# US 10,121,761 B2 · Hetero-bipolar transistor and method for producing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,121,761 B2 - Document ID: US10121761B2 - Status: Granted - Kind: B2 - Application number: 15/589,614 - Filed: 2017-05-08 - Published: 2017-09-21 - Granted: 2018-11-06 - Earliest claimed: 2014-11-18 - Assignees: Sumitomo Electric Industries, Ltd. - Applicants: Sumitomo Electric Industries, Ltd. - Inventors: Masataka Watanabe - Web page: https://patentgrep.com/patent/US10121761B2 ## CPC - H10D 62/126: {Top-view geometrical layouts of the regions or the junctions} - H10D 10/021: {of heterojunction BJTs [HBT]} - H10D 10/821: {Vertical heterojunction BJTs} - H10D 64/231: {Emitter or collector electrodes for bipolar transistors} - H10D 64/281: {Base electrodes for bipolar transistors} - H10P 50/646: {of Group III-V materials} - H10P 72/74: {using temporarily an auxiliary support} - H10W 70/09: extending onto an encapsulation that laterally surrounds the chip or wafer, e.g. fan-out wafer level package [FOWLP] RDLs - H10W 70/60: Insulating or insulated package substrates; Interposers; Redistribution layers (leadframes H10W70/40) - H10W 72/00: Interconnections or connectors in packages - H10D 62/824: comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions - H10D 62/85: being Group III-V materials, e.g. GaAs - H10P 72/7426: {used as a support during build up manufacturing of active devices} - H10P 72/7434: {used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate} - H10P 72/744: {Details of chemical or physical process used for separating the auxiliary support from a device or a wafer} - H10W 40/22: characterised by their shape, e.g. having conical or cylindrical projections - H10W 70/099: {Connecting interconnections to insulating or insulated package substrates, interposers or redistribution layers} - H10W 72/01338: {in gaseous form, e.g. by CVD or PVD} - H10W 72/073: {of die-attach connectors} - H10W 72/07331: {Connecting techniques} - H10W 72/074: {of anisotropic conductive adhesives} - H10W 72/352: {comprising metals or metalloids, e.g. solders} - H10W 72/874: {On different surfaces} - H10W 72/90: Bond pads, in general - H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu} - H10W 80/312: {characterised by the direct bonding of electrically conductive pads} - H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL} - H10W 90/794: {between a chip and a stacked insulating package substrate, interposer or RDL} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A method of producing a semiconductor device includes steps of: growing semiconductor layers to form a semiconductor stack on a semiconductor substrate; forming a first adhesive layer on the semiconductor stack; bonding a temporary support made of non-semiconductor material to the first adhesive layer; removing the semiconductor substrate from the semiconductor stack to expose a surface of the semiconductor stack; forming a second adhesive layer on the exposed surface of the semiconductor stack; bonding a support to the second adhesive layer; and removing the temporary support from the semiconductor stack. The support has a thermal conductivity greater than the thermal conductivities of the semiconductor layer in the semiconductor stack. In forming the first adhesive layer, this layer can cover the entire surface, or both the top and a side of the semiconductor stack. Before forming the first adhesive layer, a protective layer can be formed on the semiconductor stack. ## Claims ### Claim 1 A method of producing a semiconductor device, comprising steps of: growing a plurality of semiconductor layers to form a semiconductor stack on a semiconductor substrate; forming a first adhesive layer on the semiconductor stack; bonding a temporary support made of non-semiconductor material to the first adhesive layer; removing the semiconductor substrate from the semiconductor stack to expose a surface of the semiconductor stack; forming a second adhesive layer on the exposed surface of the semiconductor stack; bonding a support to the second adhesive layer; and removing the temporary support from the semiconductor stack, wherein the support bonded to the second adhesive layer has a thermal conductivity greater than thermal conductivities of the semiconductor layers forming the semiconductor stack, and wherein the step of forming the first adhesive layer includes a step of covering a whole side surface of the semiconductor stack by a metal layer made of at least one of tungsten (W), molybdenum (Mo), and tantalum (Ta). ### Claim 2 (depends on 1) The method of claim 1, wherein the step of bonding the temporary support to the first adhesive layer is carried out continuously with the step of forming the first adhesive layer without exposing the first adhesive layer to an atmosphere. ### Claim 3 (depends on 2) The method of claim 2, wherein the step of bonding the support to the second adhesive layer is carried out continuously with the step of forming the second adhesive layer without exposing the second adhesive layer to an atmosphere. ### Claim 4 (depends on 1) The method of claim 1, wherein at least one of the step of forming the first adhesive layer and the step of forming the second adhesive layer includes a step of forming a metal layer made of at least one of tungsten (W), molybdenum (Mo), and tantalum (Ta) by sputtering. ### Claim 5 (depends on 1) The method of claim 1, further including a step of etching a portion of a lowermost semiconductor layer in the semiconductor stack to form a step in the semiconductor stack after the step of removing the semiconductor substrate but before the step of forming the second adhesive layer, and wherein the step of forming the second adhesive layer includes a step of covering the step in the semiconductor stack by the second adhesive layer. ### Claim 6 (depends on 1) The method of claim 1, further including a step of removing a periphery of the semiconductor stack before the step of forming the first adhesive layer, wherein the step of forming the first adhesive layer includes a step of forming the first adhesive layer so as to cover a top of the semiconductor stack and a side of the semiconductor stack that is exposed by the step of removing the periphery of the semiconductor stack. ### Claim 7 (depends on 6) The method of claim 6, further including a step of, after the step of removing the temporary support, removing the first adhesive layer covering the top and the side of the semiconductor stack. ### Claim 8 (depends on 7) The method of claim 7, further including a steps of, after the step of removing the first adhesive layer, sequentially etching a portion of the semiconductor stack to form an emitter mesa, a portion of the semiconductor stack to form a base mesa, and a portion of the semiconductor stack to form a collector mesa, and forming electrodes on the semiconductor stack. ### Claim 9 (depends on 1) The method of claim 1, wherein the step of bonding the support to the second adhesive layer is carried out continuously with the step of forming the second adhesive layer without exposing the second adhesive layer to an atmosphere. ### Claim 10 A method of producing a semiconductor device, comprising steps of: growing a plurality of semiconductor layers to form a semiconductor stack on a semiconductor substrate; removing a periphery of the semiconductor stack; forming a first adhesive layer on the semiconductor stack after removing the periphery of the semiconductor stack; bonding a temporary support made of non-semiconductor material to the first adhesive layer; removing the semiconductor substrate from the semiconductor stack to expose a surface of the semiconductor stack; forming a second adhesive layer on the exposed surface of the semiconductor stack; bonding a support to the second adhesive layer; and removing the temporary support from the semiconductor stack, wherein the support bonded to the second adhesive layer has a thermal conductivity greater than thermal conductivities of the semiconductor layers forming the semiconductor stack, and wherein the step of forming the first adhesive layer includes a step of forming the first adhesive layer so as to cover a top of the semiconductor stack and a side of the semiconductor stack that is exposed by the step of removing the periphery of the semiconductor stack. ### Claim 11 (depends on 10) The method of claim 10, wherein the step of bonding the temporary support to the first adhesive layer is carried out continuously with the step of forming the first adhesive layer without exposing the first adhesive layer to an atmosphere. ### Claim 12 (depends on 11) The method of claim 11, wherein the step of bonding the support to the second adhesive layer is carried out continuously with the step of forming the second adhesive layer without exposing the second adhesive layer to an atmosphere. ### Claim 13 (depends on 10) The method of claim 10, wherein the step of bonding the support to the second adhesive layer is carried out continuously with the step of forming the second adhesive layer without exposing the second adhesive layer to an atmosphere. ### Claim 14 (depends on 10) The method of claim 10, wherein at least one of the step of forming the first adhesive layer and the step of forming the second adhesive layer includes a step of forming a metal layer made of a least one of tungsten (W), molybdenum (Mo), and tantalum (Ta) by sputtering. ### Claim 15 (depends on 10) The method of claim 10, further including a step of etching a portion of a lowermost semiconductor layer in the semiconductor stack to from a step in the semiconductor stack after the step of removing the semiconductor substrate but before the step of forming the second adhesive layer, and wherein the step of forming the second adhesive layer includes a step of covering the step in the semiconductor stack by the second adhesive layer. ### Claim 16 (depends on 10) The method of claim 10, further including a step of, after the step of removing the temporary support, removing the first adhesive layer covering the top and the side of the semiconductor stack. ### Claim 17 (depends on 10) The method of claim 10, further including steps of, after the step of removing the first adhesive layer, sequentially etching a portion of the semiconductor stack to form an emitter mesa, a portion of the semiconductor stack to form a base mesa, and a portion of the semiconductor stack to form a collector mesa, and forming electrodes on the semiconductor stack. ### Claim 18 A method of producing a semiconductor device, comprising steps of: growing a plurality of semiconductor layers to form a semiconductor stack on a semiconductor substrate; forming a protective layer on the semiconductor stack; forming a first adhesive layer on the protective layer; bonding a temporary support made of non-semiconductor material to the first adhesive layer; removing the semiconductor substrate from the semiconductor stack to expose a surface of the semiconductor stack; forming a second adhesive layer on the exposed surface of the semiconductor stack; bonding a support to the second adhesive layer; removing the temporary support from the semiconductor stack; and removing the protective layer, wherein the support bonded to the second adhesive layer has a thermal conductivity greater than thermal conductivities of the semiconductor layers forming the semiconductor stack. ### Claim 19 (depends on 18) The method of claim 18, wherein at least one of the step of forming the first adhesive layer includes a step of covering a whole side surface of the semiconductor stack by a metal layer made of a least one of tungsten (W), molybdenum (Mo), and tantalum (Ta) by sputtering. ### Claim 20 (depends on 18) The method of claim 18, further including a step of removing a periphery of the semiconductor stack before the step of forming the first adhesive layer, wherein the step of forming the first adhesive layer includes a step of forming the first adhesive layer so as to cover a top of the semiconductor stack and a side of the semiconductor stack that is exposed by the step of removing the periphery of the semiconductor stack.