Methods and materials for fabricating elastomers resistant to ultraviolet and plasma degradation - Patents.com

Abstract

In a further embodiment, a semiconductor processing tool is provided. In one embodiment, the semiconductor processing tool includes a chamber and a lid sealing the chamber. In one embodiment, an elastomeric seal is between the chamber and the lid. In one embodiment, the elastomeric seal includes a polymer having carbon chains, the average number of bonds between carbons in the carbon chain being greater than 1.00. In one embodiment, a portion of the processing tool is transparent to ultraviolet radiation such that the elastomeric seal is exposed to ultraviolet radiation.

Description

[Background technology]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 17 / 953,630, filed September 27, 2022, which claims the benefit of U.S. Provisional Application No. 63 / 277,021, filed November 8, 2021, the entire contents of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE

[0002] Embodiments relate to the field of semiconductor manufacturing, and in particular to elastomeric materials with improved resistance to UV degradation. [Technical field]

[0003] In semiconductor manufacturing tools, vacuum environments are commonly used for many different types of processes. For example, plasma-based processes are performed at sub-atmospheric pressures. To seal the chamber to withstand these sub-atmospheric pressures, an elastomeric seal, such as an O-ring, is fixed between the chamber and the lid of the tool. The elastomeric seal has a usable life. To prevent leakage into the chamber, the elastomeric seal is replaced before the end of its usable life.

[0004] A drawback of elastomeric seals, such as polytetrafluoroethylene (PTFE), is that they are highly susceptible to damage from ultraviolet (UV) radiation. In particular, the carbon-carbon bonds in PTFE are single bonds with relatively low bond energy. The photon energy of UV radiation (particularly UVB and UVC radiation) is high enough to break the carbon-carbon bonds. As a result, the usable life of the elastomeric seals is shortened. In particular, in some plasma-based semiconductor processing tools, components (e.g., chamber lids) may be transparent to the UV radiation generated by the plasma. In some cases, the transparent components allow UV radiation to reach the elastomeric seals, accelerating their degradation. Summary of the Invention

[0005] In one embodiment, an elastomeric seal is provided. In one embodiment, the elastomeric seal comprises an elastomeric ring. In one embodiment, the elastomeric ring comprises a polymer having carbon chains, the average number of bonds between carbons in the carbon chain being greater than 1.00.

[0006] In a further embodiment, a semiconductor processing tool is provided. In one embodiment, the semiconductor processing tool includes a chamber and a lid sealing the chamber. In one embodiment, an elastomeric seal is between the chamber and the lid. In one embodiment, the elastomeric seal includes a polymer having carbon chains, the average number of bonds between carbons in the carbon chain being greater than 1.00. In one embodiment, a portion of the processing tool is transparent to ultraviolet radiation such that the elastomeric seal is exposed to ultraviolet radiation.

[0007] In a further embodiment, a semiconductor processing tool is provided. In one embodiment, the semiconductor processing tool includes a chamber and a lid sealing the chamber. In one embodiment, the lid is transparent to one or more of UVA radiation, UVB radiation, and UVC radiation. In one embodiment, an elastomeric seal is between the chamber and the lid. In one embodiment, the elastomeric seal includes a polymer having carbon chains, the average number of bonds between carbons in the carbon chain being greater than 1.00. In one embodiment, the carbon chains are fluorine terminated. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a portion of a semiconductor processing tool having an elastomeric seal adjacent to a component that is transparent to UV radiation, according to an embodiment. [Diagram 2] FIG. 1 is an illustration of the polymerization process used to produce elastomeric seals subject to UV degradation. [Diagram 3] FIG. 2 is an illustration of a polymerization process used to produce an elastomeric seal having an average number of bonds between carbons in a carbon chain of about 1.5, according to an embodiment. [Figure 4] FIG. 2 is an illustration of a polymerization process used to produce an elastomeric seal having an average number of bonds between carbons in a carbon chain of about 1.67, according to an embodiment. [Diagram 5] FIG. 1 illustrates a block diagram of an exemplary computer system that may be used with a processing tool, according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The systems described herein include elastomeric materials with improved resistance to UV degradation. In the following description, numerous specific details are presented to provide a thorough understanding of the embodiments. It will be apparent to one of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well-known aspects have not been described in detail so as not to unnecessarily obscure the embodiments. Furthermore, it should be understood that the various embodiments illustrated in the accompanying figures are illustrative representations and are not necessarily drawn to scale.

[0010] As discussed above, elastomeric seals are susceptible to UV degradation, which results in a shortened usable life of the elastomeric seals. This increases material and labor costs (to replace seals) for semiconductor processing tools. The shortened usable life may result in shorter intervals between planned maintenance and longer tool downtime. These effects are particularly problematic when elastomeric seals are directly exposed to UV radiation through transparent components such as chamber lids or viewport windows.

[0011] Generally, UV radiation has a photon energy greater than the bond energy of a single carbon-carbon bond. Therefore, UV radiation breaks the carbon-carbon bonds in the polymer chain, resulting in a more brittle material that is not suitable for maintaining the subatmospheric pressure conditions in the chamber. Existing elastomeric materials, such as polytetrafluoroethylene (PTFE), have a polymer structure with long carbon chains containing single-bonded carbon atoms, thus providing less protection against damage from UV radiation.

[0012] 1, a cross-sectional view of a portion of a semiconductor processing tool 100 is shown, according to one embodiment. As shown, the tool 100 includes a chamber 110. The chamber 110 may include a pedestal 112 to which a substrate 120 is secured (e.g., by a vacuum chuck, an electrostatic chuck, or the like). The substrate 120 may be a semiconductor substrate, such as a silicon wafer or any other type of wafer. In other embodiments, additional non-semiconductor substrates may be provided within the chamber 110. For example, a glass substrate 120 may be present in some processing tools 100.

[0013] In one embodiment, the lid 130 may seal the chamber 110. An elastomeric seal 135 may be pressed between the lid 130 and the surface 111 of the chamber 110. In one embodiment, the elastomeric seal 135 (e.g., an O-ring) may be a polymer that is resistant to UV radiation. For example, the elastomeric seal 135 may include a polymer having carbon chains, where the average number of bonds between the carbon atoms is greater than one. That is, some of the carbon-carbon bonds may be double bonds. In some embodiments, the average number of bonds between the carbon atoms may be about 1.5 or greater, or about 1.66 or greater. In certain embodiments, the elastomeric seal 135 may include polytetrafluoropropadiene or polydifluoroacetylene.

[0014] Increasing the average number of bonds between carbon atoms reduces damage caused by UV radiation. In particular, increasing the number of bonds increases the bond energy, which increases the strength of the bonds between carbon atoms. The increased bond energy may be greater than the photon energy of UV radiation. Thus, exposure to UV radiation may not break the carbon-carbon bonds as in existing elastomeric seals.

[0015] In one embodiment, one or more components of the semiconductor processing tool 100 may include a material that is transparent to UV radiation. For example, the lid 130 may be transparent to UV radiation. For example, the lid 130 may include sapphire. The use of a material that is transparent to UV radiation may result in increased UV exposure to the elastomeric seal 135. The elastomeric seal 135, according to embodiments disclosed herein, allows for an extended life despite the increased exposure.

[0016] In one embodiment, the semiconductor processing tool 100 is a plasma processing tool. For example, the semiconductor processing tool 100 may be a remote plasma source (RPS) processing tool 100. In such an embodiment, the plasma may be struck in a chamber (not shown) outside the chamber 110. In other embodiments, the semiconductor processing tool 100 is a plasma processing tool 100 and the plasma may be struck in the chamber 110. Although the plasma source may provide UV radiation, other types of chambers may provide UV exposure as well. For example, in a radical oxidation chamber, a lamp on the lid 130 may expose the elastomeric seal 135 to UV radiation. Additionally, while the lid 130 is described as a UV-transparent component, it should be understood that any component of the semiconductor processing tool 100 may be transparent to UV radiation, resulting in increased UV radiation exposure to the elastomeric seal 135.

[0017] Referring now to Figure 2, the polymerization process for forming PTFE is shown. As illustrated, the polymerized monomer may be tetrafluoroethylene. Tetrafluoroethylene contains a carbon-carbon double bond, with each carbon further bonded to a pair of fluorine atoms. The polymerization process, represented by the arrows, breaks the double bond and replaces it with a single bond to another carbon. That is, each carbon atom is bonded to two carbon atoms and two fluorine atoms.

[0018] The disadvantage of such a structure is that the bond energy of the single carbon-carbon bond is low. For example, a single bond between carbon atoms may have a bond energy of about 3 eV. Unfortunately, UV radiation (particularly UVB radiation and UVC radiation) has a photon energy higher than 3 eV. Therefore, PTFE is susceptible to UV damage when exposed.

[0019] Thus, embodiments disclosed herein include elastomeric seals that have a higher average number of bonds between carbon-carbon bonds. Increasing the average number of bonds increases the bond energy such that the bond energy is greater than the photon energy of UV radiation. As a result, the bonds are not substantially damaged by UV radiation and UV degradation is significantly reduced.

[0020] Referring now to Figure 3, an illustration of polymerization to form polydifluoroacetylene is shown, according to an embodiment. As shown, the monomer to be polymerized is difluoroacetylene. Difluoroacetylene comprises a pair of carbon atoms bonded together with a triple bond. Each carbon is further bonded to a fluorine atom.

[0021] As indicated by the arrows, a polymerization process is performed on the monomer to form a polymer. In an embodiment, the polymerization process may be any suitable polymerization process common to elastomer manufacturing. For example, the polymerization process may include high temperature and / or high pressure polymerization. High temperature processes may refer to temperatures of about 300 degrees Celsius or greater. In some embodiments, a catalyst may be used to improve the polymerization.

[0022] As shown on the right side of the figure, polydifluoroacetylene contains double bonded carbon-carbon bonds. Each carbon is further bonded to an additional carbon atom and a fluorine atom by a single bond. Thus, half of the carbon-carbon bonds are double bonds and the other half of the carbon-carbon bonds are single bonds. This results in an average number of bonds of approximately 1.5 bonds between each carbon-carbon bond. The bond energy of the 1.5 bonds is greater than the photon energy of UV radiation, resulting in reduced UV degradation.

[0023] Referring now to Figure 4, an illustration of polymerization to form polytetrafluoropropadiene is shown, according to an embodiment. As shown, the monomer to be polymerized is tetrafluoropropadiene. Tetrafluoropropadiene contains three carbon atoms bonded together with double bonds. The central carbon is further double bonded to two additional carbon atoms, and the outer carbons are double bonded to the central carbon and to two fluorine atoms.

[0024] A polymerization process is performed on the monomer to form a polymer, as indicated by the arrow. In an embodiment, the polymerization process may be any suitable polymerization process common to elastomer manufacturing. For example, the polymerization process may include high temperature and / or high pressure polymerization. High temperature processes may refer to temperatures of about 300 degrees Celsius or greater. In some embodiments, a catalyst may be used to improve the polymerization.

[0025] As shown on the right side of the figure, polytetrafluoropropadiene contains a carbon chain with three carbon atoms doubly bonded to each other. The inner carbon atom is doubly bonded to both of the outer carbon atoms. The outer carbon atom is single bonded to another carbon atom and to a fluorine atom. Thus, the average number of bonds between the carbon atoms is about 1.66 or more. The bond energy of the 1.66 bonds is greater than the photon energy of UV radiation, resulting in reduced UV degradation.

[0026] Referring now to FIG. 5, a block diagram illustrating an exemplary computer system 500 of a processing tool is shown according to one embodiment. In one embodiment, the computer system 500 is connected to the processing tool and controls processing at the processing tool. The computer system 500 may be connected (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. The computer system 500 may operate in the role of a server or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system 500 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web appliance, a server, a network router, switch, or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify operations to be performed by that machine. Additionally, although only a single machine is shown as computer system 500, the term "machine" should further be interpreted to include any collection of machines (e.g., computers) that individually or in concert execute a set (or sets) of instructions to perform any one or more of the methodologies described herein.

[0027] The computer system 500 may include a computer program product, or software 522, having a non-transitory machine-readable medium having instructions stored thereon that may be used to program the computer system 500 (or other electronic devices) to perform processes according to embodiments. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., computer) readable storage medium (e.g., read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.), a machine (e.g., computer) readable transmission medium (in the form of electrical, optical, acoustic, or other propagated signals (e.g., infrared signals, digital signals, etc.)), etc.

[0028] In one embodiment, computer system 500 includes a system processor 502, a main memory 504 (e.g., read only memory (ROM), flash memory, dynamic random access memory (DRAM), such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM)), a static memory 506 (e.g., flash memory, static random access memory (SRAM), etc.), and a secondary memory 518 (e.g., a data storage device), which communicate with each other via a bus 530.

[0029] The system processor 502 represents one or more general-purpose processing devices, such as a microsystem processor, a central processing unit, or the like. More specifically, the system processor may be a complex instruction set computing (CISC) microsystem processor, a reduced instruction set computing (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor that executes other instruction sets, or a system processor that executes a combination of instruction sets. The system processor 502 may also be one or more special-purpose processing devices, such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal system processor (DSP), a network system processor, or the like. The system processor 502 is configured to execute processing logic 526 for performing the operations described herein.

[0030] The computer system 500 may further include a system network interface device 508 for communicating with other devices or machines. The computer system 500 may further include a video display unit 510 (e.g., a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 512 (e.g., a keyboard), a cursor control device 514 (e.g., a mouse), and a signal generating device 516 (e.g., a speaker).

[0031] The secondary memory 518 may include a machine-accessible storage medium 532 (or, more specifically, a computer-readable storage medium) having stored thereon one or more sets of instructions (e.g., software 522) that embody any one or more of the methods or functions described herein. The software 522 may reside, completely or at least partially, within the main memory 504 and / or the system processor 502 during execution by the computer system 500. Furthermore, the main memory 504 and the system processor 502 may constitute machine-readable storage media. The software 522 may be further transmitted or received over the network 520 via the system network interface device 508. In one embodiment, the network interface device 508 may operate using RF, optical, acoustic, or inductive coupling.

[0032] While in the illustrated embodiment, the machine-accessible storage medium 532 is shown as a single medium, the term "machine-readable storage medium" should be understood to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. Furthermore, the term "machine-readable storage medium" should be interpreted to include any medium that is capable of storing or encoding a set of instructions for execution by a machine and causing the machine to perform any of one or more of the methods. Thus, the term "machine-readable storage medium" should be interpreted to include, but is not limited to, solid-state memories, optical media, and magnetic media.

[0033] In the foregoing specification, certain exemplary embodiments have been described. It will be apparent that various modifications may be made thereto without departing from the scope of the following claims. The specification and drawings are therefore to be regarded in an illustrative rather than a restrictive sense.

Claims

1. An elastomeric seal comprising: Elastomeric ring containing a polymer having carbon chains wherein the average number of bonds between carbons in the carbon chain is greater than 1.

00.

2. 2. The elastomeric seal of claim 1, wherein the average number of bonds is 1.50 or greater.

3. 2. The elastomeric seal of claim 1, wherein the average number of bonds is 1.66 or greater.

4. The elastomeric seal of claim 1 , wherein the polymer is polytetrafluoropropadiene.

5. The elastomeric seal of claim 1 , wherein the polymer is polydifluoroacetylene.

6. The elastomeric seal of claim 1 , wherein the polymerization process for forming the polymer is a high temperature polymerization.

7. The elastomeric seal of claim 6, wherein said elevated temperature is greater than or equal to about 300°C.

8. The elastomeric seal of claim 1 , wherein the polymerization process for forming the polymer includes the use of a catalyst.

9. 2. The elastomeric seal of claim 1, wherein the average bond energy of the bonds between carbons in the carbon chain is greater than 3 eV.

10. 1. A semiconductor processing tool comprising: Chamber, and The lid seals the chamber with an elastomeric seal between the chamber and the lid.

16. A semiconductor processing tool comprising: an elastomeric seal comprising: a polymer having carbon chains, the average bond energy of bonds between carbons in the carbon chains being greater than 1.00; and a portion of the processing tool being transparent to ultraviolet radiation such that the elastomeric seal is exposed to ultraviolet radiation.

11. The semiconductor processing tool of claim 10 , wherein the lid is transparent to ultraviolet radiation.

12. The semiconductor processing tool of claim 11 , wherein the lid comprises sapphire.

13. The semiconductor processing tool of claim 10 , wherein the semiconductor processing tool is a remote plasma source processing tool.

14. The semiconductor processing tool of claim 10 , wherein the average number of bonds is 1.50 or greater.

15. The semiconductor processing tool of claim 10 , wherein the average number of bonds is 1.66 or greater.

16. The semiconductor processing tool of claim 10 , wherein the polymer is polytetrafluoropropadiene.

17. The semiconductor processing tool of claim 10 , wherein the polymer is polydifluoroacetylene.

18. 1. A semiconductor processing tool comprising: Chamber, a lid sealing the chamber, the lid being transparent to one or more of UVA radiation, UVB radiation, and UVC radiation; and An elastomeric seal between the chamber and the lid wherein the elastomeric seal comprises a polymer having carbon chains, an average number of bonds between carbons in the carbon chains being greater than 1.00, and the carbon chains being fluorine terminated.

19. The semiconductor processing tool of claim 18 , wherein the polymer comprises polytetrafluoropropadiene or polydifluoroacetylene.

20. 20. The semiconductor processing tool of claim 18, wherein the average number of bonds is greater than or equal to 1.50.

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