Polymer solder hybrid

Details Polymer solder hybrid Polymer solder hybrid

2002-09-18

2004-11-02

Thompson, Gregory D. (Department: 2835)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C165S080200, C165S080300, C165S011200, C174S016300, C174S015200, C257S707000, C257S713000, C361S704000, C361S702000, C361S708000, C228S180210, C228S123100, C428S040500, C428S041300, C428S673000, C428S402000, C428S645000, C428S616000

Reexamination Certificate

active

06813153

ABSTRACT:

BACKGROUND
1. Technical Field
An embodiment relates generally to thermal interface materials, and in particular relates to thermal interface materials to secure a heat management device to a die surface.
2. Description of the Related Art
In the fabrication of semiconductors devices, wafers are processed and sliced into individual dice. The dice may then be used in a wide variety of devices. For example, a die may be used in an electronic device by being electronically coupled to a printed circuit board (PCB) of the device. A thermal management device such as a heat pipe assembly is often attached to a surface of the die to dissipate heat to prevent damage to the die during operation.
In order to attach a thermal management device to a die surface, a thermal interface material (TIM) adhesive is placed at a surface of the die and used to secure the device. Conventional TIMs include polymer solder hybrids (PSHs). Such a hybrid may include a siloxane-based polymer and a solder such as indium-silver, indium-tin, tin-bismuth, gallium-tin-indium, gallium-indium-tin-zinc, indium-bismuth, gold-tin or other solder material. Additionally, thermally conductive fillers such as aluminum, silver, copper, or graphite may also be added to the PSH TIM. The combination of conductive filler and solder allows for the formation of thermally conductive pathways or chains throughout the PSH TIM. In this manner, heat generated within the die may be readily transferable across such chains to the attached thermal management device for dissipation as noted above.
In order to form the indicated chains and properly secure the thermal management device to the die, the PSH TIM is heated by a reflow process to at least the melting point of the solder. 183° C. is considered the industry standard dividing line between ‘low melt’ and ‘high melt’ solders. Where conventional solders, such as those noted above, are used, the PSH TIM may be a high melt solder requiring reflow at temperatures in excess of about 260° C., for the solder to melt and allow the filler to diffuse thereinto. For example, a temperature of 260° C. may be required where a gold-tin solder is employed in the PSH TIM. However, even where other conventional solders are employed, it is not uncommon for a temperature in excess of about 183° C. to be employed.
A PSH TIM may be employed to secure a thermal management device to a temperature sensitive assembly. For example, larger mobile or bare die assemblies incorporated into an already assembled computing box, such as a laptop, may require use of a PSH TIM. Such assemblies may include a die requiring attachment of a heat management device such as a heat pipe. These assemblies include more than just a die or individual semiconductor package. Rather, these assemblies are closer to being a completed computer, such as the indicated laptop, with added temperature sensitive features.
For temperature sensitive assemblies as noted above, low melt solders are available having melting points lower than about 183° C. However, a PSH to serve as a TIM that employs a low melt solder tends to be highly susceptible to degradation when subjected to standard industry testing. Industry tests may include a Highly Accelerated Stress Test (HAST) which includes PSH exposure to more than 100° C. (e.g., about 130° C.) with relative humidity of more than 50% (e.g., about 85%) for in excess of about 75 hours (e.g. about 100 hours), or a standard bake test which includes PSH exposure to even higher temperature (e.g., 150° C. for about 100 hours) without degradation. Unfortunately, a PSH employing a low melt solder tends to degrade in between about 24 and 48 hours when subjected to such tests.


REFERENCES:
patent: 5513070 (1996-04-01), Xie et al.
patent: 5598320 (1997-01-01), Toedtman et al.
patent: 6108208 (2000-08-01), Tustaniwskyj et al.
patent: 6339120 (2002-01-01), Misra et al.
U.S. 2001/0032719 Kim et al “Thermal Joint and Method of Use” Oct. 25, 2001.*
U.S. 2003/0077478 Dani et al “ Thermal Interface Material and Electronic Assembly Having Such a Thermal Interface Material” Apr. 24, 2003.

Affiliated with

Also associated with

Rating

Polymer solder hybrid does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Polymer solder hybrid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polymer solder hybrid will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3289827