KR101310521B1 - Heating apparatus with enhanced thermal uniformity and method for making thereof - Google Patents

Abstract

The present invention relates to a heating device for adjusting / adjusting the surface temperature of a substrate. For relatively uniform substrate temperatures where the temperature difference between the highest and lowest temperature points on the substrate is less than 10 ° C., at least one layer of pyrolytic graphite (TPG) is embedded in the heater to diffuse the temperature difference of the various components in the heating device. And the surface temperature of the substrate is controlled in terms of time and space.

Description

HEATING APPARATUS WITH ENHANCED THERMAL UNIFORMITY AND METHOD FOR MAKING THEREOF

1 is a perspective view showing one embodiment of a heating device.

2 is a cross-sectional view of one embodiment of a metal heater of the prior art.

3A, 3B and 3C are cross-sectional views of various embodiments of a heater including a metal based substrate.

4 is a cross-sectional view of one embodiment of a heater of the prior art in a heater having a ceramic core.

5A, 5B, 5C, 5D and 5E are cross-sectional views of various aspects of a heater including a ceramic core for a substrate.

5F and 5G are cross-sectional views of various embodiments of a heater that includes a pyrolytic graphite layer as an electrode.

5H is a cross-sectional view of one embodiment of a heater in which a pyrolytic graphite layer is encapsulated in a susceptor.

5I is a cross-sectional view of one embodiment of a heater used in a configuration in which pyrolytic graphite is vertically superimposed.

5J is a top view of the embodiment of FIG. 5I.

6 is a cross-sectional view of one embodiment of a heater of the prior art in a heater having a graphite core.

7A, 7B, 7C, 7D and 7E are cross-sectional views of various embodiments of heaters utilizing a graphite core.

8A and 8B are schematic diagrams of a thermal module (FIG. 8A with an AlN substrate) comprising a prior art heater and an embodiment of the heater of the present invention (TPG layer embedded in an AlN substrate). The module uses computational fluid dynamics (CFD) to examine the surface temperature of the wafer substrate in semiconductor processing operations.

9 is a graph illustrating the temperature distribution of the top surface of a substrate in a prior art heater with an AlN substrate.

10, 11 and 12 are graphs illustrating the temperature distribution of the top surface of a substrate of various heater embodiments of the present invention in which TPG layers having 1 mm, 3 mm and 6 mm thickness are embedded in an AlN substrate.

DESCRIPTION OF THE REFERENCE NUMERALS

1, 1000 metal substrates

2 can-cooling path

3 electric heating coil

4 TPG layer

5, 7 dielectric layers

6 conductive electrode layer

8 annular rings of heat insulating material

10 base plate

12 ceramic substrate

13 upper surface

15 electrical terminals

30, 200 overcoat layer

33 heating device

41, 401, 4001 electrodes

70, 71, 72 layers

300 etching resistant protective coating film

600 TPG Heat Dissipation Plate

600a, 600b line of TPG strips

This application claims the benefit of US patent application Ser. No. 60/826931, filed Sep. 26, 2006, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION The present invention generally relates to heating apparatus for providing a relatively uniform temperature distribution to a substrate in a semiconductor processing chamber or for heating a metal or ceramic mold for a compression molded glass lens.

Many semiconductor processes are typically performed in a sealed chamber containing a vacuum environment, ie an assembly for supporting a wafer substrate disposed therein. In a semiconductor process, a heating device is typically a ceramic support, in which an electrode may be disposed therein for heating the support, and additionally an electrode, ie an electrostatic chuck, that electrostatically holds the wafer or substrate to the ceramic support. Or ESC (or susceptor). Semiconductor device fabrication processes include deposition, etching, implantation, oxidation, and the like, and can occur in a chamber. As an example of a deposition process, a physical vapor deposition (PVD) process, known as sputter deposition, may be considered where a target, typically comprised of a material to be deposited on a wafer substrate, is supported on a substrate and typically adheres to the top of the chamber. have. The plasma is formed from a gas such as argon supplied between the substrate and the target. The target is biased to allow ions in the plasma to accelerate towards the target. Ions in the plasma interact with the target material, causing material atoms to sputter, move past the chamber towards the wafer, and cause redeposition on the semiconductor wafer surface to be processed into an integrated circuit (IC). Other deposition processes include plasma enhanced chemical vapor deposition (PECVD), high density plasma chemical vapor deposition (HDP-CVD), low pressure chemical vapor deposition (LPCVD), atmospheric chemical vapor deposition (SACVD), and metalorganic chemical vapor deposition (MOCVD). And molecular beam evaporation deposition (MBE), but are not limited thereto.

In some of the processes, it is preferable to heat the wafer by heating the support. The chemical reaction rate of the material to be deposited, etched, or implanted is controlled to some extent by the wafer temperature. If the wafer temperature is greatly changed in the entire wafer area, undesirable unevenness may easily occur in deposition, etching, implantation, etc. on the wafer surface. In most cases, deposition, etching, and implantation are required to be nearly uniform, since otherwise ICs fabricated at various locations on the wafer have off-standard electronic features beyond what is desirable.

Molded aspherical lenses are commonly used in ordinary cameras, camera phones and CD players because of their low cost and good performance. They are commonly used for laser diode collimation and are also used to couple light into or out of the optical fiber. A pair of metal or ceramic molds are used to mold the glass gob to make aspherical lenses. In this process a number of heaters are used to heat the mold until the glass mass softens and the glass mass temperature reaches 600 ° C. In the case of using a semiconductor processing chamber, it is preferable that the mold is uniformly heated and its temperature is closely controlled.

Various attempts have been made in the prior art to adjust the temperature of a substrate such as a wafer or a molded lens. In one example of a semiconductor process, an inert cooling gas (such as helium or argon) is introduced at a single pressure in a single narrow space between the top of the ESC and the bottom of the wafer holding the wafer. This method is called backside gas cooling. Another prior art dealing with the need for zone cooling, ie uniform temperature control, is to cut the relief pattern or change the surface roughness to effectively change the local contact area. However, another way to deal with the need for zone cooling is to use a cooling gas that increases and fine-tunes the thermal shift by its pressure change.

US Patent Publication No. 2006 / 0144516A1 describes an adhesive material, ie, a first layer of adhesive material that couples a metal plate and a heater to a top surface of a temperature controlled substrate, and a second layer of adhesive material that couples a dielectric material layer to a top surface of a metal plate. To control the substrate temperature. The adhesive has a physical property that allows the thermal pattern to be maintained under changing external process conditions.

During wafer processing in semiconductor device fabrication and for other substrates in similar processes, there is still a need for a heating device that provides a relatively uniform temperature distribution to the substrate and a method of controlling the temperature of the substrate thereon.

In one aspect, the invention provides a substrate support having a top surface modified to support a substrate; A heating element for heating the substrate to a temperature of at least 300 ° C .; And a layer of pyrolytic graphite material disposed on the substrate with a thermal conductivity of at least 1000 W / m ° C. in a plane parallel to the substrate to be supported, wherein the surface temperature of the substrate is a maximum of the lowest and highest temperature points on the substrate surface. A device for supporting a substrate in a processing chamber and adjusting the surface temperature of the substrate, the temperature difference being adjusted to be 10 ° C.

In another aspect, the invention provides a substrate support having a top surface modified to support a substrate; A heating element for heating the substrate to a temperature of at least 300 ° C .; And processing the substrate on a device having a layer of pyrolytic graphite material (TPG) disposed on the substrate with thermal conductivity of at least 1000 W / m ° C. in a plane parallel to the substrate to be supported, wherein the surface temperature of the substrate is at the lowest A method of adjusting the surface temperature of a substrate is adjusted such that the maximum temperature difference between the temperature point and the highest temperature point is 10 ° C.

Approximating terms, when used herein, may be applied to adjust any quantitative expression that may change without changing the underlying function involved. Thus, the value adjusted by terms such as "about" and "substantially" may not in some cases be limited to the exact value specified.

When a "heating device" is used herein, specifically "processing device", "heater" refers to a device containing one or more heating and / or cooling elements that adjust the temperature of the substrate supported thereon by heating or cooling the substrate. It can be used interchangeably with "electrostatic chuck", "chuck" or "processing device".

The term "substrate" as used herein refers to a semiconductor wafer or glass mold supported / heated by the processing apparatus of the present invention. As used herein, "sheet" can be used interchangeably with "layer."

As used herein, the term "circuit" can be used interchangeably with "electrode" and the term "heating element" is used interchangeably with "heating electrode", "electrode", "register", "heating resistor" or "heater". Can be. The term "circuit" may be used in the singular or plural form indicating that one or more units are present.

As used herein, thermal uniformity or relatively uniform temperature means that the difference between the highest and lowest temperature points on the substrate is less than 10 ° C. In one embodiment thermal uniformity means that the substrate temperature is relatively uniform such that the difference between the highest and lowest temperatures is less than 7 ° C. In another embodiment, the substrate temperature is maintained within a deviation range of less than 5 ° C. In a fourth aspect, the substrate temperature is kept uniform so as to have a deviation of less than 2 ° C.

In a plasma chamber for processing a substrate such as a semiconductor wafer or glass lens, the substrate temperature greatly affects the process. In the case of a processing apparatus that uniformly adjusts the substrate temperature to be treated, it is preferable that the apparatus adjust the substrate surface temperature temporally and spatially. Graphite is an anisotropic material with a unique ability to send heat in a specified direction. Pyrolytic graphite (TPG) is a unique graphite material consisting of highly aligned or oriented and well aligned carbon layers or highly sized microcrystals with highly specified microcrystalline orientations with respect to each other. TPG can be used interchangeably with "highly oriented pyrolytic graphite (" HOPG ") or compression-annealed pyrolytic graphite (" CAPG "). TPG has an in-plane (ab direction) thermal conductivity of greater than 1000 W / mK. Whereas the out-of-plane (z-direction) thermal conductivity is extreme thermal conductivity ranging from 20 to 30 W / mK In one embodiment, the TPG has an in-plane thermal conductivity of greater than 1,500 W / mK.

In various embodiments of the heater device, one or more layers of TPG are embedded in the heater to spatially adjust the surface temperature of the substrate and to dissipate the temperature difference of the various components in the heater device, such as in a heating element having a contact surface in the form of an indented concave-convex shape. Allow the temperature to be relatively uniform. In operation, the semiconductor wafer substrate or glass mold is typically heated to a temperature of at least 300 ° C. and then cooled to room temperature. Heating devices having one or more embedded TPG layers provide a substrate with effective thermal conduction / cooling and good thermal uniformity between heating / cooling elements.

In one embodiment, the TPG layer has a thickness in the range of about 0.5 mm to 15 mm and the thickness deviation (parallel position) is within 0.005 mm. In another embodiment, the TPG layer has a thickness in the range of 1 mm to 10 mm. In a third aspect, the TPG layer has a thickness in the range of 2 mm to 8 mm. The TPG layer is itself embedded as a single layer in the heater of the present invention, or in one embodiment for a heater having a metal substrate (see FIGS. 2 and 3A-3C), the TPG layer is in encapsulated form, such as a structural metal shell. TPG core encapsulated in (shell). Encapsulated TPG is commercially available as TC1050® encapsulated TPG from GE Advanced Ceramics (Strongsville, Ohio). The TPG may be included in the heater as a single continuous sheet or in one aspect as illustrated in FIGS. 5B and 7E as a plurality of small TPG pieces in an overlap / mosaic configuration.

In one embodiment the TPG is fixed and embedded in place in the heater by merely adhering the underlying substrate and / or overcoat they contact. In another embodiment, TPG (pure TPG sheet form, or small piece sizes such as rectangular, square pieces; random sizes; or as TPG cores encapsulated in the metal shell as pure pyrolytic graphite in "strip" form) are known in the art. It is bonded in place using a high temperature adhesive, such as CERAMBOND from Aremco, a silicone binder having a thermal transfer coefficient.

Embodiments of the heating apparatus are described as follows with reference to the materials used, the assembly of the components, their preparation methods and the figures.

General aspect of the heating device

In one embodiment a substrate comprising a disk metal or ceramic substrate 12 having an electrode 16 embedded therein (not shown) and whose upper surface 13 is a wafer or glass mold having a typical diameter of, for example, 300 mm. A heating device 33 which serves as a support surface for W) is illustrated in FIG. 1. In one embodiment the top surface 13 is made of a high plan view (within 0.05 mm surface deviation) to further enhance the temperature control of the substrate W. An electrical terminal 15 for supplying electricity to the heating resistor may be attached to the center of the lower surface of the substrate 12 or in one aspect to the side of the substrate 12.

In one embodiment the upper surface 13 has a relatively uniform temperature, ie the difference between the highest and lowest temperatures on the upper surface is less than 10 ° C. In a second embodiment the temperature difference is less than 5 ° C. The temperature uniformity of the upper surface 13 corresponds to the uniform temperature of the substrate W to be heated. In one embodiment the maximum temperature deviation of the substrate W is 5 ° C. and in the second embodiment the maximum temperature deviation of the substrate is 2 ° C.

One or more electrodes may be used in the heater device. Depending on the application, the electrodes can function as resistive heating elements, plasma-generating electrodes, electrostatic chuck electrodes or electron-beam electrodes. The electrode may be buried upwards (close to the wafer substrate) or buried downwards (away from the wafer substrate) in the heater substrate. The lower position dissipates the electrode pattern and aids in the heat distribution to the wafer substrate.

In one embodiment the electrode is in the form of a film electrode, screen-printing, spin coating, plasma spray, spray pyrolysis, reactive spray deposition, sol-gel, combustion torch, electric arc, ion plating, ion implantation, sputter deposition, laser It is formed by processes known in the art including flux, evaporation deposition, electroplating and laser surface alloys. In one embodiment, the film electrode comprises a metal having a high melting point, such as tungsten, molybdenum, rhenium, platinum or alloys thereof. In another embodiment the film electrode comprises one or more of hafnium, zirconium, carbides or oxides of cerium, and mixtures thereof.

In another embodiment the electrode layer is in the form of a long continuous pyrolytic graphite strip. Pyrolytic graphite (“PG”) is first deposited on heater substrates, such as pyrolytic boron nitride coated graphite substrates, first by processes known in the art such as chemical vapor deposition. The PG is then machined into a predetermined pattern, such as a spiral or serpentine shape. The formation of the electrical pattern of the heating zone, ie the electrically isolated resistive heater path, includes, but is not limited to, micromachining, micro-brading, laser cutting, chemical etching or e-beam etching. ) May be carried out by a method known in the art.

Metal burner

Aspects of the heater can be described by first referring to various aspects of the prior art as illustrated in FIG. 2. The prior art heater 33 in FIG. 2 comprises a metal substrate 1000 made of a high temperature material, such as copper or an aluminum alloy such as A6061. The electrode 4001 is embedded in the metal substrate 1000. In one embodiment the electrode comprises an electrical wire surrounded by a thermally conductive ceramic insulator sold with a Calrod® heating element. In one embodiment the Calrod® heating element has a non-uniform serpentine pattern to provide tailored heat distribution across the top surface of the heater.

In a typical embodiment of the prior art as illustrated in FIG. 2, the temperature generated by the embedded heating element 4001 is not evenly distributed, so that T1-T2 may differ by substantially 50 ° C. or more. As a result, the temperatures on the top surface of the heater, such as T1 'and T2', generally have a temperature difference that can be 20 ° C or higher and are not evenly distributed. As a result, the temperature distribution on the substrate W has a temperature difference that can be greater than 10 ° C. between two extreme temperature points and is not evenly distributed. Non-uniform wafer temperatures (eg, T1 "-T2"> 10 ° C) are undesirable in terms of semiconductor processing because they can cause a loss in yield in semiconductor device fabrication.

In embodiments of the metal heater as illustrated in FIGS. 3A-3C, one or more TPG heat dissipation plates 600 are embedded in the metal substrate 1000 to have a relatively uniform temperature across the substrate W so that the substrate W Spatially distribute and adjust the heat removal and / or distribution for. In one embodiment the heat dissipation plate 600 includes a TPG core encapsulated within a structural metal shell.

3A illustrates one aspect of a metal heater having an electrode 4001 in the form of an electrical wire surrounded by a thermally conductive ceramic insulator (not shown) and embedded in a metal substrate 1000. 3B illustrates another embodiment of a heater having a metal substrate and a film electrode 4001 formed on the metal substrate substrate 18 having a thickness in the range of 5 to 1000 μm and electrically insulated. 3C illustrates another embodiment of a heater 33 having a metal substrate. The metal substrate 1 comprises a copper or aluminum alloy and houses a plurality of water-cooling paths 2 and an electric heating coil 3. The top surface of the metal substrate 1 comprises a conductive electrode layer 6 located between two dielectric layers 5, 7 comprising diamond-like carbon (DLC). The TPG layer 4 is added between the heater 3, the cooler 2 and the top surface. The TPG layer enhances thermal conductivity due to its anisotropic thermal conductivity and adjusts the temperature distribution for the wafer located on the heater 33 (not shown). Outside the heater assembly there is an annular ring 8 of heat insulating material such as alumina to further enhance thermal uniformity.

Ceramic core burner

The aspect of the heater with the ceramic core can be described by first referring to the ceramic core heater of the prior art as shown in FIG. The substrate substrate 18 in the ceramic core heater comprises oxides, nitrides, carbides, carbonitrides and oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals; And electrically insulating materials selected from the group consisting of combinations thereof (eg, sintered substrates). The base substrate 10 is characterized by having high wear resistance and high heat resistance. In one embodiment, the substrate substrate 10 comprises a sintering agent selected from the group consisting of AlN of purity greater than 99.7%, and Y ₂ O ₃ , Er ₂ O _3, and combinations thereof.

Substrate substrate 10 is coated with an electrically insulating overcoat layer 30. In one embodiment there is an optional connection layer (not shown) to assist in strengthening the adhesion between the overcoat layer 30 and the substrate substrate 10. Examples of electrically conductive materials include graphite; Refractory metals, transition metals, rare earth metals and alloys such as W and Mo; Oxides and carbides of hafnium, zirconium and cerium; And mixtures thereof.

With respect to the overcoat layer 30, the layer 30 comprises oxides, nitrides, carbides, carbonitrides or oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals; Oxides or oxynitrides of aluminum; Combinations thereof; High-heat stable zirconium phosphate having an NZP structure of NaZr ₂ (PO ₄ ) ₃ ; Glass-ceramic compositions containing one or more elements selected from the group consisting of Group 2a, Group 3a, and Group 4a elements; BaO-Al ₂ O ₃ -B ₂ O ₃ -SiO ₂ glass; And a mixture of plasma resistant materials comprising SiO ₂ and oxides or fluorides such as Y, Sc, La, Ce, Gd, Eu, Dy, or yttrium-aluminum-garnet (YAG); And combinations thereof.

With regard to the optional linking layer, the layer is Al, Si, and nitrides, carbides, carbonitrides of elements selected from the group consisting of refractory metals including Ta, W, Mo, and transition metals including titanium, chromium, iron Borides, oxides, oxynitrides; And mixtures thereof. Examples include TiC, TaC, SiC, MoC and mixtures thereof.

Conductive electrode 41 having an optimal circuit design is formed on ceramic substrate 10. The electrode 41 includes tungsten, molybdenum, rhenium, platinum and alloys thereof; Carbides and nitrides of metals belonging to groups IVa, Va, and VIa of the periodic table; Carbides or oxides of hafnium, zirconium and cerium, and combinations thereof. In one embodiment the electrode 41 comprises a material having a CTE close to the CTE of the substrate 10 (or coating layer 30 thereof). Proximity of the CTE means that one material has a CTE in the range of 0.75 to 1.25 of the CTE of the second material.

In prior art heaters the temperature distribution on the substrate W is typically not uniformly distributed, for example T1 "-T2" is greater than 10 ° C. In various embodiments of a heater with a ceramic core as illustrated in FIGS. 5A-5E, in a substrate W having a relatively uniform temperature distribution in which, in one embodiment, T1 "-T2" is less than 10 ° C and in other embodiments less than 5 ° C. The embedded TPG heat dissipation plate 600 spatially distributes and / or adjusts heat removal and / or distribution to the substrate W so that the temperature is relatively uniform.

In one embodiment as illustrated in FIG. 5A, one or more TPG layers 600 are inserted between two layers (or slabs) of green body prior to the final sintering process. In another embodiment, the TPG layer is inserted into a ceramic material, such as AlN, prior to hot compression. In another embodiment, the TPG layer (pure TPG form or encapsulated TPG form) is embedded in the ceramic substrate through processes known in the art, including but not limited to slip casting. After the TPG layer is embedded, the electrode 41 is patterned on the ceramic substrate 10, and the substrate substrate along the electrode 41 is overcoated with the electrically insulating layer 30.

In another embodiment of the heater as illustrated in FIG. 5B, two layers of TPG are used in the ceramic substrate. As shown, holes are drilled through the TPG layer to promote adhesion between the ceramic material layers. Holes can be positioned to offset one another for better temperature distribution and adjustment.

In FIG. 5C, the TPG layer is not embedded in the ceramic substrate 10 as in the previous embodiment. In this embodiment the TPG layer is located on top of the ceramic substrate 10 (opposite to the electrode 41) prior to applying the overcoat 30. In one embodiment, the TPG layer 600 is first firmly adhered to the ceramic substrate 10 before the overcoat 30 is applied.

In FIG. 5D, a heater 33 is provided in which the TPG layer 600 is first coated by a ceramic coating layer or a connecting layer (not shown) prior to being embedded in the ceramic substrate 10 through sintering. In one embodiment the coating of TPG layer 600 comprises Al, Si, and refractory metals including Ta, W, Mo, and nitrides, carbides, carbonitrides, and the like selected from the group consisting of transition metals including titanium, chromium, iron, Borides, oxides, oxynitrides; And mixtures thereof.

5E illustrates an embodiment in which the heater also functions as an electrostatic chuck. Layers 70 and 72 in this embodiment comprise the same or different dielectric materials, such as alumina or diamond-like carbon (DLC). Layer 71 is a conductive layer, such as a chuck electrode, for example a metallized film. The layers are bonded to each other and to the substrate 10 using high temperature adhesives known in the art. One or more TPG layers (as TPG sheets or encapsulated TPG cores) 600 are patterned and embedded in ceramic core 10 using ceramic fabrication methods known in the art.

In FIG. 5F, the pyrolytic graphite layer 600 is patterned and embedded in the ceramic core 10 using ceramic fabrication methods known in the art, although in this embodiment the TPG layer 600 is also a thermal electrode as well as a continuous electrode. It also functions as. TPG is also electrically conductive with a resistance of ˜0.5 × 10 ⁻³ ohm-cm, and thus serves as a heating element if the substrate temperature can be adjusted. In addition, the high thermal conductivity of the TPG distributes the heat generated more evenly and as a result helps to achieve the desired thermal uniformity.

In FIG. 5G, the TPG layer is embedded in the ceramic substrate and electrically connected to an external power source or ground. In addition to its function as a high thermal conductivity plane, the TPG layer of this configuration may be used as an RF electrode to enhance plasma inside the wafer processing apparatus, or as an RF shield to eliminate electrical interference between the RF field and the heating element. .

5H illustrates an embodiment in which susceptor 20 rests on top of heater 33. The TPG layer 600 is encapsulated in a susceptor 20 that includes materials known in the art, such as metals, ceramics, graphite, polymeric materials, or combinations thereof, for the manufacture of susceptors. The high thermal conductivity direction of the TPG is in the plane of the TPG layer 600. In one embodiment the susceptor 20 comprises aluminum. In another embodiment, susceptor 20 comprises anodized aluminum in which TPG layer 600 is encapsulated.

In the embodiment of FIG. 5I a number of small TPG pieces or strips are used in a vertically overlapping configuration to form a “stripe”. In one embodiment, a row of TPG strips 600a are embedded in the heater in one plane such that the longitudinal directions of the TPG strips are substantially parallel to each other. Another row of TPG strips 600b is embedded in another plane lower than the first plane 600a, with the longitudinal direction of the strip 600b being substantially perpendicular to the longitudinal direction of the TPG strip 600a of the first plane. to be. The high thermal conductivity direction of the TPG in both planes is in the same plane of the TPG strip. FIG. 5J is a top view of the overlapping configuration of FIG. 5I.

Graphite core burner

One aspect of a prior art graphite core heater 33 having a graphite core substrate 100 is referred to in connection with FIG. 6. Although graphite is shown as the core 100, it is graphite according to the use; Refractory metals, transition metals, rare earth metals and alloys such as W and Mo; Other electrically conductive materials can be used, including but not limited to oxides and carbides of hafnium, zirconium and cerium, and mixtures thereof. The core 100 is coated with an electrically insulating overcoat layer 200, and optionally with a connection layer (not shown) to help strengthen adhesion between the overcoat layer 200 and the substrate substrate core 100. In relation to the overcoat layer 200, the layer comprises oxides, nitrides, carbides, carbonitrides, oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals; Oxides, oxynitrides of aluminum; And combinations thereof. One example is pyrolytic boron nitride (pBN). With respect to the optional linking layer, the layer comprises Al, Si, and refractory metals including Ta, W, Mo, and nitrides, carbides, carbonitrides, of elements selected from the group consisting of transition metals including titanium, chromium, iron, Borides, oxides, oxynitrides, and mixtures thereof. Examples include TiC, TaC, SiC, MoC and mixtures thereof.

The electrode 401 includes a film electrode 16 having a thickness in the range of 5 to 1000 μm and formed on the electrically insulating layer 200 by a method known in the art. In one embodiment the film electrode 401 comprises a metal having a high melting point, such as tungsten, molybdenum, rhenium, platinum or alloys thereof. In another embodiment the film electrode 401 includes one or more of hafnium, zirconium, carbides or oxides of cerium, and mixtures thereof. In one embodiment, an electrolytic copper foil having an 18 μm film thickness is used as the electrode 401. Heater 33 includes at least one of nitride, carbide, carbonitride or oxynitride of an element selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloy and transition metal, and combinations thereof It is further coated with a etch resistant protective coating film 300 having a CTE in the range of 2.0 × 10 ⁻⁶ / K to 10 × 10 ⁻⁶ / K in a temperature range of 25 to 1000 ° C. In another embodiment, the layer 300 comprises high-heat stable zirconium phosphate. In a third aspect, the layer 300 contains a glass-ceramic composition containing one or more elements selected from the group consisting of elements of Groups 2a, 3a, and 4a of the Periodic Table of Elements. Examples of suitable glass-ceramic compositions include lanthanum aluminosilicate (LAS), magnesium aluminosilicate (MAS), calcium aluminosilicate (CAS) and yttrium aluminosilicate (YAS). The thickness of the protective coating layer 300 varies from 1 μm to several hundred μm depending on the application and the process used, such as CVD, ion plating, ETP, and the like.

In various embodiments of a heater having a graphite core as a variant of the prior art heater illustrated in FIG. 6, the heater has a substrate (T1 " -T2 " W) Use one or more embedded TPG heat dissipation plates 600 to distribute and / or adjust the temperature throughout. Various aspects of the heater 33 are illustrated in FIGS. 7A-7E.

FIG. 7A illustrates a heater 33 in which a TPG heat release plate 600 is embedded in a heater between substrate coating 200 and overcoat layer 300. The TPG layer 600 is fixed in place by merely adhering the overcoat and substrate coat that they contact. In one aspect, the TPG layer 600 includes a plurality of through-holes at selected locations where the overcoat and substrate coat layer may be connected and bonded. In another embodiment, the TPG 600 is adhered in place by a high temperature compatible adhesive, such as Cerabond® adhesive from Aremco Corporation.

In FIG. 7B, the TPG heat dissipation plate 600 is embedded in a heater between the graphite substrate 100 and the substrate coating layer 200 (on the top surface close to the substrate W). The TPG 600 may simply adhere the substrate coat and substrate to which they are in contact, or simply include a number of through holes in the substrate coat to be connected to the substrate 100 for further adhesion, or by using only a high temperature adhesive It can be fixed in place. In another embodiment, pyrolytic graphite is deposited on the graphite substrate 100 and then moved through a thermal annealing process to form a TPG layer 600 that is directly bonded to the graphite substrate 100.

FIG. 7C is a variation of the heater 33 of FIG. 7B in which the position of the TPG heat dissipation plate 600 has been changed, such that the TPG heat dissipation plate 600 is also between the graphite substrate 100 and the substrate coat 200 and also graphite. It is embedded in the heater at the bottom of the substrate 100.

In FIG. 7D, two or more TPG heat dissipation plates 600 are used which are buried above both the top and bottom of the heater between the graphite substrate 100 and the substrate coat layer 200.

FIG. 7E illustrates one embodiment of a heater 33 in which a number of TPG heat dissipation plates 600 are used and embedded on top of the heater 33. In one embodiment a plurality of through holes are provided in the TPG layer 600 to promote adhesion between the graphite substrate, the substrate coat 200 and the overcoat 300. In another embodiment, small pieces of TPG are used so that most of the holes and the majority of the boundaries are offset relative to each other and form a mosaic configuration in the overlapping layer.

In the illustrated embodiment, the electrode is located at the bottom of (or near) the heater 33 for optimal thermal design. However, another aspect is contemplated (not shown) with a patterned electrode on top of the heater 33 (near the support wafer) for a heater with a uniform temperature distribution on the substrate. In another embodiment (not shown), the TPG layer is positioned between the patterned electrode and the wafer substrate W located on top of the heater 33. In another embodiment (not shown), the TPG layer where the c-direction of the TPG layer is a barrier to heat flow is as effective as located under the heater pattern for improved efficacy and heater distribution.

Heaters of the present invention include, but are not limited to, many different processes, including, but not limited to, plasma-etching chambers for processed glass molds, or atomic layer epitaxy (ALD), low pressure CVD (LPCVD), and plasma-enhanced CVD (PECVD). It may be used in a semiconductor processing chamber.

The invention is further illustrated by the following non-limiting examples.

Example

In the examples, computational fluid dynamics (CFD) calculations were performed to design heater assemblies. 8A and 8B are schematic diagrams of models fabricated to compare the performance of prior art heaters with one embodiment of a heater having one or more embedded TPG layers. The model is an axis-symmetric two-dimensional model.

Sintered AlN in prior art heater models is used in ceramic cores with isotropic thermal conductivity of 160 W / m-K. In a model of one embodiment of the heater of the present invention, the TPG layer is embedded in a sintered AlN ceramic core. The TPG layer has anisotropic thermal conductivity of 1500 W / m-K in the horizontal plane and anisotropic thermal conductivity of 20 W / m-K in the vertical plane. In the calculations, full contact between TPG and AlN is expected. The TPG thickness th and the distance d from the top surface on which the TPG is located vary.

In the model, a single wafer is heated by varying power input levels. Power is input to the electrode at the bottom of the substrate / electrode system and the temperature is determined on top of the structure as a function of position. From these data, the highest and lowest temperature differences are calculated. As explained, the surface (with a virtual emissivity of 0.4) is radiated into free space with a 0 ° C. background temperature. Temperature uniformity on the wafer surface is defined as the difference between the highest temperature and the lowest temperature measured by a thermocouple placed across the wafer surface. The need for uniformity is strict for metalorganic chemical vapor deposition (MOCVD) processes. Thus, a 1 ° C. change in temperature uniformity affects the deposition process. The results of the computer model are illustrated in Figures 9-12.

9 is a profile of wafer temperature in a prior art heater with 10 W, 200 W and 1000 W power inputs in the electrode. Model the temperature distribution on the top surface of the wafer structure.

10-12 are profiles of various embodiments of heaters of the present invention. 10 shows the temperature profile of a heater using a 1 mm thick TPG layer embedded in an AlN core substrate. The TPG layer is located 2.5 mm away from the top, but the results indicate that the temperature distribution is relatively unaffected by the position of the TPG layer.

In FIG. 11, a thicker 3 mm thick TPG layer is embedded in one embodiment of an AlN core heater, with 10 W, 200 W or 1000 W power input to the electrode. The results show a significant improvement in temperature uniformity, especially at lower power inputs. The model results also indicate that the temperature distribution is relatively unaffected by the position of the TPG layer.

12 shows a remarkably uniform temperature distribution on the top surface of the structure in which a 6 mm thick TPG layer is embedded 2.5 mm away from the top of the heater (away from the wafer). T _max -T _min varies from 0.03 to 7.7 ° C. depending on the power input level. As shown, at each power level, the TPG thickness has a maximum temperature uniformity across the wafer substrate, i.e. in one embodiment T _max -T _min is less than 5 ° C., in some applications, T _max -T _min is 2 ° C. Can be optimized to be less than.

The detailed description of the invention uses examples to describe the invention, including the best embodiments, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the following claims, and may include other examples that occur to those skilled in the art. Such other embodiments are considered to be within the scope of the claims as long as they have structural elements that do not depart from the description of the claims, or include equivalent structural elements that do not differ substantially from the claims. All citations described herein are expressly incorporated herein by reference.

According to the present invention, there is provided a heating device that provides a relatively uniform temperature distribution to a substrate for another substrate during wafer processing in semiconductor device fabrication, and a method of controlling the temperature of the substrate overlying the wafer temperature so that It hardly changes, and as a result, deposition, etching, implantation, etc. on the wafer surface can be performed uniformly.

Claims (20)

A substrate support having a surface modified to support a substrate; A heating element for heating the substrate to a temperature of at least 300 ° C .; And At least one layer of pyrolytic graphite (TPG) disposed on the substrate support having a thermal conductivity of at least 1000 W / m ° C. in a plane parallel to the substrate being supported. Wherein the maximum temperature difference between the lowest temperature point and the highest temperature point on the substrate support surface is 10 ° C., wherein the apparatus is for supporting the substrate in the processing chamber and adjusting the surface temperature of the substrate. The method of claim 1, Supporting a wafer substrate in a semiconductor processing chamber, wherein the maximum temperature difference on the surface of the wafer substrate is 5 ° C. 3. The method according to claim 1 or 2, The device of which the thickness of the TPG layer is 0.5 to 15 mm. 3. The method according to claim 1 or 2, Wherein the thickness difference of the TPG layers is less than 0.005 mm. 3. The method according to claim 1 or 2, And the TPG layer comprises a plurality of TPG pieces having the same or different size and geometry. 3. The method according to claim 1 or 2, The TPG layer comprises a plurality of TPG strips having a longitudinal direction, wherein the strips are used in a vertically overlapping configuration to form stripes; Two or more TPG strips are located in the first plane, wherein the longitudinal directions of the TPG strips are substantially parallel to each other; Two or more TPG strips are located in a second plane away from the first plane, wherein the longitudinal direction of the TPG strip is perpendicular to the longitudinal direction of the TPG strip in the first plane; The TPG layer has a thermal conductivity of at least 1000 W / m-K in both the first plane and the second plane, Device. 3. The method according to claim 1 or 2, Further comprising a susceptor disposed on the substrate support to directly support the substrate, Wherein the susceptor comprises aluminum or an aluminum alloy; The base substrate is an oxide, nitride, carbide, carbonitride and oxynitride of an element selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals; And a sintered material selected from the group consisting of: Device. 3. The method according to claim 1 or 2, The substrate support for supporting the substrate to be processed includes high temperature metals and alloys thereof; Bulk graphite; Refractory metals, transition metals, rare earth metals and alloys thereof; Oxides and carbides of hafnium, zirconium and cerium, and mixtures thereof; Oxides, nitrides, carbides, carbonitrides and oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals; And combinations thereof. 3. The method according to claim 1 or 2, Used to support wafer substrates in semiconductor processing chambers, Wherein the substrate support for supporting the wafer comprises a substrate substrate comprising at least one of copper, aluminum and alloys thereof; At least one TPG layer is embedded in the metal based substrate; A heating element for heating the substrate to a temperature of 300 ° C. or higher is fitted to the metal substrate substrate under the TPG layer and in a direction away from the wafer substrate, Device. 3. The method according to claim 1 or 2, Used to support wafer substrates in semiconductor processing chambers, Wherein the substrate support for supporting the wafer substrate comprises a substrate substrate comprising at least one of copper, aluminum and alloys thereof; A heating element is positioned between the two dielectric layers to heat the substrate to a temperature of at least 300 ° C. and disposed on the metal based substrate; At least one TPG layer is fitted to the metal based substrate under the heating element and dielectric layer and away from the wafer group, Device. 3. The method according to claim 1 or 2, Used to support wafer substrates in semiconductor processing chambers, At this time, the substrate support for supporting the wafer substrate is an oxide, nitride, carbide, carbonitride and oxynitride of an element selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloy and transition metal, and combinations thereof A substrate substrate comprising a ceramic material selected from said ceramic substrate substrate having a top surface and a bottom surface facing away from a wafer supported on said device; At least one TPG layer is embedded in the ceramic base substrate; A heating element for heating the substrate to a temperature of 300 ° C. or more is disposed on the lower surface of the ceramic base substrate, Device. 3. The method according to claim 1 or 2, And the TPG layer is electrically connected to an external power source or ground for use as an RF electrode. Oxides, nitrides, carbides, carbonitrides and oxynitrides of an element having a surface modified to support a substrate and selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals, and combinations thereof A substrate support comprising a substrate substrate comprising a ceramic material selected from the group consisting of: wherein the ceramic substrate substrate has an upper surface and a lower surface facing away from the wafer supported on the device, wherein the substrate substrate is a ceramic substrate Further comprising a first coating layer for coating the substrate, said coating layer being an oxide, nitride and oxynitride of an element selected from the group consisting of Al, B, Si, Ga, refractory hard alloys and transition metals, and combinations thereof A substrate support comprising one of; A heating element disposed on the bottom surface of the ceramic base substrate for heating the substrate to a temperature of at least 300 ° C; And One or more layers of TPG material disposed on the substrate support, having a thermal conductivity of at least 1000 W / m ° C. in a plane parallel to the substrate being supported and sandwiched within or between the ceramic substrate substrate and the first coating layer. Wherein the maximum temperature difference between the lowest temperature point and the highest temperature point on the substrate support surface is 10 ° C., wherein the apparatus is for supporting the substrate in the processing chamber and adjusting the surface temperature of the substrate. A substrate substrate comprising bulk graphite having an upper surface and a lower surface facing away from the wafer supported on the device; An agent for coating a graphite based substrate comprising an electrically insulating material selected from oxides, nitrides and oxynitrides of an element selected from the group consisting of Al, B, Si, Ga, refractory hard alloys and transition metals, and combinations thereof. 1 coating layer; At least one TPG layer disposed on the first coating layer or disposed between the graphite based substrate and the first coating layer; A heating element disposed on the bottom surface of the coated graphite substrate substrate for heating the substrate to a temperature of at least 300 ° C; And Nitrides, carbides, carbonitrides and oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals, and combinations thereof; Zirconium phosphate having an NZP structure of NaZr ₂ (PO ₄ ) ₃ ; Glass-ceramic compositions containing one or more elements selected from the group consisting of Group 2a, Group 3a, and Group 4a elements; BaO-Al ₂ O ₃ -B ₂ O ₃ -SiO ₂ glass; And a mixture of SiO ₂ and a plasma resistant material comprising oxides or fluorides of Y, Sc, La, Ce, Gd, Eu, Dy and yttrium-aluminum-garnet (YAG). Overcoat layer An apparatus for supporting a wafer substrate in a semiconductor processing chamber having a substrate support comprising a temperature difference of 10 ° C. between a lowest temperature point and a highest temperature point on a wafer supported by the device. 15. The method of claim 14, Wherein the substrate support comprises two layers of TPG, a first layer and a second layer, wherein the first layer is disposed on an upper surface of the graphite substrate and the second layer is disposed on a lower surface of the graphite substrate. 15. The method of claim 14, The substrate support comprises two layers of TPG, a first layer and a second layer, wherein the first layer is disposed between the graphite substrate and the first coating layer on the top surface of the graphite substrate, and the second layer is at the top surface of the graphite substrate. Disposed on the first coating layer. 15. The method of claim 14, The substrate support comprises two layers of TPG, a first layer and a second layer, wherein the first layer is disposed between the graphite substrate and the first coating layer on the lower surface of the graphite substrate, and the second layer is at the upper surface of the graphite substrate. Disposed on the first coating layer. 15. The method of claim 14, At least one TPG layer is disposed between the graphite based substrate and the first coating layer on the upper surface of the graphite based substrate. 15. The method of claim 14, At least one TPG layer is disposed between the graphite based substrate and the first coating layer on the bottom surface of the graphite based substrate. Ceramic materials selected from oxides, nitrides, carbides, carbonitrides and oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals, and combinations thereof, wherein the ceramic A base substrate having an upper surface and a lower surface directed in a direction away from the wafer supported by the apparatus; One or more TPG layers disposed on the top surface of the substrate substrate; Oxides, nitrides, carbides, carbonitrides and oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals; Oxides and oxynitrides of aluminum; And a first coating layer for coating the TPG layer and the ceramic base substrate comprising an electrically insulating material selected from the group consisting of a combination thereof. Pyrolytic graphite; Refractory metals; Transition metals, rare earth metals and alloys; Oxides and carbides of hafnium, zirconium and cerium; And a heating element disposed on the first coating layer, the heating element comprising one of a mixture thereof. And Nitrides, carbides, carbonitrides and oxynitrides of elements selected from the group consisting of B, Al, Si, Ga, Y, refractory hard alloys and transition metals, and combinations thereof; Zirconium phosphate having an NZP structure of NaZr ₂ (PO ₄ ) ₃ ; Glass-ceramic compositions containing one or more elements selected from the group consisting of Group 2a, Group 3a, and Group 4a elements; BaO-Al ₂ O ₃ -B ₂ O ₃ -SiO ₂ glass; And a mixture of SiO ₂ and a plasma resistant material comprising oxides or fluorides of Y, Sc, La, Ce, Gd, Eu, Dy and yttrium-aluminum-garnet (YAG). Overcoat layer 10. An apparatus for use in supporting a wafer substrate in a semiconductor processing chamber having a substrate support comprising a temperature difference of 10 ° C. between a lowest temperature point and a highest temperature point on a wafer supported by the device.

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