KR200383348Y1 - Thermally matched support ring for substrate processing chamber - Google Patents

Abstract

The substrate support ring has a band having an inner perimeter that at least partially surrounds the periphery of the substrate. The band has a radiation absorbing surface. The lip extends radially inward from the inner circumference of the band to support the substrate. The band and lip can be formed from silicon carbide, such as a sintered composition of silicon carbide, and the radiation absorbing surface can be an oxide layer of silicon carbide. In one version, the band and lip have a combined thermal mass (T _m ) and the radiation absorbing surface has a ratio (A × S _a ) / T _m of about 4 × 10 ⁻⁵ _m ² K / J to about 9 × 10 ^{− It} has water absorption (A) and surface area (S _a ) to be ^{4 m 2} K / J.

Description

Thermally Harmonized Support Ring for Substrate Processing Chamber {THERMALLY MATCHED SUPPORT RING FOR SUBSTRATE PROCESSING CHAMBER}

Embodiments of the present invention relate to a support ring for supporting a substrate in a process chamber.

In the processing of substrates such as semiconductor wafers and displays, the substrate is placed on a support in the process chamber and appropriate processing conditions are maintained in the process chamber. For example, the substrate is heated and thermally processed in a controlled heating cycle. The substrate may be heated, for example, by an array of heating lamps disposed above or below the substrate in the chamber. Thermal processing can be used, for example, to anneal an ion impregnated layer on a substrate, to perform a thermal oxidation or nitriding process, or to perform a thermal chemical vapor deposition process on a substrate.

However, changes in temperature gradient across the substrate can cause non-uniform processing of the substrate. Non-uniform temperatures occur in different substrate regions, for example, due to non-uniform convection or conduction heat losses from regions of the substrate that are in contact with the support or other chamber components and regions of the substrate that are not in contact with the support. In particular, it is difficult to achieve temperature uniformity across the substrate when the substrate is heated at a rapid heating rate, such as in a rapid thermal processing (RTP) system. Therefore, there is a need to maintain a uniform temperature across the substrate during thermal processing to provide uniform processing results.

The temperature gradient of the substrate was reduced using a substrate support ring extending outwardly from the substrate to surround the substrate's periphery. The ring expands or pushes the temperature gradient of the substrate from the periphery of the substrate to the outer edge of the ring. The support may also have an upper surface made of a material having heat absorption properties similar to the heat absorption properties of the substrate to equalize the temperature between the substrate center and the periphery. For example, a support ring comprising silicon carbide coated with silicon is disclosed in US Pat. Nos. 6,280,183 to Jennings et al., Assigned to Mayur et al., Assigned to Applied Materials and referenced herein. US Pat. No. 6,200,388.

However, such support rings may not provide adequate temperature uniformity across the substrate in a rapid heating process, for example, a process having a heating rate of about 200 ° C./sec or more. In this process, the difference in heating rate between the support ring and the substrate results in a temperature gradient along the periphery of the substrate that is unacceptably high during the heating process step. For example, using a conventional ring in a rapid heating process may change the temperature about 15 ° C. or more, which is excessively high across the substrate.

Accordingly, it is an object of the present invention to provide a support ring that does not cause excessive temperature gradients in the substrate during thermal processing. It is also an object of the present invention to provide a support ring that is heated at a rate sufficiently close to the heating rate of the substrate to reduce the formation of temperature gradients in the substrate.

In one embodiment of the present invention, the substrate support ring has a band having an inner perimeter that at least partially surrounds the periphery of the substrate. The band has a radiation absorbing surface. The lip extends radially inward from the inner circumference of the band to support the substrate. The band and lip can be formed from silicon carbide, such as a sintered composition of silicon carbide, and the radiation absorbing surface can be an oxide layer of silicon carbide.

In another embodiment of the support ring, the band and lip have a combined thermal mass (T _m ) and the radiation absorbing surface has a ratio (A × S _a ) / T _m of about 4 × 10 ⁻⁵ _m ² K / J to It has an absorption rate (A) and a surface area (S _a ) to be about 9 × 10 ⁻⁴ m ² K / J.

In one embodiment, a substrate support ring is fabricated for supporting a substrate in a process chamber. The substrate has a thermal mass (T _ms ), and an upper surface having an absorptance (A _s ) and a surface area (S _as ). The substrate has a substrate heating rate of (A _s × S _as ) / T _ms . To produce the support ring, a band is formed having an inner perimeter that at least partially surrounds the periphery of the substrate. Lips extending from the inner circumference of the band radially inward are also formed. The band and lip have a support ring heating rate value that includes the combined thermal mass (T _mr ) and (A _r × S _ar ) / T _mr . The radiation absorbing surface is also formed on the band. Copy absorbing surface has a water absorption (A _r) and a specific surface area (S _ar) so that the ratio of the support ring heating value for the substrate heating rate value within a predetermined range.

These features, aspects, and advantages of the present invention will be more readily understood with reference to the detailed description, utility model registration claims, and accompanying drawings that describe embodiments of the present invention. However, each feature may be generally used in the present invention as well as the content of a particular figure, and the present invention includes any combination of these features.

Embodiments of the present invention relate to a support ring 102 that supports the substrate 104 during processing in the process chamber 206. The support ring 102 includes an outer band 105 and an inner lip 106 that cooperate to support the substrate 104 during processing as shown in FIG. 1. Band 105 and lip 106 are substantially annular in shape. The outer band 105 includes an inner perimeter 107 that surrounds at least a portion of the perimeter 103 of the substrate 104. The band 105 serves to effectively extend the heating diameter of the substrate 104 to reduce the formation of a temperature gradient within the substrate 104.

The inner lip 106 of the ring 102 extends inward radially from the inner circumference 107 of the band 105 to form a support ledge for supporting the substrate 104. The substrate support surface 109 of the inner lip 106 is the top surface 110 of the outer band 105 to form a recess 116 that holds the substrate 104 within the perimeter 107 of the band 105. Is below. The lip 106 is sized according to the size of the substrate 104, for example the lip 106 can extend a sufficient distance below the substrate 104, such as about 0.1 cm to about 0.5 cm. In FIG. 1, the inner perimeter 118 of the lip 106 defines an open region 121 that extends across at least about 75% of the region of the substrate 104.

The support ring 102 can further include an annular support sidewall 112 that holds the ring 102 on a lower structure, such as the lower support cylinder 209. 1 and 2, the support sidewall 112 extends down at the outer perimeter 114 of the band 105 to support the ring 102 on the cylinder 209. The support ring 102 may also include an annular connecting sidewall 122 extending downward from the inner perimeter 107 of the band 105 to connect the band 105 to the lip 106. Alternatively, the lip 106 may be attached directly to the band 105.

The support ring 102 includes a radiation absorbing surface 111 that absorbs energy directed to the surface 111 of the support ring 102. The radiation absorbing surface 111 is provided to reduce the temperature gradient resulting from the temperature difference between the ring 102 and the substrate 104 at the periphery 103 of the substrate 104. Absorbing surface 111 comprises a portion of the upper surface of support ring 102 exposed to radiation source 210. For example, the absorbent surface 111 may be part of the upper surface 110 of the band 105, and may even include the entire upper surface 110 of the band 105. Absorbing surface 111 may also include exposed surface portions 117 of inner lip surface 109 that are between the perimeter 103 of substrate 104 and the inner perimeter 107 of band 105.

The properties of the absorbent surface 111 are selected in relation to the thermal mass T _m of the support ring 102 to improve processing. For example, it is known that a good heating result is provided as the ratio R of [absorption rate of the absorption surface 111 x surface area S _a of the absorption surface 111] to the thermal mass T _m within a predetermined range. have. The formula for the ratio R is represented by the following equation (1).

1) R = (A × S _a ) / T _m

In one version, the ratio R ranges from about 4 × 10 ^{−5 m 2} K / J to about 9 × 10 ⁻⁴ m ² K / J. For example, the ratio R may range from about 5.7 × 10 ^{−5 m 2} K / J to about 8.8 × 10 ⁻⁴ m ² K / J to process a substrate 104 having a diameter of about 200 mm, and about It may range from about 5.2 × 10 ^{−5 m 2} K / J to about 8.1 × 10 ⁻⁴ m ² K / J to process the substrate 104 having a diameter of 300 mm. The substrate processed with the support ring 102 with the desired ratio is the substrate 104, such as the temperature range of the substrate across the substrate of about 2 ° C. or less, which is a range small enough to be controlled through modulation of the radiation source 210. ) Shows a reduced temperature deviation.

In order to determine the ratio R of the support ring 102, the absorbance of the absorbent surface 111 of the support ring 102 is measured. Absorption is a measure of the fraction of radiation incident on a substrate absorbed by a surface as opposed to being reflected by or penetrating the surface. The absorptivity of the surface depends on the composition and reflectance of the surface and therefore surfaces with different compositions will generally have variable absorptivity values. For example, a surface comprising silicon carbide generally absorbs different incident radiant fractions and therefore has a different absorption rate than a surface comprising silicon oxide. For example, various spectroscopic techniques such as reflectance measurements of partial hemispheres, measurements of complete hemispheres, emissivity measurements of partial hemispheres, and emissivity measurements of complete hemispheres are known to those of ordinary skill in the art. Can be used to measure. Absorption can be measured for a given wavelength of incident radiation or over a wavelength range, for example, in the range of about 0.2 microns to about 5 microns.

In one version, the absorptivity is measured by detecting partial hemispheric reflectance of the irradiated surface, which is a subspace averaged measure of radiation reflected from the surface, an example of which is referenced herein and assigned to Hitachi Kokusai Electric. US Patent Application No. 2003/0027364 to Ikeda. In this version, the support ring 102 is located in the measurement chamber and the radiation is directed to the absorbing surface 111 of the support ring 102. The nature of the radiation reflected from the surface of the support ring 102 or the substrate 104 is detected. For example, the intensity of reflected radiation at one or more wavelengths can be detected, such as intensity at wavelengths in the range of about 0.2 microns to about 5 microns. The support ring 102 may be rotated while detecting the reflected radiation to provide a spatial average of the reflected radiation. Although a reflectance value of a full hemisphere can be obtained that represents the spatial average of the radiation reflected from the surface 111 in all directions, only a measure of the partial hemisphere averaged over a portion of the reflected radiation can be used. For example, in one version, the detected reflected radiation is that reflected from the irradiation surface within a 90 degree cone centered on a vector perpendicular to the surface.

Absorption can be determined from reflectance measurements according to the following relationship.

2) A + r + t = 1

Where the absorbance (A) is the fraction of incident radiation absorbed by the surface, the reflectance (r) is the fraction of incident radiation reflected by the surface, and the transmittance (t) is the fraction of incident radiation penetrating the object, which is supported Close to zero for ring 104 and substrate 102. The reflectance is equal to the detected radiation intensity reflected from the surface divided by the intensity of radiation incident on the surface. Thus, the absorbance of the surface can be determined by inserting the reflectance value obtained by detecting the reflected radiation into Equation 2). Therefore, the reflectance measurement of the partial hemisphere can determine the absorptivity of the irradiating absorbing surface 111 of the support ring 102, from which the ratio R of equation 1) can be determined.

The thermal mass (T _m ) of the support ring 102 in Equation 1) is multiplied by the mass (m) of the ring 102 to give a numerical value of the total heat capacity of the entire support ring 102. (C). The heat capacity of a material is the thermal mass required to change the temperature of the unit mass material by 1 degree. Therefore, the heat capacity is a proportionality constant associated with the temperature change of the object with respect to the thermal mass delivered to or from the object as indicated in equation 3).

3) q = mC △ T

Where q is the heat transferred to or from the object, m is the mass of the object, and ΔT is the temperature change of the object resulting from the transfer of heat q.

The heat capacity can be determined from a reference table or thermogravimetric values. Moreover, since the heat capacity of the material can vary over a temperature range, the heat capacity used in equation 1) can be taken as an average of the heat capacity of the material over the temperature range of interest, such as the temperature range that occurs during processing of the substrate 104. have. In one version, the heat capacity of the support ring 102 can vary from a ring (over a temperature range used in the thermal spike annealing process, such as a temperature range of about 100 ° C to about 1350 ° C, and even a temperature range of about 550 ° C to about 1050 ° C). 102 is taken as the average heat capacity. The mass of the support ring 102 can be determined by measuring the weight of the support ring 102 or by determining the volume of the support ring 102 and multiplying the volume by the density of the material from which the support ring 102 is made. .

The surface area of the support ring surface irradiated by the radiation source is the final amount determined to find the ratio R of the support ring 102 according to equation 1). The irradiated surface area of the support ring 102 is the area of the absorbent surface 111, which may include the region of the upper surface 110 of the support ring band 105, and also the substrate 104 on the support ring lip 106. It may also include an area of the surface portion 117 exposed in the periphery 103 of the (). For example, the surface area of the support ring absorbing surface 111 can be determined according to the formula (π (R ₂ ) ² -π (R ₁ ) ² ), where R ₁ is the radius of the substrate 104 and R ₂ is Radius of the outer perimeter 114 of the band 105.

In one version, the support ring 102 with the predetermined ratio R can be designed by selecting the characteristics of the support ring, such as the radiation absorbing surface 111 which provides the ratio R within the predetermined range. For example, to provide a larger ratio R, the support ring 102 can be made to have an absorbent surface that includes a material having a higher absorption rate that absorbs a larger portion of incident radiation. Coatings with greater absorption can also be provided. The surface area of the irradiated surface can be increased, for example, to increase the structural size of the surface and also to increase the surface roughness to provide a larger area where incident radiation is absorbed. Conversely, providing an absorbent surface with lower absorptivity, or reducing the irradiated surface area, will reduce the ratio R of the support ring 102. In another method of reducing the ratio R of the support ring 102, the thermal mass of the support ring 102 can be increased, for example, by making the support ring from a material having a greater heat capacity. The thermal mass of the support ring 102 can be increased by increasing the mass of the ring 102, for example by increasing the dimensions of the support ring 102 or by making the support ring 102 from a material having a greater density. Can be. Conversely, selecting a support ring material having a lower heat capacity, reducing the mass of the support ring 102 by reducing the dimension of the ring 102, or selecting a less dense ring material, It will increase the thermal mass and increase the proportion of the support ring 102.

In one version, the support ring 102 with the predetermined ratio R comprises a silicon carbide material with an integrated surface coating 113 comprising oxidized silicon carbide. The integrated surface coating 113 forms a single continuous structure that is separated from the ring 102 and does not have sharp crystal boundaries, as shown schematically in dashed lines in FIG. 1. Absorbent surface 111 includes a portion of the upper surface of integrated surface coating 113. In one version, the integral surface coating 113 is formed in-situ from the surface of the ring 102 by "growing" the integral surface coating 113 from the lower ring 102. Integrated surface coating 113 is more strongly bonded to the lower ring material than conventional coatings, such as thermal sprayed coatings having an interface separate from the lower ring structure. Integrated surface coating 113 comprising oxidized species may include a thickness in the range of about 1 nm to about 5000 nm. By way of example, the oxidized coating may be a layer of oxidized silicon carbide.

In one version, the support ring 102 comprises a sintered material comprising a composition of silicon carbide and nitrogen, and the surface coating 113 comprises oxide species. The sintered silicon carbide and nitrogen material may be formed by mixing the silicon carbide powder with a nitrogen source, such as a polyimide resin or an amine compound, and an auxiliary sintering agent. The mixture is then placed in a mold having a predetermined shape and suitable sintering temperature under a predetermined pressure in an inert atmosphere, such as a sintering temperature of about 2,000 ° C. to about 2,400 ° C. at a pressure of about 300 to 700 kgf / cm 2. Heated to. Various pretreatment steps can be performed to remove impurities from the mixture, for example by preheating the mixture before sintering. The sintered material preferably has a density of about 2.5 to about 3.2 g / cm 3. The sintered material preferably has a sufficiently high nitrogen content such that the material is substantially opaque to incident radiation, such as radiation ranging from about 0.2 microns to about 5 microns. Preferred nitrogen content may be at least about 1 ppm, such as in the range of about 1 ppm to about 150,000 ppm. The sintered material can be machined into any shape, such as the support ring shape shown in FIG. To form an integrated surface coating 113 with oxidized species, the sintered material is placed in a furnace and heated in an oxygen containing atmosphere to oxidize the silicon containing species at the surface of the material, including an oxidized layer of silicon carbide. To form an integrated surface coating 113. For example, the sintered material may be heated to a temperature of about 1000 ° C. or higher in an O ₂ -containing atmosphere.

The support ring 102 comprising a sintered silicon carbide material containing nitrogen and having an integrated surface coating 113 comprising an oxide layer is preferably made to provide a range of ratios R. The support ring 102 comprising the sintered material has an absorbent surface 111 having an absorptivity value in the range of about 0.1 to about 1.0, even in the range of about 0.8 to about 1, such as about 0.94, as measured by the reflectance method of the partial hemisphere. Has The heat capacity (C) of the sintered material ranges from about 900 J / Kg / K to about 1300 J / Kg / K, such as about 1130 J / Kg / K as averaged over a temperature range of about 550 ° C. to about 1050 ° C. The irradiated surface area S ranges from about 2 × 10 ⁻³ m 2 to about 3 × 10 ⁻² m 2, such as about 1.4 × 10 ⁻² m 2.

The dimensions of the support ring 102 are chosen to provide a suitable thermal mass T _m . For example, the dimension may be selected to provide a mass equal to a mass in the range of about 4 g to about 40 g, such as about 20 g, for processing a substrate having a 300 mm diameter and a substrate having an absorption of about 0.95, such that about 2 J / It provides a thermal mass (T _m ) in the range of K to about 750 J / K. For example, the thermal mass is about 3 J for an irradiated ring surface area in the range of about 2 × 10 ⁻³ m 2 to about 3 × 10 ⁻² m 2 to process a substrate having a diameter of about 300 mm and an absorption of about 1.0. It may be equal to the thermal mass in the range of / K to about 45J / K. As yet another embodiment, the thermal mass is for an irradiated ring surface area in the range of about 3 × 10 ⁻³ m 2 to about 3 × 10 ⁻² m 2 to process a substrate having a diameter of about 300 mm and an absorption of about 0.1. It may be equal to a thermal mass in the range of about 30 J / K to about 450 J / K. In one version, the thermal mass of the support ring 102 is about 4 J / K to about 44 J / K, such as about 23 J / K. The dimension can be selected, for example, by increasing or decreasing the thickness of one or more of the support ring band 105 and the lip 106. For example, to process a substrate 104 having a diameter of about 300 mm, the appropriate thickness w ₁ of the band 105 may be from about 2.3 × 10 ⁻⁴ m to about 2.5 × 10 ⁻⁴ m, such as about 2.5 × 10 ⁻⁴ m. The thickness may be equal to a thickness in the range of 2.8 × 10 ⁻⁴ m, and the appropriate thickness w ₂ of the lip 106 may be from about 1.8 × 10 ⁻⁴ m to about 2.3 ×, such as about 2.0 × 10 ⁻⁴ m. It may be the same thickness as the thickness in the range of 10 ⁻⁴ m. The diameters of the band 105 or the lip 106 as well as the dimensions of the support sidewall 112 and the connecting sidewall 122 can be varied to provide the desired mass. In addition, maintaining the ratio of the band thickness w ₁ to the lip thickness w ₂ from about 1.14 to about 1.3 provides good mass distribution to the support ring 102 and reduces temperature variations within the substrate 104. Found to be desirable. In one version, the characteristics of the support ring 102 with the integrated surface coating 113 comprising silicon carbide and nitrogen and having oxidizing species are about 5.2 × 10 ⁻ , such as about 6.4 × 10 ⁻⁴ m ² K / J. ^It is selected to provide a ratio R in the range of ⁴ to about 7.6 × 10 ⁻⁴ m ² K / J.

The improved substrate processing result given by the support ring 102 with a range of ratios R is due to the "thermal matching" of the support ring 102 with the ratio to the substrate 104 being processed. It is believed. In this “thermally matched” support ring 102, the temperatures of the support ring 102 and the substrate 104 vary by substantially the same amount during unit time during substrate processing, such that the support ring 102 and the substrate 104 are changed. ) Ensures that the temperature remains substantially balanced throughout the process. This thermal coordination is important because the hotter or colder support rings 102 can exchange heat with the edges of the substrate 104, and the temperature variation can be adversely affected by the process uniformity. To follow. For the support ring 102 having a "harmonized" heating rate, the effect of temperature variation at the edge of the substrate is reduced, improving the process uniformity and overall yield of the substrate. Preferably, the support ring characteristic is selected to provide a heating rate of the support ring 102 that is within a predetermined range of the substrate heating rate, such as a support ring heating rate that ranges from about 105% to about 130% of the substrate heating rate.

It was unexpectedly found that a good value of the relative heating rate of the support ring 102 and the substrate 104 can be obtained by comparing the ratio R of the support ring 102 to the ratio R to the substrate 104. . The ratio R to the substrate 104 is determined according to equation 1). The substrate ratio R includes [absorption rate A of the upper surface 101 of the substrate 102 x surface area S _a of the upper surface 101] / thermal mass T _m . The thermal mass and absorptivity of the substrate 104 can be determined according to the techniques described above for the support ring 104, the surface area of the substrate 104 being equal to π (R ₁ ) ² , where R ₁ is the substrate 104. Is the radius of. The ratio R is an approximation of the actual heating rate of the support ring 102 and the substrate 104 and is believed to take into account factors that greatly influence the heating rate of the ring 102 and the substrate 104. Therefore, a support ring can be devised with a good relative heating rate for the substrate 104 being processed. For example, a support ring 102 may be provided having a ring ratio R _{r that} is within a range from about 5% to about 30% of the substrate ratio R _s . Also, since the ratio R is generally an approximation of the correct heating rate, the preferred heating rate ratio R _r of the support ring 102 may be different from the heating rate ratio R _s of the substrate 104. In one version, the preferred relative heating rate R _rs of the support ring 102 to the substrate 104 takes into account the ratio of the support ring heating rate ratio R _r to the substrate heating rate ratio R _s , It may be determined by determining whether the ratio is within a predetermined range. For example, the preferred relative heating rate (R _rs = R _r / R _s ) of the support ring 102 relative to the substrate 104 ranges from about 1.05 to about 1.30, such as about 1.10 to about 1.20, even as about 1.14. Or from about 1.12 to about 1.15.

It is unexpected that the comparison of the ratios R _r and R _{s of the} support ring 102 to the substrate 104 can provide a good estimate of the relative heating rate, which is due to the large number of differences between the substrate, support ring and chamber environments. It is believed that complex heat transfer mechanisms should be evaluated to provide useful figures of heating rates. For example, the complete heat transfer model is itself a very complex modeling of the conductive heat exchange between the support ring 102 and the substrate 104, as well as the conductivity between the support ring 102 and other parts of the chamber, such as the lower support cylinder. Modeling of heat exchange will be required. This perfect model determines the degree of thermal coupling between the substrate or support ring and peripheral components such as chamber walls, and radiant heat exchange between the substrate and the reflecting plate in the open area below the substrate, as well as some other heat transfer source. Will require modeling. In addition, the convective losses of heat in the chamber atmosphere must be modeled, which is difficult to calculate for the rotatable support, especially as used in the thermal process chamber of FIG. 2. However, despite the complex nature of the heat transfer process, Applicants have found that comparing the heating ratios R _r and R _s does not require powerful and complicated calculations, but rather does not require thermally harmonized support ring 102 and substrate 104. It has been found that for the purpose of manufacture it provides a good value of the relative heating rate of the support ring 102 to the substrate 104.

A support ring 102 having a predetermined ratio R may be provided in a process chamber 206, such as a rapid thermal process chamber 206, an embodiment of which is shown in FIG. 2. The rapid thermal process chamber 206 is, for example, thermal annealing, thermal cleaning, thermal chemistry, as disclosed in US Pat. No. 6,200,388 to Jennings and US Pat. No. 6,048,403 to Deaton et al. It may provide a controlled thermal cycle of heating the substrate 104 for processes such as vapor deposition, thermal oxidation, and thermal nitriding. The process chamber 206 includes a chamber wall 204 that encloses the process zone 205. The substrate support 208 with the support ring 102 keeps the substrate 104 in the process region 205 during processing. The substrate support 208 can include a rotatable structure that rotates the support ring 102 and the substrate 104 during processing. For example, the support 208 is a ring that is assigned to Applied Materials and rotated by magnetically leviating and rotating a cylinder as disclosed in US Patent Application No. 2003/0183611 to Gregor et al., Incorporated herein by reference. Quartz support cylinder 209 for supporting 102. The support 208 may also include a reflective plate 211 positioned below the substrate 104 to form a reflective cavity 217. One or more temperature sensors 219, such as a pyrometer with an optical fiber probe, may be provided to detect the temperature of the substrate 104 during processing.

The radiation source 210 directs radiation on the surfaces of the substrate 104 and the support ring 102 and may be positioned over the substrate 104, such as the ceiling 213 of the chamber 206. The radiation source 210 generates radiation of a predetermined wavelength that heats the substrate 104 and the support ring 102, such as radiation having a wavelength in the range of about 0.2 microns to about 5 microns. In one version, the radiation source 210 includes a honeycomb arrangement 212 of a tungsten halogen lamp 214 in a fluid cooling jacket. Honeycomb arrangement 212 may include one or more radial heating zones that may be independently adjusted to control the temperature for substrate 104. Radiation source 210 may heat substrate 104 rapidly, for example, at a rate ranging from about 50 ° C./second to about 300 ° C./second, even at about 200 ° C./second or more, for thermal processing. A radiation transmitting window 218, such as a quartz window, facilitates the transfer of radiation from the radiation source 210 to the substrate 104.

The gas source 221 may provide process gas into the process zone 205 or control the atmosphere within the process chamber. Gas source 221 includes a conduit having a process gas source and a flow control valve connecting the source to a gas inlet in process chamber 206 to provide gas to chamber 206. The outlet 216 controls the gas pressure in the process chamber 206 and discharges the process gas from the chamber 206. Outlet 216 may include one or more outlet ports for passing spent gas to an exhaust conduit that receives spent process gas and supplies one or more outlet pumps. The throttle valve in the exhaust conduit controls the gas pressure in the chamber 206.

The chamber 206 is controlled by a controller 300 that includes program code having a set of instructions for operating the components of the chamber 206 to maintain conditions within the chamber suitable for processing the substrate 104. For example, the controller 300 may include a set of substrate positioning instructions that enable one or more of the substrate support 208 and substrate transfer (not shown) to operate to position and rotate the substrate 104 within the chamber 206; A set of temperature control instructions to operate the radiation source 210 to control the heating of the substrate 104 and to operate the temperature sensor 219 to monitor the temperature of the substrate 104; A gas flow control instruction set for operating the flow control valve to set gas flow to the chamber 206; And a gas pressure control instruction set that operates the discharge throttle valve to maintain pressure in the chamber 206.

Example

The following example shows the improved process performance of the support ring 102 with the desired predetermined ratio R. In this embodiment, support rings 102 having different properties, such as different compositions and dimensions, are used to process the substrate in a thermal spike annealing process performed in a thermal process chamber, such as process chamber 206 shown in FIG. Was used. The temperature occurring along the different radii of each substrate 104 was measured while processing the substrate 104 with the support ring 102. The ratio R _r of each support ring 104 was compared to the ratio R _s of each substrate 104 to determine the relative heating rate ratio R _rs = R _ring / R _substrate . Table 1 provides the results obtained for each support ring 102.

Substrate 104 processed with support ring 102 comprises a silicon wafer having a 300 mm diameter that is ion permeated in a conventional ion permeation process. The substrate includes an upper surface 101 with an absorption of 0.67 and has a thermal mass per irradiation surface area of 1715 J / Km ² . In order to process the substrate 104, a rapid thermal spike annealing process is performed and rapidly heating the substrate 104 to anneal the ionically penetrated portion of the substrate 104. In the process, each substrate 104 is positioned within one of the support rings 102 listed in Table 1 below in the process chamber 206. The temperature of the substrate 104 was increased in the temperature spike at a rate of about 250 ° C./second until a final temperature of about 1050 ° C. was achieved.

To determine the temperature difference that occurs across the surface 101 of each substrate 104 during processing, the electrical resistance of the annealed substrate 104 crosses the 4-point resistance contour across the surface 101 of the substrate 104. Measured on a contour map. The measured electrical resistance was converted to temperature according to a predetermined process sensitivity relationship. The difference in average temperature at radius 147 mm from the center 100 of each substrate 104 was subtracted from the average temperature at radius 137 mm to determine the temperature range ΔT per substrate. The measured temperature ranges are recorded for each substrate in Table 1. The positive value of the average temperature indicates a higher temperature at the periphery 103 of the substrate 104.

The support ring 102 tested in this embodiment includes support rings having different compositions and dimensions. The first support ring comprises a conventional support ring 102 formed by a chemical vapor deposition process and then coated with a silicon layer having an oxidized surface and comprising a substantially carbide free silicon carbide material. The support ring 2 comprises a silicon carbide material coated with a layer of silicon that contains nitrogen and has no oxidized surface. Support rings 3 and 9 comprise sintered silicon carbide material containing nitrogen and having an unoxidized surface. The support rings 4-8 comprise sintered silicon carbide material having an integrated surface coating 113 containing nitrogen and comprising oxidizing species. The dimensions of the support ring 102 vary from one another to provide different masses and different heating rate ratios (R). In support ring 5, the dimensions change for support ring 4 by evenly distributing excess mass in band 105 and ribs 106, providing a more uniform radial dimensional change. In support rings 6-9, the dimensions change for support ring 4 only by changing the thickness of the band 105 while keeping the thickness of the lip 106 the same.

Table 1 irradiation, thermal mass per unit area of the band 105 and the absorption rate of the thickness of the absorbent surface 111 of the lip (106) (A), each support ring 102 for the support ring tested respectively (T _m / S _a ), the relative heating rate R _rs of the support ring 104 relative to the substrate 102, and the temperature range across the measured substrate 104 after processing with each support ring 102. The value and result to be shown are shown. The absorptivity of the support ring 102 and the substrate 104 is determined from the reflectance measurements of the partial hemispheres, and the heat capacity for each ring is taken as average over the process range of 550 ° C to 1050 ° C.

Support ring Band thickness (mils) Lip thickness (mils) A T _m / S _a J / K / ㎡ R _ring / R _board ΔT (K) One 13 + 8 10 0.93 2360 1.01 -5.0 2 13 10 0.79 1756 1.14 -1.2 3 13 10 0.87 1756 1.27 5.0 4 13 10 0.94 1756 1.38 8.4 5 15.8 14 0.94 2068 1.16 1.5 6 15.7 10 0.94 1967 1.22 7.5 7 17.1 10 0.94 2083 1.16 6.0 8 27.8 10 0.94 2846 0.85 -11.6 9 13.9 10 0.88 1830 1.23 5.1

According to Table 1, the minimum range of substrate temperatures is obtained in support rings 2 and 5, with temperature ranges of -1.2 and 1.5K, respectively. However, in general use, the second support ring comprising an unoxidized silicone coating produces consistently good processing results because the surface of the coating is oxidized gently over time, changing the absorption and heating rate of the ring 102. It is not expected to provide. This will limit its use to oxidant free processes. Support ring 4 has the same dimensions as support ring 2, but the oxidized surface of support ring 4 has a higher absorption rate, resulting in greater relative heating rates and poor temperature range results. Support rings 6-8 do not provide good temperature range results, with temperature ranges of 6, 7.5 and -11.6K. A support ring No. 5 containing sintered silicon carbide material containing nitrogen and having an oxidized surface and having the listed dimensions provides a heating rate relative to the substrate 104 that is only about across the substrate 104. It provides improved processing results including a reduced temperature range of 1.5K.

3 shows a graph of the substrate temperature range (ΔT) as increasing the relative heating rate (R _rs = R _ring / R _substrate ), graphed using the data in Table 1 above. The data is plotted against two separate data sets. The first data set, represented by line 400, includes a support ring 102 having a similar radial mass distribution, that is, a mass uniformly distributed relative to the band 105 and the lip 106 of the support ring. The second data set, represented by line 402, includes a support ring 102 having a less uniform radial distribution, ie, a mass distributed only in the band 105. The graph shows that a temperature range across the substrate close to zero is achieved for a relative heating rate R _rs ranging from 1.12 to about 1.15, such as about 1.14. Thus, by selecting a ring 102 having a relative heating rate within this range, a support ring 102 can be devised that is in thermal harmony with the substrate 104 and reduces temperature variations within the substrate 104.

While exemplary embodiments of the present invention have been shown and described, those skilled in the art can devise the present invention and devise other embodiments that fall within the scope of the present invention. For example, support ring materials other than those specifically mentioned may be used to devise support rings with preferred relative heating rates. Moreover, the terms relative or positional indicated in the context of an exemplary embodiment are alternative. Therefore, the utility model registration claims of the present invention should not be limited to the description of the preferred versions, materials, or spatial arrangements disclosed for describing the present invention.

Therefore, the present invention can provide a support ring that does not generate excessive temperature gradients in the substrate during thermal processing. The present invention can also provide a support ring that is heated at a rate sufficiently close to the heating rate of the substrate to reduce the formation of temperature gradients within the substrate.

1 is a cross-sectional view of an embodiment of a substrate support ring.

2 is a cross-sectional view of an embodiment of a thermal processing chamber with a support ring.

3 is a graph showing a temperature range measured across the surface of a thermally processed substrate as it increases the relative heating rate of the support ring used to thermally process the substrate.

※ Explanation of symbols about main part of drawing ※

100: center 101: surface

102: ring 103: surrounding

104: substrate 105: band

106: lip 107: circumference

109: inner surface 110: upper surface

111 absorption surface 112 support sidewall

113: coating 114: outer circumference

116 recess 117 surface portion

118: inner circumference 121: area

122: connecting side wall

Claims (10)

As a substrate support ring, (a) a band comprising an inner perimeter surrounding at least a portion of the periphery of the substrate and a radiation absorbing surface; And (b) a lip extending radially inward from the inner circumference of the band to support the substrate, The band and lip comprise a sintered composition of silicon carbide, and The radiation absorbing surface comprises an oxidized silicon carbide layer, Substrate support ring. The method of claim 1, Wherein the sintered composition comprises a sufficiently high nitrogen content to be substantially opaque to incident radiation, Substrate support ring. The method of claim 1, The band and lip have a combined thermal mass (T _m ) and the radiation absorbing surface has a ratio (A × S _a ) / T _m of about 4 × 10 ⁻⁵ _m ² K / J to about 9 × 10 ⁻⁴ m 2 Including the water absorption (A) and the surface area (S _a ) to be K / J, Substrate support ring. The method of claim 3, wherein The radiation-absorbing surface is the ratio _{(A × S a) / T} m of about 5.2 × 10 ^-4 ㎡K / J to about 7.6 × 10 ^-4 ㎡K absorption (A) and surface area such that the / J (S _a) Including, Substrate support ring. The method of claim 1, The radiation absorbing surface comprises an absorbance in the range of about 0.1 to about 1.0 and a surface area in the range of about 2 × 10 ⁻³ m 2 to about 3 × 10 ⁻² m ² , Substrate support ring. The method of claim 1, The band and lip comprises a heat capacity in the range of about 900 J / Kg / K to about 1300 J / Kg / K, and wherein the thermal mass is in the range of about 2 J / K to about 750 J / K, Substrate support ring. As a substrate support ring, (a) a band comprising an inner perimeter surrounding at least a portion of the periphery of the substrate and a radiation absorbing surface; And (b) a lip extending radially inward from the inner circumference of the band, The band and lip comprise a combined thermal mass (T _m ), The radiation-absorbing surface is the ratio _{(A × S a) / T} m is about 4 × 10 ^-5 ㎡K / J to about 9 × 10 such that the water absorption ^-4 ㎡K / J (A) and surface area (S _a) the Included, Substrate support ring. The method of claim 7, wherein The radiation-absorbing surface is the ratio _{(A × S a) / T} m of about 5.2 × 10 ^-4 ㎡K / J to about 7.6 × 10 ^-4 ㎡K absorption (A) and surface area such that the / J (S _a) Including, Substrate support ring. The method of claim 7, wherein The radiation absorbing surface comprises an absorbance in the range of about 0.1 to about 1.0 and a surface area in the range of about 2 × 10 ⁻³ m 2 to about 3 × 10 ⁻² m ² , Substrate support ring. The method of claim 7, wherein Wherein the band and lip comprise a sintered composition of silicon carbide and the radiation absorbing surface of the band comprises an oxidized layer of the sintered composition of silicon carbide Substrate support ring.