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EP-4739626-A1 - CARRIER STACK FOR TRANSFERRING A TWO-DIMENSIONAL, 2D, MATERIAL TO A TARGET SUBSTRATE, AND METHOD FOR TRANSFERRING THE 2D MATERIAL TO A TARGET SUBSTRATE

EP4739626A1EP 4739626 A1EP4739626 A1EP 4739626A1EP-4739626-A1

Abstract

A carrier stack for transferring a two-dimensional, 2D, material layer to a rigid target substrate and a method of producing the stack, the method including: - providing a rigid or semi-rigid carrier substrate; and - coating at least one of the carrier substrate and the 2D material layer with an adhesion layer; and - bonding the 2D material layer to the carrier substrate through the at least one adhesion layer, wherein bonding the 2D material layer comprises: - positioning the carrier substrate facing the 2D material layer, the 2D material layer supported by a growth substrate, and bringing them into contact; - bonding the 2D material layer to the carrier substrate through the at least one adhesive layer by applying heat and/or pressure; and - de-bonding the 2D material layer from the growth substrate; wherein the 2D material comprises one or more of graphene, hexagonal Boron Nitride, h-BN, and a transition metal dichalcogenide, TMDC, material; and when the 2D material comprises graphene or h-BN, the step of de-bonding comprises an electrochemical process; and when the 2D material comprises a TMDC material, the adhesion layer comprises a metal, an eutectic material or a metal compound, and the step of de-bonding comprises mechanical debonding.

Inventors

  • VAN RIJN, RICHARD
  • BARNES, Matthew David
  • Buscema, Michele
  • WEHENKEL, Dominique Joseph
  • SOFRONIEV, Rosen

Assignees

  • Black Semiconductor Netherlands B.V.

Dates

Publication Date
20260513
Application Date
20240705

Claims (19)

  1. 1. A method of producing a carrier stack (1) for transferring a two-dimensional, 2D, material layer (8) to a rigid target substrate (14), the method comprising: providing a rigid or semi-rigid carrier substrate (2) having a first surface; and coating at least one of the first surface of the carrier substrate and a surface of the 2D material layer with at least one adhesion layer (4, 6); and bonding the 2D material layer (8) to the rigid or semi-rigid carrier substrate through the at least one adhesion layer, wherein the step of bonding the 2D material layer comprises: positioning the first surface of the carrier substrate facing the 2D material layer, the 2D material layer supported by a growth substrate (12), and bringing them into contact; performing the bonding of the 2D material layer to the carrier substrate through the at least one adhesive layer by applying heat and/or pressure; and subsequently de-bonding the 2D material layer from the growth substrate; wherein the 2D material (8) comprises one or more of graphene, hexagonal Boron Nitride, h-BN, and a transition metal dichalcogenide, TMDC, material; and wherein when the 2D material comprises graphene or h-BN, the step of de-bonding comprises an electrochemical process; and when the 2D material comprises a TMDC material, the adhesion layer comprises a metal, an eutectic material or a metal compound, and the step of de-bonding comprises mechanical debonding.
  2. 2. Method according to claim 1, wherein adhesion layer comprises at least one of bismuth, gold, indium, lead, tin, gallium, or an eutectic material comprising at least one of these or a compound comprising at least one of these.
  3. 3. Method according to claim 1 or 2, wherein the step of de-bonding the 2D material layer from the growth substrate comprises one or more of mechanical debonding the 2D material from the growth substrate, electro-chemical release of the 2D material from the growth substrate, or electro-chemical delamination of the 2D material from the growth substrate.
  4. 4. Method according to any one of the preceding claims, wherein the 2D material layer comprises graphene or h-BN, and the step of de-bonding the 2D material layer from the growth substrate comprises a combination of an electrochemical process and mechanical de-bonding.
  5. 5. Method according to claim 4, further comprising making electrical contact to the surface of the growth substrate supporting the 2D material layer, the growth substrate comprising a metallic surface, wherein the electrical contact is achieved by one of - bonding a metal strip at an outer edge of the growth substrate, such that the metal strip is bonded between the growth substrate and the carrier substrate and allows for electrical contact to realize an electrochemical process; - making a cut-out in the carrier substrate, allowing to contact the metallic surface of the growth substrate through a contact element; or - positioning the carrier substrate and the growth substrate such as to be disaligned and/or displaced with respect to one another prior to bringing them into contact and performing the step of bonding.
  6. 6. Method according to any one of the preceding claims, further comprising bonding a second 2D material layer on top of the 2D material layer to form a stack of 2D material layers on the carrier stack.
  7. 7. Method according to any one of the preceding claims, wherein the at least one adhesion layer comprises an adhesive layer and a sacrificial layer, the method comprising applying the adhesive layer to the first surface of the carrier substrate and applying the sacrificial layer to a surface of the 2D material layer prior to bonding the 2D material layer to the carrier substrate.
  8. 8. Method according to any one of the preceding claims, wherein the rigid or semi-rigid carrier substrate has dimensions corresponding to dimensions of a semiconductor wafer, wherein the dimensions comprise one or more of substrate diameter, thickness, weight, opacity, and material.
  9. 9. Method according to any one of the preceding claims, wherein the rigid or semi-rigid carrier substrate is a wafer made of glass, sapphire, or silicon.
  10. 10. Method according to any one of the preceding claims, wherein the at least one adhesion layer (4, 6) comprises at least one of PMMA, PPC, PC, PBzMA, bismuth, gold, or an eutectic material such as bismuth-tin.
  11. 11. Method of transferring a two-dimensional, 2D, material layer (8) to a rigid target substrate (14), the method comprising: Producing a carrier stack (1) by the method according to any one of claims 8-17; positioning the carrier stack with the 2D material layer facing a target surface of the rigid target substrate; bonding the carrier stack to the target substrate by bonding the 2D material layer to the target surface of the target substrate; and debonding the carrier substrate from the 2D material layer.
  12. 12. Method according to claim 11, wherein the step of debonding the carrier substrate from the 2D material layer comprises thermal slide debonding.
  13. 13. A carrier stack (1) for transferring a two-dimensional, 2D, material layer (8) to a rigid target substrate (14), wherein the carrier stack has been produced by the method according to any one of claims 1-10, and the carrier stack comprising: a rigid or semirigid carrier substrate (2), and - the 2D material layer (8) bonded to the carrier substrate (2) through at least one adhesion layer (4, 6), wherein the adhesion layer comprises at least one of PMMA, PPC, PC, PBzMA, a metal, an eutectic material comprising metal, or a metal compound, and is configured to provide adhesion between the carrier substrate and the 2D material layer and to allow for subsequent de-bonding of the 2D material layer from the carrier substrate.
  14. 14. The carrier stack according to claim 13, wherein the 2D material comprises one or more of graphene, hexagonal boron nitride, h-BN, and a transition metal dichalcogenide, TMDC, material.
  15. 15. The carrier stack according to claim 13 or 14, wherein the adhesion layer comprises at least one of bismuth, gold, indium, lead, tin, gallium, or an eutectic material comprising at least one of these or a compound comprising at least one of these.
  16. 16. The carrier stack according to claim 13 or 14, wherein the rigid or semi-rigid carrier substrate has dimensions corresponding to dimensions of a semiconductor wafer, wherein the dimensions comprise one or more of substrate diameter, thickness, weight, opacity, and material.
  17. 17. The carrier stack according to any one of claims 13 to 16, wherein the rigid or semirigid carrier substrate is a wafer made of glass, sapphire, or silicon.
  18. 18. The carrier stack according to any one of claims 13 to 17, wherein the at least one adhesion layer comprises an adhesive material allowing one or more of thermal slide de-bond or laser de-bond.
  19. 19. The carrier stack according to any one of claims 13 to 18, wherein the 2D material comprises a stack of 2D materials.

Description

Carrier stack for transferring a two-dimensional, 2D, material to a target substrate, and method for transferring the 2D material to a target substrate Field of the invention [0001] The present invention relates to a transfer carrier or carrier stack for transferring a two-dimensional, 2D, material to a target substrate, a method for producing the carrier stack, and a method for transferring the 2D material from the carrier stack to the target substrate. The transfer carrier and the associated methods are compatible with semiconductor industry high- volume manufacturing. Background art [0002] Two-dimensional, 2D, materials refer to materials having macroscopic dimensions in two dimensions, while having a thickness of only one or a few atoms in a third dimension. Graphene is a well-known example of a 2D material, which has attracted much scientific and technologic interest lately. Other examples include graphene-based materials, materials comprising graphene, chemically modified graphene, hexagonal boron nitride (h-BN) and TMDC materials, such as M0S2, WS2, MoSe2, WSe2, etc.. [0003] Such 2D materials have been observed as having specific properties, for example relating to electrical and/or chemical properties. The specific properties of 2D materials, such as graphene or graphene-containing materials or TMDCs, render them very interesting for a wide range of applications, including electronics, lasers, bio-sensors, photonic switches, light emitting diodes (LED), infrared sensors, protective coatings, hydrogen storage and energy storage. [0004] 2D materials, such as graphene or TMDCs, are commonly grown on a growth substrate, eventually processed, and subsequently transferred to a target substrate. [0005] However, in order to achieve materials with high quality, these 2D material need to be grown at very high temperatures, potentially on catalytic substrates. The growth temperatures required for obtaining high-quality 2D materials are not compatible with semiconductor manufacturing, e.g. with integrated circuits or components thereof previously formed on a target substrate, where the 2D material is to be applied. [0006] Therefore, TMDC and graphene layers need to be grown on a specific substrate, which is compatible with the high temperatures needed, and subsequently transferred to a target substrate (fabrication-capable) at lower temperatures. [0007] One of the major reasons for slow adoption of 2D materials such as graphene and TMDCs into the semiconductor industry is the lack of compatibility between the tools, techniques, and/or substrates commonly used in the graphene research vs. the semiconductor industry. [0008] Over the past -15 years, the majority of examples of graphene produced by CVD is grown on thin metal foils (copper/nickel, ~25 microns thick), and then removed from the metal foil using a thin supporting (<1 micron) polymer film by using wet chemistry (metal etching, electrochemical de-lamination). This results in a floating graphene/polymer film on a liquid, usually de-ionized water. The transfer of the graphene layer to a target wafer/ substrate is then achieved by “scooping” the graphene layer onto the target wafer from said water solution. Such a technique is hard to automate due to complicated handling mechanics of 1- micron thin polymer films floating on aqueous layers. Further, the wet-scoop technique will always result in a thin layer of water at the interface between 2DM and substrate/2DM, which must be removed before further processing. However, some residual water molecules likely remain, which has been shown to reduce device performance (doping, mobility reduction, transconductance hysteresis). [0009] The case of transfer of transition metal dichalcogenides (TMDCs) grown by CVD, MOCVD, or ALD on non-catalytic substrate is very similar. Literature recipes often include etching the surface of the growth substrate and let the TMDC layer/polymer support float on top of the liquid. [0010] As the community has moved towards wafer scale processing of 2D materials several example carrier layers have emerged. Some of these include stacks having a thermal release tape or similar materials as carrier substrate. These carriers however are not compatible with high through-put or high-volume manufacturing, e.g., due to not being compatible with various systems conventionally used in semiconductors manufacturing or semiconductor fabs. [0011] A known example includes systems comprising a Tape supporting films (-100 microns thick), a thermal-release adhesive (-50 microns thick) and a PMMA sacrificial layer (<1 micron thick). This offers some ease of handling on the wafer scale and can be shipped in a box to a wafer foundry. However, the carrier stack still has 2 main drawbacks; 1) the flexible tape support layer is not easily manipulated by wafer handling robots and 2) the thermal release adhesive is not considered suitable as a high through-put carrier release method in a fab setting. [0012] M