TWI424524B - Apparatus and method for substrate clamping in a plasma chamber - Google Patents

Description

Apparatus and method for substrate clamping in a plasma chamber

Embodiments of the present invention generally relate to an apparatus and method for processing a semiconductor substrate. More particularly, embodiments of the invention relate to an electrostatic chuck for use in a plasma chamber.

Plasma enhanced processes, such as plasma enhanced chemical vapor deposition (PECVD) processes, high density plasma chemical vapor deposition (HDPCVD) processes, plasma immersion ion implantation (P3I) processes, and plasma Etching processes have become important in semiconductor processing.

Plasma provides many advantages for the fabrication of semiconductor components. For example, the use of plasma can have a wide range of applications due to low processing temperatures, and plasma enhanced deposition has good interstitial capacity and high deposition rates for high aspect ratio gaps.

One problem that occurs during plasma processing is the deformation of the substrate being processed (especially a component substrate, i.e., a patterned substrate). The semiconductor element is formed by stacking a material layer of a specific pattern on the semiconductor substrate. The patterned substrate may "bow" during processing during the process due to differences in thermal expansion between layers having different materials, especially when the substrate is being heated. Bending of the substrate can result in non-uniformity of the process surface. The sides and back of the curved substrate are treated such that not only waste of processing material (usually very expensive for plasma processing) but also contamination and other problems for subsequent processing steps.

Figure 1 (Prior Art) shows the bending condition of one of the substrates during the plasma process. The plasma reactor 10 includes an electrode 12 that is coupled to a radio frequency (RF) power source 17 via an impedance matching circuit 16. A ground electrode 11 is constructed to support the substrate 13 thereon. The electrode 12 and the ground electrode 11 form a capacitive plasma generator. When appropriate RF power is applied to the electrode 12, a plasma 15 can be generated from any precursor gas supplied between the electrode 12 and the ground electrode 11 to process the substrate 13. The substrate 13 can be heated by a heater 18 embedded in the ground electrode 11. The plasma 15 also heats the substrate 13 during the process. The plasma treatment temperature can be between about 250 ° C and about 450 ° C. As the temperature rises, the substrate 13 bends. In some cases, the edge of a 300 mm substrate can bend up to 0.4 mm. A curved substrate is sometimes referred to as a substrate having a high curvature.

The bending of the substrate presents a challenge to process uniformity on the component side 14 of the substrate 13, which becomes more critical as the feature size shrinks. An external device, such as an electrostatic or vacuum clamp, is used to keep the substrate flat during processing. However, the clamped substrate will still be deformed by the heat emitted by the plasma during the plasma process.

Accordingly, there is a need for an apparatus and method for holding a substrate while maintaining planarity of the substrate during the plasma process.

The present invention generally provides methods and apparatus for monitoring and maintaining the flatness of a substrate in a plasma reactor.

A specific embodiment of the present invention provides a method for processing a substrate, the method comprising: positioning the substrate on an electrostatic chuck; applying an RF power between an electrode of the electrostatic chuck and a counter electrode Wherein the counter electrode is disposed parallel to the electrostatic chuck; applying a DC bias to the electrode in the electrostatic chuck to clamp the substrate on the electrostatic chuck; and measuring a virtual impedance of the electrostatic chuck.

A particular embodiment of the present invention provides a method for monitoring a substrate during a plasma process, the method comprising: positioning the substrate in a plasma generator having one of first and second parallel electrodes, wherein a substrate positioned between the first and second parallel electrodes and substantially parallel to the first and second parallel electrodes; applying an RF power between the first and second parallel electrodes of the plasma generator; And monitoring the substrate by measuring the characteristics of one of the plasma generators.

A specific embodiment of the present invention provides an apparatus for processing a substrate, comprising: an electrostatic chuck comprising a first electrode, the first electrode being coupled to a DC power supply, wherein the electrostatic chuck has a a support surface for supporting the substrate thereon; a reverse electrode disposed substantially parallel to the support surface of the electrostatic chuck, wherein the reverse electrode is spaced apart from the electrostatic chuck by a distance at which the substrate is positioned Between the fixture and the counter electrode; an RF power supply for applying an RF power between the first electrode and the counter electrode; and a sensor for measuring one of the electrostatic chucks characteristic.

The present invention generally provides a method and apparatus for monitoring and maintaining sufficient flatness of a substrate being processed in a plasma reactor, wherein the plasma reactor has a plasma generator with parallel electrodes.

Figure 2 is a cross-sectional view of a PECVD system 100 in accordance with the present invention. A similar PECVD system is described in U.S. Patent Nos. 5,855,681, 6, 495, 233, and 6,364,954.

The PECVD system 100 generally includes a chamber body 102 that supports a chamber cover 104 that can be attached to the chamber body 102 by a pivot. The chamber body 102 includes a sidewall 112 and a bottom wall 116 that define a processing region 120. The chamber cover 104 includes one or more gas distribution systems 108 therethrough to deliver reactants and cleaning gases into the processing region 120. A peripheral ram suction channel 125 is formed in the sidewall 112 and is coupled to a cartridge suction system 164 for venting gas from the processing zone 120 and controlling the pressure within the processing zone 120. Two channels 122, 124 are formed in the bottom wall 116. One of the rods 126 of the electrostatic chuck passes through the passage 122. A rod 130 passes through the passage 124 for actuating the substrate lifting tip 161.

A chamber liner 127 (preferably made of ceramic or the like) is disposed in the processing region 120 to protect the sidewalls 112 from corrosive processing environments. The chamber liner 127 is supported by a projection 129 formed therein in the sidewall 112. A plurality of discharge ports 131 are formed in the chamber liner 127. The plurality of discharge ports 131 are configured to connect the processing region 120 to the cartridge suction channel 125.

The gas distribution system 108 is configured to deliver reactants and cleaning gases and is disposed through the chamber cover 104 to deliver gas into the processing region 120. The gas distribution system 108 includes a gas inlet passage 140 that delivers gas into a showerhead assembly 142. The sprinkler head assembly 142 is comprised of an annular base plate 148 having a baffle 144 positioned between the annular base plate 148 and a panel 146.

A cooling channel 147 is formed in the base plate 148 of the gas distribution system 108 to cool the base plate 148 during operation. A cooling inlet 148 delivers a coolant fluid (e.g., water or the like) into the cooling channel 147. The coolant fluid exits the cooling channel 147 via a coolant outlet 149.

The chamber cover 104 has a plurality of mating passages for delivering gas from one or more gas inlets 168, 163, 169 to a gas inlet manifold 167 via a remote plasma source 162, wherein the gas inlet manifold 167 is disposed On top of the chamber cover 104. The PECVD system 100 can include one or more liquid delivery sources 150 and one or more gas delivery sources 172 for providing carrier gas and/or precursor gases.

The electrostatic chuck 128 is used to support and hold the substrate being processed. In one embodiment, the electrostatic chuck 128 includes at least one electrode 123, wherein a voltage is applied to the electrode 123 to electrostatically secure the upper substrate thereof. Electrode 123 is powered by a direct current (DC) power supply 176 that is coupled to electrode 123 via a low pass filter 177.

Although a unipolar DC clamp is described and discussed below, any type of electrode structure and drive voltage combination that allows measurement of electrostatic clamp impedance can be used to operate the present invention. The electrostatic chuck 128 can be bipolar, tripolar, DC, interdigitated, zonal, and the like.

In an embodiment, the electrostatic chuck 128 is movably disposed in the processing region 120 and is driven by a drive system 103 coupled to the stem 126. The electrostatic chuck 128 can include a plurality of heating members (eg, resistive members) to heat the upper substrate thereto to a desired process temperature. Alternatively, the electrostatic chuck 128 can be heated by an external heating member, such as a light assembly. The drive system 103 can include a plurality of linear actuators, or a motor and a reduction gearing assembly to lower or raise the electrostatic chuck 128 within the processing region 120.

An RF source 165 is coupled to the showerhead assembly 142 via an impedance matching circuit 173. The face plate 146 of the showerhead assembly 142 and the electrode 123 (which may be grounded via a high pass filter, such as capacitor 178, ground) form a capacitive plasma generator. RF source 165 provides RF energy to sprinkler head assembly 142 to facilitate the generation of capacitive plasma between panel 146 of sprinkler head assembly 142 and electrostatic chuck 128. Thus, electrode 123 provides a ground path for RF source 165 and an electrical bias from DC source 176 to enable electrostatic clamping of the substrate.

The RF source 165 can include a high frequency radio frequency (HFRF) power source (eg, a 13.56 MHz RF generator) and a low frequency radio frequency (LFRF) power source (eg, a 300 kHz RF generator). . The LFRF power source provides low frequency generation as well as fixed matching components. The HFRF power source is designed to be used with a fixed match and to control the power delivered to the load, removing concerns about feed forward and reflected power.

In a particular embodiment, the properties of the substrate that is secured to the electrostatic chuck 128 can be monitored during the plasma process. In a particular embodiment, the flatness of the substrate that is secured to the electrostatic chuck 128 can be monitored during the plasma process. In one embodiment, the flatness of the substrate secured to the electrostatic chuck 128 can be monitored by measuring the characteristics of the electrostatic chuck 128 having the substrate secured thereto. In one embodiment, the impedance of the electrostatic chuck 128 can be measured to monitor the flatness of the substrate to which it is attached.

In one embodiment, the impedance of the electrostatic chuck 128 is measured by a sensor 174 that is coupled to the panel 146. In an embodiment, the sensor 174 can be a VI probe that is coupled between the panel 146 and the impedance matching circuit 173. The sensor 174 is configured to measure the impedance of the electrostatic chuck 128 by measuring the voltage and current of the capacitor formed by the panel 146 and the electrode 123.

It has been observed that the capacitance between the panel 146 and the electrode 123 is achieved by the flatness of the substrate 121 between the panel 146 and the electrode 123. An electrostatic chuck (e.g., electrostatic chuck 128) has an increased capacitance when the substrate disposed thereon becomes less flat. When the substrate is not flat (for example, due to heat of the plasma), the air gap between the substrate and the electrostatic chuck 128 is non-uniformly distributed. Therefore, variations in the flatness of the substrate in the electrostatic chuck cause a change in the capacitance of the plasma reactor, which can be measured by fluctuations in the imaginary impedance of the electrostatic chuck.

During the plasma process, the substrate disposed on the electrostatic chuck may increase in curvature due to heating, increased thickness of the deposited film, loss of clamping power, or a combination thereof. Deformation of the substrate increases the non-uniformity of the process. In one embodiment, the flatness of the substrate being processed can be monitored by measuring the virtual impedance of the electrostatic chuck holding the substrate. In an embodiment, the clamping voltage of the electrostatic chuck can be adjusted to correct substrate deformation.

As shown in FIG. 2, the sensor 174 can be coupled to a system controller 175. The system controller 175 is used to calculate and adjust the flatness of the substrate 121 being processed in the PECVD system 100. In an embodiment, the system controller 175 can calculate the flatness or clamping state of the substrate 121 by monitoring the virtual impedance of the electrostatic chuck 128. When the measured value of the virtual impedance indicates that the flatness of the substrate 121 is reduced, the system controller 175 increases the clamping power by adjusting the DC source 176. In an embodiment, the reduced flatness of the substrate 121 may be displayed by a virtual impedance that is increased in the negative direction of the electrostatic chuck 128.

3 is a side elevational view of a plasma processing chamber 200 having a substrate support 210 in accordance with an embodiment of the present invention.

The plasma processing chamber 200 includes a plurality of side walls 202, a bottom 203, and a cover 204 to define an interior volume 220. The internal volume 220 is in fluid communication with a vacuum system 264. A substrate support 210 for supporting the substrate 221 and a panel 246 or a showerhead for supplying a process gas are disposed in the internal volume 220.

An RF source 265 is coupled to panel 246 via an impedance matching circuit 273. Panel 246 and electrode 223 (which may be connected via a high pass filter, such as a capacitor, ground) to form a capacitive plasma generator. RF source 265 provides RF energy to panel 246 to facilitate the generation of capacitive plasma between panel 246 and substrate support 210.

The RF source 265 can include a high frequency radio frequency (HFRF) power source (eg, a 13.56 MHz RF generator) and a low frequency radio frequency (LFRF) power source (eg, a 300 kHz RF generator). The LFRF power source provides low frequency generation as well as fixed matching components. The HFRF power source is designed to be used with a fixed match and to control the power delivered to the load, removing concerns about feed forward and reflected power.

In this embodiment, the substrate support 210 is an electrostatic chuck that provides support during handling and holds the substrate 220, and in one embodiment, the electrostatic chuck is a unipolar electrostatic chuck. The substrate support 210 includes a body 228 coupled to a support rod 226. Body 228 may comprise a ceramic material such as alumina (Al ₂ O ₃ ), aluminum nitride (AlN), cerium oxide (SiO ₂ ), or other ceramic materials. In one embodiment, the body 228 of the substrate support 210 is used at a temperature ranging from about -20 °C to about 700 °C.

The body 228 can also be disposed in a dielectric layer 222 or coated with a dielectric layer 222. The body 228 also includes an in-line electrode 288, which may be a resistive heater, a cartridge heater, or the like to provide heat to the body 228. Heat from heater 288 is then transferred to substrate 221 to facilitate the fabrication process (e.g., deposition process). Heater 288 is coupled via rod 226 to a power source 283 to supply power to heater 288. The heater 288 can be a mesh or a perforated sheet of molybdenum (Mo), tungsten (W), or other material having a coefficient of expansion substantially similar to that of the ceramic material constituting the body 228. production. A temperature sensor 285 is embedded in the body 228. In an embodiment, temperature sensor 285 can be a thermocouple. Temperature sensor 285 can be coupled to a temperature controller 284 that provides control signals to power source 283 to control the temperature of body 228.

The body 228 of the substrate support 210 further includes an electrode 223 that provides a ground path for at least radio frequency (RF) power. Some commercially available substrate supports have a biasing electrode (not shown) that is embedded or disposed within the body of the substrate support. The biasing electrode is used to provide an electrical bias to the substrate to facilitate or enhance electrostatic clamping of the substrate. As will be explained in more detail below, the bias electrode is replaced by an electrode 223 which provides a ground path for RF power and provides an electrical bias to the substrate 221 to electrostatically clamp the substrate.

Although the heater 288 is shown below the electrode 223, the electrode can be placed along the same plane as the heater 288 or below the heater 288. The electrode 223 may be a mesh or a perforated sheet made of a material of molybdenum (Mo), tungsten (W), or other material having a coefficient of expansion substantially similar to that of the ceramic material constituting the body 228. to make.

Electrode 223 is coupled to a conductive element 286. Conductive element 286 can be a rod, tube, wire, or the like, and can be made of molybdenum (Mo), tungsten (W), or other material that has a coefficient of expansion that is substantially similar to other materials that make up substrate support 210. Made of materials. Similar to electrode 123 of Figure 2, electrode 223 provides a ground path for RF source 265 and an electrical bias to electrostatically clamp the substrate. In order to provide an electrical bias to the substrate 221, the electrode 223 is electrically coupled to a power supply system 280, wherein the power supply system 280 provides a bias to the electrode 223. The DC power supply 280 includes a power source 276 that can be a direct current (DC) power source to supply DC signals to the electrodes 223. In one embodiment, power source 276 is a 24 volt DC power source and the electrical signal can provide a positive or negative bias.

Power source 276 can be coupled to an amplifier 279 to amplify electrical signals from power source 276. The amplified electrical signal travels through a connector 282 to the conductive element 286 and can travel through a filter 277 to filter the amplified signal to remove noise from the power supply system 280 and/or Any RF stream. An amplified and filtered electrical signal is provided to the electrode 223 and the substrate 221 to electrostatically clamp the substrate 221.

Electrode 223 also acts as an RF grounding member in which RF power is coupled to the grounding member by a connector 281. A capacitor 278 is also connected to the ground path to avoid biasing to the ground. In one embodiment, the capacitance 278 can be 0.054 microfarads (μF), 10-15 amps at about 2000 volts. In this manner, the electrode 223 is used as a substrate bias electrode and an RF return electrode.

In an embodiment, the chamber impedance is evaluated and monitored to monitor the positive clamping of the substrate to substrate support 210. Impedance can be used Z-SCAN ^TM tradename probe, the current / voltage probe, or the like by the RF detecting method for monitoring, such as monitoring an RF matching. In one embodiment, the impedance of the chamber is measured by a sensor 274 that is coupled to the panel 246. In an embodiment, the sensor 274 can be a VI probe that is coupled between the panel 146 and the impedance matching circuit 273. The sensor 274 can be configured to measure the impedance of the electrostatic chuck 210 by measuring the voltage and current of the capacitance formed by the panel 246 and the electrode 223.

It has been observed that the capacitance between the panel 246 and the electrode 223 is achieved by the flatness of the substrate 221 between the panel 246 and the electrode 223. An electrostatic chuck (e.g., substrate support 210) has an increased capacitance when the substrate disposed thereon becomes less flat. When the substrate is not flat (for example, due to heat of the plasma), the air gap between the substrate and the substrate support 210 is non-uniformly distributed. Therefore, variations in the flatness of the substrate in the electrostatic chuck cause a change in the capacitance of the plasma reactor, which can be measured by the virtual impedance variation of the electrostatic chuck.

Sensor 274 can be coupled to a system controller 275. The system controller 275 is used to calculate and adjust the flatness of the substrate 221 being processed in the plasma processing chamber 200. In an embodiment, system controller 275 can calculate the flatness or clamping state of substrate 221 by monitoring the virtual impedance. When the measured value of the virtual impedance indicates that the flatness of the substrate 221 is reduced, the system controller 275 increases the clamping power by adjusting the power source 276. In an embodiment, the reduced flatness of the substrate 221 may be displayed by a negatively increasing virtual impedance of the substrate support 210.

Figure 4 is an exploded view showing the electrostatic chuck clamping design in accordance with an embodiment of the present invention. As shown in FIG. 3, the electrode 223 of the substrate support 210 is coupled to the ground to provide a return path for the RF source 265 (which provides RF energy for plasma generation) and is also coupled to the power supply system 280 to provide bias. The substrate 221 is held electrostatically by pressure. Electrode 223 is coupled to conductive element 286, wherein the conductive element 286 extends through support rod 226. An extension clamp 291 is clamped to the conductive element 286. A multi-contact connector 292 is coupled to the extension clamp 291. In an embodiment, the multi-contact connector 292 is silver that is brazed to the extension clamp 291. The multi-contact connector 292 is inserted into an RF strip 293 that is constructed to provide one or more electrical connections. An exemplary multi-contact connector 292 is available from Multi-Contact AG, Basel, Switzerland. In an embodiment, the connectors 281, 282 (which are respectively electrically coupled to the return path of the RF source 265 and the power supply system 280) may be coupled to the conductive element 286 via the RF strip 293.

Figure 5 is a graph showing the virtual impedance of the chamber, while Figure 6 shows the true chamber impedance when the electrode 223 is used with the power supply system 280. For the results shown, a bare-die substrate wafer is used, and a film or layer material is disposed thereon (which causes the wafer to become uneven or curved to a distance of about 10 microns flat, a distance of about 300 microns flat, and a distance) A wafer that is flat about 400 microns). The graph shows the positive clamping and flattening of the wafer by biasing over time. Wafer clamping is observed by monitoring the chamber impedance. When the impedance of the chamber is constant, a positive grip of the wafer can be observed.

The substrate support 210 having the electrodes 223 and the power supply system 280 provide plasma processing of the semiconductor substrate with a number of advantages. Power adjustment and positive clamping can increase throughput by eliminating or reducing the adverse effects produced by non-planar substrates. For example, when an uneven substrate (such as a concave or convex substrate) is provided to the substrate support 210, the electrical signal from the power source 276 can be slowly increased as needed to bring the center or edge of the substrate into contact with the substrate support. The receiving surface. When the center or edge is clamped, the substrate is planarized and more uniformly communicated with the substrate support (which can increase the overall thickness uniformity of the deposited material). Normalization between the chambers can also be enhanced when the substrate is transferred from the chamber to the chamber with varying degrees of curvature. The positive clamping of the substrate provided by electrode 223 also increases plasma stability by improving thermal communication between the substrate and heater 288.

Figure 7 is a diagram showing the coordinates between the virtual impedance of the electrostatic chuck and the flatness of the substrate positioned on the electrostatic chuck. The x-axis of Figure 7 represents time. The y-axis of Figure 7 represents the virtual impedance of the electrostatic chuck in the plasma reactor, which acts as an electrode of the capacitive plasma generator of the plasma reactor. When RF power is applied to the capacitive plasma generator, the virtual impedance of the electrostatic chuck can be measured by the VI probe. The VI probe measures voltage and current, so Ohm's Law can be used to calculate the impedance.

Curve 1 of Fig. 7 shows the virtual impedance measurement of the electrostatic chuck when the substrate positioned on the electrostatic chuck is flat. The flatness of the substrate typically changes during processing unless the substrate is a bare wafer or the substrate is sufficiently clamped by the electrostatic chuck. The virtual impedance of curve 1 has an overall positive slope.

Curve 2 of Fig. 7 shows the virtual impedance measurement value of the electrostatic chuck when the substrate positioned on the electrostatic chuck is curved and no electrostatic clamping is applied to the substrate. The virtual impedance of curve 2 has an overall negative slope.

Curve 3 of Fig. 7 shows the virtual impedance measurement of the electrostatic chuck when the substrate positioned on the electrostatic chuck is curved. Electrostatic clamping is applied to the substrate until time T. At time T, the substrate is detached from clamping. The virtual impedance of curve 3 has a positive slope before time T when the substrate is clamped. Curve 3 has a negative slope when the substrate is removed from clamping.

The curve 4 of Fig. 7 shows the virtual impedance measurement value of the electrostatic chuck when the substrate positioned on the electrostatic chuck is curved. Prior to time T, no electrostatic clamping was applied to the substrate. At time T, the substrate is clamped. The virtual impedance of curve 4 has a negative slope before time T when the substrate is not clamped. Curve 4 has a positive slope shortly after the substrate is clamped.

In one embodiment, the flatness of the substrate positioned on the electrostatic chuck during the plasma process can be monitored by calculating the slope of the virtual impedance of the electrostatic chuck.

Figure 8 is a diagram showing the coordinates between the virtual impedance measurements of the electrostatic fixture and the estimated virtual impedance slope. As shown in Fig. 7, the virtual impedance of the electrostatic chuck is related to the flatness of the substrate held on the electrostatic chuck during the plasma process.

The curves M1, M2, and M3 of Fig. 8 show sensor measurements of the virtual impedance of an electrostatic chuck. In an embodiment, the virtual impedance can be measured periodically, and a slope can be calculated from the measured values over a period of time to reduce the measured value noise. In an embodiment, slope linear regression (Slop Linear Regression) can be used to calculate the slope. As shown in Fig. 8, the measured values of the curves M1, M2, M3 can be linearly regressed into straight lines S1, S2, S3. The slope of the straight lines S1, S2, S3 substantially provides the flatness of the substrate disposed on the electrostatic chuck. Line S1 has a positive slope which indicates that the substrate may be fairly flat due to proper clamping. Line S2 has a small negative slope which indicates that the flatness of the substrate is at the borderline. It is necessary to increase the clamping voltage to reduce substrate deformation. Line S3 has a relatively large negative slope which indicates that the substrate may be curved due to insufficient clamping of the electrostatic chuck.

It should be noted that any suitable method (including other numerical methods) and appropriate filters can be used to obtain the slope of the virtual impedance.

Although the electrostatic chuck described herein is used as a grounding electrode as one of the plasma generators, it can also be applied to other wiring. Those skilled in the art can adjust the circuit of the filter, the impedance matching network, and/or the sensor to measure the electrical characteristics of the electrostatic chuck.

Although described herein as a PECVD system, the apparatus and method of the present invention can be applied to any suitable plasma process.

While the foregoing is a description of the embodiments of the present invention, the invention may be

1-4. . . curve

M1, M2, M3. . . curve

S1, S2, S3. . . straight line

10. . . Plasma reactor

11. . . Ground electrode

12. . . electrode

13. . . Substrate

14. . . Component side

15. . . Plasma

16. . . Impedance matching circuit

17. . . Radio frequency (RF) power supply

18. . . Heater

100. . . PECVD system

102. . . Chamber body

103. . . Drive System

104. . . Chamber cover

108. . . Gas distribution system

112. . . Side wall

116. . . Bottom wall

120. . . Processing area

121. . . Substrate

122. . . aisle

123. . . electrode

124. . . aisle

125. . . Surrounding cylinder suction groove

126. . . Rod

127. . . Chamber lining

128. . . Static fixture

129. . . Projection

130. . . Baton

131. . . Discharge

140. . . Gas inlet channel

142. . . Sprinkler head assembly

144. . . Baffle

146. . . panel

147. . . Cooling trench

148. . . Base plate

149. . . Coolant outlet

150. . . Liquid delivery source

161. . . Substrate lifting tip

162. . . Remote plasma source

163. . . Gas inlet

164. . . Cylinder suction system

165. . . RF source

167. . . Gas inlet manifold

168. . . Gas inlet

169. . . Gas inlet

172. . . Gas delivery source

173. . . Impedance matching circuit

174. . . Sensor

175. . . System controller

176. . . DC source

177. . . Low pass filter

178. . . capacitance

200. . . Plasma processing chamber

202. . . Side wall

203. . . bottom

204. . . cover

210. . . Substrate support

220. . . Internal volume

221. . . Substrate

222. . . Dielectric layer

223. . . electrode

226. . . Support rod

228. . . Ontology

246. . . panel

264. . . Vacuum system

265. . . RF source

273. . . Impedance matching circuit

274. . . Sensor

275. . . System controller

276. . . Power source

277. . . Filter

278. . . capacitance

279. . . Amplifier

280. . . Power supply system

281. . . Connector

282. . . Connector

283. . . Power source

284. . . Temperature Controller

285. . . Temperature sensor

286. . . Conductive component

288. . . Heater

291. . . Extension fixture

292. . . Multi-contact connector

293. . . RF strip

The invention will be described in more detail and briefly summarized with reference to the embodiments of the invention illustrated in the drawings. It is to be understood, however, that the appended claims

Figure 1 (Prior Art) shows the bending condition of one of the substrates during the plasma process.

Figure 2 is a cross-sectional view showing a PECVD system in accordance with an embodiment of the present invention.

Figure 3 is a side elevational view of a plasma processing chamber in accordance with an embodiment of the present invention, wherein the plasma processing chamber has an electrostatic chuck.

Figure 4 is an exploded view showing the electrostatic chuck clamping design in accordance with an embodiment of the present invention.

Figure 5 is a graph showing the impedance of the virtual chamber.

Figure 6 is a graph showing the true chamber impedance.

Figure 7 is a diagram showing the coordinates between the virtual impedance of the electrostatic chuck and the flatness of the substrate positioned on the electrostatic chuck.

Figure 8 is a graph showing the coordinates between the virtual impedance measurements and the calculated virtual impedance slope of the electrostatic chuck.

To facilitate understanding, the same reference symbols are used to represent the same elements. It will be appreciated that the elements of the embodiments can be effectively utilized in other embodiments without further recitation.

200. . . Plasma processing chamber

202. . . Side wall

203. . . bottom

204. . . cover

210. . . Substrate support

220. . . Internal volume

221. . . Substrate

222. . . Dielectric layer

223. . . electrode

226. . . Support rod

228. . . Ontology

246. . . panel

264. . . Vacuum system

265. . . RF source

273. . . Impedance matching circuit

274. . . Sensor

275. . . System controller

276. . . Power source

277. . . Filter

278. . . capacitance

279. . . Amplifier

280. . . Power supply system

281. . . Connector

282. . . Connector

283. . . Power source

284. . . Temperature Controller

285. . . Temperature sensor

286. . . Conductive component

288. . . Heater

Claims (16)

A method for processing a substrate, comprising at least the steps of: positioning the substrate on an electrostatic chuck in a processing chamber; applying an RF power between one of the electrodes in the electrostatic chuck and a counter electrode, Wherein the opposite electrode is disposed parallel to the electrostatic chuck; applying a DC bias to the electrode in the electrostatic chuck to clamp the substrate on the electrostatic chuck; monitoring the virtual impedance of the electrostatic chuck over a period of time a change in slope; and a change in the slope of the virtual impedance of the electrostatic chuck associated with the flatness of the substrate. The method of claim 1, further comprising adjusting a DC bias applied to the electrode of the electrostatic chuck according to a change in slope of the virtual impedance of the electrostatic chuck. The method of claim 1, further comprising correlating an overall negative slope change of the virtual impedance of the electrostatic chuck with a decrease in flatness of the substrate. The method of claim 3, further comprising increasing a DC bias applied to the electrostatic chuck when the slope of the virtual impedance is negative. The method of claim 1, wherein the step of monitoring the change in the virtual impedance comprises measuring the voltage and current of the electrostatic chuck. The method of claim 5, wherein the VI probe connected to the counter electrode is used to measure voltage and current. A method for monitoring a substrate during a plasma process, comprising at least the step of positioning the substrate in a plasma generator having one of first and second parallel electrodes, wherein the substrate is positioned at the first And between the second parallel electrode and substantially parallel to the first and second parallel electrodes; applying an RF power between the first and second parallel electrodes of the plasma generator; applying a DC bias to the a first parallel electrode for directly or indirectly fixing the substrate on the first parallel electrode; and monitoring the flatness of the substrate by determining a slope change of the virtual impedance of the plasma generator over a period of time. The method of claim 7, wherein the virtual impedance is determined using a VI probe connected to one of the parallel electrodes of the parallel electrodes of the plasma generator. The method of claim 7, wherein a negative slope is displayed The reduction in substrate flatness. The method of claim 9, further comprising applying a sufficient clamping voltage to the first parallel electrode to achieve a desired substrate flatness. An apparatus for processing a substrate comprises at least: an electrostatic chuck comprising a first electrode, the first electrode being coupled to a DC power supply, wherein the electrostatic chuck has a support surface for supporting the substrate on the support a counter electrode disposed substantially parallel to the support surface of the electrostatic chuck, wherein the counter electrode is spaced apart from the electrostatic chuck, the substrate being positioned between the electrostatic chuck and the counter electrode An RF power supply for applying an RF power between the first electrode and the opposite electrode; a sensor for determining a change in impedance of the electrostatic chuck; and a system controller The system controller is configured to receive an input from the sensor, wherein the system controller is configured to correlate a change in impedance of the electrostatic fixture with a flatness of the substrate by monitoring a virtual impedance of the electrostatic fixture. The device of claim 11, further comprising: a capacitor connected between the first electrode and the grounding member, wherein The RF power supply is coupled to the counter electrode via a matching network, the first electrode and the capacitor providing a return path for the RF power supply; and a filter coupled to the first electrode and the DC Between the power supplies, the filter is used to remove noise and/or any RF current from the bias of the DC power supply. The device of claim 11, wherein the sensor is a VI probe connected to the counter electrode. The device of claim 11, wherein the system controller is configured to adjust the DC power supply according to a slope of the virtual impedance of the electrostatic chuck over a period of time, wherein when the flatness of the substrate is reduced, The system controller increases the DC power. The method of claim 1, wherein the step of monitoring the change in the slope of the virtual impedance of the electrostatic chuck is performed without measuring the capacitance involved in the processing chamber. The method of claim 7, further comprising adjusting the DC bias applied to the first parallel electrode based on a slope of the virtual impedance.