Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1996-08-02
1998-05-19
Yoon, Tae
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524440, 524709, 524236, 528422, 252500, 252511, C08K 517, C08K 549, H01B 120
Patent
active
057537488
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to adhesive compositions. In a particular aspect, the present invention relates to modified adhesive compositions having reduced propensity to bleed upon application to a substrate.
BACKGROUND OF THE INVENTION
Monomer vehicles used in die attach paste compositions tend to bleed out onto the substrate during cure, and even (in some cases) during room temperature staging of the adhesive. Indeed, resin bleed is a serious issue for die attach in electronic packaging. "Bleed" is defined herein as separation of the monomer vehicle phase and filler during staging or cure, resulting in spread of resin away from the die bond area. Resin bleed can generate wire bond non-sticks if it flows up onto bonding pads of the microelectronic device itself or the package into which it has been placed.
There are several potential impacts of this problem, e.g., a package assembler must deal with the likelihood of reduced product yields (and the attendant increased costs for manufacture), the part-to-part variability of the bleed phenomenom results in unacceptable part-to-part variability of the desired product, thereby necessitating the additional expense of 100% visual inspection of each component before being passed onto the wire bond step, and the like.
U.S. Pat. No. 4,483,898, issued to Harold Schonborn, et. al., and assigned to AT&T, discloses the use of alcohols, amides, amines, carboxylic acids, and esters containing two to twelve carbon atoms as allegedly being effective for the reduction of spreading of liquid films on substrates. The inhibition of resin bleed for epoxy, acrylate and silicone adhesive systems was the specific focus of this patent. The preferred bleed inhibiting compounds were poly-fluorinated (i.e. where most or all of the hydrogens of the hydrocarbon residue had been replaced by fluorine). The effective range contemplated by this patent is 0.05 to 5% by weight of the liquid phase. It is interesting to note, however, that the bleed control failed at 0.2% by weight of the most preferred bleed inhibiting agent in the absence of any "coupling agent" (see example VII). Furthermore, several of the compounds cited in '898 had deleterious effects on the pot life of the epoxy systems in which they were used (see, for example, Example VIII).
Accordingly, there is still a need in the art for compositions and methods useful for reducing the occurrence of resin bleed when die-attach compositions are applied to a substrate.
BRIEF DESCRIPTION OF THE INVENTION
In accordance with the present invention, we have discovered that the addition of small amounts of bleed control agent(s) to adhesive formulations renders such compositions extremely resistant to resin bleed. Several different types of bleed control agents are contemplated for use in the practice of the present invention, e.g., cationic surfactants, tertiary amines, tertiary phosphines, amphoteric surfactants, polyfunctional compounds, and the like, as well as mixtures of any two or more thereof.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, there are provided compositions for attaching a device to a substrate. Invention compositions comprise: application of said composition to a substrate; and optionally
Invention compositions can optionally contain filler material. Fillers contemplated for use in the practice of the present invention can be thermally and/or electrically conductive, and can be present in widely varying amounts, typically falling in the range of about 20 to about 92 wt. percent, based on the total weight of the attach paste.
Examples of electrically conductive fillers contemplated for use in the practice of the present invention include, for example, silver, nickel, cobalt, copper and aluminum fillers, as well as alloys of such metals. Both powder and flake forms of filler may be used in the attach paste compositions of the present invention. The preferred thickness of flake is under 2 microns with a dimension of about 20 to about 25 microns. Flake e
REFERENCES:
patent: 4401776 (1983-08-01), Munk
patent: 4483898 (1984-11-01), Schonhorn et al.
patent: 4513114 (1985-04-01), Kunugi et al.
patent: 4552690 (1985-11-01), Ikeguchi et al.
patent: 4604452 (1986-08-01), Shimp
patent: 4608434 (1986-08-01), Shimp
patent: 4709008 (1987-11-01), Shimp
patent: 4740584 (1988-04-01), Shimp
patent: 4785075 (1988-11-01), Shimp
patent: 4839442 (1989-06-01), Craig, Jr.
patent: 4847233 (1989-07-01), Shimp
patent: 4861823 (1989-08-01), Qureshi
patent: 4999699 (1991-03-01), Christie et al.
patent: 5002818 (1991-03-01), Licari et al.
patent: 5077319 (1991-12-01), Wang et al.
patent: 5150195 (1992-09-01), Nguyen
patent: 5155066 (1992-10-01), Nguyen
patent: 5186880 (1993-02-01), Gaku et al.
patent: 5232613 (1993-08-01), Bacon et al.
patent: 5338594 (1994-08-01), Wang et al.
patent: 5358992 (1994-10-01), Dershem et al.
patent: 5371178 (1994-12-01), Nguyen
patent: 5386000 (1995-01-01), Nguyen
Shimp and Craig, "New Liquid Dicyanate Monomer for Rapid Impregnation of Reinforcing Fibers" 34th International Sampe Symposium, Reno, pp. 1326-1346 (1989).
Hi-tek Polymers, "AroCy Cyanate Ester Safety and Handling Bulletin" AroCy Safety and Handling (May 1989).
Shimp, D.A., "Thermal Performance of Cyanate Functional Thermosetting Resins" SAMPE Quarterly pp. 41-46 (Oct. 1987).
"AroCy L-10 Cyanate Ester Monomer" Rhone-Poulenc (4 pg. brochure) (Oct. 9, 1990).
Shimp et al., "AroCy Cyanate Ester Resins, Chemistry, Properties and Applications" Rhone-Poulenc Inc., Table of Contents & Introduction, pp. 1-9 and Bibliography, pp. 35-36 (May 1991).
Derfelt Deborah L.
Dershem Stephen M.
Quantum Materials Inc.
Reiter Stephen E.
Yoon Tae
LandOfFree
Bleed resistant cyanate ester-containing compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bleed resistant cyanate ester-containing compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bleed resistant cyanate ester-containing compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1853872