# US 5,341,980 A · Method of fabricating electronic circuit device and apparatus for performing the same method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,341,980 A - Document ID: US5341980A - Status: Granted - Kind: A - Application number: 07/890,255 - Filed: 1992-05-29 - Granted: 1994-08-30 - Earliest claimed: 1990-02-19 - Assignees: Hitachi, Ltd. - Inventors: Toru Nishikawa; Ryohei Satoh; Masahide Harada; Tetsuya Hayashida; Mitugu Shirai - Web page: https://patentgrep.com/patent/US5341980A ## CPC - H05K 3/3436: {having an array of bottom contacts, e.g. pad grid array or ball grid array components} - B23K 1/0016: {Soldering of electronic components} - B23K 1/008: Soldering within a furnace (B23K1/012 takes precedence) - B23K 1/206: {Cleaning} - H05K 3/3489: Composition of fluxes; Application thereof; Other processes of activating the contact surfaces - H10P 72/74: {using temporarily an auxiliary support} - H10W 70/099: {Connecting interconnections to insulating or insulated package substrates, interposers or redistribution layers} - H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps - H10W 74/012: {of encapsulations on active surfaces of flip-chip devices, e.g. forming underfills} - H10W 74/15: on active surfaces of flip-chip devices, e.g. underfills - H10W 90/701: {characterised by the relative positions of pads or connectors relative to package parts} - B23K 2101/40: Semiconductor devices - H05K 3/3426: {characterised by the leads} - H05K 2201/10984: Component carrying a connection agent, e.g. solder, adhesive - H05K 2203/025: Abrading, e.g. grinding or sand blasting - H05K 2203/0278: Flat pressure, e.g. for connecting terminals with anisotropic conductive adhesive - H05K 2203/041: Solder preforms in the shape of solder balls - H05K 2203/0435: Metal coated solder, e.g. for passivation of solder balls - H05K 2203/086: Using an inert gas - H05K 2203/087: Using a reactive gas - H05K 2203/095: Plasma, e.g. for treating a substrate to improve adhesion with a conductor or for cleaning holes - H05K 2203/1157: Using means for chemical reduction - H10W 72/011: {Apparatus therefor} - H10W 72/0112: {Apparatus for manufacturing bump connectors} - H10W 72/01204: {using temporary auxiliary members, e.g. using sacrificial coatings or handle substrates} - H10W 72/01225: {in solid form, e.g. by using a powder or by stud bumping} - H10W 72/0711: {Apparatus therefor} - H10W 72/07227: {involving guiding structures, e.g. spacers or supporting members} - H10W 72/07236: {Soldering or alloying} - H10W 72/07251: {characterised by changes in properties of the bump connectors during connecting} - H10W 72/251: {Materials} - H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu} - H10W 72/856: {Bump connectors and die-attach connectors (bumps embedded in underfills H10W74/15)} - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - 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 - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract In a method of soldering for use in fabricating electronic circuit device, after an oxide layer and/or contaminated layer on a surface of a soldering material and members to be soldered thereby is removed by sputter-cleaning with atom or ion, the members are aligned in an oxidizing atmosphere within a predetermined time period and, then, the soldering material is heated in non-oxidizing atmosphere to performe soldering. An apparatus for performing the above method comprises a sputter cleaning device, an alignment device operable in atmospheric condition and a heating and soldering device in the form of a belt furnace operable in non-oxidizing or reducing environment. Instead of the sputter cleaning device, a mechanical polishing or cutting device can be used to cleaning a surface of solder or a member to be bonded or a solder ball plated with gold may be used. An alignment between two members to be bonded is provided by an alignment mark means which comprises a protrusion on a surface of one member and a complimental recess formed at a center portion of a protrusion means formed on a corresponding surface of the other member. ## Claims ### Claim 1 A method of soldering for use in fabricating an electronic circuit device, comprising the steps of: removing at least one of an oxide layer and contamination layer both from a surface of a soldering material and from a surface of members to be soldered thereby, by sputter-cleaning with at least one of atom and ion; aligning said members in an oxidizing atmosphere; and heating said soldering material and performing a soldering operation in a non-oxidizing atmosphere. ### Claim 2 A method of soldering for use in fabricating an electric circuit device, comprising the steps of: removing at least one of an oxide layer and a contamination layer from surfaces of a soldering material and members to be soldered thereby, by sputter-cleaning with at least one of atom or ion; supplying oxygen to said surfaces to form thin oxide films thereon; aligning said members; and heating said soldering material and performing a soldering operation in a non-oxidizing atmosphere. ### Claim 3 (depends on 1, 2) The method claimed in claim 1 or 2, wherein said soldering material is at least one selected from a group consisting of alloys of Pb and Sn, alloys of Sn and Ag, alloys of Au and Sn, alloys of Au and Ge and alloys of Au and Si, and wherein said aligning step in an oxidizing atmosphere is performed for at most six hours. ### Claim 4 (depends on 2) The method claimed in claim 2, wherein said non-oxidizing atmosphere is inert gas. ### Claim 5 (depends on 4) The method claimed in claim 4, wherein said non-oxidizing atmosphere is He. ### Claim 6 (depends on 4) The method claimed in claim 4, wherein said non-oxidizing atmosphere is argon gas. ### Claim 7 (depends on 4) The method claimed in claim 4, wherein said non-oxidizing atmosphere is N.sub.2. ### Claim 8 (depends on 1, 2) The method claimed in claim 1 or 2, wherein said non-oxidizing atmosphere is reducing gas. ### Claim 9 (depends on 8) The method claimed in claim 8, wherein said non-oxidizing atmosphere is an active gas atmosphere. ### Claim 10 (depends on 9) The method claimed in claim 9, wherein said active gas atmosphere is selected from the group consisting of (1) a mixture of H.sub.2 and N.sub.2 and (2) H.sub.2. ### Claim 11 (depends on 1, 2) The method claimed in claim 1 or 2, wherein, during said heating, any oxide film formed on the soldering material during the aligning step is segmented so as to expose soldering material during the soldering operation. ### Claim 12 (depends on 1, 2) The method claimed in claim 1 or 2, wherein the aligning in an oxidizing atmosphere is performed for a maximum of 8 hours. ### Claim 13 (depends on 1, 2) The method claimed in claim 1 or 2, wherein the aligning in an oxidizing atmosphere is performed for a time sufficiently limited such that an oxide film formed on the soldering material during the aligning has a thickness of at most 5 nm. ### Claim 14 (depends on 1, 2) The method claimed in claim 1 or 2, wherein two members are joined by said soldering material. ### Claim 15 (depends on 1, 2) The method claimed in claim 1 or 2, wherein said non-oxidizing atmosphere is fluorocarbon vapor. ### Claim 16 A method of soldering for use in fabricating an electric circuit device, comprising the steps of: removing at least one of an oxide layer and a contamination film from surfaces of a solder material and at least one member to be connected thereto; aligning said at least one member and said solder material in an oxidizing atmosphere; and heating said solder material in a non-oxidizing atmosphere to melt it. ### Claim 17 (depends on 16) The method claimed in claim 16, wherein said solder material has an oxide film of a thickness of at most 5 nm when said solder material is heated in the non-oxidizing atmosphere to melt it. ### Claim 18 (depends on 17) The method claimed in claim 17, wherein said oxide film having a thickness of at most 5 nm is an oxide film formed at least in part during said aligning in an oxidizing atmosphere. ### Claim 19 A method of soldering for use in fabricating an electric circuit device, comprising the steps of: preliminarily processing solder material so as to provide solder material that does not have at least one of an oxide layer and contamination film thereon; aligning said solder material and at least one member in an oxidizing atmosphere; and heating said solder material in a non-oxidizing atmosphere to melt said solder material and bond said solder material to said at least one member. ### Claim 20 (depends on 19) The method claimed in claim 19, wherein said preliminary processing includes providing solder balls each plated with gold. ### Claim 21 (depends on 20) The method claimed in claim 20, wherein the solder material and two members are aligned in the oxidizing atmosphere, and in the heating step the solder material is melted so as to bond the two members to each other. ### Claim 22 (depends on 19) The method claimed in claim 19, wherein said preliminary processing includes removing at least one of oxide layer and contamination layer from surface of said solder material. ### Claim 23 A fluxless bonding method for bonding connecting members of an integrated circuit, comprising the steps of: removing at least one of oxide film and contamination film on at least one of said connecting members and a solder material; aligning said connecting members is an oxidizing atmosphere; and heating said solder material in a non-oxidizing atmosphere to melt it. ### Claim 24 (depends on 23) The method claimed in claim 23, wherein said non-oxidizing atmosphere is prepared by supplying non-oxidizing gas to a vacuum atmosphere. ### Claim 25 (depends on 24) The method claimed in claim 24, wherein said non-oxidizing gas is inert gas selected from the group consisting of N.sub.2, Ar and He and a mixture thereof, and wherein said atmosphere during the heating is controlled by controlling said vacuum pressure and concentration of said gas. ### Claim 26 (depends on 27) The method claimed in claim 27, wherein said non-oxidizing atmosphere is a mixture of H.sub.2 and N.sub.2 and wherein said non-oxidizing atmosphere during the heating is controlled by controlling concentration of said mixture. ### Claim 27 (depends on 23, 24, 25, 26) The method claimed in any one of claims 23 to 26, further comprising the steps of: preliminarily evacuating a prenum chamber, equipped with a vacuum system and gas supply system each having a gate valve, and having said connecting members therein; heating and melting said connecting members in a belt furnace equipped with a vacuum system and a gas supply system each having a gate valve; and cooling said connecting members in a cooling chamber. ### Claim 28 (depends on 23, 24, 25, 26) The method claimed in any one of claims 23 to 26, wherein said step of removing at least one of oxide film and contamination film of at least one of said connecting members and said solder material is performed by sputter-cleaning using at least one of atom and ion beam irradiation. ### Claim 29 (depends on 23, 24, 25, 26) The method claimed in any one of claims 23 to 26, wherein said step of removing at least one of oxide film and contamination film of at least one of said connecting members and said solder material is performed mechanically. ### Claim 30 (depends on 23, 24, 25, 26) The method claimed in any one of claims 23 to 26, wherein said step of removing is performed mechanically. ### Claim 31 (depends on 23, 24, 25, 26) The method claimed in any one of claims 23 to 26, wherein said step of aligning is performed by fitting protrusions formed on one of said connecting members in recesses formed in protrusion means formed on another connecting member. ### Claim 32 (depends on 23) The method claimed in claim 23, wherein said step of aligning is performed by fitting protrusions formed on one of said connecting members in recesses formed in protrusion means formed on another connecting member. ### Claim 33 (depends on 32) The method claimed in claim 32, wherein at least one of (a) protrusion and (b) at least a portion of said protrusion means is formed of a refractive resin. ### Claim 34 (depends on 32) The method claimed in claim 32, wherein at least one of (a) said protrusion and (b) at least a portion of said protrusion means is formed from at least one solder ball welded to said members.