DIRECTING THE FLOW OF UNDERFILL MATERIALS USING MAGNETIC PARTICLES

• US 20090168390A1
• Filed: 12/28/2007
• Published: 07/02/2009
• Est. Priority Date: 12/28/2007
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: MANEPALLI, Rahul N., LEHMAN, Stephen E. JR., CHAN, Wendy, ARANA, Leonel R.
• Granted Patent: US 8,009,442 B2
• Time in Patent Office: Days
• US Class Current: 361/820
• 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 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/2929 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/2936 Iron [Fe] 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 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/831 the layer connector being supplied to the parts to be connected in the bonding apparatus
• CPC Class Codes: H01L 2224/92125 the second connecting process involving a 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/01012 Magnesium [Mg]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/0665 Epoxy resin
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

Electronic devices and methods for fabricating electronic devices are described. One method includes providing a substrate and a die, and coupling the die to the substrate, wherein a gap remains between the die and the substrate. The method also includes placing an underfill material on the substrate and delivering at least part of the underfill material into the gap. The method also includes controlling the flow of the underfill material in the gap using magnetic force. Other embodiments are described and claimed.

Claims

1. A method comprising:

providing a first body and a second body;

coupling the first body to the second body, wherein a gap remains between the first body and the second body;

placing an underfill material on the second body; and

delivering a flow of at least part of the underfill material into the gap; and

controlling the flow of the underfill material using magnetic force.

2. The method of claim 1, wherein the placing the underfill material on the second body comprises depositing a material comprising a polymer and magnetic particles adjacent to the gap, and wherein the controlling the flow of the underfill material using magnetic force comprises applying a magnetic field in at least one direction that causes the underfill material to be drawn into the gap.

3. The method of claim 1, wherein the placing the underfill material on the second body includes placing a material comprising a polymer epoxy and magnetic particles on the second body.

4. The method of claim 3, further comprising curing the polymer epoxy.

5. The method of claim 1, wherein the placing the underfill material on the second body includes placing a material comprising a polymer epoxy, magnetic particles, and silica particles on the second body.

6. The method of claim 1, wherein the controlling the flow of the underfill material using magnetic force comprises applying a static magnetic field to the underfill material.

7. The method of claim 1, wherein the controlling the flow of the underfill material using magnetic force comprises applying a non-uniform magnetic field to the underfill material.

8. The method of claim 1, wherein the controlling the flow of the underfill material using magnetic force comprises using an electromagnet to generate the magnetic force.

9. An assembly comprising:

a first body;

a second body;

the first body electrically coupled to the second body through a plurality of electrically conductive bumps positioned between the first body and the second body;

a gap between the first body and the second body; and

an underfill material positioned in the gap between the first body and the second body, the underfill material comprising a polymer and magnetic particles.

10. The assembly of claim 9, wherein the electrically conductive bumps comprise a solder composition.

11. The assembly of claim 9, wherein the underfill material comprises a polymer epoxy, magnetic particles, and silicon oxide particles.

12. The assembly of claim 9, wherein the first body comprises a semiconductor die, and the second body comprises a substrate.

13. The assembly of claim 12, wherein the die covers a die attach area on the substrate, the die attach area being rectangular in shape, and wherein the underfill material does not extend on the substrate outside of the die attach area a distance of greater than 1 mm.

14. The assembly of claim 12, wherein the die covers a die attach area on the substrate, the die attach area being rectangular in shape, and wherein the underfill material does not extend on the substrate outside of the die attach area.

15. A system comprising:

a central processing unit including the assembly of claim 12;

a memory electrically coupled to the central processing unit;

an input device electrically coupled to the central processing unit;

an output device electrically coupled to the central processing unit; and

a video controller electrically coupled to the central processing unit.

16. A method comprising:

providing a semiconductor die and a substrate;

coupling the semiconductor die to the substrate, wherein a gap remains between the semiconductor die and the substrate;

placing an underfill material on the substrate, the underfill material comprising a polymer material and magnetic particles; and

positioning at least part of the underfill material in the gap;

controlling the positioning of the underfill material using magnetic force; and

solidifying the polymeric material.

17. The method of claim 16, wherein the magnetic particles include an electrically insulating layer thereon.

18. The method of claim 16, wherein the magnetic particles include a alkyl surface layer thereon.

19. The method of claim 16, wherein the underfill material further comprises silica particles.

20. The method of claim 16, wherein the controlling the positioning of the underfill material using magnetic force comprises applying a non-uniform magnetic field to the underfill material.