The attachment points 222 provide substantially all the thermal communication between the positioning plate 200 and the cold source 230, and provide numerous and evenly distributed arrangements of the attachment points 222, so that the provided reference temperature is uniformly applied. For example, a positioning disk 200 at least ten inches in diameter may have at least twenty attachment points or more, and a positioning disk 200 at least twelve inches in diameter may have at least thirty attachment points or more.

The related advantage is that the cold source 230 can provide rapid heat sinking performance, so that when the temperature setting of the heater 220 (for example, the current passes through the resistance wire) is reduced, the adjacent part of the positioning plate 200 responds with a relatively rapid temperature decrease. . This, for example, provides the following benefits: the workpiece 50 can be loaded on the positioning plate 200, heat is provided through the heater 220, and the temperature on the workpiece 50 can be quickly stabilized, so that the processing can be started quickly to maximize the total processing of the system the amount. Without allowing some heat to be dissipated to the heat connection of the cold source 230, the temperature reached by the portion of the positioning plate 200 will only decrease as quickly as other heat dissipation paths will allow.

The heater 220 and the cold source 230 are generally arranged in different degrees of thermal communication with the positioning plate 200; for example, the heater 220 can be said to be in direct thermal communication with the positioning plate 200, and the cold source and the positioning plate 200 are in indirect thermal communication. That is, the heater 220 is generally positioned for a high degree of thermal coupling with the positioning plate 200, and the cold source 230 is positioned for a lower degree of thermal coupling with the positioning plate 200 (at least compared to the heater 220 and the positioning plate 200 for a lower degree of heat). Coupling). In addition, the heater 220 has sufficient heat generation efficiency, so that the heat applied by the heater 220 can be pressed through the thermal coupling between the positioning plate 200 and the cold source 230, so that even some heat generated by the heater 200 penetrates While the supercooling source 230 is dissipated, the heater 220 can also increase the temperature of the inner part 212 and the outer part 214 of the positioning plate 200. Therefore, the heat provided by the heater 220 may (but not immediately) be dissipated through the cold source 230. In an embodiment, the placement and degree of thermal coupling among the positioning plate 200, the heater 220, and the cold source 230 can be adjusted according to the principles herein, for example, to balance the following considerations: each of the inner part 212 and the outer part 214 Temperature uniformity, rapid thermal stabilization, manufacturing complexity and cost, and overall energy consumption.

Another advantage of the cold source 230 is that the heat generated by the heater 220 is limited to the vicinity of the positioning plate 200. That is, the cold source 230 can provide an upper thermal limit for adjacent system components to protect such components from the high temperature generated at the positioning plate 200. This can improve the mechanical stability of the system and/or prevent damage to temperature-sensitive components.

The heater 220 and the cold source 230 may be implemented in various ways. In one embodiment, the heater 220 is provided by a cable-type heating member, which is integrated with the positioning plate 200 and then (optionally) integrated with the cold source 230 to form a wafer chuck assembly. The embodiments designed, assembled, and operated as disclosed herein allow for the explicit control of the temperature of the edge region of the workpiece (eg wafer) relative to the central region, and the explicit center-to-edge temperature control to facilitate processing. To the edge temperature control is generally not achieved by the prior art system.

4 is a schematic cross-sectional view showing a part of a wafer holder, which shows the characteristics of the positioning plate 200, the resistance heater serving as the heater 220-1, and the cold source 230. In order to clearly illustrate the smaller features, FIG. 4 shows a part of the wafer holder close to its cylindrical axis Z, and is not drawn to scale. The positioning plate 200 is generally formed of aluminum alloy, such as the well-known "6061" alloy type. The positioning disk 200 is illustrated as defining a surface groove or channel 205 connected to the upper surface 202 of the positioning disk 200, and is defined as having a central channel 201 centered around the axis Z. Vacuum can be supplied to the central channel 201 to reduce the pressure in the channel 205, so that atmospheric pressure (or relative high-pressure plasma or low-pressure deposition system gas pressure, for example, about 10-20 Torr (Torr)) will make the workpiece 50 (see figure 1. 2) Push against the positioning plate 200 to provide good thermal communication between the positioning plate 200 and the workpiece 50.

The internal resistance heater 220-1 is shown in FIG. 4, but it should be understood that the description of the internal resistance heater 220-1 and the following description are equally applied to the external resistance heater 220-2. The resistance heater 220-1 includes a cable heater 264 that is wound in the positioning disk 200 in a spiral or other manner. The cable heater 264 is assembled into the positioning disk 200 by placing it in the groove in the positioning disk 200 and capping the groove (refer to FIG. 5 ). After the cable heater 264 is assembled as an internal resistance heater 200-1 (and the second cable heater is assembled as an external resistance heater 200-2), the positioning plate 200 is assembled to the cold by the holder 270 Source 230. The area where both the positioning plate 200 and the cold source 230 provide attachment points for the holder 270 is arranged to manage the heat transfer characteristics between the positioning plate 200 and the cold source 230 around the holder 270, as discussed in further detail below ( Refer to Figures 6A, 6B, 6C).

FIG. 5 schematically shows the lower side of the positioning plate 200-1, and the lower side has cable heaters 264-1 and 264-2 installed in the lower side as inner and outer resistance heaters, respectively. The heat interrupter 210 is a notch defined in the bottom surface 204 of the positioning plate 200-1 and forms a radial boundary between the inner part 212 and the outer part 214 of the positioning plate 200 (refer to FIGS. 2 and 3 ). The cable heater 264-1 extends from the connector 262-1 along a substantially spiral path, which is arranged for uniform heat transfer to all areas of the inner portion 212. The heater cover 266-1 is shown as the shaded portion of the spiral path; the heater cover 266-1 is coupled in place after the cable heater 264-1 is placed in place. In one embodiment, the heater cover 266-1 is a corrugated strip preformed into a groove shape, the cable heater 264-1 is installed in the groove, and the heater cover 266-1 is fixed in place. The heater cover 266-1 can be welded in place using electron beam welding technology, but it can also be fixed with adhesive or filler (such as epoxy resin). The corrugated strips are preferably welded in place at least along the arc length of the cable heater, but do not need to be welded along the entire arc length of the cable heater (for example, the part may not be welded to avoid damage to the overlying structure (such as the cable heater). 264-2) damage). In one embodiment, the heater cover 266-1 is welded in place using electron beam welding technology. The cold-to-heat transfer point 265-1 indicates the wire in the cable heater 264-1 (extending from the connector 262-1 and hidden under the heater cover 266-1) and the resistance material in the cable heater 264-1 Where to connect. Therefore, a small amount of heat is generated between the connector 262-1 and the transfer point 265-1, but a uniform amount of heat per unit length is generated in the cable heater 264-1 passing through the transfer point 265-1. The cable heater 264-2 extends from the connector 262-2, first extends radially outward from the center area of the positioning disk 200 (where the connection is made through the axis of the wafer holder), and then extends along the direction for uniform heat transfer The substantially circular path of the arrangement extends to the outer portion 214. The heater cover 266-2 is shown as the shaded portion of the spiral path; the heater cover 266-2 is coupled into place after the cable heater 264-2 is placed in place. In one embodiment, the heater cover 266-2 is a corrugated strip pre-formed into a groove shape, the cable heater 264-2 is installed in the groove, and the heater cover 266-2 uses electron beam welding technology Solder in place. Similar to the heater cover 266-1, the corrugated strip forming the heater cover 266-2 is preferably welded in place at least along the arc length thereof, but need not be welded along the entire arc length. The cold-to-heat transfer point 265-2 indicates the wire in the cable heater 264-2 (extending from the connector 262-2 and hidden under the heater cover 266-2) and the resistance material in the cable heater 264-2 Where to connect. Therefore, a small amount of heat is generated between the connector 262-2 and the transfer point 265-2, but a uniform amount of heat per unit length is generated in the cable heater 264-2 passing the transfer point 265-2. The collection of protrusions 268 is also shown in FIG. 5. The protrusions 268 are protrusions protruding from the bottom surface 204 to the drawing plane (for example, so that they will face the cold source 230, refer to FIG. 3). The convex portion 268 forms a position for the attachment point 222, which cooperates with fixing it 270 (FIG. 4), and is discussed in more detail in connection with FIGS. 6A and 6B below.

6A is a detailed view of a part of the positioning plate 200 shown in FIG. 4 and an optional cold source 230 near the holder 270. The positioning disk 200 includes a cable heater 264 sealed into the positioning disk 200 with a heater cover 266, as discussed above in connection with FIG. 5. As mentioned further above, the optional cold source 230 can provide a reference temperature for the positioning plate 200. However, it is ideal that the cold source 230 and the positioning plate 200 are targeted at a lower level than the positioning plate 200 and the heater 220. The heat is connected and arranged. Therefore, the attachment points that allow thermal communication between the cold source 230 and the positioning plate 200 are preferably arranged to manage the heat transfer characteristics therebetween. For example, the positioning plate 200 and the cold source 230 may be manufactured such that a lateral gap 276 exists between the protrusion 268 and the cold source 230, as shown. That is, the thickness of the cold source 230 is reduced in the thinned area 235 near the convex portion 268, and the lateral width of the thinned area 235 is greater than that of the convex portion 268, forming the entire thickness of the convex portion 268 and the cold source 230 The lateral gap 276 between the parts. The cold source 230 forms an aperture for the holder 270 to pass through, and the convex portion 268 defines an internal aperture 275, a part of the aperture 275 may have a thread inside for the holder 270 to be coupled to the aperture 275. However, the aperture 275 may be longer than the length of the holder 270 (for example, as shown in FIG. 6A) to limit the heat transfer from the positioning disk 200 through the protrusion 268. The physical attachment point where the positioning plate 200 is attached to the cold source 230 includes a dual of the protrusion 268, the holder 270, and the gasket 272. The primary heat transfer path near the holder 270 is illustrated as a solid, wavy arrow 278 in FIGS. 6A and 6B, and the secondary (eg, radiant) heat transfer path is illustrated as a imaginary, wavy arrow 279 in FIGS. 6A and 6B. The aperture 231 is discussed below in connection with FIG. 6C.

FIG. 6B schematically illustrates an embodiment of a wave washer 272 in an uncompressed state. Although flat washers may be utilized in some embodiments, wave washers are advantageous in other embodiments. The advantage of the wave form in the orientation of the washer 272 is that the positioning disk 200 can be coupled with the cold source 230 at a plurality of points without excessively restricting the positioning disk 200 or the cold source 230 relative to each other. That is, assuming that there are only three points forming a plane in the mathematical sense, more than three attachment points between the positioning plate 200 and the cold source 230 form an over-restricted system. Very strict mechanical tolerances are imposed on the plurality of attachment points between the parts 268. The use of a wave washer 272 allows for looser planarity tolerances in such features, because the washer 272 will provide mechanical coupling everywhere in a range of compression, instead of requiring the attachment points of individual components to be positioned along a perfectly flat surface. Similarly, the compression range of the wave washer 272 allows the local thermal expansion effect in the 200 and/or cold source 230 to be determined. In some embodiments, the wave washer 272 has an uncompressed thickness 273 that is at least twice the compressed thickness 274; in other embodiments, the wave washer 272 has an uncompressed thickness 273 that is at least five times the compressed thickness 274. Although the washer 272 is illustrated with a flat cross-sectional profile in FIG. 6A for clarity, after reading and understanding the present disclosure, it will be understood that the holder 270 may not be completely compressed to the point of the flattened wave washer 272, resulting in some waveforms There will be many (if not all) instances of wave washer 272 at installation. In addition, when in use, the wave washer 272 forces heat to pass from the convex portion 268 to the local peak of the washer 272 contacting the convex portion 268, and then laterally passes through the washer 272 to the local through hole of the washer 272 contacting the cold source 230 , To reduce the thermal communication between the convex portion 268 and the cold source 230. The gasket 272 may be formed of beryllium copper, for example. Some embodiments utilize two washers 272, one of which is on either side of the cold source 230 (as shown), while other embodiments use only a single washer 272, which is generally on the convex portion 268 and the cold Source 230.

FIG. 6C provides a bottom plan view of the vicinity of the holder 270 looking upward. In FIG. 6C, dashed lines 6A-6A indicate the cross-sectional plane shown in FIG. 6A. The cold source 230 forms one or more pores 231 in the thinned area 235 near the holder 270. The aperture 231 further reduces the thermal communication between the positioning plate 200 and the cold source 230. The number and arrangement of the apertures 231 in the cold source 230 shown in FIG. 6C are not necessary; after reading and understanding this disclosure, it will be understood that the apertures 231 can be changed in size, number and arrangement to adjust the cooling The thermal coupling characteristics between the source 230 and the positioning plate 200. For example, the thermal coupling between the cold source 230 and the positioning plate 200 can be further reduced by the following steps: providing a collection of second apertures 231 (radially outward from the apertures 231, as shown in FIG. 6C), and relative The illustrated apertures 231 are arranged in a staggered and additional set to lengthen the thermal path between the protrusion 268 and the main body of the cold source 230. And, although FIG. 6C illustrates the outer edge of the thinned region 235 as being coincident with the outer edge of the aperture 231, this is not always the case. Some embodiments may have pores 231 deep in the edge of the thinned area 235, or the pores 231 may partially extend into the cold source 230 outside the thinned area 235. Similarly, the number, placement, and wall thickness of the protrusions 268 can be changed to achieve higher or lower heat conduction between the positioning plate 200 and the cold source 230.

A further advantage of providing at least one heat interrupter 210 that intersects the top surface of the positioning plate 200 is that certain mechanical features can be at least partially disposed in the heat interrupter so that the mechanical features do not generate heat on the surface of the positioning plate 200 abnormal. For example, wafer chucks usually provide lift pins, which can be used to lift the wafer a short distance away from the chuck to facilitate access by the wafer handling tool (usually used to insert the wafer after the wafer is lifted). And clamps between the vanes or other devices). However, the lift pins generally retract into the holes in the fixture, and such holes and lift pin structures can locally affect the wafer temperature during processing. When the heat interrupter intersects the top surface of the positioning plate 200, there is already a position for placing such a mechanism without causing thermal abnormalities.

FIG. 7 schematically shows that the wafer chuck has a part of the lifting pin mechanism 300, the lifting pin mechanism controls the lifting pin 310, and the lifting pin is arranged in the heat interrupter 210. The part of the heater 220 and the optional cold source 230 are also shown. The cross-sectional plane shown in FIG. 7 passes through the center of the mechanism 300 so that its components are in the lower part of a single 210. In and out of the plane shown, the positioning plate 200, the heat interrupter 210, and the cold source 230 may have contours similar to those shown in FIGS. 3 and 4, so that the heat interrupter 210 will pass along the positioning plate 200 The arc length of the heat interrupter 210 continues (refer to FIG. 8 ), and the mechanism 300 is disposed in the heat interrupter 210. Moreover, the lift pin mechanism 300 is limited to a relatively small azimuth angle with respect to the central axis of the positioning plate 200 (refer to FIG. 8 again). That is, if the cross-sectional plane is taken at a certain distance from the inside or outside of the plane shown in FIG. 7, the bottom surface of the positioning plate 200 will be continuous along the same plane as the bottom surface 204 indicated in FIG. 200 times will be continuous. The small size of the lift pin mechanism 300 limits the thermal deviation of the positioning plate 200 in the area of the lift pin mechanism 300. FIG. 7 illustrates the lift pin 310 in a retracted position, where it will not generate thermal anomalies on the surface of the positioning disk 200.

FIG. 8 schematically shows an arrangement of three lifting pins in a plan view, wherein the lifting pins 310 are arranged in the heat interrupter 210. FIG. 8 is not drawn to scale. Specifically, the heat interrupter 210 is exaggerated to clearly illustrate the lifting pin mechanism 300 and the lifting pin 310. Because the lift pin 310 retracts to the bottom of the average surface of the positioning plate 200 and enters the heat interrupter 210, the lift pin 310 does not generate spatial thermal anomalies during processing, so that the part of the workpiece being processed at the position of the lift pin 310 ( For example, a specific integrated circuit located at a corresponding location on a semiconductor wafer undergoes processing consistent with processing elsewhere on the workpiece.

9 is a flowchart of a method 400 for processing wafers or other workpieces (under the understanding that these concepts can be applied to workpieces other than wafers, hereinafter referred to as "product wafers" for convenience). The method 400 can be uniquely enabled by connecting the thermal management device described in FIGS. 2-8, which can be used to provide clear center-to-edge thermal control, which in turn allows clear center-to-edge processing control. The first step 420 of the method 400 processes the product wafer with the first center-to-edge process variation. The second step 440 of the method 400 processes the product wafer with a second center-to-edge process variation that compensates for the first center-to-edge variation. Generally speaking, one of 420 or 440 will be implemented in the equipment or in a processing environment where associated center-to-edge processing changes (hereinafter referred to as "uncontrolled changes") are generated unintentionally or uncontrollably Or the other, but this is not necessary. And, generally speaking, the other is implemented in a device such as the device described in this article, so that passing through a thermal management technology that allows clear control of the center and edge portions of the product wafer causes another center-to-edge processing change (Hereinafter referred to as "controlled changes") to provide corresponding and reverse processing changes. However, uncontrolled changes and controlled changes can occur in any order. That is, 420 may cause uncontrolled or controlled changes, and 440 may cause the other of uncontrolled and controlled changes. Figures 10 and 11 provide additional guidance to those skilled in the art to allow method 400 to be used effectively.

FIG. 10 is a flowchart of a method 401 that includes (but is not limited to) step 420 of the method of FIG. 400. All 410-418 and 422 shown in FIG. 10 are considered optional when performing method 400 to achieve useful wafer processing results (but may be helpful in embodiments).

Step 410 sets the device characteristics regarding the first center-to-edge processing change, which will be generated at 420. For example, when 420 is expected to cause a controlled change, 410 may involve providing device parameters, such as settings for the heater, that will provide a controlled center-to-edge temperature change. Devices as described in Figures 2-8 herein are useful in providing controlled center-to-edge temperature changes. Step 412 measures the device characteristics regarding the first center-to-edge processing change. It is possible to acquire processing knowledge over time as to which of the device settings (or measured device characteristics) is successful (or at least providing stable processing changes, albeit unintentional) when producing known center-to-edge processing changes. When considering this processing knowledge, if the device characteristics measured in 412 may be improved, the method 401 may optionally return from 412 to 410 to adjust the device characteristics. Step 414 is to process one or more test wafers that receive the first center-to-edge process change. Step 416 measures one or more characteristics of the first center-to-edge processing variation on the test wafer processed in step 414. The method 401 may optionally return from 416 to 410 to adjust the device characteristics according to the center-to-edge processing characteristics measured in 416. Any wafers processed in 414 may optionally be stored in 418 for testing in a second process (for example, a process to be performed later in 440). And, 414 can be executed in parallel with 420. That is, when the processing equipment is properly configured, test wafers can be processed while processing product wafers (for example, if the first processing is a so-called "batch" processing, such as immersing the wafer cassette in a liquid bath, Process wafer assemblies together in ampoules, diffusion furnaces or deposition chambers, etc.).

Step 420 processes the product wafer with the first center-to-edge processing change. Step 422 measures one or more first center-to-edge characteristics on the product wafer to generate data for equipment processing control purposes, data for the production or performance of the associated product wafer, and/or The data associated with the information surrounding step 440 is described further below.

FIG. 11 is a flowchart of a method 402 that includes (but is not limited to) step 440 of the method of FIG. 400. All 430-436 and 442 shown in FIG. 11 are considered optional when performing method 400 to achieve useful wafer processing results (but may be helpful in embodiments).

Step 430 sets the device characteristics regarding the second center-to-edge processing change, which will be generated at step 440. For example, when it is desired 440 to cause a controlled change, 430 may involve providing device parameters such as heater settings that will provide a controlled center-to-edge temperature change. Devices as described in Figures 2-8 herein are useful in providing controlled center-to-edge temperature changes. Step 432 measures the device characteristics regarding the second center-to-edge processing change. When considering the processing knowledge, as discussed above, the method 402 may optionally return from 432 to 430 to adjust the device characteristics according to the device characteristics measured in 432. Step 434 processes one or more test wafers that receive the second center-to-edge processing change; the test wafers processed in 434 may include the one or more test wafers stored in the first processing step in 418 as described above . Step 436 measures one or more characteristics of the second center-to-edge process variation on the test wafer processed in 434. When considering the previously acquired processing knowledge, the method 402 may optionally return from 436 to 430 to adjust the device characteristics according to the center-to-edge processing characteristics measured in 436.

Step 440 processes the product wafer with the second center-to-edge processing change. And, although not shown in the method 402, of course additional test wafers can be processed in parallel with the production wafer. Step 442 measures one or more first center-to-edge characteristics on the product wafer to generate data for equipment processing control purposes, data for the yield or performance of related product wafers, and/or The data associated with the information surrounding 420 is as described above. This type of measurement can also be performed on any test wafer, but under any circumstances, 442 will generally not further change any conditions presented on the product wafer. That is, the results of 420 and 440 will be fixed in the product wafer at the end of 440, regardless of any further completed tests.

Several embodiments have been described, and it will be recognized by those skilled in the art that various modifications, alternative structures and equivalents can be used without departing from the spirit of the invention. In addition, many well-known processes and components are not described to avoid unnecessarily obscuring the present invention. Accordingly, the above description should not be regarded as a limitation of the present invention.

Plasma processing of workpieces other than wafers can also benefit from improved processing uniformity and is considered to be within the scope of this disclosure. Therefore, in this article, the fixture has the characteristics of a "wafer fixture" for holding a "wafer" should be understood as equivalent to a fixture for holding any kind of workpiece, and the "wafer handling system" is understood as It is similarly equivalent to the processing system.

Where a range of values is provided, it is understood that the intermediate values between the upper and lower limits of the range are also specifically disclosed (up to ten times the unit of the lower limit, unless the context clearly indicates otherwise). It includes each smaller range between any stated value or intermediate value in the stated range and any other stated or intermediate value in the stated range. The upper and lower limits of these smaller ranges can be independently included or excluded from the range, and each range that includes any limit, does not include these limits, or all includes these limits is also included in the present invention, Subject to any specifically excluded limits in the stated scope. Where the stated range includes one or both of these limits, it also includes the range excluding either or both of the included limits.

As used in this article and in the accompanying claims, the singular forms "a", "an" and "the" include plural referents, unless the context clearly indicates . Therefore, for example, the reference to "a process" includes a plurality of such processes, and the reference to "the electrode" includes one or more electrodes and their equivalents that are well-known to those skilled in the art Allegations of, and so on. In addition, the words "comprise", "comprising", "include", "including" and "includes" are used in this manual and the following request items , Are intended to specify the existence of stated features, integers, elements, or steps, but they do not exclude the existence or addition of one or more other features, integers, elements, steps, actions, or groups.

50‧‧‧Workpiece 100‧‧‧Wafer Processing System 110‧‧‧Shell 115‧‧‧Wafer interface 120‧‧‧User Interface 130‧‧‧Plasma processing unit 132‧‧‧Plasma source 134‧‧‧Processing chamber 135‧‧‧Workpiece Holder 137‧‧‧Diffuser 140‧‧‧Controller 150‧‧‧Power 155‧‧‧Gas 160‧‧‧Vacuum 165‧‧‧RF Generator 170‧‧‧External power supply 200‧‧‧Locating plate 200-1‧‧‧Internal resistance heater 201‧‧‧Central Channel 202‧‧‧Top surface 204‧‧‧Bottom 205‧‧‧Surface groove or channel 206‧‧‧Protrusion 208‧‧‧Dent 210‧‧‧Radial heat interrupter 212‧‧‧Inner part 214‧‧‧External part 220-1‧‧‧Internal resistance heater 220-2‧‧‧External resistance heater 222‧‧‧Attachment point 230‧‧‧cold source 231‧‧‧Porosity 235‧‧‧Thinned area 262-1‧‧‧Connector 262-2‧‧‧Connector 264‧‧‧Cable heater 264-1‧‧‧Cable heater 264-2‧‧‧Cable heater 265-1‧‧‧cold to heat transfer point 265-2‧‧‧cold to heat transfer point 266‧‧‧heater cover 266-1‧‧‧heater cover 266-2‧‧‧Heater cover 268‧‧‧Protrusion 270‧‧‧Fixer 272‧‧‧Washer 273‧‧‧Uncompressed thickness 274‧‧‧Compressed thickness 275‧‧‧Porosity 276‧‧‧lateral clearance 278‧‧‧Main heat transfer path 279‧‧‧ times (e.g. radiant) heat transfer path 300‧‧‧Lift pin mechanism 310‧‧‧Lift pin 400‧‧‧Method 401‧‧‧Method 402‧‧‧Method 410‧‧‧Step 412‧‧‧Step 414‧‧‧Step 416‧‧‧Step 418‧‧‧Step 420‧‧‧The first step 422‧‧‧Step 430‧‧‧Step 432‧‧‧Step 434‧‧‧Step 436‧‧‧Step 440‧‧‧The second step 442‧‧‧Step r1‧‧‧Locating disk radius r2‧‧‧Insulator radius R‧‧‧Radial direction t‧‧‧Locating plate thickness Z‧‧‧Cylindrical shaft

FIG. 1 schematically illustrates the main components of a processing system with a workpiece holder according to an embodiment.

Fig. 2 is a schematic cross-sectional view showing an exemplary configuration detail of the workpiece holder of Fig. 1.

According to an embodiment, FIG. 3 is a schematic cross-sectional view showing the integration of the heater and the cold source with the inner and outer parts of the positioning plate, and the integrated part forms a part of the workpiece holder of FIG. 1.

According to an embodiment, FIG. 4 is a schematic cross-sectional view showing a part of a wafer chuck, which shows the characteristics of a positioning plate, a resistance heater, and a cold source.

According to an embodiment, FIG. 5 schematically shows the underside of a positioning plate with a cable heater installed in the positioning plate as an inner and outer resistance heater.

Fig. 6A is a detailed view of a part of the positioning plate and optional cold source of Fig. 4 near the holder.

According to an embodiment, FIG. 6B schematically illustrates an embodiment of a wave washer in an uncompressed state.

Fig. 6C provides a bottom plan view of the positioning plate and optional cold source in Fig. 6A when viewed upward.

According to an embodiment, FIG. 7 schematically illustrates the lifting pin mechanism arranged in the heat interrupter.

According to an embodiment, FIG. 8 schematically illustrates an arrangement of three lifting pins in a plan view, wherein the lifting pins are arranged in the heat interrupter.

FIG. 9 is a flowchart of a method for processing wafers or other workpieces according to an embodiment.

FIG. 10 is a flowchart of a method including (but not limited to) one step of the method in FIG. 9.

FIG. 11 is a flowchart of a method, which includes (but is not limited to) another step of the method in FIG. 9.

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200-1‧‧‧Internal resistance heater

201‧‧‧Central Channel

204‧‧‧Bottom

210‧‧‧Radial heat interrupter

212‧‧‧Inner part

214‧‧‧External part

262-1‧‧‧Connector

262-2‧‧‧Connector

264-1‧‧‧Cable heater

264-2‧‧‧Cable heater

265-1‧‧‧cold to heat transfer point

265-2‧‧‧cold to heat transfer point

266-1‧‧‧heater cover

266-2‧‧‧Heater cover

268‧‧‧Protrusion

Claims (21)

A workpiece holder for positioning a workpiece for processing. The workpiece holder includes: a substantially cylindrical positioning disk, wherein the positioning disk is characterized by a cylindrical shaft, a positioning disk radius around the cylindrical shaft, and A substantially planar top surface, and a direction parallel to the top surface is defined as a lateral direction; a first heating device arranged in thermal communication with a radially inner portion of the positioning plate; a second heating device, Is arranged in thermal communication with a radially outer part of the positioning plate, wherein the first and second heating devices can be independently controlled with respect to each other; and a cold source is arranged in thermal communication with the positioning plate, wherein: A degree of thermal communication between the cold source and the positioning plate, the first and second heating devices and the positioning plate have greater and different degrees of thermal communication; and a plurality of pieces located between the cold source and the positioning plate The attachment point provides substantially all the thermal communication between the cold source and the positioning plate, wherein for at least one of the attachment points: the positioning plate forms a convex portion facing the cold source; the cold source Form an aperture; and A fixer passes through the aperture and is coupled in the convex portion. The workpiece holder according to claim 1, wherein at least one of the first heating device and the second heating device includes a cable heater, the cable heater is arranged in a groove, and the groove The groove is defined in a bottom surface of the positioning plate. The workpiece holder according to claim 2, further comprising a heater cover, the heater cover is placed in the groove to hold the cable heater in place, and the heater cover heats along the cable At least part of the arc length of the device is fixed to the positioning plate. The workpiece holder according to claim 1, wherein the positioning disk is at least ten inches in diameter, and the plurality of attachment points includes at least twenty attachment points. The workpiece holder according to claim 4, wherein the positioning disk is at least twelve inches in diameter, and the plurality of attachment points includes at least thirty attachment points. The workpiece holder according to claim 1, wherein at the at least one of the attachment points: the protrusion defines a first lateral amplitude, and the cold source defines a cavity, the cavity facing On a bottom surface of the positioning plate, the cavity is partially limited by a thinned portion of the cold source, the thinned portion is reduced in thickness around the aperture, and the cavity defines a greater than the first lateral amplitude The second lateral amplitude makes the lateral A gap exists between the convex portion and the multiple sides of the cavity. The workpiece holder according to claim 6, wherein the cold source defines one or more pores near the aperture and in the thinned portion to restrict flow through a thermal path extending from the positioning plate to the The heat transfer from the cold source, the heat transfer to the cold source through the holder and the material of the cold source surrounding the holder. The workpiece holder according to claim 1, further comprising a wave washer disposed around the holder between the cold source and the convex portion, wherein: the wave washer has a compressed thickness of at least two Times a net uncompressed thickness; and the retainer partially shrinks but does not completely flatten the wave washer to allow local thermal expansion effects. The workpiece holder according to claim 1, wherein the cold source includes a metal plate, the metal plate defines one or more fluid channels, and a heat exchange fluid flows through the one or more fluid channels, To define a reference temperature of the cold source. The workpiece holder according to claim 1, wherein the positioning disk is characterized by a positioning disk thickness, and the substantially cylindrical positioning disk defines a portion between the radially inner and radially outer portions of the positioning disk Or more radial heat breakers, each heat breaker is characterized as a radial notch, the radial notch At least one of the top surface and a bottom surface of the substantially cylindrical positioning plate, wherein the radial recess is characterized by a heat interrupter depth, extending through the top surface or the bottom surface of the positioning plate At least half of the thickness of the positioning plate and a radius of the heat interrupter are symmetrically arranged around the cylindrical axis and at least half of the radius of the positioning plate. The workpiece holder according to claim 1, wherein the protrusion is integrally formed with the positioning plate, and protrudes from a bottom surface of the positioning plate toward the cold source. The workpiece holder according to claim 1, wherein the holder is coupled to an internal thread surface of the convex portion. The workpiece holder according to claim 1, wherein the attachment points are substantially uniformly distributed across each of the radially inner and radially outer portions of the positioning disk. A workpiece holder for positioning a workpiece for processing. The workpiece holder includes: a substantially cylindrical positioning disk characterized by a cylindrical shaft and a substantially planar top surface, wherein the positioning disk defines two radial fractures Heater, a first of the heat interrupters is characterized as a radial notch, the radial notch intersects a bottom surface of the positioning plate with a first radius and extends through the bottom surface At least half the thickness of one of the positioning plates, A second of the heat interrupters is characterized as a radial notch that intersects the top surface of the positioning plate with a second radius greater than the first radius, and from the The top surface extends through at least half of a thickness of the positioning disk, and the first and second heat interrupters define a boundary between a radially inner portion of the positioning disk and a radially outer portion of the positioning disk; And wherein the positioning disk includes: a first heating device embedded in the radially inner part of the positioning disk, and a second heating device embedded in the radially outer part of the positioning disk; the workpiece holding The device further includes a cold source that extends substantially below the bottom surface of the positioning plate. The cold source includes a metal plate that flows a heat exchange fluid through a channel defined therein to target the positioning. The plate maintains a reference temperature; wherein the cold source is mechanically and thermally coupled with the positioning plate at a plurality of attachment points, and the plurality of attachment points provide a degree of thermal communication between the cold source and the positioning plate, and the heat The degree of communication is less than a degree of thermal communication between each of the first and second heating devices and the positioning plate. The workpiece holder according to claim 14, wherein the cold source includes a metal plate, the metal plate defines one or more fluid channels, and wherein a heat exchange fluid flows through the one or more fluid channels Channel to define a reference temperature of the cold source. The workpiece holder according to claim 14, wherein the plurality of attachment points between the cold source and the positioning plate substantially provide all the thermal communication between the cold source and the positioning plate. The workpiece holder according to claim 16, wherein the attachment points are substantially uniformly distributed across each of the radially inner and radially outer portions of the positioning disk. The workpiece holder according to claim 16, wherein the positioning disk is at least ten inches in diameter, and the plurality of attachment points includes at least twenty attachment points. The workpiece holder according to claim 18, wherein the positioning disk is at least twelve inches in diameter, and the plurality of attachment points includes at least thirty attachment points. The workpiece holder according to claim 14, wherein at least one of the first heating device and the second heating device includes a cable heater, the cable heater is arranged in a groove, and the groove The groove is defined in a bottom surface of the positioning plate. The workpiece holder according to claim 20, further comprising a heater cover which is placed in the groove to hold the cable heater in place, and the heater cover heats along the cable At least part of the arc length of the device is fixed to the positioning plate.

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