Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead – Die bond
Reexamination Certificate
1999-06-10
2001-03-20
Mis, David (Department: 2817)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
Die bond
C257S782000
Reexamination Certificate
active
06204565
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor carrier suitable for mounting a semiconductor device with a high density and method for manufacturing the same.
2. Description of the Related Art
The semiconductor carrier for mounting the semiconductor device is known in the art, for example, as disclosed in the “Electric Component & Technology Conference”, No. 46, pp. 727-732.
FIG. 4
depicts a cross section of the carrier, in which a copper interconnection pattern
41
, a base layer
42
consisting of a polyimide film, and an adhesive layer
43
consisting of a thermoplastic polyimide construct a tape substrate
44
. A through hole bump
45
to be connected electrically with a chip is formed in the tape substrate
44
. A cover resist layer
48
, which includes an aperture
46
for connecting the semiconductor carrier with a mount board electrically and a slit
47
for bonding, is formed on the copper interconnection pattern
41
.
In the above-mentioned conventional semiconductor carrier, a substance of the adhesive layer
43
and a technology for forming a through hole in the base layer
42
and adhesive layer
43
to form the through hole bump
45
greatly affect the performance and reliability of the semiconductor carrier. Essential properties required for the adhesive layer
43
are an advantageous heat resistance, moisture resistance, adhesion and low stress which enable to endure various treatments suffered from post-processes such as a process for mounting the semiconductor carrier on the mount board as well as a drug resistance without degrading its characteristics through plating and cleaning processes.
On the other hand, the through hole forming method for forming the through hole bump
45
also greatly affects the performance and reliability of the semiconductor carrier. A method using a laser such as an excimer, carbonic acid gas or YAG laser is generally well known as the through hole forming method. In the method, however, process conditions are unstable so that an etching remainder or sludge may be left on the via bottom. The method further includes a disadvantage that a reliable bump can not be formed because a thermal damage is given to a surface of the copper interconnection pattern
41
according to a type of the laser, resulting in an unstable adhesion of the interface between the copper interconnection pattern
41
and the through hole bump
45
.
The formation of the through hole by the laser reduces the throughput and makes a limitation for the yield. In addition, it is not suitable for the mass production and is disadvantageous with respect to the cost. Further, the carbonic acid gas laser and YAG laser are difficult to form a fine through hole because of their long wavelengths. It is desirable for the method as the means to solve such the disadvantages that the adhesive layer
43
has a photosensitivity and that the through hole is formed by the conventional photolithography process.
There is a subject under consideration to construct the semiconductor carrier with an adhesive that has the advantageous heat resistance, moisture resistance, adhesion, low stress and drug resistance as described above. The adhesive should also have the photosensitivity and advantageous resolution, and enable to form a fine through hole by the conventional photolithography process.
The known adhesives with photosensitivity include those of polyimide series as disclosed in JPA 4-337380 and those of epoxy series as disclosed in JPA 6-19134 and JPA 6-27660.
The photosensitive adhesive of polyimide series, however, has a particularly large contraction stress caused during setting. The stress affects to bend the semiconductor carrier unfavorably, and prevents a practical semiconductor carrier to be formed. On the other hand, the photosensitive adhesive of epoxy series is difficult to form a reliable semiconductor carrier because of its essential disadvantage in the heat resistance and moisture resistance. In addition, it has a low resolution and is not suitable for forming the fine through hole.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above disadvantages.
The present invention is provided with a semiconductor carrier having a bump formed by coating a photosensitive adhesive consisting of an epoxy acrylate having a fluorene skeleton or polybenzoxazole over a support substrate having a conductive interconnection pattern, exposing and developing the adhesive for forming a through hole therein, and plating for filling a metal within the through hole.
The epoxy acrylate having a fluorene skeleton preferably comprises a material represented by the following general formula (I):
where R is a hydrogen atom or low-grade alkyl group, and n is an integer of 0-20.
The material for an optical usage is disclosed in JPA 4-292611.
The polybenzoxazole is preferably selected from those disclosed in JPA 5-11451 and JPA 5-11452.
The epoxy acrylate having a fluorene skeleton and the polybenzoxazole are the most suitable for the use of the above photosensitive adhesive because they have an advantageous heat resistance, moisture resistance, adhesion and drug resistance. They also have a low stress because of their small contraction during setting. They further enable to form a fine through hole by the conventional photolithography process because of their photosensitivity.
If the photosensitive adhesive is the epoxy acrylate having a fluorene skeleton, coating it on a support substrate having a conductive interconnection pattern, opening a hole in it by exposing and developing processes, and thereafter heating it at a temperature of 80-160° C. or at a temperature of 80-250° C. if the photosensitive adhesive is the polybenzoxazole. Through these processes, it becomes apparent that an advantageous semiconductor carrier may be obtained, which can sustain the adhesion of the adhesive, prevent the degradation of characteristics due to the affection from the post-process such as the plating process, and fabricate the semiconductor device with ease.
Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof.
REFERENCES:
patent: 4769399 (1988-09-01), Schenz
patent: 59-22393 (1984-02-01), None
patent: 3-177034 (1991-08-01), None
patent: 4-292611 (1992-10-01), None
patent: 4-337380 (1992-11-01), None
patent: 5-11452 (1993-01-01), None
patent: 5-11451 (1993-01-01), None
patent: 5-259223 (1993-10-01), None
patent: 5-327224 (1993-12-01), None
patent: 6-19134 (1994-01-01), None
patent: 6-27660 (1994-02-01), None
patent: 6-334343 (1994-12-01), None
patent: 9-116267 (1997-05-01), None
patent: 9-214141 (1997-08-01), None
patent: 9-219590 (1997-08-01), None
Abstract—pub-No. SU 598916A, Derwent database, Feb. 1978, one page, Akutin et al.*
1996 Electronic Components and Technology Conference pp. 727-732, “Development of Molded Fine-Pitch Ball Grid Array (FPBGA) Using Through-Hole Bonding Process”, Matsuda et al.
Matsui Koji
Shimoto Tadanori
Mis David
NEC Corporation
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