# US 8,541,293 B2 · Method of controlled lateral etching > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,293 B2 - Document ID: US8541293B2 - Status: Granted - Kind: B2 - Application number: 13/509,604 - Filed: 2011-11-23 - Published: 2013-03-21 - Granted: 2013-09-24 - Earliest claimed: 2011-09-21 - Assignees: Institute of Microelectronics, Academy of Sciences - Applicants: Huilong Zhu; Zhijiong Luo; Haizhou Yin - Inventors: Huilong Zhu; Zhijiong Luo; Haizhou Yin - Web page: https://patentgrep.com/patent/US8541293B2 ## CPC - H10D 30/024: {of fin field-effect transistors [FinFET]} - H10D 84/038: {using silicon technology, e.g. SiGe} - H10D 84/0158: {the components including FinFETs} - H10D 84/0193: {the components including FinFETs} - H10D 86/01: Manufacture or treatment - H10D 86/011: {comprising FinFETs} - H10P 50/73: {using masks for insulating materials} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A method of controlled lateral etching is disclosed. In one embodiment, the method may comprise: forming on a first material layer, which comprises a protruding structure, a second material layer; forming spacers on outer surfaces of the second material layer opposite to vertical surfaces of the protruding structure; forming a third material layer on surfaces of the second material layer and the spacers; forming on the third material layer a mask layer which extends in a direction lateral to a surface of the first material layer; and laterally etching portions of the respective layers arranged on the vertical surfaces of the protruding structure. ## Claims ### Claim 1 A method of controlled lateral etching, comprising: forming a second material layer on a first material layer having a protruding structure, the second material layer comprising laterally extending portions and vertically extending portions; forming spacers on outer surfaces of the second material layer opposite to vertical surfaces of the protruding structure; forming a third material layer on surfaces of the second material layer and the spacers, the third material layer comprising laterally extending portions and vertically extending portions; forming a mask layer, which extends in a direction lateral to a surface of the first material layer, on the third material layer; and laterally etching the vertically extending portions of the third material layer, the spacers, and the vertically extending portions of the second material layer sequentially, to leave a functional layer composed of the laterally extending portions of the second material layer and the laterally extending portions of the third material layer on the first material layer. ### Claim 2 (depends on 1) The method of controlled lateral etching according to claim 1, wherein the mask layer comprises doped polysilicon. ### Claim 3 (depends on 2) The method of controlled lateral etching according to claim 2, wherein forming the mask layer comprises: forming a undoped amorphous silicon layer on the third material layer; implanting dopants into portions of the amorphous silicon layer extending in the direction lateral to the surface of the first material layer; performing annealing to activate the dopants and convert the amorphous silicon into polysilicon; and selectively etching the undoped polysilicon with respect to the doped polysilicon so as to form the mask layer. ### Claim 4 (depends on 2) The method of controlled lateral etching according to claim 2, wherein the second and third material layers both comprise oxide, and the spacers comprise undoped polysilicon. ### Claim 5 (depends on 1) The method of controlled lateral etching according to claim 1, wherein before formation of the mask layer, the method further comprises: forming further spacers on outer surfaces of the third material layer opposite to the vertical surfaces of the protruding structure; forming a further material layer on surfaces of the third material layer and the further spacers, wherein the mask layer is formed on the further material layer. ### Claim 6 (depends on 1) The method of controlled lateral etching according to claim 1, wherein the protruding structure comprises a fin. ### Claim 7 (depends on 6) The method of controlled lateral etching according to claim 6, wherein a plurality of fins are formed on the first material layer, and wherein at least two of the fins have different heights. ### Claim 8 (depends on 7) The method of controlled lateral etching according to claim 7, wherein the fins are formed by: patterning the first material layer in a first region thereof to form a first fin; and patterning the first material layer in a second region thereof to form a second fin, wherein the first fin has a different height than the second fin. ### Claim 9 (depends on 8) The method of controlled lateral etching according to claim 8, wherein the first material layer comprises a plurality of semiconductor sub-layers, wherein adjacent semiconductor sub-layers have different materials so that they can be selectively etched with respect to each other; patterning the first material layer in the first region thereof comprises patterning the first material layer so that the first fin is formed by a first number of semiconductor sub-layers; and patterning the first material layer in the second region thereof comprises patterning the first material layer so that the second fin is formed by a second number of semiconductor sub-layers. ### Claim 10 (depends on 9) The method of controlled lateral etching according to claim 9, wherein the first material layer comprises a stack of fin main-body sub-layers and etching stop sub-layers which are arranged alternately, wherein the fin main-body sub-layers are thicker than the etching stop sub-layers. ### Claim 11 (depends on 10) The method of controlled lateral etching according to claim 10, wherein the fin main-body sub-layers comprise Si, and the etching stop sub-layers comprise SiGe.