Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
1999-11-10
2001-08-28
Riley, Shawn (Department: 2838)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C361S749000, C361S760000
Reexamination Certificate
active
06281437
ABSTRACT:
TECHNICAL FIELD
The invention relates to flexible circuitized substrates and particularly to such substrates which are adapted especially for being electrically coupled to electrical conductors such as contact sites on an integrated circuit chip, a copper pad on a printed circuit board (PCB), etc.
BACKGROUND OF THE INVENTION
Flexible circuitized substrates (often called simply “flex circuits” in the industry) are well known for providing effective connections between electronic components as may be found in information handling (e.g., personal computers (PCs), mainframe processors, etc.) and other electrical systems. One particular usage for such substrates is to electrically couple, directly or indirectly, an integrated circuit (semiconductor) chip to a PCB, such as may be found in a typical PC. Such a structure is often referred to in the industry as an electronic package, which will include a flexible substrate, a chip electrically coupled to the circuitry of the substrate, and perhaps a heatsink-stiffener component, all of which are designed for being mounted on and coupled to a PCB. Numerous examples of such electronic packages are known, with some representative examples being defined in the following patents, all of which are assigned to the same assignee as the present invention and are incorporated herein by reference:
U.S. Pat. No. 4,937,707—McBride
U.S. Pat. No. 4,967,950—Legg et al
U.S. Pat. No. 4,987,100—McBride, et al
U.S. Pat. No. 5,057,969—Ameen et al
U.S. Pat. No. 5,115,964—Ameen et al
U.S. Pat. No. 5,159,535—Desai et al
U.S. Pat. No. 5,170,931—Desai et al
U.S. Pat. No. 5,261,155—Angulas et al
U.S. Pat. No. 5,367,435—Andros et al
U.S. Pat. No. 5,435,732—Angulas et al
U.S. Pat. No. 5,519,936—Andros et al
U.S. Pat. No. 5,561,323—Andros et al
U.S. Pat. No. 5,633,533—Andros et al
U.S. Pat. No. 5,773,884—Andros et al
In Ser. No. 08/883,167, now U.S. Pat. No. 6,093,894, the flexible circuitized substrate includes a uniformly thick polyimide dielectric base layer having copper circuitry located thereon which in turn is designed for being directly coupled to a semiconductor chip. As explained in this application, the preferred approach for providing such a connection is to use what is referred to in the industry as thermocompression (TC) bonding, a well known procedure for bonding relatively small conductors. During such TC bonding, the bonder's thermode (anvil) is placed in direct contact with the uniformly thick dielectric while the circuit line or pad of the substrate engages the corresponding contact site of the chip. Heat and pressure normally used in TC bonding is applied from the dielectric's side, resulting is deformation (melting away) of the dielectric and a bond between the two metallic conductors (circuit line or pad and chip contact site). The bonding heat thus transfers through the interim dielectric to the copper circuit line or pad and corresponding contact site.
It has been discovered that an effective connection between a flexible circuitized substrate and a semiconductor chip can be achieved quickly and effectively by reducing the thickness of the dielectric in the region immediately below the circuit line or pad which is being bonded to the chip. Effective heat transference and a successful bond is attained, utilizing convention TC bonding apparatus. Such a connection is also attainable between the flexible substrate and several extremely small solder ball elements, should such elements be preferred for the chip (e.g., located on respective ones of the chip's contact sites).
It is believed that such an electrical connection and the products resulting therefrom will constitute significant advancements in the art.
OBJECTS AND SUMMARY OF THE INVENTION
It is a primary object of the present invention to enhance the art of electrical connections between flexible circuitized substrates and external conductors such as contact sites on a semiconductor chip.
It is another object of the invention to provide an electrical connection and various electrical circuitized structures using same which can be formed expeditiously and in a manner which makes the invention particularly adaptable to mass production.
According to one aspect of the invention, there is provided a method of forming an electrical connection comprising providing a dielectric layer having a first portion with a first thickness and a second portion with a second thickness, the second thickness of the second portion being less than the first thickness of the first portion, providing at least one conductive member on both the first and second portions of the dielectric layer, providing an electrical component having at least one conductor, and applying heat and/or pressure onto only the second portion of the dielectric layer and the at least one conductive member through the second portion to form an electrical connection between the at least one conductive member and the at least one conductor.
According to another aspect of the invention, there is provided a method of forming an electronic package comprising the steps of providing an electrical component having at least one conductor, providing a flexible circuitized substrate including a dielectric layer having a first portion with a first thickness and a second portion with a second thickness and at least one conductive member on both of the first and second portions of the dielectric layer, aligning the at least one conductive member with the at least one conductor, and forming an electrical connection between the at least one conductive member and the at least one conductor to thereby electrically connect the flexible circuitized substrate and the electrical component and form the electronic package.
According to still another aspect of the invention, there is provided an electrical connection comprising at least one conductor, and a substrate including a dielectric layer having a first portion with a first thickness and a second portion with a second thickness, the second thickness of the second portion being less than the first thickness of the first portion, and at least one conductive member on both the first and second portions of the dielectric layer, the at least one conductive member and the at least one conductor being bonded together to form the electronic connection.
According to yet another aspect of the invention, there is provided an electronic package comprising a flexible circuitized substrate including a dielectric layer having a first portion with a first thickness and a second portion with a second thickness less than the first thickness, the flexible circuitized substrate not including a cover layer or the like on the at least one conductive member, at least one conductive member positioned on the dielectric layer over both the first and second portions, and an electrical component including at least one conductor, the conductor bonded to the at least one conductive member of the flexible circuitized substrate of the dielectric layer.
REFERENCES:
patent: 4937707 (1990-06-01), McBride et al.
patent: 4967950 (1990-11-01), Legg et al.
patent: 4987100 (1991-01-01), McBride et al.
patent: 5057969 (1991-10-01), Ameen et al.
patent: 5065506 (1991-11-01), Kiribayashi
patent: 5115964 (1992-05-01), Ameen et al.
patent: 5159535 (1992-10-01), Desai et al.
patent: 5170931 (1992-12-01), Desai et al.
patent: 5261155 (1993-11-01), Angulas et al.
patent: 5321583 (1994-06-01), McMahon
patent: 5367435 (1994-11-01), Andros et al.
patent: 5435732 (1995-07-01), Angulas et al.
patent: 5519936 (1996-05-01), Andros et al.
patent: 5561323 (1996-10-01), Andros et al.
patent: 5633533 (1997-05-01), Andros et al.
patent: 5737191 (1998-04-01), Horiuchi et al.
patent: 5773884 (1998-06-01), Andros et al.
Anderson Steven W.
Armezzani Gregg J.
Labzentis Daniel P.
Fraley Lawrence R.
International Business Machines - Corporation
Riley Shawn
LandOfFree
Method of forming an electrical connection between a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of forming an electrical connection between a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of forming an electrical connection between a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2520104