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

• US 6,227,436 B1
• Filed: 09/25/1998
• Issued: 05/08/2001
• Est. Priority Date: 02/19/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shirai, Mitugu, Nishikawa, Toru, Harada, Masahide, Satoh, Ryohei, Hayashida, Tetsuya
• Primary Examiner(s): Evans, Geoffrey S.
• Assistant Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US09/160,288
• Time in Patent Office: 956 Days
• Field of Search: 228/205, 228/180.21, 228/219, 228/180.2, 228/206, 228/207, 228/220, 228/180.22, 228/221, 228/6.2, 228/8, 228/42, 228/231, 228/49.5, 228/56.3, 134/40, 134/42, 134/228, 134/134, 219/121.68
• US Class Current: 228/180.22
• 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 2224/05184 Tungsten [W] as principal constituent
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/11003 for holding or transferring the bump preform
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/13111 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• 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 2224/7501 : Means for cleaning, e.g. brushes, for hydro blasting, for ultrasonic cleaning, for dry ice blasting, using gas-flow, by etching, by applying flux or plasma
• CPC Class Codes: H01L 2224/757 : Means for aligning
• CPC Class Codes: H01L 2224/7901 : Means for cleaning, e.g. brushes, for hydro blasting, for ultrasonic cleaning, for dry ice blasting, using gas-flow, by etching, by applying flux or plasma
• CPC Class Codes: H01L 2224/81012 : Mechanical cleaning, e.g. abrasion using hydro blasting, brushes, ultrasonic cleaning, dry ice blasting, gas-flow
• 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 24/16 : of an individual bump connector
• 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 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• 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 2924/01039 : Yttrium [Y]
• 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 2924/01054 : Xenon [Xe]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• 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: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H05K 2201/10984 : Component carrying a connection agent, e.g. solder, adhesive
• CPC Class Codes: H05K 2203/025 : Abrading, e.g. grinding or sand blasting
• 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
• 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 soldering together two members such as electronic circuit devices, after an oxide or contaminated layer has been removed from the surface of a solder material or bonding pad, for example, the members are aligned in an oxidizing atmosphere. Then the solder material is heated in a nonoxidizing atmosphere to melt the solder and bond the members. Cleaning of the solder material or bonding pad is performed by sputter-cleaning, laser cleaning, mechanical polishing, or cutting.

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 a contamination layer from respective surfaces of a solder material and at least one member to be connected thereto, by laser beam cleaning;

aligning said at least one member and said solder material in an oxidizing atmosphere; and

heating said solder material in a nonoxidizing atmosphere to melt the solder material.

2. A method of soldering as claimed in claim 1, wherein said solder material is at least one selected from the group consisting of alloys of Pb and Sn, alloys of Sn and Ag, alloys of Au and Pb, alloys of Au and Ge, and alloys of Au and Si.

3. A method of soldering as claimed in claim 1, wherein said aligning step is performed in said oxidizing atmosphere for at most six hours.

4. A method of soldering as claimed in claim 1, wherein said nonoxidizing atmosphere is prepared by supplying nonoxidizing gas to a vacuum atmosphere.

5. A method of soldering as claimed in claim 4, wherein said nonoxidizing gas is an inert gas.

6. A method of soldering as claimed in claim 5, wherein said inert gas is selected from the group consisting of (1) N₂, (2) Ar, (3) He, and (4) a mixture of N₂, Ar, and He.

7. A method of soldering as claimed in claim 5, wherein said inert gas is selected from the group consisting of (1) N₂, (2) Ar, (3) He, and (4) a mixture of N₂, Ar, and He, and wherein said heating step atmosphere is controlled by controlling the pressure of said vacuum atmosphere and the concentration of said nonoxidizing gas.

8. A method of soldering as claimed in claim 4, wherein said nonoxidizing gas is a reducing gas.

9. A method of soldering as claimed in claim 4, wherein said nonoxidizing gas is an active gas.

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

11. A method of soldering as claimed in claim 4, wherein said nonoxidizing gas is a fluorocarbon vapor.

12. A method of soldering as claimed in claim 1, wherein said aligning step is performed in said oxidizing atmosphere for at most 8 hours.

13. A method of soldering as claimed in claim 1, wherein said aligning step is performed for a time sufficiently limited such that an oxide layer formed on the solder material during the aligning step has a thickness of at most 5 nm.

14. A method of soldering as claimed in claim 1, wherein said aligning step is performed by fitting protrusions formed on a first member in recesses formed by protrusions formed on a second member.

15. A method of soldering as claimed in claim 1, wherein said heating step is performed to segment any oxide layer formed on the solder material during the aligning step so as to expose the solder material.

16. 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 a contamination layer from respective surfaces of a solder material and at least one member to be connected thereto, by laser beam cleaning;

oxidizing said surfaces to form a thin oxide layer thereon;

aligning said at least one member and said solder material; and

heating said solder material in a nonoxidizing atmosphere to melt the solder material.

17. A method of soldering for use in fabricating an electronic circuit device, comprising the steps of:

processing a solder material to ensure that no oxide layer and no contamination layer are present thereon, by laser beam cleaning;

thereafter, aligning at least one electronic circuit device member and said solder material in an oxidizing atmosphere; and

then heating said solder material in a nonoxidizing atmosphere to melt the solder material.

18. A method of soldering as claimed in claim 17, wherein said processing step includes the step of providing solder balls each plated with gold.

19. A method of soldering as claimed in claim 17, wherein said processing step includes the step of removing at least one of an oxide layer and a contamination layer from a surface of said solder material.

20. A fluxless bonding method for bonding a connecting member of an integrated circuit, comprising the steps of:

removing at least one of an oxide layer and a contamination layer from respective surfaces of a solder material and at least one connecting member to be connected thereto, by laser beam cleaning;

aligning said at least one connecting member and said solder material in an oxidizing atmosphere; and

heating said solder material in a nonoxidizing atmosphere to melt the solder material.