Diamond structure for touring

Abstract

A tool such as a wafer handler or wafer chuck can include a surface having at least one protrusion. The diamond coating is formed from diamond particles sized such that 90% of the particles are 200-300 nanometers, and the diamond coating is deposited on the surface on the at least one protrusion at a temperature below 500 degrees Celsius. A dopant can be used to provide the electrical conductivity required for an electrostatic wafer chuck.

Description

[Technical field]

[0001] This disclosure is part of a provisional patent application claiming priority to U.S. Patent Application No. 63 / 223,752, filed July 20, 2021, and is incorporated by reference in its entirety.

[0002] The present disclosure relates generally to the field of materials and coatings for improving tool properties. More specifically, a diamond bump structure and manufacturing method for wafer support tools is disclosed. [Background technology]

[0003] There is a demand for tools with coatings and structures that improve performance. For example, tools may have coatings that improve hardness, reduce wear, decrease chemical reactivity, or increase or decrease frictional properties.

[0004] For example, semiconductor wafers can be handled with vacuum or electrostatic chuck tools that can be coated with materials that reduce wear. Coated chuck tools are required to support and move the wafer during many steps of wafer lithography with nanometer-scale precision. Unfortunately, the wafer can twist or sag. When lowered onto the wafer chuck, friction between the wafer and the chuck tool can prevent the wafer from flattening or moving into the correct position. To reduce such frictional effects, the contact area between the wafer and the chuck tool can be reduced by providing raised areas of approximately uniform height, usually at regular intervals, on the chuck tool. These raised areas are known as burls and help reduce friction so that the wafer can move across the burls as it flattens and settles onto the chuck tool. Often, uneven or misshapen burls can cause wear or damage to the wafer.

[0005] Materials, structures and procedures are needed that reduce or eliminate tool friction and wear problems. [Brief description of the drawings]

[0006] Non-limiting and non-exhaustive embodiments of the present disclosure are described with reference to the following figures, in which like reference numerals refer to like parts throughout the various views unless otherwise specified. [Figure 1A] 1A and 1B show cross-sectional and top views of a conformal diamond coated tool surface with protrusions. [Figure 1B] 1A and 1B show cross-sectional and top views of a conformal diamond coated tool surface with protrusions. [Figure 1C] FIG. 1C is a photograph of a cross section of a conformal diamond coated protrusion. [Figure 1D] FIG. 1D shows selected diamond particle sizes. [Diagram 2] FIG. 2 illustrates one embodiment of a process for producing a conformal diamond coated tool surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] In some embodiments as described with respect to the disclosed drawings and specification, a tool such as a wafer handler or wafer chuck can include a surface having at least one protrusion. The diamond coating is formed from diamond particles sized such that 90% of the particles are 200-300 nanometers, and the diamond coating is deposited on the at least one protrusion at a temperature less than 600 degrees Celsius, 500 degrees Celsius, or 450 degrees Celsius, respectively. A dopant can be used to obtain the electrical conductivity required for the electrostatic wafer chuck.

[0008] In some embodiments, the at least one protrusion is a burl or multiple burls that extend at least partially above the tool surface and are capable of supporting a wafer or other object.

[0009] In some embodiments, the diamond coating is formed to have grains of equal size less than 1 micron. The diamond coating can be formed to continuously or partially cover the tool or burr projections.

[0010] In some embodiments, the diamond coating has a thickness between 200 nanometers and 100 microns. The diamond coating can be uniformly thick over selected areas of the tool or can be conformal over areas of the tool.

[0011] In one embodiment, a method of diamond coating a tool includes providing a surface of the tool having at least one protrusion and forming a diamond coating on the at least one protrusion. The diamond coating can be formed from diamond particles sized such that 90% of the particles are 200-300 nanometers in size. The diamond coating can be deposited on the at least one protrusion at a temperature of less than 500 degrees Celsius.

[0012] 1A and 1B are a cross-sectional view (FIG. 1A) and a top view (FIG. 1B) of a portion of a tool 100A. The tool 100A includes a substrate 112 having a surface 114. There are also protrusions 120 extending from the substrate 112. These protrusions 120 can be coated with a diamond film 130 that extends over the protrusions 120 (e.g., diamond film portion 132) and other portions of the tool surface 114 (e.g., diamond film portion 134) to provide friction reduction, protection, heat transfer, or other desired properties. In some embodiments, the diamond film 130 conformally coats the protrusions, with the thickness of the coating remaining constant or varying by less than 500, 300, or 100 nanometers as it extends over each protrusion 120, respectively. The tool 100A can be coated entirely with a diamond film, coated on one or more faces, or coated in selected areas.

[0013] Tools include, but are not limited to, precision carriers, graspers, lifters, or other handling tools. Tools may also include needles, pins, injectors, nano- or micropipes, fluid handling channels or manifolds. Additionally, tools can be used for drilling, cutting, grinding, polishing, or insertion.

[0014] In some embodiments, the tool can be a semiconductor wafer handling tool such as a wafer chuck, wafer holder, wafer stage, wafer table, wafer substrate, die scanner, wafer table for chemical mechanical polishing (CMP), or wafer carrier. In the case of an electrostatic wafer chuck or other electrically active tool, p or n doping of the diamond film can be performed. In other embodiments, tools that require or use nanoscale protrusions to affect the mechanical, electrical, or chemical properties of the tool can be coated with diamond material. In still other embodiments, the tool can be a sensor or other system that can use nanoscale protrusions to provide multiple point contacts with other materials or the environment. For example, a diamond coated sensor can be integrated into a wafer chuck.

[0015] In some embodiments, substrate materials for tool 100A can include Si, SiC, SiSiC, amorphous silicon, diamond-like carbon, metal-doped oxide glass materials; polymeric materials; ceramics such as quartz, sapphire; metals and alloys; and mixtures and combinations thereof.

[0016] In some embodiments, the protrusions may include burls, mesas, bumps, pins, islands, surface structures, nano-protrusions, etc. According to one embodiment, the protrusions on the wafer chuck may have a size, spacing, and composition that enables them to maintain a substantially uniform pressure across the surface of the wafer and a substantially uniform distribution of force between the protrusions and the substrate.

[0017] In one embodiment, the wafer handling protrusions may include burls formed on a wafer tool by selective growth. Alternatively, the burls may be formed by applying photoresist, patterning the photoresist, and dissolving the unprotected areas. In yet another embodiment, the tool burls may be formed using laser sintering or other additive manufacturing techniques. The burls may be formed from the substrate material, thin films deposited on the substrate, low thermal expansion glass ceramics such as cordierite, silicon carbide (SiC), SiSiC, aluminum nitride, or may include SiC in the form of a composite material such as reaction-bonded SiC.

[0018] In some embodiments, hundreds or thousands of burls are distributed throughout the wafer tool, and each burl can have a diameter of at least 200 mm, 300 mm, or 450 mm. The tips of the burls typically have a small area, e.g., less than 1 square millimeter. The burls can have a width (e.g., diameter) of 0.5 mm or less. In one embodiment, the burls have a width (e.g., diameter) in the range of about 200 μm to about 500 μm. The spacing between the burls can be between about 1.5 mm to about 3 mm.

[0019] The burls can be arranged to form a pattern and / or have a periodic arrangement. The arrangement of the burls can have equilateral triangular, hexagonal, square, or radial symmetry and can be varied to provide the required distribution of force from the wafer tool to the wafer. Alternatively, the burls can be laid out in a semi-random, random, or partially symmetrical layout. The burls can have the same shape and dimensions throughout their height, but are commonly dome-shaped, conical, hemispherical, pyramidal, needle-like, or tapered. Typically, the burls protrude from the wafer tool in the range of about 1 μm to about 5 mm, and often protrude from about 5 μm to about 250 μm. For best wafer handling results, the burls can be formed to have consistent dimensions. For best wafer handling results, minimize the variation between the heights of the different burls.

[0020] In some embodiments, the burrs or other projections coated with diamond film 120 may include coatings of various diamond, diamond-like, or diamond-containing materials and structures. For purposes of this disclosure, diamond refers to sp 3 It refers to the crystal structure of carbon atoms bonded to other carbon atoms in a lattice of tetrahedral coordination known as bonding. Each carbon atom can be surrounded and bonded to four other carbon atoms, each located at the tip of a regular tetrahedron. In some embodiments, the tetrahedral bonding configuration of the carbon atoms can be irregular or distorted, or can otherwise deviate from the standard tetrahedral configuration of diamond as described above. Such distortion generally results in some bonds being longer and others being shorter, as well as changes in the bond angles between the bonds. In addition, tetrahedral distortion changes the properties of carbon, resulting in sp 3 Carbon bonded in the configuration (i.e. diamond) and sp 2The properties of carbon bonded in a distorted tetrahedral configuration (i.e., graphite) fall substantially between those of carbon bonded in a distorted tetrahedral configuration. One example of a material with carbon atoms bonded in distorted tetrahedral configuration is amorphous diamond. In one embodiment, the amount of carbon in amorphous diamond is at least about 90%, with at least about 20% of such carbon bonded in distorted tetrahedral configuration. Amorphous diamond can have a higher atomic density than diamond. In other diamond film embodiments, diamond-like carbon can be formed as a carbonaceous material having carbon atoms as the majority element, with a significant amount of such carbon atoms bonded in distorted tetrahedral configuration. Diamond films can include a variety of other elements as impurities or dopants, including, but not limited to, hydrogen, sulfur, phosphorus, boron, nitrogen, silicon, or tungsten. This can be useful, for example, to modify the electrical or chemical diamond film properties to support tool requirements.

[0021] Diamond deposition can be performed by any process, including, but not limited to, chemical vapor deposition (CVD) or physical vapor deposition (PVD). A wide variety of embodiments of deposition methods can be used. Examples of deposition methods include hot filament CVD, rf-CVD, laser CVD (LCVD), laser ablation, conformal diamond coating processing, metal organic CVD (MOCVD), sputtering, thermal evaporation PVD, ionized metal PVD (IMPVD), electron beam PVD (EBPVD), reactive PVD, cathodic arc, and the like.

[0022] In some embodiments, diamond films can be deposited at relatively low temperatures, below 600, 500, or 450 degrees Celsius, using an activating medium such as plasma, argon gas, and a carbon source such as methane. In other embodiments, deposition can be performed at temperatures between 375 and 425 degrees Celsius. Advantageously, such low temperatures, compared to the traditional temperatures of 700-800 degrees Celsius for diamond film growth, significantly reduce thermal distortion of tools, including wafer handling tools. Distortion is reduced in tools that are partially coated, coated on one side with diamond, coated on both sides, or entirely coated with diamond films.

[0023] In some embodiments, deposition gases are ignited to form small diamonds that grow on the wafer, producing a continuous thin conformal layer. The type and structure of the deposited diamond depends on the seeding method used. Larger grain seeds can produce microcrystalline diamonds with increased hardness. Smaller grain sizes of nanocrystalline diamonds result in lower surface roughness.

[0024] The properties of diamond films can be measured and characterized using Raman spectroscopy. Cubic diamond has a single Raman active first order phonon mode at the center of the Brillouin zone. The presence of sharp Raman lines allows cubic diamond to be recognized against a background of graphite or other carbon crystal types. Small shifts in the band wavenumbers can indicate the composition and properties of diamond.

[0025] In some embodiments, the full width at half maximum (FWHM) obtained from Raman characterization of diamond films formed as set forth in the present disclosure may be between 5-10.

[0026] In some embodiments, the diamond film can be conformally deposited as a continuous layer on the surface 114 of the tool 100A. Alternatively, masking, etching, or appropriate growth promoting or growth inhibiting techniques can be used to provide the diamond film only in selected areas. In some embodiments, the thickness of the diamond film can be constant across the entire surface, while in other embodiments, the thickness can vary with position.

[0027] In some embodiments, the thickness of the diamond film may be constant across the surface, while in other embodiments, the thickness may vary with location. The diamond coating may be between 200 nm and 100 microns thick. In some embodiments, the diamond coating may be between 200 nm and 10 microns thick. In some embodiments, the diamond coating may be between 200 nm and 1 micron thick. In some embodiments, the diamond grain size may be between 200 nanometers and 300 nanometers. In some embodiments, 90% of the diamond grains are between 200 and 300 nanometers. In other embodiments, 95% of the diamond grains are between 200 and 300 nanometers, and in still other embodiments, 99% of the diamond grains are between 200 and 300 nanometers.

[0028] FIG. 1C is a photograph of a cross section of a conformal diamond coated protrusion.

[0029] FIG. 1D shows selected diamond particle sizes. As shown, particle sizes of 200 nm, 400 nm, and 1 micron are shown. As can be seen, the particle sizes are nearly uniform, with at least 90% of the diamond particles being between 200 and 300 nanometers in size.

[0030] FIG. 2 shows one embodiment of a process 200 for producing a diamond coated tool surface. In the first process step 210, diamond seeds are attached to the tool surface. Suitable diamond seeds, sized between 5 nm and 25 um, can be attached to the substrate by ultrasonic processing. This increases nucleation density, improves uniformity, and speeds up growth rates. The seeding technique can be modified as needed to provide the desired diamond film thickness and grain size.

[0031] In the second process step 212, the temperature, pressure, and precursor gas ratios can be selected to achieve the desired film thickness and grain size. In some embodiments, the precursor gases can include methane, hydrogen, and argon. Small amounts of other gases such as boron, nitrogen, and phosphorus can also be used if desired. Low temperature growth at pressures between 10 and 100 Torr can be selected.

[0032] In the third process step 214, a diamond film is grown in either a hot filament CVD (HFCVD) reactor or a microwave plasma reactor. For HFCVD reactors, a tungsten or tantalum filament is used, which can be carburized prior to nucleation and growth. In some embodiments, the grown diamond film can have a grain size classified as microcrystalline (typically 500 nm or larger), nanocrystalline (typically 10-500 nm), or ultrananocrystalline (typically 2-10 nm). EXAMPLES

[0033] In another embodiment, nanocrystalline diamond can be deposited on SiSiC substrates with diameters between 2 and 12 inches. The SiSiC components may have burls (or outwardly extending sprouts) that are flat on top and have angled sidewalls with a pronounced slope. These burls are approximately 1-1.5 mm thick. Various sizes of seeds are available. By seeding with 20-30 nm particles spaced at 10, 15, and 25 um intervals, high nucleation densities can be obtained and uniform diamond coatings can be achieved across a 12 inch SiSiC wafer. EXAMPLES

[0034] After deposition of a continuous diamond film, the diamond film can be etched using an aluminum mask. Islands of square and circular structures can be defined, including but not limited to those formed as SiC / SiSiC bars or other substrates. By employing different seed mixtures, the final thickness and grain size of the diamond can be determined. EXAMPLES

[0035] Typically, tools with structures configured as pyramids or cones with tip radii between 200 nm and 2 μm can be fabricated by reactive ion etching by using Al as a mask.

[0036] In the foregoing description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration specific exemplary embodiments in which the present disclosure may be practiced. These embodiments have been described in sufficient detail to enable those skilled in the art to practice the concepts disclosed herein, it being understood that modifications can be made to the various disclosed embodiments and other embodiments can be utilized without departing from the scope of the invention. Accordingly, the foregoing detailed description is not to be construed in a limiting sense.

[0037] References throughout this specification to "one embodiment," "embodiment," "one example," or "example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the present disclosure. Thus, the phrases "in one embodiment," "in an embodiment," "one example," or "example" appearing in various places throughout this specification do not necessarily all refer to the same embodiment or example. Furthermore, particular features, structures, databases, or characteristics may be combined in any suitable combinations and / or subcombinations in one or more embodiments or examples. Additionally, it should be understood that the figures provided herein are for illustrative purposes to persons skilled in the art and are not necessarily drawn to scale.

[0038] Numerous modifications and other embodiments of the invention will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing description and the associated drawings. It is understood, therefore, that the invention is not limited to the particular embodiments disclosed, and modifications and embodiments are intended to be included within the scope of the appended claims. It is also understood that other embodiments of the invention can be practiced in the absence of elements / steps not specifically disclosed herein.

Claims

1. A tool, a surface having at least one protrusion; a diamond coating formed from diamond particles sized such that 90% of the diamond particles are between 200 nanometers and 300 nanometers in size, the diamond coating being deposited on the surface on the at least one protrusion at a temperature of less than 500 degrees Celsius; A tool having:

2. 10. The tool of claim 1, wherein the tool is a wafer handling tool that can include one or more of a wafer chuck, a wafer holder, a wafer stage, a wafer table, a wafer substrate, a die scanner, a wafer table for chemical mechanical polishing (CMP), and a wafer transport device.

3. The tool of claim 1 , wherein the at least one protrusion is a crowbar.

4. 2. The tool of claim 1, wherein the diamond coating on the surface is formed to have equally sized grains of less than 1 micron.

5. 2. The tool of claim 1, wherein the diamond coating on the surface is formed so as to continuously cover the surface of the tool.

6. The tool of claim 1 , wherein the diamond coating on the surface is formed to partially cover the tool.

7. 2. The tool of claim 1, wherein the diamond coating on the surface is formed to partially cover burl projections on the tool.

8. The tool of claim 1 , wherein the thickness of the diamond coating on the surface is between 200 nm and 100 microns.

9. The tool of claim 1 , wherein the thickness of the diamond coating on the surface is uniform over selected areas of the tool.

10. The tool of claim 1 , wherein the thickness of the diamond coating on the surface is a conformal thickness over the area of ​​the tool.

11. 1. A method for diamond coating a tool, comprising the steps of: Providing a tool having a surface with at least one protrusion; forming a diamond coating on the surface on the at least one protrusion, the diamond coating being formed from diamond particles sized such that 90% of the particles are between 200 and 300 nanometers, the diamond coating being deposited on the surface on the at least one protrusion at a temperature of less than 600 degrees Celsius; The method according to claim 1,

12. 12. The method of claim 11, wherein the tool is a wafer handling tool which may include one or more of a wafer chuck, a wafer holder, a wafer stage, a wafer table, a wafer substrate, a die scanner, a chemical machine wafer table, or a wafer transport apparatus.

13. The method of claim 11 , wherein the at least one protrusion is a crowbar.

14. 12. The method of claim 11, wherein the diamond coating on the surface is formed to have equally sized grains less than 1 micron.

15. The method of claim 11 , wherein the diamond coating on the surface is formed to continuously cover the tool.

16. The method of claim 11 , wherein the diamond coating on the surface is formed to partially cover the tool.

17. The method of claim 11 , wherein the diamond coating on the surface is formed to partially cover burl projections on the tool.

18. The method of claim 11, wherein the thickness of the diamond coating on the surface is between 200 nm and 100 microns.

19. The method of claim 11 , wherein the thickness of the diamond coating on the surface is uniform over selected areas of the tool.

20. The method of claim 11 , wherein the thickness of the diamond coating on the surface is a conformal thickness over the area of ​​the tool.

Images