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EP-4735934-A2 - SURFACE ACTIVATED CHEMICAL VAPOR DEPOSITION AND USES THEREOF

EP4735934A2EP 4735934 A2EP4735934 A2EP 4735934A2EP-4735934-A2

Abstract

Surface activated chemical vapor deposition (SACVD) methods and uses thereof are described herein. Polymeric coatings deposited by SACVD demonstrate high uniformity and conformality, as compared to other deposition techniques, such as initiated chemical vapor deposition (iCVD).

Inventors

  • CHEN, BENNY
  • O'SHAUGHNESSY, W. SHANNAN

Assignees

  • Gvd Corporation

Dates

Publication Date
20260506
Application Date
20240701

Claims (20)

  1. We claim: 1. A method for forming a polymeric coating on at least one substrate or device, the method comprising the steps of: (i) placing the at least one substrate or device into a reaction chamber; (ii) sealing and purging the reaction chamber under a vacuum; (iii) wherein the reaction chamber is at an initiation temperature sufficient to activate one or more gaseous initiators; wherein one or more surfaces of the at least one substrate or device have a surface temperature equal to or substantially equal to the initiation temperature; and (iv) flowing one or more gaseous monomers, the one or more gaseous initiators, and optionally one or more carrier gases into the reaction chamber to form the polymeric coating on at least a portion of the one or more surfaces of the at least one substrate or device; wherein the partial pressure of the one or more gaseous monomers is sufficient to form the polymeric coating on the portion of the one or more surfaces of the at least one substrate or device at the surface temperature; and optionally wherein the surface temperature during step (iv) is sufficient to preclude the one or more gaseous monomers or the one or more gaseous initiators from exceeding their saturation pressure at the surface temperature. 2. A method for forming a polymeric coating on at least one substrate or device, the method comprising the steps of: (i) placing the at least one substrate or device onto a platform within a reaction chamber; wherein the reaction chamber and/or components thereof and the platform are independently temperature controlled; (ii) sealing and purging the reaction chamber under a vacuum; (iii) wherein the platform is at an initiation temperature sufficient to activate one or more gaseous initiators; wherein one or more surfaces of the at least one substrate or device have a surface temperature equal to or substantially equal to the initiation temperature; and 69 45664801.1 (iv) flowing one or more gaseous monomers, the one or more gaseous initiators, and optionally one or more carrier gases into the reaction chamber to form the polymeric coating on at least a portion of the one or more surfaces the at least one substrate or device; wherein the reaction chamber and/or components thereof are independently heated to a reaction chamber temperature, wherein the reaction chamber temperature is lower than the initiation temperature and the surface temperature during step (iv); optionally wherein the components comprise walls of the reaction chamber; wherein the partial pressure of the one or more gaseous monomers is sufficient to form the polymeric coating on the portion of the one or more surfaces of the at least one substrate or device at the surface temperature; and optionally wherein the reaction chamber temperature during step (iv) is sufficient to preclude the one or more gaseous monomers or the one or more gaseous initiators from exceeding their saturation pressure at the reaction chamber temperature. 3. The method of any one of claims 1-2, wherein the time period between steps (i) and (iii) is a dwell time during which the temperature of the surface of the substrate increases to become the surface temperature, and wherein the dwell time is at least about 1,
  2. 2,
  3. 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 minutes.
  4. 4. The method of any one of claims 1-3, wherein step (iv) is performed for a period of time ranging from about 30 to 800 minutes.
  5. 5. The method of any one of claims 1-4, wherein following step (iv) the reaction chamber is purged and allowed to cool to room temperature followed by venting of the reaction chamber.
  6. 6. The method of any one of claims 1-5, wherein the polymeric coating is formed under a pressure ranging from between about 1 to 760,000 mTorr.
  7. 7. The method of any one of claims 1-5, wherein the polymeric coating is formed under a pressure ranging from between about 100 mTorr to 10 Torr. 70 45664801.1
  8. 8. The method of any one of claims 1-7, wherein during step (iv), the one or more gaseous monomers, the one or more gaseous initiators, and/or the one or more carrier gases flow continuously through the reaction chamber.
  9. 9. The method of any one of claims 1-7, wherein during step (iv), the one or more gaseous monomers, the one or more gaseous initiators, and/or the one or more carrier gases do not flow continuously through the reaction chamber.
  10. 10. The method of claim 2, wherein the at least one substrate or device comprises a plurality of substrates and/or devices and optionally each of the substrates and/or devices in the plurality is independently placed on a separate temperature-controlled platform.
  11. 11. The method of any one of claims 1-10, wherein the at least one polymeric coating is formed continuously or semi-continuously on the at least one substrate or device.
  12. 12. The method of any one of claims 1-11, wherein step (iv) is repeated at least one or more times with the same or different types of the one or more gaseous monomers and/or the one or more gaseous initiators to form a polymeric coating comprising a plurality of layers; wherein step (iii) is optionally repeated before step (iv) is repeated, when the type of the one or more gaseous initiators is changed.
  13. 13. The method of claim 12, wherein at least one of the plurality of layers is formed of a polymer different from a polymer forming at least one other layer of the plurality of layers.
  14. 14. The method of any one of claims 1-13, wherein the polymeric coating forms via vinyl polymerization, wherein the one or more gaseous monomers comprise monomers having at least one vinyl moiety thereon.
  15. 15. The method of claim 14, wherein the vinyl polymerization is a free-radical vinyl polymerization. 71 45664801.1
  16. 16. The method of any one of claims 1-15, wherein the at least one polymeric coating is formed of one or more polymers, copolymers, and/or one or more cross-linked polymers by flowing at least two different types of the one or more gaseous monomers during step (iv); and wherein one or more gaseous crosslinkers are further optionally flowed during step (iv), when forming the cross-linked polymers.
  17. 17. The method of any one of claims 1-16, wherein the one or more gaseous monomers are selected from the group consisting of acrylate monomers, methacrylate monomers, vinyl- containing monomers, paracyclophane monomers, oxirane-based monomers, and combinations thereof.
  18. 18. The method of claim 17, wherein: the acrylate monomers are selected from the group consisting of hydroxyethyl acrylate, ethylene glycol diacrylate, 1H,1H,2H,2H-perfluorodecyl acrylate, and combinations thereof; the methacrylate monomers are selected from the group consisting of hydroxyethyl methacrylate, ethylene glycol dimethacrylate, 1H,1H,2H,2H-perfluorodecyl methacrylate, and combinations thereof; and/or the vinyl containing monomers are selected from the group consisting of 1,3,5- trivinyl-1,3,5,-trimethylcyclotrisiloxane, divinylbenzene, 4-vinylpyridine, styrene, 1H,1H,2H-perfluoro-1-dodecene, di(ethylene glycol) divinyl ether, and combinations thereof.
  19. 19. The method of claim 17, wherein the paracyclophane monomers are selected from the group consisting of [2,2]paracyclophane, dichloro-[2,2]-paracyclophane, 1,1,2,2,9,9,10,10- octafluoro[2.2]paracyclophane, and 4,5,7,8,12,13,15,16-octafluoro[2.2]paracyclophane.
  20. 20. The method of claim 17, wherein the oxirane-based monomer is hexafluoropropylene oxide.

Description

SURFACE ACTIVATED CHEMICAL VAPOR DEPOSITION AND USES THEREOF CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of and priority to U.S. Provisional Application No.63/510,920, filed June 29, 2023, which is hereby incorporated by reference in its entirety. FIELD OF THE INVENTION This invention is in the field of polymeric coatings formed via surface activated chemical vapor deposition methods. BACKGROUND OF THE INVENTION Coatings play a critical role throughout many industries where they are applied to surfaces for a variety of reasons such as sealing to protect a surface from the environment, adding mechanical protection, imparting optical effects, modifying surface properties, and enhancing biological or chemical compatibility. A significant benefit of modifying a surface with a coating is that a relatively small quantity of material can be used to dictate surface properties over a large area without altering the properties of the bulk material. Typical processes for applying coatings include spraying, dipping, painting, and immersion in chemical baths. These application methods utilize liquids which add complications related to curing, surface tension, and viscous effects that can lead to pinholes, limit conformality, and increase the minimum practical thickness of the coating. In many industries, the importance of coating conformality has become increasingly important as substrates become more intricate and surface area to volume ratios increase. Chemical vapor deposition (CVD) is a subset of coating application processes which apply coatings directly from the vapor phase. The desired coating material is directly synthesized from gaseous precursors. However, typical CVD processes rely on a spatially-located energy source to activate the chemical synthesis process, such as filaments, plasma, ultraviolet irradiation, or lasers. These energy 1 45664801.1 sources can cause conformality issues imposed by line-of-sight limitations, directionally influenced electric fields, and high energy molecules that readily react upon impact which can also cause damage to the resultant coating. These factors ultimately limit the conformality of the resultant coating. Thus, there exists a need for alternate deposition methods which permit facile deposition of coatings without unduly limiting the conformality of coatings produced. Further, there is a need for improved methods for coating, for example, microelectronics stacks, boards, electronic device components, and 3-D integrated heterogeneous packages, having high aspect ratio features, and can benefit from coatings exhibiting high conformality which provide protective benefits. Therefore, it is an object of the invention to provide deposition methods which produce coatings with high conformality. Therefore, it is also an object of the invention to provide deposition methods where the conformal coatings produced can provide protective benefits to coated substrates and devices. Therefore, it is a further object of the invention to use such methods to produce substrates or devices having highly conformal coatings for various application. SUMMARY OF THE INVENTION Methods for surface activated chemical vapor deposition (SACVD) and uses thereof to form highly conformal coatings are described herein. In general, the SACVD process functions by thermally assisting the formation of chemically reactive species, such as initiator radicals, directly on one or more surfaces to be in situ coated with a polymer. The SACVD methods can be used to deposit one or more conformal polymeric coatings on various types of substrates or devices, such as microelectronics, that have one or more high aspect ratio features thereon. Forming highly conformal coatings on such devices can be achieved using the SACVD methods described herein. In a first instance, surface activated chemical vapor deposition (SACVD) may be carried out under isothermal conditions. Under isothermal conditions, at least one substrate or device to be coated is placed within a reaction chamber and the reaction chamber is heated to an initiation temperature sufficient to activate one or more gaseous initiators. In such methods, heating to the initiation temperature also heats one or more 2 45664801.1 surfaces of the substrate(s) or device(s) within the reaction chamber to decompose the one or more initiators and thereby form/deposit a polymeric coating on a least a portion of the one or more surfaces of the substrate(s) or device(s). A non-limiting first example of an isothermal SACVD method includes: (i) placing the at least one substrate or device into a reaction chamber; (ii) sealing and purging the reaction chamber under a vacuum; (iii) wherein the reaction chamber is at an initiation temperature sufficient to activate one or more gaseous initiators; wherein one or more surfaces of the at least one substrate or material have a surface temperature which is equal to or substantially equal to the initia