Method for making a solder joint

• US 8,925,793 B2
• Filed: 10/30/2012
• Issued: 01/06/2015
• Est. Priority Date: 01/05/2012
• Status: Active Grant

• Current Assignee: Dunan Microstaq, Inc. (Zhejiang Dun'an Artificial Environment Co., Ltd.)
• Original Assignee: Dunan Microstaq, Inc. (Zhejiang Dun'an Artificial Environment Co., Ltd.)
• Inventors: Arunasalam, Parthiban, Bhopte, Siddharth, Ojeda, Joe Albert Sr.
• Primary Examiner(s): Patel, Devang R
• Application Number:
  US13/663,698
• Publication Number:
  US 20130175330A1
• Time in Patent Office: 798 Days
• Field of Search: 228/56.3, 228/224, 228/245, 228/246
• US Class Current: 228/246
• CPC Class Codes: B23K 1/0016 Brazing of electronic components
• CPC Class Codes: B23K 1/203 Fluxing, i.e. applying flux onto surfaces
• CPC Class Codes: B23K 2101/42 Printed circuits
• CPC Class Codes: B23K 35/3612 with organic compounds as principal constituents
• CPC Class Codes: H01L 2224/27332 using a powder
• CPC Class Codes: H01L 2224/29011 comprising apertures or cavities
• CPC Class Codes: H01L 2224/29015 comprising protrusions or indentations
• CPC Class Codes: H01L 2224/29076 being mutually engaged together, e.g. through inserts
• CPC Class Codes: H01L 2224/29082 Two-layer arrangements
• CPC Class Codes: H01L 2224/29116 Lead [Pb] as principal constituent
• CPC Class Codes: H01L 2224/29294 with a principal constituent of the material being a liquid not provided for in groups H01L2224/292 - H01L2224/29291
• CPC Class Codes: H01L 2224/29309 Indium [In] as principal constituent
• CPC Class Codes: H01L 2224/29311 Tin [Sn] as principal constituent
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/32 of an individual layer connector
• CPC Class Codes: H01L 24/83 using a layer 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 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/1461 : MEMS
• CPC Class Codes: H05K 2203/0415 : Small preforms other than balls, e.g. discs, cylinders or pillars
• 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 3/3478 : Applying solder preforms; Transferring prefabricated solder patterns
• CPC Class Codes: H05K 3/3485 : Applying solder paste, slurry or powder thick film methods for applying conductive paste or ink patterns H05K3/12

Abstract

A method of bonding an electrical component to a substrate includes applying solder paste on to a substrate. Solder preform has an aperture is formed therethrough and is then urged into contact with the solder paste, such that solder paste is urged through the aperture. An electrical component is then urged into contact with the solder preform and into contact with the solder paste that has been urged through the aperture, thereby bonding the electrical component, the solder preform, and the substrate together to define a reflow subassembly.

Claims

1. A method of bonding a component to a substrate comprising:

applying solder paste on to a substrate;

urging a solder preform made of solder or braze material into contact with the solder paste, the solder preform having a channel in the form of at least one of an aperture and a notch formed therethrough, such that solder paste is urged through the channel in an amount sufficient to fill and at least partially spill over edges of the channel; and

urging a component into contact with the solder preform and into contact with the solder paste that has been urged through the channel, thereby bonding the component, the solder preform, and the substrate together to define a reflow subassembly.

2. The method according to claim 1, wherein the component is a MEMS device.

3. The method according to claim 1, wherein the solder paste includes flux.

4. The method according to claim 1, wherein the substrate is metal.

5. The method according to claim 1, further including the step of moving the reflow subassembly to a source of heat.

6. The method according to claim 5, further including the step of applying heat from the source of heat to the reflow subassembly, thereby reflowing the solder preform to bond the component and the substrate together, and defining a solder joint.

7. The method according to claim 1, wherein the bond between the component, the solder preform, and the substrate is strong enough to allow the reflow subassembly to be moved to a subsequent process step without an assembly fixture.

8. The method according to claim 1, wherein the solder paste is applied on to the substrate using a screen printing process.

9. A method of bonding a MEMS device to a substrate comprising:

applying solder paste on to a substrate;

urging a solder preform made of solder or braze material into contact with the solder paste, the solder preform having an aperture formed therethrough, such that solder paste is urged through the aperture in an amount sufficient to fill and at least partially spill over edges of the aperture; and

urging a MEMS device into contact with the solder preform and the solder paste that has been urged through the aperture, thereby bonding the MEMS device, the solder preform, and the substrate together to define a reflow subassembly.

10. The method according to claim 9, wherein the solder paste includes flux.

11. The method according to claim 10, wherein the limited amount of solder paste that is urged through the aperture provides flux between the solder preform and the MEMS device via the solder paste.

12. The method according to claim 9, wherein the substrate is formed from metal.

13. The method according to claim 9, further including the step of moving the reflow subassembly to a source of heat.

14. The method according to claim 13, further including the step of applying heat from the source of heat to the reflow subassembly, thereby reflowing the solder preform to bond the MEMS device and the substrate together, and defining a solder joint.

15. The method according to claim 9, wherein the bond between the MEMS device, the solder preform, and the substrate is strong enough to allow the reflow subassembly to be moved to a subsequent process step without an assembly fixture.

16. A method of bonding a component to a substrate comprising:

a) applying a quantity of a fluxing agent on to a substrate;

b) providing a solder preform made of solder or braze material having at least one channel in the form of at least one of an aperture and a notch formed therethrough,

c) urging the solder preform into the fluxing agent, such that a portion of the fluxing agent is displaced through the channel formed in the solder preform in an amount sufficient to fill and at least partially spill over edges of the channel; and

d) urging a component into contact with some of the fluxing agent that has been urged through the channel.

17. The method of claim 16 where the fluxing agent is a solder paste containing solder and flux.

18. The method of claim 16 wherein the component has a flat surface, and wherein the flat surface of the component is urged into contact with the portion of the fluxing agent displaced through the channel, such that the portion of the fluxing agent disposed in an interface of the solder preform and the component provides a quantity of flux quantity required to achieve a good solder joint and not a quantity of flux excessive to that required to achieve a good solder joint.