# US 9,437,438 B2 · Electroless plating process and tin-silver plating solution therein > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,438 B2 - Document ID: US9437438B2 - Status: Granted - Kind: B2 - Application number: 14/797,320 - Filed: 2015-07-13 - Published: 2016-05-12 - Granted: 2016-09-06 - Earliest claimed: 2014-11-12 - Assignees: National Pingtung University of Science and Technology - Applicants: National Pingtung University of Science & Technology - Inventors: Wei-Hua Lu - Web page: https://patentgrep.com/patent/US9437438B2 ## CPC - H10P 14/46: using a liquid - C23C 18/1844: {with use of organic or inorganic compounds other than metals, first} - C23C 18/48: Coating with alloys - C23C 18/54: Contact plating, i.e. electroless electrochemical plating - H10P 70/27: {during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers} - H10W 20/031: {of conductive parts of the interconnections} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract An electroless plating process includes providing a semiconductor substrate which has a substrate and a copper pillar disposed on the substrate; providing a tin-silver plating solution includes 0.1-50 wt % tin and 1×105-2 wt % silver; and performing a reduction reaction, wherein the semiconductor substrate is disposed in the tin-silver plating solution for making tin and silver of the tin-silver plating solution deposit jointly on the copper pillar surface to form a tin-silver co-deposition layer. The tin-silver co-deposition layer is able to enhance the coupling strength between the copper pillar of the semiconductor substrate and the other semiconductor substrate and is also able to reduce the time and cost of the process performing tin-plating and silver-plating separately. ## Claims ### Claim 1 An electroless plating process includes: providing a semiconductor substrate having a substrate and at least one copper pillar disposed on the substrate; performing a micro etching procedure using an etching solution having 1-20 wt % solute in reference to a total amount of etching solution used to micro etch the copper pillar surface; providing a tin-silver plating solution includes 0.1-50 wt % tin and 1×10−5-2 wt % silver; and performing a reduction reaction, the semiconductor substrate is disposed in the tin-silver plating solution for making tin and silver of the tin-silver plating solution deposit jointly on the copper pillar surface to form a tin-silver co-deposition layer, wherein the tin-silver co-deposition layer is able to enhance the coupling strength between the copper pillar of the semiconductor substrate and another semiconductor substrate. ### Claim 2 (depends on 1) The electroless plating process in accordance with claim 1, wherein the reaction temperature of the reduction reaction is controlled between 40 and 90 degrees Celsius. ### Claim 3 (depends on 1) The electroless plating process in accordance with claim 1, wherein the reaction time of the reduction reaction is controlled between 5 and 20 minutes. ### Claim 4 (depends on 1) The electroless plating process in accordance with claim 1, wherein the time of the micro etching procedure is controlled between 1 and 5 minutes. ### Claim 5 (depends on 1) The electroless plating process in accordance with claim 1 further includes a first cleaning procedure performed after the micro etching procedure, wherein the first cleaning procedure uses liquid at 30-60 degrees Celsius to clean the semiconductor substrate for 1-5 minutes to remove the etching solution remained on the copper pillar surface. ### Claim 6 (depends on 1) The electroless plating process in accordance with claim 1 further includes a second cleaning procedure performed after the reduction reaction, wherein the second cleaning procedure uses liquid at 30-60 degrees Celsius to clean the semiconductor substrate for 1-5 minutes to remove the tin-silver plating solution remained on the semiconductor substrate. ### Claim 7 An electroless plating process includes: providing a semiconductor substrate having a substrate and at least one copper pillar disposed on the substrate; providing a tin-silver plating solution includes 0.1-50 wt % tin and 1×10−5-2 wt % silver; performing a reduction reaction, the semiconductor substrate is disposed in the tin-silver plating solution for making tin and silver of the tin-silver plating solution deposit jointly on the copper pillar surface to form a tin-silver co-deposition layer, wherein the tin-silver co-deposition layer is able to enhance the coupling strength between the copper pillar of the semiconductor substrate and another semiconductor substrate; and performing a cleaning procedure using liquid at 30-60 degrees Celsius to clean the semiconductor substrate for 1-5 minutes to remove the tin-silver plating solution remained on the semiconductor substrate. ### Claim 8 (depends on 7) The electroless plating process in accordance with claim 7, wherein the reaction temperature of the reduction reaction is controlled between 40 and 90 degrees Celsius. ### Claim 9 (depends on 7) The electroless plating process in accordance with claim 7, wherein the reaction time of the reduction reaction is controlled between 5 and 20 minutes.