Adhesive-bonded substrates in a multi-chip module

• US 8,698,322 B2
• Filed: 03/24/2010
• Issued: 04/15/2014
• Est. Priority Date: 03/24/2010
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Drost, Robert J., Krishnamoorthy, Ashok V., Cunningham, John E.
• Primary Examiner(s): Malsawma, Lex
• Assistant Examiner(s): ZHU, SHENG-BAI
• Application Number:
  US12/730,823
• Publication Number:
  US 20110233789A1
• Time in Patent Office: 1,483 Days
• Field of Search: 257/777, 257/734, 257/746, 257/773, 257/778, 257/E23.169, 438/244, 438/108, 438/31
• US Class Current: 257/777
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2225/06531 Non-galvanic coupling, e.g. capacitive coupling
• CPC Class Codes: H01L 2225/06555 Geometry of the stack, e.g. form of the devices, geometry to facilitate stacking
• CPC Class Codes: H01L 23/48 Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• CPC Class Codes: H01L 23/5389 the chips being integrally enclosed by the interconnect and support structures
• CPC Class Codes: H01L 25/0657 Stacked arrangements of devices
• CPC Class Codes: H01L 2924/15153 the die mounting substrate comprising a recess for hosting the device

Abstract

A multi-chip module (MCM) is described in which at least two substrates are mechanically coupled by an adhesive layer that maintains alignment and a zero (or near zero) spacing between proximity connectors on surfaces of the substrates, thereby facilitating high signal quality during proximity communication between the substrates. In order to provide sufficient shear strength, the adhesive layer has a thickness that is larger than the spacing. This may be accomplished using one or more positive and/or negative features on the substrates. For example, the adhesive may be bonded to: one of the surfaces and an inner surface of a channel that is recessed below the other surface; inner surfaces of channels that are recessed below both of the surfaces; or both of the surfaces. In this last case, the zero (or near zero) spacing may be achieved by disposing proximity connectors on a mesa that protrudes above at least one of the substrate surfaces.

Claims

1. A multi-chip module (MCM), comprising:

a first substrate having a first surface, wherein a first set of proximity connectors are disposed on the first surface;

a second substrate having a second surface that faces the first surface, wherein a second set of proximity connectors are disposed on the second surface, wherein the first set of proximity connectors and the second set of proximity connectors are separated by a spacing, wherein the second surface includes a channel that is defined by an opening in the second substrate along the second surface, wherein the channel comprises an inner surface that faces the first surface and is recessed in the second substrate away from the second surface, and wherein the channel extends to an edge of the second substrate that is perpendicular to the second surface; and

an adhesive, mechanically coupled to the first substrate and the inner surface, having a thickness that is larger than the spacing, thereby maintaining alignment and providing shear strength in the MCM, the adhesive configured so that at least the spacing between the first and second surfaces in an area where the first and second sets of proximity connectors are located is free of adhesive.

2. The MCM of claim 1, wherein the adhesive is one or more of, air cured, thermally cured, pressure cured and optically cured.

3. The MCM of claim 1, wherein the channel extends to at least an edge of the second substrate that is approximately perpendicular to the second surface, thereby defining an opening in the edge into which the adhesive is deposited during assembly of the MCM.

4. The MCM of claim 1, wherein the proximity communication includes at least one of, electrical proximity communication, inductive proximity communication, conductive proximity communication and optical proximity communication.

5. The MCM of claim 1, wherein the first surface includes another channel having another inner surface that is recessed below the first surface;

and

wherein the adhesive is mechanically coupled to the first substrate via the other inner surface.

6. The MCM of claim 1, wherein the channel is enclosed by only three sides, wherein the three sides comprise the inner surface and two sides perpendicular to the second surface.

7. The MCM of claim 1, wherein the first substrate comprises a first semiconductive material and the second substrate comprises a second semiconductive material.

8. The MCM of claim 1, wherein the first substrate comprises a first semiconductor die and wherein the second substrate comprises a second semiconductor die.

9. An MCM, comprising:

a first substrate having a first surface, wherein a first set of proximity connectors are disposed on the first surface;

a second substrate having a second surface that faces the first surface, wherein a mesa having a third surface protrudes above the second surface, wherein the mesa is between edges of the second substrate that are perpendicular to the second surface, wherein the mesa comprises at least one of a semiconductive and an electrically insulating material, wherein a second set of proximity connectors are disposed on the third surface, and wherein the first set of proximity connectors and the second set of proximity connectors are separated by a spacing; and

an adhesive, mechanically coupled to the first surface and the second surface and bonded to the first surface and the second surface, having a thickness that is larger than the spacing, thereby maintaining alignment and providing shear strength in the MCM, the adhesive configured so that at least the spacing between the first and second surfaces in an area where the first and second sets of proximity connectors are located is free of adhesive,

wherein the adhesive is not in contact with the mesa.

10. The MCM of claim 9, wherein the adhesive is one or more of, air cured, thermally cured, pressure cured and optically cured.

11. The MCM of claim 9, wherein the spacing is less than 5 μ

m.

12. The MCM of claim 9, wherein the thickness is greater than 5 μ

m and less than 200 μ

m.

13. The MCM of claim 9, wherein the proximity communication includes one or more of, electrical proximity communication, inductive proximity communication, conductive proximity communication and optical proximity communication.

14. The MCM of claim 9, wherein the mesa has edges that are perpendicular to the third surface, and wherein each edge for the mesa is between the edges of the second substrate that are perpendicular to the second surface.

15. The MCM of claim 9, wherein the mesa is an extension of the second substrate, and wherein the second substrate comprises the at least one of the semiconductive and the electrically insulating material.

16. A system, comprising an MCM, wherein the MCM includes:

a first substrate having a first surface, wherein first proximity connectors are disposed on the first surface;

a second substrate having a second surface that faces the first surface, wherein a second set of proximity connectors are disposed on the second surface, wherein the first set of proximity connectors and the second set of proximity connectors are separated by a spacing, wherein the second surface includes a channel that is defined by an opening in the second substrate along the second surface, wherein the channel comprises an inner surface that faces the first surface and is recessed in the second substrate away from the second surface, and wherein the channel extends to an edge of the second substrate that is perpendicular to the second surface; and

an adhesive, mechanically coupled to the first substrate and the inner surface, having a thickness that is larger than the spacing, thereby maintaining alignment and providing shear strength in the MCM, the adhesive configured so that at least the spacing between the first and second surfaces in an area where the first and second sets of proximity connectors are located is free of adhesive.

17. The system of claim 16, wherein the adhesive is one or more of air cured, thermally cured, pressure cured and optically cured.

18. The system of claim 16, wherein the channel extends to at least an edge of the second substrate that is approximately perpendicular to the second surface, thereby defining an opening in the edge into which the adhesive is deposited during assembly of the MCM.

19. The system of claim 16, wherein the proximity communication includes one or more of electrical proximity communication, inductive proximity communication, conductive proximity communication and optical proximity communication.

20. The system of claim 16, wherein the first surface includes another channel having another inner surface that is recessed below the first surface;

and

wherein the adhesive is mechanically coupled to the first substrate via the other inner surface.