Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Adhesive outermost layer
Reexamination Certificate
2002-02-11
2003-09-09
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Adhesive outermost layer
C428S413000, C428S447000, C428S041800, C428S901000, C525S101000, C525S106000, C525S476000, C525S479000, C528S027000, C528S033000, C528S038000
Reexamination Certificate
active
06617021
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an adhesive composition and to an adhesive sheet suitable for use in semiconductor devices using various semiconductors, particularly a semiconductor device having a structure in which an IC chip is laminated on an IC board consisting of an IC insulator layer and a conductor circuit, a surface-mounting type semiconductor device and a multi IC chip type semiconductor device, and more particularly relates to an adhesive composition and an adhesive sheet for bonding an IC chip or a radiator plate, or laminating with an increased density on an IC board, i.e., for bonding an IC chip to an IC board, insulating layers together for a higher-density lamination on an IC board, an IC chip and a radiator plate, a radiator plate and an IC board, and/or IC chips together.
2. Description of the Related Art
With the recent spread of portable personal computers and cellular phones, there has been an increase in demand for electronic equipment which is reduced in size, is thicker, and is multifunctional.
In order to meet these demands, electronic parts must be reduced in size with an increased scale of integration, and furthermore, a high-density mounting technique of electronic parts is necessary.
As for IC packages constituting the core of electronic parts in recent years, periphery-mounting types such as a QFP (Quad Flat Package) and an SOP (Small Outline Package) have been typically used. Recently, however, IC packages of a surface-mounting type called BGA (Ball Grid Array), CSP (Chip Size Package) and BOC (Board On Chip) and packages of a multi IC chip type called MCP (Multi Chip Package) have been highlighted as IC packages capable of high-density mounting.
In the BGA, CSP and BOC, solder balls are provided in the form of a surface lattice on their back surface as connecting terminals to the outside. An electrode of the IC (semiconductor integrated circuit) is connected to an electrode of a printed circuit board through an IC board or wiring-pattern-of-a-circuit switching board. There have been developed, depending on the type of the IC board, a plastic BGA (hereinafter referred to as “P-BGA”), a ceramic BGA (hereinafter referred to as “C-BGA”), a tape BGA (hereinafter referred to as “T-BGA”), an enhanced BGA (hereinafter referred to as “E-BGA”) and the like.
Until recently, the P-BGA, which is capable of making use of a wire bonding technique in the QFP, has been widely used. However, the T-BGA which utilizes a TAB (Tape Automated Bonding) technique is becoming increasingly common because it enables further densification (pin multiplication) and is excellent in heat radiation.
The CSP is a package made by further size reduction and densifying the BGA and is called a “micro-BGA” or “fine pitch BGA”. Owing to its structure, the CSP has excellent electrical reliability such as low impedance and a rapid frequency response.
One example of a fine pitch BGA is shown in cross section in FIG.
1
.
An IC board
1
in this example consists of an insulator layer
2
and a conductor circuit of a conductor electrode
3
and the like formed on one surface of the insulator layer
2
, with a central hole provided therein. The IC board
1
is laminated through an adhesive layer
4
on an IC chip
5
. The IC chip
5
is connected through a bump formed thereon to the conductor electrode
3
with a metal wire
6
. The wiring and connections are covered with resin
7
. Wiring
8
is formed on those portions of the conductor electrode
3
that are not covered with resin
7
, with a solder ball
9
formed on the wiring so as to electrically connect the BGA to the outside.
Another example of a fine pitch BGA is shown in cross section in FIG.
2
. An IC board
1
in this example consists of an insulator layer
2
and a conductor electrode
3
formed on one surface of the insulator layer. The insulator layer
2
is provided with a plurality of throughholes for solder connection, from the side where the conductor electrode
3
is not formed, to the conductor electrode. A first IC chip
5
a
and a reinforcing plate
10
are laminated through an adhesive layer
4
onto the conductor electrode
3
formed on the insulator layer
2
, and a second IC chip
5
b
is laminated through an adhesive layer
4
on the first IC chip
5
a.
The IC chips
5
a
and
5
b
are connected through bumps formed thereon to the conductor electrode
3
with metal wires
6
. The wiring and connections are covered with resin
7
. A solder ball
9
is formed in the throughholes provided in the insulator layer
2
so as to come into contact with the conductor electrode
3
and electrically connect the BGA to the outside.
Another example of a fine pitch BGA is shown in cross section in FIG.
3
. In the fine pitch BGA of this example, a conductor electrode
3
and an IC chip
5
are laminated through an adhesive layer
4
on one surface of a radiator plate
11
. On that surface of the conductor electrode
3
which has no adhesive layer
4
thereon, an insulator layer
2
is provided which has throughholes for solder connection to the conductor electrode
3
, so as to constitute an IC board
1
. The IC chip
5
is connected through a bump formed thereon to the conductor electrode
3
with a metal wire
6
. The wiring and connections are covered with resin
7
. A solder ball
9
is formed in the throughholes provided in the insulator layer
2
so as to come into contact with the conductor electrode
3
and electrically connect the BGA to the outside.
For forming the insulator layer
2
, which constitutes the IC board, a board material employing polyimide resin, epoxy resin, phenolic resin or the like is usually used. Furthermore, for forming the adhesive layer
4
, an epoxy resin/NBR (acrylonitrile-butadiene copolymer) based adhesive, an epoxy resin/phenolic resin based adhesive and a rubber-modified epoxy resin/phenolic resin based adhesive have conventionally been used.
An IC package, when driven, reaches temperatures of 100° C. or more due to heat generated by the IC and is exposed to changes in temperature from room temperature to an elevated temperature (100° C. or more). Accordingly, the IC package is required to have heat resistance to withstand the stress changes in that case, humidity resistance under high temperature conditions, and a stress relaxing property.
Especially in recent years, the mounting density has been increased, with the result that the proportion of wired conductive metal is made larger, thereby making it necessary to bond together materials having different coefficients of thermal expansion. An IC package is also required to be capable of withstanding stresses caused in that case. The adhesive as composed above, however, does not have sufficient resistance to long-term temperature changes, nor sufficient resistance to high temperatures and high humidity.
More specifically, due to the stress resulting from repetition of cycling the temperature change between room temperature and an elevated temperature (100° C. or more), delamination often occurs between the above IC-board-constituting insulator layer
2
and the IC chip
5
, or inside the laminated board. Furthermore, as a method for enhancing the mounting density, insulator layers may be laminated to form a three-dimensional wiring pattern. This method also has the same drawback. In this laminating-type high density mounting method, as laminating substrates, there has been in many cases employed, in addition to a glass epoxy board, a TAB board, a flexible board or the like for the purpose of thinning the package, most of the materials of which are polyimide resin and the like.
Generally speaking, polyimide resin and the like are very difficult to bond and are susceptible to influences from the conditions of absorbed water, interface and the like. Thus, an adhesive composition of low water absorption and excellent adhesion has been demanded.
Furthermore, in this laminating-type high density mounting method, a wiring pattern must be embedded during lamination. Thus, an adhesive composit
Kobayashi Masaharu
Oka Osamu
Yoshii Yasuhiro
Keehan Christopher M.
Nixon & Vanderhye P.C.
Tomoegawa Paper Co., Inc.
LandOfFree
Adhesive composition and adhesive sheet for semiconductor... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adhesive composition and adhesive sheet for semiconductor..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adhesive composition and adhesive sheet for semiconductor... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3088757