Workpiece holder and etching system including the same

Abstract

A workpiece holder and etching system and method for etching a workpiece in a uniform manner are disclosed. The system includes a semiconductor processing system that generates a ribbon ion beam and a workpiece holder that scans the workpiece through the ribbon ion beam. The workpiece holder includes a plurality of independently controlled thermal zones so that the temperature of different areas of the workpiece can be separately controlled. In some embodiments, the etching rate uniformity can be a function of the distance from the center of the workpiece, also known as radial non-uniformity. In addition, when scanning the workpiece, there may also be etching rate uniformity problems in the translation direction, known as linear non-uniformity. The workpiece holder of the present invention includes a plurality of independently controlled thermal zones to compensate for radial and linear etching rate non-uniformities.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to workpiece holders and etching systems and methods for improving etch rate uniformity, and more particularly to systems and methods for improving etch rate uniformity of a workpiece scanned through a ribbon ion beam. Background Art

[0002] Ion beams can be used to implant dopants, etch materials, or amorphize a workpiece (e.g., a silicon substrate). These ion beams can be created using a semiconductor processing system that includes an ion source that produces ions of a desired species. In some embodiments, these ions are extracted and manipulated by multiple components that select the desired species and direct the ions toward the workpiece. In other embodiments, the ion source is located near the workpiece, and the ions are attracted from the ion source toward the workpiece.

[0003] In some embodiments, it may be necessary to strictly control the uniformity of various parameters. For example, in some applications, it may be desirable to have a wafer width (WiW) etch rate in the range of 3-5% (3σ value) or better. However, this may be difficult to achieve due to variations in beam current across its width and other phenomena.

[0004] For example, for ribbon ion beams, these ribbon beams typically have non-uniform beam current in the X-direction, especially at the ends of the ribbon beam.

[0005] In addition, the etch rate of many substances is known to be temperature dependent. For example, etching oxide films with CF4-based chemistries can show that the etch rate is directly related to the platform temperature. Etching nitride films with CH3F-based chemistries can show that the etch rate is inversely proportional to the platform temperature. Maintaining a uniform workpiece temperature can be problematic because the outer edge of the workpiece is typically cooler than the center of the workpiece. In addition, the interface between the edge of the workpiece and the workpiece support can affect the plasma sheath, etchant concentration, or other parameters.

[0006] Therefore, it would be beneficial if there were a system and method for achieving a desired etch rate uniformity using a scanning ribbon ion beam. In addition, it would be beneficial if the system could be easily adapted to different etching materials. Summary of the invention

[0007] A system and method for etching a workpiece in a uniform manner are disclosed. The system includes a semiconductor processing system that generates a ribbon ion beam and a workpiece holder that scans the workpiece through the ribbon ion beam. The workpiece holder includes a plurality of independently controlled thermal zones so that the temperature of different areas of the workpiece can be separately controlled. In some embodiments, the etch rate uniformity can be a function of the distance from the center of the workpiece, also known as radial non-uniformity. In addition, when scanning the workpiece, there may also be etch rate uniformity issues in the translation direction, known as linear non-uniformity. The workpiece holder of the present invention includes a plurality of independently controlled thermal zones to compensate for both radial etch rate non-uniformity and linear etch rate non-uniformity.

[0008] According to one embodiment, a workpiece holder is disclosed. The workpiece holder includes: an inner hot zone; and at least one concentric ring, the at least one concentric ring surrounding the inner hot zone, wherein at least one of the at least one concentric ring is divided into a plurality of outer hot zones. In some embodiments, the inner hot zone and the plurality of outer hot zones can be independently controlled. In some embodiments, a heating element is embedded in the inner hot zone and each of the outer hot zones. In some embodiments, radial spokes are used to divide one of the at least one concentric rings. In some further embodiments, the plurality of outer hot zones are of the same size. In some embodiments, horizontal and vertical boundaries are used to divide one of the at least one concentric rings.

[0009] According to another embodiment, an etching system is disclosed. The etching system includes: a semiconductor processing system to generate a ribbon ion beam; a workpiece holder; and a scanning motor to move the workpiece holder through the ribbon ion beam, wherein the workpiece holder includes multiple hot zones to compensate for both radial etching rate non-uniformity and linear etching rate non-uniformity. In some embodiments, the workpiece holder includes an inner hot zone; at least one concentric ring surrounding the inner hot zone, wherein at least one of the at least one concentric ring is divided into multiple outer hot zones. In some embodiments, the inner hot zone and the multiple outer hot zones can be independently controlled. In some embodiments, heating elements are embedded in the inner hot zone and each of the outer hot zones. In some embodiments, radial spokes are used to divide one of the at least one concentric rings. In some further embodiments, the multiple outer hot zones are of the same size. In some embodiments, horizontal and vertical boundaries are used to divide one of the at least one concentric rings. In some embodiments, the workpiece holder includes a central hot zone and one or more horizontal hot zones disposed on opposite sides of the central hot zone. In certain embodiments, the etching system includes a thermal controller and a controller in communication with the thermal controller, the thermal controller including a plurality of power supplies in communication with the plurality of thermal zones, wherein the workpiece type and etching material are input to the controller and the thermal controller supplies power to the plurality of thermal zones to achieve a desired temperature profile.

[0010] According to another embodiment, an etching system is disclosed. The etching system includes: a semiconductor processing system to generate a ribbon ion beam; a workpiece holder; and a scanning motor to move the workpiece holder through the ribbon ion beam, wherein the workpiece holder includes a plurality of hot zones to compensate for linear etching rate non-uniformity. In some embodiments, the workpiece holder includes a central hot zone and one or more vertical hot zones disposed on opposite sides of the central hot zone. In some embodiments, the central hot zone and the one or more vertical hot zones can be independently controlled. In some embodiments, a heating element is embedded in each of the central hot zone and the one or more vertical hot zones. In some embodiments, the etching system includes a thermal controller and a controller in communication with the thermal controller, the thermal controller including a plurality of power supplies in communication with the plurality of hot zones, wherein the workpiece type and etching material are input to the controller and the thermal controller supplies power to the plurality of hot zones to achieve a desired temperature profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] For a better understanding of the present disclosure, reference is made to the accompanying drawings, which are hereby incorporated herein by reference.

[0012] in:

[0013] Figure 1 A semiconductor processing system according to one embodiment.

[0014] Figure 2 A semiconductor processing system according to a second embodiment.

[0015] Figure 3A-3E Etch rate maps showing various etching species and workpiece types.

[0016] Figure 4 The invention is the first embodiment of a multi-zone heating workpiece support.

[0017] Figure 5A-5E Show Figure 4 Heating patterns of the workpiece holder for various etch rate maps.

[0018] Figure 6 The invention is a second embodiment of the multi-zone heating workpiece support.

[0019] Figure 7 The present invention is the third embodiment of the multi-zone heating workpiece support.

[0020] Figure 8A-8E Show Figure 7 Heating patterns of the workpiece holder for various etch rate maps.

[0021] Fig. 9 The present invention is a fourth embodiment of the multi-zone heating workpiece holder.

[0022] Fig.10 The present invention is a fifth embodiment of the multi-zone heating workpiece support. DETAILED DESCRIPTION

[0023] As described above, the present system may be used to improve etch rate uniformity in a system that employs a workpiece that is scanned through a ribbon ion beam.

[0024] The semiconductor processing system 1 includes an ion source including an ion source chamber 100 composed of a plurality of chamber walls 101. In certain embodiments, one or more of the chamber walls 101 may be constructed of a dielectric material such as quartz. An RF antenna 110 may be disposed on an outer surface of a first dielectric wall 102. The RF antenna 110 may be powered by an RF power supply 120. The energy delivered to the RF antenna 110 is radiated within the ion source chamber 100 to ionize a feed gas introduced via a gas inlet 130.

[0025] One chamber wall, referred to as an extractor plate 104, includes an extraction aperture 105 through which an ion beam 106 can exit the ion source chamber 100. The ion beam 106 can be much wider in the horizontal direction (also referred to as the X direction) than in the height direction. An ion beam having these characteristics can be referred to as a ribbon beam. The extractor plate 104 can be made of a conductive material such as titanium, tantalum, or other metal. The width of the extractor plate 104 can exceed 300 millimeters. In addition, the extraction aperture 105 can be wider in the X direction than the diameter of the workpiece 10. This extractor plate 104 can be biased at an extraction voltage. In other embodiments, the extractor plate 104 can be grounded.

[0026] In addition to the semiconductor processing system 1, there is a workpiece holder 155. The workpiece holder 155 can be arranged near the extraction hole 105. The workpiece 10 can be arranged on the workpiece holder 155. The workpiece holder 155 is scanned using a scanning motor 160 that moves in a vertical direction 171. This direction is also referred to as the Y direction. Therefore, the workpiece holder 155 is configured so that there is a relative vertical movement between the ion beam 106 and the workpiece holder 155.

[0027] Surrounding the workpiece 10 is a shield 165, which may also be referred to as a halo. The shield 165 surrounds the workpiece 10 and has an opening in its center that corresponds to the position of the workpiece 10. The shield 165 may be made of a conductive material such as metal. The shield 165 may be made of titanium, silicon, silicon carbide, or other materials. The shield 165 may be considered to be part of the workpiece holder 155.

[0028] The workpiece bias power supply 170 may be used to bias the shield 165 and the workpiece support 155. In certain embodiments, the output from the workpiece bias power supply 170 is a pulsed DC voltage having a frequency between 5 kHz and 50 kHz and an amplitude of 100 to 5,000 volts.

[0029] Although the above disclosure describes the output from the workpiece bias power supply 170 as a pulsed DC voltage, it should be understood that the workpiece bias power supply 170 may be constant while the extraction voltage supply biasing the extractor plate 104 may provide a pulsed DC output.

[0030] When pulsed, the voltage applied to the workpiece support 155 and the shield 165 is more negative than the voltage applied to the extractor plate 104. In other words, if the extractor plate 104 is grounded, the workpiece bias power supply 170 generates negative pulses. During these negative pulses, positive ions are attracted from the interior of the ion source chamber 100 to the workpiece 10. If the extractor plate 104 is positively biased, the workpiece bias power supply 170 generates smaller positive or negative pulses such that positive ions are attracted from the interior of the ion source chamber 100 to the workpiece 10 during these pulses.

[0031] The thermal controller 190 may also be in communication with the workpiece holder 155. The thermal controller may include a plurality of power supplies that supply voltage or current to each of a plurality of thermal zones in the workpiece holder 155, as described in greater detail below.

[0032] The controller 180 may be in communication with the workpiece bias power supply 170, the workpiece support 155, the thermal controller 190, and other components. The controller 180 may include a processing unit 181, such as a microcontroller, a personal computer, a dedicated controller, or other suitable processing unit. The controller 180 may also include a non-transitory storage element 182, such as a semiconductor memory, a magnetic memory, or other suitable memory. This non-transitory storage element 182 may contain instructions 183 and other data that allow the controller 180 to perform the functions described herein. The controller 180 is capable of controlling the movement of the workpiece support 155 and controlling the temperature of the workpiece support 155 via the scanning motor 160 and the thermal controller 190, respectively.

[0033] Of course, other configurations are possible. For example, Figure 2A different type of semiconductor processing system 2 is shown, which includes an ion source 200, which includes a plurality of chamber walls that define an ion source chamber in which a plasma is generated. In certain embodiments, the ion source 200 may be an RF ion source. In this embodiment, an RF antenna may be positioned against a dielectric window. This dielectric window may include a portion or all of one of the chamber walls. The RF antenna may include a conductive material, such as copper. An RF power supply is electrically connected to the RF antenna. The RF power supply may provide an RF voltage to the RF antenna. The power supplied by the RF power supply may be between 0.1 and 10 kW and may be any suitable frequency, such as between 1 and 100 MHz. In addition, the power supplied by the RF power supply may be pulsed.

[0034] In another embodiment, a cathode is disposed in the ion source chamber. A filament is disposed behind the cathode and energized to emit electrons. These electrons are attracted to the cathode, which in turn emits electrons into the ion source chamber. This cathode may be referred to as an indirectly heated cathode (IHC) because the cathode is indirectly heated by the electrons emitted from the filament.

[0035] Other embodiments are also possible. For example, the plasma can be generated in different ways, such as by a Bernas ion source; a capacitively coupled plasma (CCP) source, a microwave or an ECR (electron cyclotron resonance) ion source. The manner of generating the plasma is not limited by the present disclosure.

[0036] One chamber wall, referred to as an extractor plate, includes an extraction aperture. The extraction aperture may be an opening through which ions 201 generated in the ion source chamber are extracted and directed through the mass analyzer and toward the workpiece 10. The extraction aperture may be any suitable shape. In some embodiments, the extraction aperture may be an elliptical or rectangular shape with one dimension, referred to as the width (the x dimension), which may be much larger than a second dimension, referred to as the height (the y dimension).

[0037] Disposed outside and adjacent to the extraction aperture of the ion source 200 is an extraction optical device 210. In some embodiments, the extraction optical device 210 includes one or more electrodes. Each electrode may be a single conductive component having an aperture disposed therein. Alternatively, each electrode may include two conductive components that are spaced apart so as to form an aperture between the two components. The electrodes may be metals, such as tungsten, molybdenum, or titanium. One or more of the electrodes may be electrically grounded. In some embodiments, an electrode power supply may be used to bias one or more of the electrodes. The electrode power supply may be used to bias one or more of the electrodes relative to the ion source so as to attract ions through the extraction aperture. The extraction aperture is aligned with the aperture in the extraction optical device so that the ions 201 pass through the two apertures.

[0038] The mass analyzer 220 is located downstream of the extraction optics 210. The mass analyzer 220 uses a magnetic field to direct the path of the extracted ions 201. The magnetic field affects the flight path of the ions according to their mass and charge. A mass resolving device 230 having a resolving aperture 231 is disposed at the output or distal end of the mass analyzer 220. By appropriately selecting the magnetic field, only those ions 201 having a selected mass and charge will be directed through the resolving aperture 231. Other ions will hit the walls of the mass resolving device 230 or the mass analyzer 220 and will not travel further in the system.

[0039] In certain embodiments, ions passing through mass analyzer 220 may form a spot beam.

[0040] The spot beam may then enter a scanner 240, which is disposed downstream of the mass resolving device 230. The scanner 240 fans out the spot beam into a plurality of diverging sub-beams. The scanner 240 may be electrostatic or magnetic.

[0041] In other embodiments, ions passing through the mass analyzer 220 may form a ribbon ion beam, where a broad beam migrates throughout the semiconductor processing system. For example, the ribbon beam may be extracted from the ion source 200. In this embodiment, the scanner 240 is not required.

[0042] In certain embodiments, the collimation corrector magnet 250 then transforms these diverging beamlets into a plurality of parallel beamlets that are directed toward the workpiece 10 .

[0043] The output from this semiconductor processing system is a ribbon ion beam that is directed toward a workpiece 10 .

[0044] The workpiece 10 is disposed on a movable workpiece holder 260 disposed downstream of the collimation corrector magnet 250. The movable workpiece holder 260 is scanned using a scanning motor 160 that moves in a direction perpendicular to the longer dimension of the ribbon beam.

[0045] In some embodiments, the direction of the ion beam is referred to as the Z direction, the direction perpendicular to this direction and horizontal may be referred to as the X direction, and the direction perpendicular to the Z direction and vertical may be referred to as the Y direction. In this example, it is assumed that the wider dimension of the ribbon ion beam is the X direction, and the movable workpiece holder 260 is translated in the Y direction by the scanning motor 160.

[0046] The thermal controller 190 may also be in communication with the movable workpiece support 260. The thermal controller 190 may include a plurality of power supplies that provide voltage or current to each of the plurality of thermal zones in the movable workpiece support 260, as described in greater detail below.

[0047] A controller 180 such as described above may be used to control the system. The actual implementation of the controller 180 is not limited by the present disclosure.

[0048] The controller 180 may be in communication with the movable workpiece holder 260 , the thermal controller 190 , and other components, as described in greater detail below.

[0049] Thus, there are a variety of semiconductor processing systems that may utilize the movable workpiece holder described herein.

[0050] As mentioned above, there can be two types of etch rate non-uniformity. The first, called radial non-uniformity, is the result of discontinuities at the edge of the workpiece. These discontinuities can be chemical, thermal, or electrical. For example, as with respect to Figure 1 As described, a shield may be present around the workpiece 10. If the material used to construct the shield is more resistant to chemical etching than the workpiece, there may be an excess of available etching material at this interface, resulting in faster etching of the outer edge of the workpiece. Conversely, if the material used to construct the shield is less resistant to chemical etching than the workpiece, the shield may act as a groove, and there may be insufficient available etching material at this interface, resulting in slower etching of the outer edge of the workpiece. If the dielectric constant of the shield is different from that of the workpiece, the electric field at the edge of the workpiece may be deformed. When the extraction bias is pulsed, this deformation can attract or repel ions from the edge of the workpiece 10. In addition, if the shield is cooler than the workpiece, the shield can collect deposits from the polymerizing gas chemistry at a faster rate, which may also affect the etching rate at the edge of the workpiece.

[0051] The second type of non-uniformity is referred to as linear non-uniformity. As described above, the workpiece 10 is scanned through the ribbon beam in the Y direction. Typically, the beam current profile of the ribbon beam in the X direction is not constant. Rather, typically the current profile near the end of the ribbon beam may be smaller or larger than the current profile near the center of the ribbon beam.

[0052] Figure 3A-3EEtch rate maps for five different combinations of etching species and workpiece types are shown. These etch rate maps are created by measuring the thickness of the workpiece at multiple locations before the etching operation and measuring the thickness at those same locations after the etching operation. Region 280 is etched more than other regions. Region 282 is etched less than other regions. Region 281 is those regions where the etching rate is between these two extremes.

[0053] Note that each of these etch rate maps shows radial non-uniformity, linear non-uniformity, or a superposition of both types of non-uniformity. Specifically, Figure 3A and Figure 3C Mainly shows linear inhomogeneity. Figure 3B and Figure 3D Mainly shows radial inhomogeneity. Figure 3E Two types of inhomogeneity are shown. Specifically, Figure 3E In the example above, there is a radial non-uniformity that causes the outer edges of the workpiece to be etched more than the center. Additionally, there is a linear non-uniformity that causes the ends of the ribbon beam to be etched less than the center of the beam. When these two non-uniformities are combined, only the top and bottom edges of the workpiece are etched more than the rest of the workpiece.

[0054] Figure 4 A front view of a workpiece holder 300 that can be used to compensate for radial non-uniformity and / or linear non-uniformity according to one embodiment is shown. The workpiece holder 300 includes multiple independently controlled thermal zones. A thermal zone is defined as an area of ​​the workpiece holder that is independently controlled and maintained at a selected temperature.

[0055] exist Figure 3A-3E In FIG. 5 , five heat zones are defined. The inner heat zone 301 is a circular area whose center corresponds to the center of the workpiece. The radius of the inner heat zone 301 is smaller than the radius of the workpiece. The concentric rings extend beyond the inner heat zone 301 in the radial direction. The concentric rings can be divided into two or more heat zones. For example, Figure 4 The concentric rings are shown divided into four outer heat zones 302-305. In some embodiments, each of the outer heat zones is equal in size. Figure 4 The boundaries between the external thermal zones in the embodiment are at 45°, 135°, 225°, and 315°. However, other sizes are also possible. For example, the two external thermal zones 302, 304 may be larger or smaller than the other two external thermal zones 303, 305. For example, if the two external thermal zones 302, 304 are to be larger than the other two external thermal zones, the boundaries between the external thermal zones may be at 60°, 120°, 240°, and 300°. Similarly, if the two external thermal zones 302, 304 are to be smaller than the other two external thermal zones, the boundaries between the external thermal zones may be at 30°, 150°, 210°, and 330°.

[0056] In some embodiments, each of these external thermal zones 302-305 can be independently controlled. In other embodiments, two or more external thermal zones can be controlled together. For example, the two external thermal zones 302, 304 corresponding to the location where the end of the ribbon ion beam strikes the workpiece can be controlled together. Similarly, the other two external thermal zones 303, 305 can be controlled together.

[0057] These thermal zones can be implemented in a variety of ways. In one embodiment, one or more heating elements are embedded in each thermal zone. All heating elements in a particular thermal zone can be controlled together. For example, all heating elements in a thermal zone can be provided with the same current or voltage by the thermal controller 190. In operation, the power provided by the thermal controller 190 is supplied to the heating elements through wires, which convert electrical energy into heat. A temperature sensor can be provided in each thermal zone to measure the actual temperature and provide feedback to the thermal controller 190. In this way, each thermal zone can be maintained at its desired temperature.

[0058] Thus, in one embodiment, the controller 180 receives information about the etching material being used and the type of workpiece. This information can be input via an input device such as a keyboard or touch screen. Based on this information, the controller 180 indicates to the thermal controller 190 the desired temperature for each thermal zone in the workpiece holder 300. The thermal controller 190 then provides power to each thermal zone to achieve the desired temperature profile.

[0059] For example, Figure 5A-5E Display separately Figure 3A-3E Etch rate maps of , and the corresponding temperature profiles for each. Note that Figure 5A and Figure 5C In the embodiment of the present invention, the etching rate along the left and right edges is less than the etching rate at other locations on the workpiece. Therefore, in this case, the temperature of the outer hot zones 302, 304 is set to be different from the other hot zones. For many workpieces and etching substances, the etching rate is proportional to the temperature. Therefore, in order to increase the etching rate along the left and right edges of the workpiece, the temperature of the outer hot zones 302, 304 is set higher than the other hot zones. Of course, for some etching chemicals, the etching rate may be inversely proportional to the temperature. In this case, in order to increase the etching rate along the left and right edges of the workpiece, the temperature of the outer hot zones 302, 304 is set lower than the other hot zones.

[0060] Figure 5B and Figure 5DRadial non-uniformity is shown, where the etch rate at the outer edge is lower than the rest of the workpiece. In these cases, all of the outer thermal zones 302-305 are maintained at a different temperature than the inner thermal zone 301. If the etch rate is proportional to temperature, the temperature of the outer thermal zones 302-305 is set higher than the inner thermal zone 301. If the etch rate is inversely proportional to temperature, the temperature of the outer thermal zones 302-305 is set lower than the inner thermal zone 301.

[0061] Figure 5E An example is shown where the top and bottom edges of the workpiece have a higher etch rate than the rest of the workpiece. Therefore, if the etch rate is proportional to the temperature, the temperature of the outer thermal zones 303, 305 is set lower than the rest of the thermal zones. If the etch rate is inversely proportional to the temperature, the temperature of the outer thermal zones 303, 305 is set higher than the rest of the thermal zones.

[0062] therefore, Figure 4 The workpiece holder 300 can be used to compensate for both radial non-uniformity and linear non-uniformity.

[0063] Of course, other designs may be used. Figure 6 Another workpiece holder 400 is shown, which includes an inner hot zone 401, four outer hot zones 402-405 and four intermediate hot zones 406-409. This design can allow for increased finesse, especially with respect to radial non-uniformity. In an alternative embodiment, the four intermediate hot zones 406-409 are replaced by a single intermediate zone.

[0064] In other words, the workpiece holder may include an internal hot zone and one or more concentric rings surrounding the internal hot zone, wherein one or more of those concentric rings are divided into a plurality of hot zones. The number of concentric rings is not limited by the present disclosure and may be any number greater than or equal to one. Similarly, the plurality of hot zones into which the concentric rings are divided is not limited by the present disclosure and may be any number greater than one. In addition, the number of hot zones in a particular concentric ring may be the same as or different from the number of hot zones in a different concentric ring. As described above, this configuration is effective for compensating for both radial and linear non-uniformities.

[0065] Figure 7 Another design is shown that can be used to compensate for both radial and linear non-uniformities. Figure 4 and Figure 6, this workpiece holder 500 includes an inner hot zone and one or more concentric rings, wherein at least one of those concentric rings is divided into multiple hot zones. In those embodiments, the boundaries of the hot zones in the concentric rings are created using radial spokes. In this embodiment, the boundaries of the hot zones in the outer concentric rings are created using horizontal segments and vertical segments. Therefore, in this embodiment, there is an inner hot zone and at least one concentric ring surrounding the inner hot zone, wherein at least one of the concentric rings is divided using vertical and horizontal boundaries. Horizontal boundaries and vertical boundaries refer to boundaries that are perpendicular to each other, and these boundaries touch the inner boundary of the ring at the intersection and are tangent to it. In addition, these boundaries are perpendicular to the radius passing through the intersection. In Figure 7 In the workpiece holder 500, there is an inner hot zone 501, a first middle concentric ring hot zone 502, and an outer concentric ring divided into eight outer hot zones 503-510. Of course, the boundaries between the hot zones in the outer concentric rings may not be vertical and horizontal. This illustration shows a possible implementation. Figure 7 The workpiece holder 500 can be used to compensate for both radial non-uniformity and linear non-uniformity. Figure 8A-8E show Figure 3A-3E Five etch rate maps and corresponding thermal profiles of the workpiece holder 500 are presented in FIG.

[0066] This design provides a higher level of refinement than previous designs. Fig. 8A In the embodiment, if the etching rate is proportional to the temperature, the temperature of the outer thermal zones 503, 507 is set higher than the remaining thermal zones. If the etching rate is inversely proportional to the temperature, the temperature of the outer thermal zones 503, 507 is set lower than the remaining thermal zones.

[0067] exist Figure 8B In the embodiment of the present invention, if the etching rate is proportional to the temperature, the temperature of the outer heat zones 503-510 is set higher than the remaining heat zones, and the temperature of the first middle concentric ring heat zone 502 is set higher than the inner heat zone 501. If the etching rate is inversely proportional to the temperature, the temperature of the outer heat zones 503-510 is set lower than the remaining heat zones, and the temperature of the first middle concentric ring heat zone 502 is set lower than the inner heat zone 501.

[0068] Fig.8D The pattern is similar to Figure 8B pattern, however, the first middle concentric ring hot zone 502 can be maintained at the same temperature as the inner hot zone 501.

[0069] exist Figure 8CIn the embodiment, if the etching rate is proportional to the temperature, the temperature of the outer thermal zones 503, 504, 506-508, 510 is set higher than the remaining thermal zones, and the temperature of the outer thermal zones 505, 509 is set higher than the inner thermal zone 501. If the etching rate is inversely proportional to the temperature, the temperature of the outer thermal zones 503, 504, 506-508, 510 is set lower than the remaining thermal zones, and the temperature of the outer thermal zones 505, 509 is set lower than the inner thermal zone 501.

[0070] exist Fig. 8E In the embodiment, if the etching rate is proportional to the temperature, the temperature of the outer thermal zones 505 and 509 is set lower than the remaining thermal zones. If the etching rate is inversely proportional to the temperature, the temperature of the outer thermal zones 505 and 509 is set higher than the remaining thermal zones, and the temperature of the outer thermal zones 505 and 509 is set lower than the inner thermal zone 501.

[0071] Although the workpiece holders described above are designed to accommodate both radial and linear non-uniformities, other workpiece holders may be utilized to correct only one type of non-uniformity. Fig. 9 A workpiece holder 600 is shown that can be used to correct for linear non-uniformity. In this embodiment, the workpiece holder 600 has a central hot zone 601, and one or more vertical hot zones disposed on opposite sides of the central hot zone 601. In this embodiment, there are two vertical hot zones on either side of the central hot zone 601. Of course, there may be more or fewer vertical hot zones. The outermost vertical hot zones 602, 605 are located near the ends of the ribbon ion beam. The intermediate vertical hot zones 603, 604 are located between the central hot zone 601 and the outermost vertical hot zones.

[0072] The workpiece holder 600 can be used to compensate Figure 3A and Figure 3C In addition, if the workpiece holder 600 is rotated a quarter turn, it can be used to compensate for Figure 3E The etch rate map shown. In this case, the workpiece holder includes a central hot zone and one or more horizontal hot zones disposed on opposite sides of the central hot zone. Thus, Fig. 9 An example of a workpiece holder having hot zones that can be used in a scanning system to compensate for linear non-uniformities of a ribbon ion beam is shown.

[0073] Fig.10 A workpiece holder 700 is shown which can be used to compensate for radial non-uniformity. Figure 4 , however, the concentric rings are not divided into multiple hot zones. In other words, there is an inner hot zone 701 and multiple concentric ring hot zones. Each concentric ring 702-704 represents a concentric ring hot zone. This workpiece holder 700 can be used to compensate Figure 3B and Figure 3D The etch rate map shown in .

[0074] Thermal controller 190 can be implemented in a variety of ways. In one embodiment, each hot zone in the workpiece holder has a corresponding dedicated power supply. In other embodiments, certain hot zones can always be set to the same temperature. In these embodiments, a single power supply can be used to supply power to more than one hot zone.

[0075] In another embodiment, thermal controller 190 may have one power supply for each power level. The outputs of these power supplies are used as inputs to multiple switches or multiplexers, where each switch is used to select which output is applied to each thermal zone.

[0076] The embodiments described above in the present application may have many advantages. As described above, some processes employ very tight tolerances on the etch rate of the entire workpiece, such as a 3σ value equal to or less than 3%. By controlling the temperature of various regions of the workpiece, the etch rate associated with each region may be varied, thereby obtaining a more uniform result across the entire workpiece. For example, in one experiment, Figure 3A As shown, using a consistent platform temperature, the etch non-uniformity exhibits a 3σ value of 6%. Figure 5A The multi-zone platform temperature control shown can reduce the etch non-uniformity to achieve a 3σ value of 3% or less. In other words, compared with a uniform platform temperature, the multi-zone platform temperature control can reduce the 3σ value of the etch non-uniformity by 2 times or more.

[0077] The scope of the present disclosure is not limited by the specific embodiments described herein. In fact, various other embodiments of the present disclosure and various modifications to the present disclosure in addition to the embodiments and modifications described herein will also be apparent to those of ordinary skill in the art upon reading the above description and accompanying drawings. Therefore, these other embodiments and modifications are intended to fall within the scope of the present disclosure. In addition, although the present disclosure has been described herein in the context of a specific embodiment in a specific environment for a specific purpose, a person of ordinary skill in the art will recognize that the practicality is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Therefore, the claims set forth should be viewed in light of the full scope and spirit of the present disclosure set forth herein.

Claims

1. An etching system comprising: A semiconductor processing system includes an ion source to generate a ribbon ion beam, wherein the ribbon ion beam is extracted through an extraction aperture of the ion source; Workpiece support; and a scanning motor to move the workpiece holder through the ribbon beam, wherein the workpiece holder includes a plurality of thermal zones, the temperature of at least one of the plurality of thermal zones being maintained at a selected temperature different from the temperatures of the remaining thermal zones of the plurality of thermal zones to compensate for both radial etch rate non-uniformity and linear etch rate non-uniformity, The workpiece holder is arranged to be located outside the ion source and close to the extraction hole of the ion source, and the ribbon ion beam is suitable for impacting a workpiece arranged on the workpiece holder.

2. The etching system of claim 1, wherein the workpiece holder comprises an internal hot zone; and At least one concentric ring surrounds the inner thermal zone, wherein at least one of the at least one concentric ring is divided into a plurality of outer thermal zones.

3. The etching system of claim 2, wherein the inner thermal zone and the plurality of outer thermal zones are independently controllable.

4. The etching system of claim 2, wherein heating elements are embedded in the inner hot zone and each outer hot zone.

5. The etching system of claim 2, wherein the at least one of the at least one concentric rings is divided using radial spokes. The etching system of claim 5 , wherein the plurality of external thermal zones are of equal size.

7. The etching system of claim 2, wherein the at least one of the at least one concentric rings is divided using horizontal and vertical boundaries.

8. The etching system of claim 1, wherein the workpiece holder comprises a central hot zone and one or more horizontal hot zones disposed on opposite sides of the central hot zone.

9. The etching system according to claim 1 further includes a thermal controller and a controller connected to the thermal controller, wherein the thermal controller includes multiple power supplies connected to the multiple hot zones, wherein the workpiece type and etching material are input to the controller and the thermal controller supplies power to the multiple hot zones to achieve a desired temperature profile.

10. An etching system comprising: A semiconductor processing system includes an ion source to generate a ribbon ion beam, wherein the ribbon ion beam is extracted through an extraction aperture of the ion source; Workpiece support; and a scanning motor to move the workpiece holder through the ribbon beam, wherein the workpiece holder includes a plurality of thermal zones, the temperature of at least one of the plurality of thermal zones being maintained at a selected temperature different from the temperatures of the remaining thermal zones of the plurality of thermal zones to compensate for linear etch rate non-uniformity, The workpiece holder is arranged to be located outside the ion source and close to the extraction hole of the ion source, and the ribbon ion beam is suitable for impacting a workpiece arranged on the workpiece holder.

11. The etching system of claim 10, wherein the workpiece holder comprises a central hot zone and one or more vertical hot zones disposed on opposite sides of the central hot zone.

12. The etching system of claim 11, wherein the central hot zone and the one or more vertical hot zones are independently controllable.

13. The etching system of claim 11, wherein a heating element is embedded in the central hot zone and each of the one or more vertical hot zones.

14. The etching system of claim 10, further comprising a thermal controller and a controller in communication with the thermal controller, the thermal controller comprising a plurality of power supplies in communication with the plurality of thermal zones, wherein the workpiece type and etching material are input into the controller and the thermal controller supplies power to the plurality of thermal zones to achieve a desired temperature profile.

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