Method of fabricating electronic circuit device and apparatus for performing the same method

• US 5,341,980 A
• Filed: 05/29/1992
• Issued: 08/30/1994
• Est. Priority Date: 02/19/1990
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nishikawa, Toru, Harada, Masahide, Satoh, Ryohei, Hayashida, Tetsuya, Shirai, Mitugu
• Primary Examiner(s): Bradley, P. Austin
• Assistant Examiner(s): Miner, James
• Application Number:
  US07/890,255
• Time in Patent Office: 823 Days
• Field of Search: 228/206, 228/207, 228/205, 228/180.2, 228/219, 228/220, 228/180.21, 228/180.22
• US Class Current: 228/205
• CPC Class Codes: B23K 1/0016 Brazing of electronic components
• CPC Class Codes: B23K 1/008 Soldering within a furnace B23K1/012 takes precedence
• CPC Class Codes: B23K 1/206 Cleaning
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2224/11003 for holding or transferring the bump preform
• CPC Class Codes: H01L 2224/11334 using preformed bumps
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/742 Apparatus for manufacturing bump connectors
• CPC Class Codes: H01L 2224/749 Tools for reworking, e.g. for shaping
• CPC Class Codes: H01L 2224/75 Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 2224/81141 Guiding structures both on and outside the body
• CPC Class Codes: H01L 2224/81801 Soldering or alloying
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 24/11 Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/12 : Structure, shape, material or disposition of the bump connectors prior to the connecting process
• CPC Class Codes: H01L 24/75 : Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01018 : Argon [Ar]
• CPC Class Codes: H01L 2924/01032 : Germanium [Ge]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01042 : Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H05K 2201/10984 : Component carrying a connection agent, e.g. solder, adhesive soldering leadless components having an array of bottom contacts H05K3/3436; BGA components H05K2201/10734
• CPC Class Codes: H05K 2203/025 : Abrading, e.g. grinding or sand blasting deburring, rounding, bevelling or smoothing conductor edges H05K2203/0346
• CPC Class Codes: H05K 2203/0278 : Flat pressure, e.g. for connecting terminals with anisotropic conductive adhesive
• CPC Class Codes: H05K 2203/041 : Solder preforms in the shape of solder balls soldering leadless components having an array of bottom contacts H05K3/3436
• CPC Class Codes: H05K 2203/0435 : Metal coated solder, e.g. for passivation of solder balls
• CPC Class Codes: H05K 2203/086 : Using an inert gas
• CPC Class Codes: H05K 2203/087 : Using a reactive gas
• CPC Class Codes: H05K 2203/095 : Plasma, e.g. for treating a substrate to improve adhesion with a conductor or for cleaning holes
• CPC Class Codes: H05K 2203/1157 : Using means for chemical reduction
• CPC Class Codes: H05K 3/3426 : characterised by the leads
• CPC Class Codes: H05K 3/3436 : having an array of bottom contacts, e.g. pad grid array or ball grid array components
• CPC Class Codes: H05K 3/3489 : Composition of fluxes; Methods of application thereof; Other methods of activating the contact surfaces
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

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

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.

3. 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.

8. The method claimed in claim 1 or 2, wherein said non-oxidizing atmosphere is reducing gas.

9. The method claimed in claim 8, wherein said non-oxidizing atmosphere is an active gas atmosphere.

10. The method claimed in claim 9, wherein said active gas atmosphere is selected from the group consisting of (1) a mixture of H₂ and N₂ and (2) H₂.

11. 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.

12. The method claimed in claim 1 or 2, wherein the aligning in an oxidizing atmosphere is performed for a maximum of 8 hours.

13. 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.

14. The method claimed in claim 1 or 2, wherein two members are joined by said soldering material.

15. The method claimed in claim 1 or 2, wherein said non-oxidizing atmosphere is fluorocarbon vapor.

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.

4. The method claimed in claim 2, wherein said non-oxidizing atmosphere is inert gas.

5. The method claimed in claim 4, wherein said non-oxidizing atmosphere is He.

6. The method claimed in claim 4, wherein said non-oxidizing atmosphere is argon gas.

7. The method claimed in claim 4, wherein said non-oxidizing atmosphere is N₂.

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.

17. 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.

18. 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.

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.

20. The method claimed in claim 19, wherein said preliminary processing includes providing solder balls each plated with gold.

21. 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.

22. 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.

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.

24. The method claimed in claim 23, wherein said non-oxidizing atmosphere is prepared by supplying non-oxidizing gas to a vacuum atmosphere.

25. The method claimed in claim 24, wherein said non-oxidizing gas is inert gas selected from the group consisting of N₂, 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.

26. The method claimed in claim 27, wherein said non-oxidizing atmosphere is a mixture of H₂ and N₂ and wherein said non-oxidizing atmosphere during the heating is controlled by controlling concentration of said mixture.

27. 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.

28. 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.

29. 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.

30. The method claimed in any one of claims 23 to 26, wherein said step of removing is performed mechanically.

31. 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.

32. 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.

33. 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.

34. 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.