Clamping device, substrate processing system and ion implantation system

Abstract

The present invention provides a clamping device, a substrate processing system and an ion implantation system. The clamping device may include: a clamp for clamping a substrate, wherein the clamp is arranged opposite to the back side of the substrate; and an illumination system, configured to direct radiation to the substrate when the substrate is set on the clamp, wherein the radiation includes radiation energy equal to or higher than a threshold energy to generate mobile charges in the substrate, wherein the illumination system is configured to direct the radiation to the back side of the substrate.

Description

Technical Field

[0001] The present embodiments relate to substrate processing, and more particularly to electrostatic chucks for holding substrates. Background Art

[0002] Substrate holders, such as electrostatic clamps (also known as electrostatic chucks), are widely used in many manufacturing processes, including semiconductor manufacturing, solar cell manufacturing, and other component processing. Electrostatic clamping employs the principle of electrostatic induction, in which charge is redistributed in an object due to the direct influence of nearby charges. For example, a positively charged object near an electrically neutral substrate will induce a negative charge on the surface of the substrate. This charge creates an attractive force between the object and the substrate. To clamp conductive substrates and semiconductive substrates with relatively low bulk resistivity, the redistribution of charge is easily achieved by applying a voltage to electrodes embedded in an insulator adjacent to the conductive substrate. Therefore, electrostatic clamps have been widely used to hold semiconductor substrates, such as silicon wafers with relatively low bulk resistivity.

[0003] One type of electrostatic clamp applies an AC voltage to produce clamping, thereby allowing rapid clamping and unclamping of conductive substrates or low resistivity semiconductive substrates. However, known DC electrostatic clamps or AC electrostatic clamps are ineffective at clamping high resistivity semiconductor substrates or electrically insulating substrates.

[0004] In addition, substrate charging issues can adversely affect substrate processing, such as in ion implantation, particularly processing of highly resistive substrates. In addition to electrostatic chucks, non-electrostatic chucks, such as mechanical chucks, may incorporate conductive lift pins, ground pins, where the operation of such pins may be substandard when the clamped substrate is highly resistive. Additionally, in ion implantation apparatus, charge buildup on the substrate during implantation may require the use of charge compensation (e.g., an electron flood gun) to counteract the charging of the substrate.

[0005] It is with respect to these and other considerations that the present disclosure is provided. Summary of the invention

[0006] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

[0007] In one embodiment, an apparatus may include a fixture for holding a substrate, wherein the fixture is arranged opposite to a back side of the substrate. The apparatus may have an illumination system configured to direct radiation to the substrate when the substrate is disposed on the fixture, wherein the radiation includes radiation energy equal to or above a threshold energy to generate mobile charges in the substrate, and the illumination system is configured to direct the radiation to the back side of the substrate.

[0008] In another embodiment, a substrate processing system may include a processing chamber and an electrostatic chuck disposed in the processing chamber, the electrostatic chuck for chuck a substrate, wherein the electrostatic chuck is arranged opposite to a back side of the substrate. The substrate processing system may also include an illumination system, the illumination system being configured to direct radiation to the back side of the substrate when the substrate is disposed on the electrostatic chuck, wherein the radiation includes radiation energy, the radiation energy being equal to or greater than 2.5 electron volts (eV).

[0009] In another embodiment, an ion implantation system may include a set of beamline components for generating an ion beam and directing the ion beam to a substrate and a chuck for holding the substrate, wherein an electrostatic chuck is arranged opposite a back side of the substrate. The ion implantation system may include an illumination system configured to direct radiation to the back side of the substrate when the substrate is disposed on the chuck, wherein the radiation includes radiation energy, the radiation energy being equal to 2.5 electron volts. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A An electrostatic chuck apparatus according to an embodiment of the present disclosure is depicted.

[0011] Figure 1B A clamp device according to other embodiments of the present disclosure is depicted.

[0012] Figure 1C An example of electrostatic clamping is shown.

[0013] Figure 2 Depicted is a side view of an electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0014] Figure 3 Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0015] Figure 4 Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0016] Figure 5 Depicted is a side view of yet another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0017] Figure 6 Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0018] Fig. 7A Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0019] Figure 7B and Figure 7C Depicted are the geometries of a scanning radiation beam according to two different embodiments.

[0020] Figure 8 Depicted is a side view of yet another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0021] Fig. 9 Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0022] Fig.10 Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0023] Fig.11 Depicted is a side view of another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0024] Fig.12 Depicted is a side view of yet another electrostatic chuck apparatus according to various embodiments of the present disclosure.

[0025] Fig.13 Depicted is a side view of a processing system according to various embodiments of the present disclosure.

[0026] Fig.14 Shows the relationship between radiation wavelength and energy.

[0027] Fig.15 An exemplary control system for electrostatic clamping is shown in accordance with some embodiments.

[0028] Fig.16 The relationship between charging time and resistivity for different substrate types is shown.

[0029] Fig.17 An exemplary irradiance curve for a radiation source suitable for use with the electrostatic chuck apparatus of this embodiment is shown.

[0030] Fig.18 The generation of photocurrent is shown as a function of the radiant energy of SiO2.

[0031] Fig.19 Another exemplary irradiance curve of a radiation source suitable for use with the electrostatic chuck apparatus of this embodiment is shown.

[0032] Fig. 20 An exemplary process flow is shown.

[0033] Fig.21 Another exemplary process flow is shown.

[0034] Fig. 22 Another exemplary process flow is shown.

[0035] Fig.23 Another exemplary process flow is shown.

[0036] Fig.24 Another exemplary process flow is shown.

[0037] Fig.25 Embodiments of a processing system are described. DETAILED DESCRIPTION

[0038] The present embodiments provide apparatus and techniques for improving substrate clamping capabilities. In various embodiments, clamping apparatus and processing systems suitable for clamping a variety of substrates, including high resistivity substrates, are disclosed. Various embodiments employ radiation sources capable of producing visible light as well as shorter wavelength radiation, including wavelengths in the ultraviolet (UV) range and vacuum ultraviolet (VUV) range (<200 nanometers). Thus, various embodiments provide what may be referred to as light-assisted electronic clamping and release of a variety of substrates, including illuminating the substrate with radiation before, during, and after clamping.

[0039] Figure 1A An electrostatic clamp system 100 is depicted in accordance with an embodiment of the present disclosure. The electrostatic clamp system 100 may be deployed in any suitable environment in which a substrate is to be clamped for any suitable purpose. In various embodiments, the electrostatic clamp system 100 may be arranged in a substrate chamber 102 for accommodating a substrate 112. In various non-limiting embodiments, the substrate chamber 102 may represent a loading chamber that loads a substrate 112 into the system, a transfer chamber that transfers a substrate 112 between locations, or a processing chamber that subjects a substrate 112 to at least one process. Suitable processing chambers include chambers for depositing layers on the substrate 112, chambers for etching the substrate 112, chambers for heating the substrate 112, chambers for implanting ions into the substrate 112, or chambers for other suitable processes.

[0040] like Figure 1A As shown in FIG. 1 , the electrostatic clamp system 100 may include a clamp device 104 including an electrostatic clamp assembly 114. The electrostatic clamp assembly 114 may include known components of a known electrostatic clamp, including a cooling block, a heater, a gas channel, electrodes, wiring, etc. For clarity, only common components of the electrostatic clamp assembly 114 are shown. Figure 1A , the electrostatic chuck assembly 114 may include an insulator portion 108 directly supporting the substrate 112 and an electrode assembly 110 that applies a voltage to the insulator portion 108. The electrode assembly 110 may include at least one electrode and may be operable to apply a DC voltage or an AC voltage in different embodiments. In some embodiments, the electrostatic chuck system 100 may function as a known electrostatic chuck for clamping low-resistivity substrates.

[0041] like Figure 1AAs further shown in FIG. 1 , the chuck device 104 may further include an illumination system 106 configured to direct radiation (shown as radiation 120) to the substrate 112. According to various embodiments, the radiation 120 may be characterized as radiation energy equal to or above a threshold energy to generate mobile charges in the substrate 112. In this manner, the illumination system 106 may generate the radiation 120 when a clamping voltage is applied to the electrostatic chuck assembly 114. Thus, in operation and with reference to FIG. Figure 1C When the substrate 112 is clamped by the electrostatic clamp assembly 114, the charges present within the substrate 112 may move to the electrodes of the electrode assembly 110, generating a higher electric field with opposite polarity and producing a larger clamping force.

[0042] In particular, the time required for such charge movement depends on the resistivity of the substrate 112, such as Fig.16 As shown in Fig.16 , the resistivity range and response time of charge for different types of common substrates are shown. The response time of a substrate clamped by a clamping voltage without the application of the illumination system 106 is shown. The substrate referred to as a "conventional silicon wafer" represents a resistivity range for a relatively low resistance silicon wafer, which shows a resistivity in the range of approximately 1 Ohm-cm to 1000 Ohm-cm. In this example, the response time is approximately 1 microsecond to 100 microseconds. Fig.16 The rise time and clamping period of the AC clamp are also shown in FIG. As shown, this rise time is consistent with the response time of a conventional silicon wafer. Fig.16 Also shown are the response times of charges in high bulk resistivity silicon wafers (HBR silicon wafers), HBR silicon carbide wafers (HBR SiC), and glass substrates. In particular, in the case of glass substrates, the bulk resistivities of these other substrates extend above 10-2 seconds up to 108 seconds. These longer response times mean that charges cannot move within these substrates within a time period consistent with the application of an AC voltage. Additionally, even with an applied DC voltage, the response times would be too slow for practical processing purposes, especially for HBR SiC and glass.

[0043] When the resistivity of the substrate 112 is too high, the charge cannot move fast enough to generate a clamping force when a clamping voltage is applied by the electrostatic clamp assembly 114. For insulating substrates such as glass wafers, the charging time is effectively infinite compared to the time scale associated with clamping and handling the substrate 112, which can be on the order of seconds to at most several minutes in duration. Thus, without the use of the illumination system 106, substantially no substrate charge is generated in response to the applied clamping voltage, so that the clamping force is nearly zero.

[0044] Thus, by using the clamping device 104, it is possible to clamp substrates including HBR semiconductor wafers and glass. In addition to solving the problem of clamping high resistivity substrates, the clamping device 104 also helps solve another problem, namely the generation of unwanted charges on high resistivity substrates, where, for example, due to triboelectric charging, it is extremely difficult to remove such charges. By generating mobile charges on the substrate 112, the clamping device 104 further helps to unclamp the substrate. The high resistivity of insulating materials comes from different factors. First, these materials generally have a very large electronic band gap. For example, for silicon oxide (such as SiO2), the band gap is about 8 electron volts. Unlike dopants in semiconductors, impurities in insulators also have much higher ionization energies. Therefore, the concentration of mobile charges in such substrates is extremely low. Secondly, many common insulating materials are amorphous, such as silica glass. The lack of a periodic crystal structure produces a relatively low charge mobility. According to embodiments of the present disclosure, under applied radiation 120, the conductivity of a high resistivity substrate (e.g., glass) can be significantly increased by imparting sufficient energy to the electrons of the high resistivity material such that the electrons enter a so-called extended state in the conduction band. For narrow bandgap semiconductors including silicon, low energy photons, such as in infrared radiation, provide sufficient energy to overcome the bandgap. For wide bandgap semiconductor materials (e.g., SiC), long-wave UV radiation (315 nanometers to 400 nanometers) can provide sufficient energy to overcome the bandgap and generate charge carriers. For such wavelength ranges, in various non-limiting embodiments, the illumination system 106 can be implemented as a light source including a laser diode, a light-emitting diode (LED), an arc lamp, or other source.

[0045] According to additional embodiments, for substrates commonly known as insulating substrates (e.g., glass substrates), other types of radiation sources may be used for the illumination system 106, as further detailed below. Generally, the illumination system 106 will be arranged to provide radiation 120 having sufficient energy to generate mobile charges for the type of substrate used as substrate 112. However, in various non-limiting embodiments, the illumination system 106 may be configured to clamp at least the following substrate types: 1) conventional silicon wafers: resistivity <1000 ohm-cm; 2) high resistivity silicon / or silicon-on-insulator (SOI) wafers: resistivity of 1000 to 100,000 ohm-cm; 3) silicon carbide wafers: usable resistivity up to 1E9 ohm-cm; and 4) glass: resistivity >1E12 ohm-cm; 5) silicon on glass.

[0046] According to various embodiments of the present disclosure, the illumination system 106 is arranged to provide illumination to a major surface of the substrate 112 (including the front surface 112A on the front side or the back surface 112B on the back side). According to different embodiments, the radiation 120 can be provided directly in a line-of-sight manner, can be provided by reflection, can be provided by blanket illumination of the substrate, by scanning the substrate, by scanning the illumination source, or a combination of methods. Ideally, high-intensity, uniform light illumination across the entire substrate is useful. Due to restrictions on the configuration of the light source and the electrostatic clamping device, certain embodiments provide novel configurations to maximize the effectiveness of light generation in the substrate. In the following Figures 2 to 8 In the embodiment of FIG. 1 , various electrostatic clamp systems are shown, wherein a substrate platform 202 is depicted, which may include an electrostatic clamp, as described above with respect to FIG. Figure 1A Generally described.

[0047] Steering Figure 1B , a fixture device 150 is shown according to an additional embodiment of the present disclosure. In this case, the fixture device 150 includes a mechanical fixture 154 (optionally including a stand off 156) that uses any suitable mechanical components to hold the substrate 112. The fixture device 150 includes the illumination system 106 described above. In operation, while the substrate 112 is held by the mechanical fixture 154, radiation 120 can be directed to the substrate 112 to increase mobile charge in the substrate 112 and help process the substrate, such as providing better electrical conduction between the substrate 112 and a lift pin or ground pin (not separately shown) or reducing surface charging of the substrate 112.

[0048] Figure 2 A side view of an electrostatic clamp system 200 is depicted according to various embodiments of the present disclosure. In this embodiment, the illumination system 201 is positioned to direct radiation 208 to the front surface of the substrate 112. While in some embodiments, the substrate platform 202 may be fixed, in other embodiments, the substrate platform 202 may include a scanning component, such as a known scanning component (not shown) that scans the substrate 112 along at least one direction. Likewise, in some embodiments, the radiation 208 may be provided in the form of a fixed beam that is arranged to cover the entirety of the substrate. In some embodiments, when the substrate platform 202 is arranged to scan the substrate, for example, along the Y-axis of the Cartesian coordinate system shown, the entire scanning range of the substrate 112 (such as the Y-axis of the Cartesian coordinate system) can be covered. Figure 2The radiation 208 is provided in a manner (described in ). For example, the illumination system 201 may include what is referred to as an illumination source 204, including components that generate the radiation 208 with an energy suitable for generating photocarriers in the substrate 112, wherein examples of different illumination sources are detailed below. The illumination source 204 may generate radiation in the form of a beam having a certain size. In some embodiments, the beam emitted by the illumination source 204 may be large enough, or may expand to become large enough to cover the substrate 112.

[0049] In other embodiments, the illumination system 201 may further include an optical system 206 arranged between the illumination source 204 and the substrate 112 to expand the radiation beam received from the illumination source 204 and expand the radiation beam to produce radiation 208, thereby covering the entirety of the substrate 112. An example of an optical system suitable for the optical system 206 is a set of refractive optical elements, such as optical lenses. In this embodiment and in the following embodiments, the "optical system" will provide the ability to process radiation in the UV range, which means that the refractive optical elements will mean the optical elements for refracting UV radiation, and the reflector optical elements will be suitable for reflecting UV radiation.

[0050] Figure 3 A side view of an electrostatic clamp system 220 is depicted according to various embodiments of the present disclosure. In this embodiment, the illumination system 211 is positioned in different ways to direct radiation 212 to the front surface of the substrate 112. Although in some embodiments, the substrate platform 202 may be fixed, in other embodiments, the substrate platform 202 may include a scanning component, such as a known scanning component (not shown) that scans the substrate 112 along at least one direction. Likewise, in some embodiments, the radiation 212 may be provided in the form of a fixed beam that is arranged to cover the entirety of the substrate. In some embodiments, when the substrate platform 202 is arranged to scan the substrate, for example, along the Y-axis of the Cartesian coordinate system shown, the entire scanning range of the substrate 112 (such as shown) can be covered. Figure 3 For example, the illumination system 211 may include an illumination source 204, as described above with respect to Figure 2As discussed above. The illumination source 204 may generate radiation in the form of a beam having a certain size. In this configuration, the illumination source 204 may emit radiation in the form of a beam that is not initially directed toward the substrate 112. The illumination system 211 may also include an optical system 210, which is arranged to reflect the beam generated by the illumination source 204 and direct the reflected beam to the substrate 112 as radiation 212. The optical system 210 may include an optical reflector, and in some embodiments, the optical reflector may be arranged in the form of an expansion reflector to expand the radiation beam received from the illumination source 204 to reflect or expand the radiation beam to produce radiation 212, thereby covering the entirety of the substrate 112. In additional embodiments, the illumination system may include a combination of refractive optics and reflector optics. The selection of optics for illumination may be guided by consideration of the spacing and placement of elements and the efficiency of generating illumination to cover the substrate 112.

[0051] Figure 4 A side view of another electrostatic clamp system 250 is depicted in accordance with various embodiments of the present disclosure. In this example, the electrostatic clamp system 250 may include a substrate platform 202 and an illumination source 204, as generally described above. Figure 2 2. In various embodiments, the electrostatic chuck system 250 may further include an illumination system 251 having an optical system 252, wherein the optical system 252 includes components for providing a scanning capability of the radiation beam received from the illumination source 204. For example, the scanning capability may be provided by a motorized component. According to various embodiments, radiation 254 may be provided in the form of a beam expanded from an initial beam size.

[0052] According to various embodiments of the present disclosure, the optical system 252 provides beam scanning of the radiation 254. In some embodiments, the optical system 252 may also scan the radiation in a configuration that scans the substrate 112 to follow the scanning of the substrate 112. For example, the illumination source 204 and the optical system 252 may include refractive optics that generate the radiation 254 in the form of a beam having a width that covers the substrate 112.

[0053] The optical system 252 may be further configured with a lens drive mechanism arranged to move the optical lens by rotation, translation, or rotation and translation. For example, the optical system 252 may be further configured with a scanning component, wherein when the substrate 112 is scanned along the Y-axis at a rate of 10 cm / min, the radiation 254 is scanned in the same direction at the same rate to cover the substrate 112 in any case. In this way, the width of the radiation 254 directed to the substrate 112 does not need to be substantially larger than the width of the substrate (even when scanning the substrate 112), thereby protecting other components in the rest of the chamber containing the substrate 112.

[0054] In other embodiments, the radiation 254 may be provided as a relatively narrow beam (e.g., a laser beam or a highly collimated incoherent beam) compared to the width of the substrate 112. This embodiment is represented by a radiation beam that is shown as having a width, at least along the Y direction, that is much smaller than the width of the substrate 112. In this embodiment, the optical system 252 may be configured to rapidly scan the radiation beam, e.g., along the Y direction, to cover all components of the substrate 112 in a manner that provides an average uniform illumination. In embodiments where the substrate 112 remains stationary, the optical system 252 may therefore simply scan the radiation beam in a rapid manner to produce a radiation umbrella that covers the stationary substrate.

[0055] Figure 5 A side view of another electrostatic clamp system 260 is depicted in accordance with various embodiments of the present disclosure. In this example, the electrostatic clamp system 260 may include a substrate platform 202 and an illumination source 204, as generally described above. Figure 3 2. In various embodiments, the electrostatic clamp system 260 may further include an illumination system 261 having an optical system 262, wherein the optical system 262 includes components for providing a scanning capability of the radiation beam received from the illumination source 204. For example, the scanning capability may be provided by a motorized component. According to various embodiments, radiation 264 may be provided in the form of a beam expanded from an initial beam size.

[0056] According to various embodiments of the present disclosure, the optical system 262 provides beam scanning of the radiation 264. In some embodiments, the optical system 262 may also scan the radiation to follow the scanning of the substrate 112 in a configuration to scan the substrate 112. For example, the illumination source 204 and the optical system 262 may include reflective optics (e.g., UV mirrors) that produce the radiation 264 in the form of a beam having a width that covers the substrate 112. The optical system 262 may be further configured with a scanning component, wherein when the substrate 112 is scanned along the Y-axis at a given rate, the radiation 264 is scanned in the same direction at the same rate to cover the substrate 112 in any case. In this way, the width of the radiation 264 directed to the substrate 112 does not need to be substantially larger than the width of the substrate (even when scanning the substrate 112), thereby protecting other components in the rest of the chamber that holds the substrate 112.

[0057] In other embodiments, the radiation from the illumination beam may be provided as a relatively narrow beam (e.g., a laser beam or a highly collimated incoherent beam) compared to the width of the substrate 112. Figure 6112. The electrostatic clamp system 270 shown in is represented. The substrate platform 202 can be configured as in the previous embodiments. In this embodiment, the illumination system 271 includes an illumination source 272, which generates a narrow light beam shown as having a much smaller width relative to the width of the substrate 112 at least in the Y direction. The illumination source 272 can be a laser source or a source of collimated incoherent light. In this embodiment, the optical system 274 can be configured to receive and transmit the light beam emitted from the illumination source 272 as a narrow light beam (shown as a radiation beam 276) and to scan the radiation beam 276 (for example, in the Y direction) to cover the entire refractive component of the substrate 112 in a manner that provides average uniform illumination.

[0058] In embodiments where the substrate 112 remains stationary, the optical system 274 may therefore scan only the radiation beam 276 in a rapid manner to produce a radiation umbrella 278 that covers the stationary substrate. In other embodiments where the substrate 112 is also scanned, for example along the Y-axis, the optical system 274 may include components for both rapidly scanning the radiation beam 276 across the substrate 112 and for slowly shifting the average position of the radiation beam 276 in sync with the movement of the substrate. In this manner, the radiation beam 276 produces a radiation umbrella 278 whose dimensions along the Y-axis closely correspond to or match the dimensions of the substrate along the Y-axis and whose position is arranged so that the radiation umbrella 278 overlaps all of the substrate 112 or a desired portion of the substrate 112 without extending beyond the substrate 112. More generally, the electrostatic clamping system 270 may include a synchronization component that synchronizes the optical lens with the movement of a substrate stage scanner (shown as a double arrow) so that the radiation beam remains aligned with the front side of the substrate 112 during scanning of the substrate 112. Another embodiment of providing a radiation beam in the form of a scanned narrow beam is in Fig. 7A This embodiment is represented by an electrostatic clamping system 280, wherein the substrate platform 202 may be configured as in the previous embodiments. In this embodiment, the illumination system 281 may include an illumination source 272 that generates a narrow beam of light, as described above with respect to Figure 6 In this embodiment, the optical system 284 may be configured to reflect the light beam emitted from the illumination source 272 as a narrow light beam (shown as radiation beam 286) and to scan the radiation beam 286 (e.g., in the Y direction) to cover all components of the substrate 112 in a manner that provides average uniform illumination.

[0059] In embodiments where the substrate 112 remains stationary, the optical system 284 may therefore scan only the radiation beam 286 in a rapid manner (e.g., rapidly moving or rotating a mirror) to produce a radiation umbrella 288 that covers the stationary substrate. In other embodiments where the substrate 112 is also scanned, such as along the Y-axis, the optical system 284 may include components for both rapidly scanning the radiation beam 286 across the substrate 112 and for slowly shifting the average position of the radiation beam 286 in sync with the movement of the substrate. In this manner, the radiation beam 286 produces a radiation umbrella 288 whose dimensions along the Y-axis closely correspond to or match the dimensions of the substrate along the Y-axis and whose position is arranged so that the radiation umbrella 288 overlaps all of the substrate 112 or a desired portion of the substrate 112 without extending beyond the substrate 112.

[0060] In different embodiments in which the optical system provides radiation to the substrate 112 in the form of a scanned narrow radiation beam, the scanned radiation beam may be provided in the plane of the substrate 112 (meaning in the XY plane) in the form of a spot beam or a ribbon beam as shown. Figure 7B An embodiment is shown in which a radiation beam 276 or a radiation beam 286 is provided in the form of a ribbon beam extending along the X-axis. The ribbon beam may have a length dimension comparable to the length of the substrate 112 along the X-axis, and thus may not be scanned along the X-axis but only along the Y-axis to produce a radiation umbrella 278 or a radiation umbrella 288. Figure 7C An embodiment is shown in which a radiation beam 276 or 286 is provided in the form of a spot beam having a relatively small size compared to the width of the substrate 112 along the X-axis and thus the radiation beam 276 or 286 can be scanned along both the X-axis and along the Y-axis to produce a radiation umbrella 278 or 288.

[0061] In additional embodiments, the electrostatic chuck system may include optics that combine a reflective mirror component with a refractive component to direct the radiation beam to the substrate.

[0062] Figure 8 A side view of yet another electrostatic clamping device according to various embodiments of the present disclosure is depicted. In this embodiment, an electrostatic clamping system 290 is depicted, which includes the substrate platform previously described. Unlike the previously described embodiments, the electrostatic clamping system 290 includes an illumination system 291, which includes multiple illumination sources. Figure 8 In the embodiment of FIG. 1 , two different illumination sources are included, shown as illumination source 204A and illumination source 204B, wherein each illumination source may be configured similarly to illumination source 204 described previously. However, in other embodiments, more than two illumination sources may be employed. Figure 8In the configuration of FIG. 2 , illumination system 291 includes an optical system 292 arranged to direct two radiation beams to substrate 112 using a mirror configuration of mirror system 292A and mirror system 292B to reflect radiation generated by illumination source 204A and illumination source 204B and are shown as radiation 294A and radiation 294B, respectively. In various variations, optical system 292 may be similar to Figure 3 , Figure 5 or Fig. 7A The above-described embodiments operate, for example, where a wide beam may be reflected to the substrate 112, a narrower beam may be reflected to the substrate, and slow or fast scanning of the radiation beam may be provided as described above. Figure 8 The advantage provided by the configuration is the ability to more uniformly illuminate the substrate 112 compared to using a single radiation beam. Figure 2 , Figure 4 as well as Figure 6 In the configuration of the embodiment of the present invention, multiple illumination sources may be coupled to corresponding multiple refractive optical systems to direct multiple radiation beams to the substrate 112, or multiple illumination sources may be coupled to a combination of at least one refractive optical system and at least one reflective mirror optical system. Such embodiments may be suitable for accommodating the optical system within a given processing apparatus, for example, where the configuration of other components including the substrate platform and the processing components may constrain the positions of the other components.

[0063] One disadvantage of directing illumination to the front surface of the substrate is that photocarriers tend to be generated near the front surface, while clamping occurs at the back surface of the substrate. For high mobility materials, generating photogenerated charge carriers near the front surface does not present a problem of clamping the substrate because the carriers can quickly traverse the substrate, but for low mobility materials (e.g., glass), it can take too long for the charge carriers to reach the back side of the wafer. In other embodiments of the present disclosure, the illumination system may be arranged to direct illumination to the back side of the substrate.

[0064] Fig. 9A side view of another electrostatic clamping device according to various embodiments of the present disclosure is depicted. In this embodiment, an electrostatic clamping system 300 is arranged with an illumination system 301, wherein at least a portion of the illumination system 301 is embedded within a substrate platform 302. In particular, the substrate platform 302 can be configured similarly to the aforementioned embodiment of the substrate platform 202, and can include an electrostatic clamp and a scanning assembly for scanning the substrate platform 302. The illumination system 301 can include a plurality of illumination sources distributed in an XY plane at a plurality of locations, illustrated as illumination source 304, illumination source 306, and illumination source 308. In general, the different illumination sources can be distributed across the substrate platform 302 in a one-dimensional array or a two-dimensional array, wherein the substrate platform includes an opening facing the substrate 112 to directly emit radiation without blocking the back side including the back surface 112B of the substrate 112. In other words, the gap between the substrate platform 302 and the substrate 112 can be used as a hollow light guide so that radiation, such as UV light, extends beyond the entry point.

[0065] Although Fig. 9 The embodiments shown herein illustrate a lighting system having multiple lighting sources, but in other embodiments, a single lighting source may be employed. Fig.10 A side view of another electrostatic clamping device according to various embodiments of the present disclosure is depicted. In this embodiment, the electrostatic clamping system 310 is arranged with an illumination system 311, wherein a portion of the illumination system 311 is embedded within the substrate platform 312 and a portion is located outside the substrate platform 312. In particular, the substrate platform 312 can be configured similarly to the aforementioned embodiment of the substrate platform 202, and can include an electrostatic clamp and a scanning component for scanning the substrate platform 312. The illumination system 311 includes an illumination source 314, which source can represent only one illumination source. The illumination source 314 is coupled to a plurality of light guides (light guides / optical guides) extending through the substrate platform 312 so that radiation can be provided directly to the back surface 112B of the substrate 112. In general, the different light guides can be distributed across the substrate platform 312 in a one-dimensional array or a two-dimensional array, wherein the substrate platform includes a plurality of openings 319 facing the substrate 112 to directly emit radiation without blocking the back surface 112B of the substrate 112. For simplicity, these light guides are shown as light guide 320, light guide 316, and light guide 318. As shown, the plurality of light guides are connected to the illumination source 314 on a distal end and have proximal ends extending through a plurality of openings 319, respectively.

[0066] therefore Fig. 9 and Fig.10 The above-described embodiments provide an efficient way of coupling higher energy radiation (eg, UV radiation) directly to a substrate and in a uniform manner.

[0067] Fig.11A side view of another electrostatic clamping device according to various embodiments of the present disclosure is depicted. In this embodiment, an electrostatic clamping system 350 includes a substrate platform 352 having an illumination system 351 embedded within the substrate platform 352. In particular, the substrate platform 352 may be configured similarly to the aforementioned embodiment of the substrate platform 202, and may include an electrostatic clamp and a scanning component for scanning the substrate platform 352. The illumination system 351 includes an illumination source 354 embedded in the substrate platform 352, and a set of coupling optical elements (shown as coupling optical elements 356) to receive radiation from the illumination source 354 and output radiation 358 in the direction of coupled radiation 358 to impinge on the back surface 112B of the substrate 112. As shown in FIG. Fig.11 As shown in FIG. 3 , the gap between the substrate platform 352 and the substrate 112 can act as a hollow light guide.

[0068] Although Figures 2 to 11 The above embodiments are described with respect to an electrostatic clamp, but in other embodiments, Figures 2 to 11 The lighting system can be implemented by a mechanical fixture.

[0069] Fig.12 A side view of yet another electrostatic chuck device according to various embodiments of the present disclosure is depicted. In this embodiment, the electrostatic chuck system 360 includes an illumination system 361 formed by an illumination source, disposed to direct radiation 366 toward the back side (see back surface 112B) of the substrate 112, and an electrode assembly 368 disposed within a substrate platform 362. In particular, the substrate platform 362 can be configured to include an electrostatic chuck and a scanning component for scanning the substrate platform 362. Unlike known electrostatic chucks, the substrate platform assembly including the electrostatic chuck assembly can be formed of a material that is transparent to the radiation 366. For example, the dielectric material used for the platform assembly and the electrostatic chuck (including a transparent plate body) and the cooling gas directed into the substrate platform 362 can be made of a material that is transparent to the UV light used to form the radiation 366.

[0070] like Fig.12 , the radiation 366 can form a wide radiation beam that covers a large portion of the substrate 112 or all of the substrate 112. In this embodiment, the electrostatic clamp portion (not separately shown) of the substrate platform 362 includes an electrode assembly 368 arranged as one or more electrodes in the form of a metal screen or metal mesh, wherein the metal mesh has a high light transmittance. In this way, the metal mesh can act as a uniform electrode system for electrostatic clamping while providing high light transmittance for UV radiation or other high energy radiation emitted by the illumination source 364.

[0071] In additional embodiments of the present disclosure, the Figures 1A to 12The electrostatic clamping system of those disclosed embodiments or variations thereof may be deployed in a substrate processing system to process a substrate. In some embodiments, an electrostatic clamping system is provided in a substrate processing chamber so that a substrate can be held while the substrate is being processed. Fig.13 A side view of one such processing system is depicted in accordance with various embodiments of the present disclosure. As shown, processing system 380 includes processing chamber 382, ​​which can house various components of an electrostatic clamping system, including substrate platform 385 and illumination system 391. In the configuration shown, illumination system 391 includes reflective optics for front-side illumination, while in other embodiments, the illumination system can be based on refractive optics for front-side illumination, or can be based on back-side illumination, wherein these various configurations have been described with respect to Figures 1A to 12 In this example, the illumination source 388 is disposed outside the substrate platform 385. In different embodiments, the illumination source 388 can be disposed within the processing chamber 382, ​​partially within the processing chamber 382, ​​or outside the processing chamber 382. Fig.13 In the example of , the illumination source 388 directs a light beam to the UV reflector 392, which reflects the light beam to direct radiation 396 to the substrate 112. The geometric configuration of the illumination source 388, the UV reflector 392, and the substrate 112 is arranged to ensure that the source UV light beam generated by the illumination source 388 expands normally to cover the substrate. Similar to some of the above-described embodiments, a reflector drive mechanism may be incorporated and arranged to move an optical reflector, such as the UV reflector 392, by rotation, translation, or rotation and translation. Fig.13 , the scanning motor 390 is mechanically coupled to the UV mirror 392 to scan the UV mirror 392 in a manner that follows the movement or scanning of the substrate 112, as discussed above. In some implementations, a control system 398 coupled to the UV mirror 392 and the substrate stage 394 is used to control the scanning of the UV mirror 392 and the substrate stage 394 so that the expanded light beam (radiation 396) follows the movement of the substrate in a manner that the radiation 396 is mostly or completely intercepted by the substrate 112. Thus, the control system 398 can generate scanning control and position sensing signals for controlling the substrate stage 394, as well as beam scanning control and position sensing signals for controlling the scanning motor 390 and the UV mirror 392.

[0072] The UV photons of radiation 396 are provided to generate sufficient mobile charge so that even substrates with high band gaps above 2.5 electron volts can be adequately clamped by an electrostatic clamp (not separately shown) within substrate platform 394 .

[0073] The processing system 380 also includes a beam generation assembly 384 that directs an ion beam 386 into the processing chamber 382. The ion beam 386 can implant ions into the substrate 112 while the substrate 112 is held in place by the action of an electrostatic chuck system including an illumination system 391 and an electrostatic chuck within a substrate stage 394. Unlike known ion implantation systems, the processing system 380 can conveniently implant into highly resistive or insulating substrates where the substrate remains electrostatically clamped to the substrate stage.

[0074] Although in Fig.13 In the embodiment shown in , the beam generation assembly 384 may represent a series of beamline components that deliver the ion beam to the substrate, but in other embodiments, the processing system of the aforementioned embodiments including the electrostatic clamping system can be used to process the substrate for any suitable process, including film deposition, etching, heating, etc.

[0075] In various embodiments of the present disclosure, the control system 398 or a similar control system may be used to enhance the ability of a UV illumination system or a high energy illumination system to assist in the electrostatic clamping of a high resistivity substrate. In particular, depending on the configuration of the processing chamber and the capabilities of the illumination source, it may be desirable to synchronize the illumination of the substrate with the scanning of the substrate and the electronic clamping of the substrate to improve the effectiveness of the radiation. As previously mentioned, when a scanning UV beam is used to illuminate the substrate, the control system 398 may synchronize the scanning of the UV beam with the scanning of the substrate stage. Fig.15 An exemplary control system arrangement 400 for electrostatic clamping is shown in accordance with some embodiments. In this example, a controller 398A is coupled to various components of the electrostatic clamping system. For simplicity, an illumination system 402 that directs radiation 404 to the front side of a substrate 112 is shown without any optical components. In particular, the illumination system 402 may include components for scanning the radiation 404 as described above. An electrostatic clamp 406 is disposed in a substrate stage 408 and includes an AC electrode system 410. A motor 412 is coupled to the substrate stage to scan the substrate stage 408. Additionally, an AC voltage source 414 is coupled to the AC electrode system 410 to supply a voltage signal including an AC voltage to an electrode of the AC electrode system 410. The controller 398A may be coupled to the illumination system 402, the motor 412, and the AC voltage source 414 to synchronize the actions of these components. For example, the controller 398A may be used to synchronize the timing of irradiating the substrate 112 with the electrical excitation of the substrate. In some embodiments, the controller 398A can be used to direct the AC voltage source 414 to provide a given voltage waveform whose amplitude, AC frequency, and rise time are arranged to ensure that sufficient photocarriers can be generated within the same half cycle of the AC voltage. The details of the given voltage waveform can be based on the available UV intensity generated by the lighting system 402.

[0076] In certain embodiments, the controller 398A may monitor the current chuck signal of the electrostatic chuck 406 to determine the charging state of the substrate 112. In some embodiments, the chuck current signal may also be used to sense the wafer type before initiating substrate chucking.

[0077] Examples

[0078] Illumination Source

[0079] According to some embodiments, the illumination system 106 or any other aforementioned illumination source may be a visible light source. These embodiments of visible light sources will be particularly suitable for use with low bandgap semiconductor substrates (e.g., silicon, II-V compound semiconductors, II-VI compound semiconductors), where the bandgap may be less than about 2.5 electron volts.

[0080] According to other embodiments, the illumination system 106 or any other of the aforementioned illumination sources may be a long wavelength UV source, producing radiation in the wavelength range of 120 nanometers to 240 nanometers, meaning an energy range of approximately 3 electron volts to 4 electron volts. These embodiments of UV radiation sources will be particularly suitable for use with wide bandgap semiconductor substrates such as silicon carbide (SiC).

[0081] According to other embodiments, the illumination system 106 or any other of the aforementioned illumination sources may be a VUV source, producing radiation in the wavelength range of 120 nanometers to 240 nanometers or less, meaning an energy range of approximately 5 electron volts to 10 electron volts or more. These embodiments of VUV radiation sources will be particularly suitable for use with insulator substrates such as glass.

[0082] In some examples, any of the above illumination sources may be multi-wavelength sources, where a wide range of wavelengths may be obtained from a single illumination source or from multiple different illumination sources. The same electrostatic chuck system may thus employ light sources with multiple wavelengths, where the shortest wavelength source is selected for substrates with the highest energy band gap, while sources with longer wavelengths and higher radiant flux may be selected for substrates that require less photon energy to bridge the band gap to achieve higher conductivity.

[0083] While in some instances lasers may be used to produce single wavelength radiation, in other instances incoherent light sources may be used to produce any radiation of a discrete wavelength spectrum (characterized as a continuous wavelength spectrum) where the power is centered around a small number of resonant spectral lines (frequencies).

[0084] In a specific example, filters can be used to further adjust the output wavelength spectrum from the illumination source. For example, for some substrate processing applications, a UV-sensitive adhesive is used to bond silicon wafers to a glass substrate. If a filter disposed between the illumination source and the substrate is used to filter out longer wavelengths that are transparent to glass from the radiation emitted by the illumination source, the shorter wavelength portion of the radiation can then be used to generate photocarriers within the glass without completely penetrating the glass and compromising the bond.

[0085] Non-limiting examples of suitable laser sources include diode lasers producing wavelengths down to 191 nanometers, other solid-state lasers, excimer lasers such as ArF, KrF, F2, continuous wave lasers, pulsed lasers, and the like.

[0086] Examples of suitable incoherent sources include deuterium lamps, electrodeless lamps, including line sources or continuous wavelength sources. Fig.19 Examples of deuterium lamp source output spectra are shown in Table 1, with some details omitted for clarity. The output of such sources may be suitable for generating charge carriers in insulators having a band gap greater than about 6 electron volts. Some examples of commercially available resonant line sources are shown in Table I. Source type and radiation wavelength are included. Some examples of commercially available continuous sources are shown in Table II.

[0087] (nanometer) hydrogen 121.6 krypton 116.5 123.6 xenon 129.6 147.0 mercury 184.9 253.7 iodine Several

[0088] Table I

[0089] (nanometer) Argon 110-140 krypton 127-160 xenon 150-190

[0090] Table II

[0091] In one example, a VUV argon continuous source is used as the illumination source to assist in electrostatically clamping a glass or fused silica substrate. Fused silica has a bandgap of approximately 8 electron volts, which requires a light source with a wavelength < 150 nanometers to generate photocarriers. Fig.18 The photocurrent generated by the glass substrate as a function of the photon energy is shown. As shown, no photocurrent is generated below 8 electron volts, which gradually rises until a photon energy of 9 electron volts is reached, above which the photocurrent increases rapidly, with saturation at a photocurrent of 10 electron volts or greater. A reference dashed line at 9.5 electron volts is shown. In one embodiment, an ArCM-LHP high power argon continuous source can be used to generate a photocurrent such as Fig.17The output spectrum shown in FIG. is an idealized output spectrum, omitting certain minor details, but showing the general characteristics of the argon emission spectrum. As shown, the peak wavelength varies between 116 nanometers and 140 nanometers, with most of the integrated intensity of the broad emission spectrum located below a wavelength of approximately 133 nanometers (indicated by the dashed line), equivalent to energies of 9.5 electron volts or greater. This energy range matches the energy range where photocurrent generation in glass is significant, such as Fig.18 Such sources are commercially available in relatively compact footprints for easy connection to a common processing chamber.

[0092] UV reflectors

[0093] In one example, aluminum mirrors with MgF2 coatings can be used as UV mirrors to produce high reflectivity in the UV and VUV ranges. Commercially available mirrors based on such materials can produce reflectivity greater than about 75% over a wavelength range of at least 300 nanometers down to 120 nanometers, providing efficient reflectivity of the initial UV beam. Such high reflectivity will facilitate beam expansion and manipulation using well-known methods for visible light mirror systems.

[0094] Electrostatic clamping using an argon arc lamp for AC clamping of glass substrates:

[0095] As mentioned, in the absence of photocarriers, such as generated according to the previous embodiments, when attempting to clamp an insulating substrate (dielectric substrate), the chuck electrodes of an electrostatic chuck (e-chuck) generate an electric field throughout the dielectric.

[0096] Using front side illumination as disclosed above, charge carriers are generated on top of the insulating substrate. Under the influence of the applied electric field, the carriers move towards the back surface of the substrate (see Figure 1C The result of this process is an enhancement of the electric field in the gap between the substrate and the e-clamp. Without generating charge carriers, the electric field in the gap is of the order of V / w, where V is the voltage difference between the electrodes and w is the spacing between the electrodes. If the surface charge layer is as Figure 1C , then the electric field in the gap is on the order of about V / d, where d is the gap between the substrate and the electrode and the dielectric thickness of the dielectric material. This thickness is typically much smaller than the electrode spacing. An electric field enhancement of 10X to 100X can be easily achieved, corresponding to a 100X to 10,000X enhancement in clamping force. Therefore, a useful goal is to generate a high enough surface charge density in a short enough time to achieve the potential benefits of increased clamping force. For example, for effective AC clamping, the time for charge accumulation needs to be much shorter than the period of the applied AC voltage.

[0097] In the following calculations, it is assumed that the known ArCM-LHP lamp is used as the one producing Fig.18 The radiation spectrum shown is for an illumination source where the lamp can deliver photons with energies above the SiO2 band gap of about 8 eV 6×10 16 photons / second / steradian, and the output angle is 2θ=45 ° , corresponding to the solid angle The calculations can be adjusted quantitatively for different output angles and photon fluxes, as will be appreciated by those skilled in the art. UV reflectors can also be used which introduce reflection losses into the beam output by the lamp. Furthermore, it can be assumed that the expanded beam area is slightly larger than the substrate area, which also reduces the utilization of the beam flux. It will be assumed that the reflector losses and the off-substrate beam losses together result in a 50% loss of the usable beam flux. This assumption indicates that 1.45×10 16 Photon flux of photons / second or Φ = 2 × 10 for a 300 mm wafer 13 photons / second / square centimeter. The transport of photocarriers in silicon dioxide has been extensively studied previously, both experimentally and numerically. Photoconduction is a complex process. The conduction current is affected by light absorption, quantum yield, lifetime of mobile carriers (which depends on recombination and capture rates and can be very different for electrons and holes), electron and hole mobilities (which can differ by many orders of magnitude), space charge accumulation in the insulator, and charge transfer across the interface between the substrate and the e-clamp. Therefore, estimating the current based on basic material properties is not appropriately reliable, and instead the current calculations herein are based on experimentally measured photocurrents. In one specific example, the e-clamp was designed so that an electric field strength of 5 kilovolts / mm was achieved in a glass substrate. Results from known studies indicate that at 5×10 11 photons / second / cm2 will produce 7.6×10 -9 The conduction current density is amperes per square centimeter. In this example, a higher lamp intensity (2×10 13 photons / second / square centimeter), the current density is estimated to be J = 3×10 -7 Amperes per square centimeter. Under experimental conditions with a target clamping pressure of 50 Torr, the charge density required to produce this clamping force is given by:

[0098]

[0099] Therefore, the characteristic charging time in this example is given by:

[0100]

[0101] This time is fast enough for low frequency AC excitation, for example, by 1 to 2 Hz frequency or 500 ms to 1 second period. It should be noted that this estimate of the characteristic charging time is an order of magnitude estimate of the response time using a realistic e-clamp electronic design and a commercially available VUV source. The estimate shows the feasibility of achieving practical AC clamping using the above method for insulating glass wafers. In other examples, the charging time can be shortened to less than 0.1 seconds by increasing the VUV intensity using multiple light sources and optimizing the e-clamp electronic design and increasing the electric field.

[0102] Clamping high resistivity silicon wafers and SiC wafers

[0103] As mentioned, commercially available HBR silicon wafers can exhibit resistivities in the 100 kiloohm-cm range and are available. For SiC substrates, 10 9 Ohm-cm resistivity. However, a practical system for generating photocarriers in a common HBR semiconductor substrate may employ a UV light source that outputs a primary energy at a slightly longer wavelength (>250 nm) than a SiO2 substrate because the band gaps in silicon and SiC are much smaller than that of SiO2. In addition, crystalline semiconductors such as silicon and SiC have high electron and hole mobilities and fewer defects to produce trapping compared to glass, and the structure also helps to reduce the transmission time of photocarriers under an electric field. Therefore, given the above experimentally based results indicating a charging time of about 0.1 seconds for SiO2, charging times significantly less than this time can be achieved for HBR silicon substrates and HBR SiC substrates using the exemplary illumination source and fixture arrangements disclosed herein.

[0104] While the foregoing embodiments focus on clamping enhancement of high resistivity substrates using high energy illumination, according to additional embodiments, de-clamping may also be enhanced. In other words, when a semiconducting substrate or an insulating substrate is being clamped using an electrostatic clamp, the clamping voltage may be removed in the case of a substrate to be de-clamped. To enhance de-clamping of a substrate, photocarriers may be generated by exposure to an illumination source according to the embodiments disclosed above. In this way, the decay rate of a previously generated electric field and the removal of certain charges, such as neutralization of residual static charges, may be accelerated. This enhancement may be applied to "conventional" semiconducting substrates with relatively low bandgaps (e.g., in the visible range) as well as HBR semiconductor substrates and insulator substrates.

[0105] Fig. 20An exemplary process flow 500 is shown. At box 502, a substrate is disposed on an electrostatic clamp assembly. In some embodiments, the substrate can be a HBR semiconductor substrate or an insulating substrate. At box 504, a clamping voltage (e.g., a DC voltage or an AC voltage) is applied to the electrostatic clamp assembly. At box 506, radiation is directed to the substrate while the substrate is disposed on the electrostatic clamp assembly. The radiation can be characterized by an energy greater than a band gap of the HBR semiconductor substrate or the insulating substrate. The radiation can be directed to the front surface of the substrate or the back surface of the substrate. Thus, the radiation can have sufficient energy and sufficient intensity to generate charge carriers within the substrate, which charge carriers generate a target clamping force when the clamping voltage is applied.

[0106] Fig.21 Another process flow 550 is shown according to an additional embodiment. At box 552, a high bandgap substrate is disposed on an electrostatic clamp assembly. At box 554, high energy radiation is directed to the substrate while the substrate is disposed on the electrostatic clamp assembly. The high energy radiation may have an energy above the bandgap of the substrate, wherein the energy may be sufficiently above the bandgap to generate charge carriers in the substrate. Non-limiting examples of high energy radiation include UV radiation or VUV radiation. At box 556, an AC clamping voltage waveform is applied to the electrostatic clamp assembly, characterized by an amplitude, a frequency, and a rise time. Thus, the AC clamping voltage waveform in combination with the high energy radiation may be configured to generate sufficient photocarriers to generate a target clamping pressure during a half period of the AC clamping voltage waveform.

[0107] Fig. 22 Another exemplary process flow 600 is shown. At block 602, a high bandgap substrate is disposed on an electrostatic chuck assembly. At block 604, a chuck current signal is detected to determine a substrate type of the high bandgap substrate. At block 606, high energy radiation is directed to the substrate while the substrate is disposed on the electrostatic chuck assembly. At block 608, an AC clamping voltage waveform is applied to the electrostatic chuck assembly from an AC power source. Thus, the AC clamping voltage waveform may be characterized by a narrow high voltage pulse portion and a longer duration low voltage portion, wherein a maximum charge transferred by the high voltage pulse portion is limited below a predetermined threshold.

[0108] Fig.23 Another exemplary process flow 650 is shown. At box 652, a substrate is clamped to a substrate platform by an electrostatic clamp assembly. The substrate can be a silicon substrate, a silicon carbide substrate, a glass substrate, or other substrate. The substrate can be a low bandgap substrate or a high bandgap substrate. At box 654, the substrate is processed while it is on the substrate platform. The processing can be any suitable process. At box 656, high energy radiation is directed to the substrate at the end of the processing to remove static charge. The high energy radiation can be an energy above the bandgap of the substrate. The high energy substrate can be applied when removing the clamping voltage generated by the electrostatic clamp assembly.

[0109] Fig.24 Another exemplary process flow 700 is shown. At box 702, a substrate is clamped to a substrate stage using an electrostatic clamp in combination with high energy radiation. The high energy radiation may have an energy above the band gap of the substrate, and an intensity sufficient to produce charge carrier movement in the substrate sufficient to produce a target clamping pressure. At box 704, the substrate is scanned while the substrate stage is used during a processing interval. At box 706, the scanning from substrate to substrate is synchronized with the scanning of the radiation beam. In some variations, the radiation beam may be a wide beam that covers most of the substrate, wherein the scanning of the radiation beam involves scanning the wide beam at the same rate as the scanning of the substrate to ensure that the radiation beam is mostly or completely intercepted by the substrate. In some variations, the radiation beam may be a narrow beam that covers a narrow portion of the substrate, wherein the scanning of the radiation beam involves quickly scanning the narrow beam back and forth to cover a target portion of the substrate producing a beam umbrella or envelope, while superimposing a slower scanning rate at the same rate as the scanning of the substrate to ensure that the beam envelope is mostly or completely intercepted by the substrate as the substrate moves.

[0110] While the foregoing embodiments focus on applications involving substrate clamping, in other embodiments, devices and techniques for reducing charging of substrates in various processing environments may be applied. In various processing devices, including plasma devices, ion beam devices, and other devices, charged particles, including ions (ionic species) or electrons, may serve as processing species to process substrates, where charging may occur in the substrate during processing. This situation is particularly acute for new types of substrates, such as SiC, silicon-on-insulator (SOI) substrates, and glass, where such substrates may generate charges during processing that are not removed due to the low mobility of charge carriers in such substrates.

[0111] According to an embodiment of the present disclosure, a lighting system (eg, relative to Figures 1A to 13 and Fig.15 The disclosed illumination system may be disposed in a processing apparatus to facilitate charge removal during substrate processing. Fig.25 An embodiment of a processing system 800 for processing a substrate 112 is depicted. According to various non-limiting embodiments, the processing system 800 may include a source 806 for directing a processing substance (e.g., an ion beam, an electron beam, or a plasma) to the substrate 112. For purposes of illustration only, Fig.25807 is shown directed to a substrate 112. The substrate 112 may be supported by a substrate holder 810. In a general embodiment, the substrate is scanned along a direction 808 to expose the entirety of a front surface 112A of the substrate 112, for example when the processing beam 807 does not cover the entirety of the substrate 112. An illumination system 106 may be provided to direct illumination to a major surface of the substrate 112, generally as described above. According to some embodiments, the substrate 112 may be an electrical insulator, a high bandgap semiconductor, or other substrate with a relatively low charge mobility. During processing by the processing beam 807, the substrate 112 may tend to accumulate charge, for example, on the front surface 112A. The illumination system 106 may be enabled to direct radiation 120 to the substrate 112 to reduce or eliminate charge accumulation on the substrate 112, and thus improve substrate processing.

[0112] In some embodiments, the following procedure may be followed. A substrate 112 is disposed in a processing chamber 802. While the substrate is disposed in the processing chamber 802, radiation 120 is directed from the illumination system 106 to the substrate 112. While the substrate is disposed in the processing chamber 802, the substrate 112 is processed, and a processing substance is provided to the substrate 112 within a processing beam 807, separate from the radiation 120 provided by the illumination system 106. According to a particular embodiment, at least a portion of the radiation 120 has a radiation energy equal to or greater than 2.5 electron volts to produce an energy above the band gap of a given substrate. Although the radiation 120 and the processing beam 807 are directed to the substrate simultaneously with each other, the duration of the radiation 120 and the processing beam 807 need not be the same, and the radiation 120 may be initiated before or after the initiation of the processing beam 807, and may end before or after the end of the processing beam 807.

[0113] The present embodiments provide at least the following advantages. For one advantage, a practical method has been created to achieve electrostatic clamping of high resistivity substrates where known electrostatic clamps are not suitable. For another advantage, in a configuration where the illumination source is mounted on a substrate platform, illumination of the substrate is not affected by movement of the substrate (e.g., substrate scanning). For another advantage, application of novel voltage waveforms can further enhance the electrostatic clamping process. For another advantage, using illumination to enhance electrostatic clamping can also be used to enhance unclamping. Additionally, as another advantage, the illumination can be used to increase and control substrate temperature.

[0114] The scope of the present disclosure is not limited by the specific embodiments described herein. In fact, those skilled in the art will understand other embodiments of the present disclosure and modifications to the present disclosure (except those embodiments and modifications described herein) according to the above description and the accompanying drawings. Therefore, such other embodiments and modifications are expected to belong to the scope of the present disclosure. In addition, although the present disclosure has been described in the context of a specific embodiment under a specific environment for a specific purpose, those skilled in the art will recognize that the practicality of the present disclosure is not limited thereto, and for any number of purposes, the present disclosure can be advantageously implemented in any number of environments. Therefore, the claims set forth below should be interpreted in view of the entire breadth and spirit of the present disclosure as described herein.

Claims

1. A clamping device, comprising: a chuck for holding a substrate, wherein the chuck is arranged opposite to a back side of the substrate, the chuck comprises an electrostatic chuck assembly, and the electrostatic chuck assembly comprises an electrostatic chuck and an electrode assembly; as well as an illumination system configured to direct radiation toward the substrate when the substrate is disposed on the fixture, wherein the radiation includes radiation energy that is equal to or greater than a threshold energy to generate mobile charges in the substrate, the illumination system being arranged to direct the radiation onto the back side of the substrate, Wherein upon application of a clamping voltage, the illumination system generates radiation and when the substrate is clamped by the electrostatic clamp assembly, charge present within the substrate moves to electrodes of the electrode assembly, generating an electric field with opposite polarity and producing a clamping force.

2. The clamping device of claim 1, wherein the electrostatic clamp comprises a plurality of openings, and wherein the illumination system comprises a plurality of radiation sources arranged to direct the radiation through the plurality of openings of the electrostatic clamp.

3. The clamping device of claim 1 , wherein the electrostatic clamp comprises a plurality of openings, the device further comprising: A plurality of light guides are connected at distal ends to an illumination source and respectively have proximal ends extending through the plurality of openings.

4. The clamping device of claim 1 , wherein the illumination system is at least partially embedded in the electrostatic clamp, the illumination system further comprising coupling optics embedded in the electrostatic clamp and arranged to receive the radiation from an illumination source and direct the radiation to the back side of the substrate.

5. The clamping device of claim 4, wherein the electrostatic clamp defines a gap between the electrostatic clamp and a substrate location, wherein the gap defines a light guide for the radiation.

6. The clamping device according to claim 1, wherein the electrostatic clamp comprises: a transparent plate body, wherein the transparent plate body is transparent to the radiation; as well as The electrode is arranged as a metal mesh, wherein the light transmittance of the metal mesh is higher than 50%.

7. The clamping device of claim 6, wherein the radiation comprises a broad beam covering the web.

8. A substrate processing system comprising: a processing chamber; an electrostatic chuck disposed in the processing chamber, the electrostatic chuck being used to chuck a substrate, wherein the electrostatic chuck is arranged opposite to a back side of the substrate, the electrostatic chuck comprising an electrode; and an illumination system configured to direct radiation to the back side of the substrate when the substrate is disposed on the electrostatic chuck, wherein the radiation comprises radiation energy equal to or greater than 2.5 electron volts, Wherein the illumination system generates radiation when a clamping voltage is applied, and when the substrate is clamped by the electrostatic clamp, charges present in the substrate move to the electrodes, generating an electric field with opposite polarity and producing a clamping force.

9. The substrate processing system of claim 8, wherein the electrostatic chuck comprises a plurality of openings, and wherein the illumination system comprises a plurality of radiation sources arranged to direct the radiation through the plurality of openings of the electrostatic chuck.

10. The substrate processing system of claim 8, wherein the electrostatic chuck comprises a plurality of openings, the substrate processing system further comprising: A plurality of light guides are connected at distal ends to an illumination source and respectively have proximal ends extending through the plurality of openings.

11. The substrate processing system of claim 8, wherein the illumination system is at least partially embedded in the electrostatic chuck, the illumination system further comprising coupling optics embedded in the electrostatic chuck and arranged to receive the radiation from an illumination source and direct the radiation to the back side of the substrate.

12. The substrate processing system of claim 11, wherein the electrostatic chuck defines a gap between the electrostatic chuck and a substrate location, wherein the gap defines a light guide for the radiation.

13. The substrate processing system of claim 8, wherein the electrostatic chuck comprises: a body that is transparent to the radiation; as well as The electrode is arranged as a metal mesh, wherein the light transmittance of the metal mesh is higher than 50%.

14. The substrate processing system of claim 13, wherein the radiation comprises a broad beam covering the web.

15. The substrate processing system of claim 8, further comprising an AC power source for applying an AC clamping voltage waveform to the electrostatic chuck, wherein the AC clamping voltage waveform comprises a short high voltage pulse portion and a long low voltage portion.

16. An ion implantation system comprising: a set of beamline components for generating an ion beam and directing the ion beam to a substrate; a chuck for holding the substrate, wherein the chuck is arranged opposite to the back side of the substrate, the chuck is an electrostatic chuck, and the electrostatic chuck includes an electrode; and an illumination system configured to direct radiation to the back side of the substrate when the substrate is disposed on the fixture, wherein the radiation comprises radiation energy, the radiation energy being equal to 2.5 electron volts, Wherein the illumination system generates radiation when a clamping voltage is applied, and when the substrate is clamped by the electrostatic clamp, charges present in the substrate move to the electrodes, generating an electric field with opposite polarity and producing a clamping force.

17. The ion implantation system of claim 16, wherein the electrostatic chuck comprises a plurality of openings, and wherein the illumination system comprises a plurality of radiation sources arranged to direct the radiation through the plurality of openings of the electrostatic chuck.

18. The ion implantation system of claim 16, wherein the illumination system is at least partially embedded in the electrostatic chuck, the illumination system further comprising coupling optics embedded in the electrostatic chuck and arranged to receive the radiation from the illumination source and direct the radiation to the back side of the substrate.

19. The ion implantation system of claim 16, wherein the electrostatic chuck comprises: a body that is transparent to the radiation; as well as The electrode is arranged as a metal mesh, wherein the light transmittance of the metal mesh is higher than 50%.

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