Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead – Of specified configuration
Reexamination Certificate
2000-06-14
2002-10-08
Lee, Eddie (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
Of specified configuration
C257S510000, C257S698000, C257S773000
Reexamination Certificate
active
06462419
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a semiconductor device and a method for manufacturing the same and, more specifically, to the structure and formation method of a conductor penetrating a semiconductor substrate which connects both sides of the semiconductor substrate electrically.
2. Description of Related Art
In order to ground the analog integrated circuit and the output element of a high frequency transistor, an electric connection is carried out between a group of circuit elements on the front surface of a semiconductor chip and the back surface thereof through a conductor disposed in a through hole of a substrate thereof. The semiconductor chip is connected to an electrode of a mounting substrate or package such that the back surface of the chip is bonded to the metallic surface of the mounting substrate or package with a solder material, and a metallic wire is bonded to a wiring pad of the front surface of the chip. Grounding can be also performed by the use of the metallic wire here. However, if so, the circuit is liable to become unstable because the metallic wire includes an inductor component or resistance component. Accordingly, in order to restrain the inductor component or resistance component and stabilize high frequency performance, grounding is performed such that a direct connection is formed by penetrating the substrate from the front surface to the back surface thereof over a short distance.
In general, the semiconductor substrate penetrative conductor is conventionally formed by grinding and thinning the substrate first and then disposing a photoresist film pattern on the back surface and using a through hole made by dry etching etc. In this case, it is necessary to align the receiving electrode on the front surface with the etched hole from the back surface. However, the alignment accuracy between the front surface and the back surface of the substrate is prone to error, and therefore the receiving electrode of the front surface is required to be of a sufficient size.
In order to solve this problem, the present applicant has proposed in Japanese Laid-Open Patent Publication No. H5-47937 that the semiconductor substrate penetrative conductor be holed directly from the front surface. FIG.
1
A through
FIG. 1D
are typical sectional views for explaining a conventional method of forming the semiconductor substrate penetrative conductor.
FIG. 1A
shows a step of forming a non-through hole,
FIG. 1B
shows a step of forming a buried wiring line,
FIG. 1C
shows a step of grinding the back surface of the substrate, and
FIG. 1D
shows a step of forming a metallic layer on the back surface.
Referring to
FIG. 1A
, elements and circuits, not shown, are formed on the front surface of the semiconductor substrate
51
. Additionally, a non-through hole
61
from the front surface to a certain depth of the semiconductor substrate
51
is formed by dry etching during this step. The depth is, for example, 100 &mgr;m with respect to the substrate thickness of 400 &mgr;m.
Thereafter, as shown in
FIG. 1B
, a wiring metal is put into the non-through hole
61
by plating it with Au etc. so as to form a buried wiring line
53
as a part of the wiring step.
Thereafter, as shown in
FIG. 1C
, the back surface of the semiconductor substrate
51
is ground until the substrate
51
attains the thickness of 100 &mgr;m, and thereby the bottom of the buried wiring line
53
is exposed, and the semiconductor substrate penetrative conductor
52
is completed.
Thereafter, as shown in
FIG. 1D
, a back surface metal
55
for grounding is formed on the back surface of the semiconductor substrate
51
, and thereby the semiconductor substrate penetrative conductor
52
is grounded.
However, in the conventional manufacturing method, it is difficult to accurately stop the grinding of the back surface at the bottom of the buried wiring line
53
. As a countermeasure against this, an attempt is carried out to form the semiconductor substrate penetrative conductor
52
deeply and grind the back surface to beyond the bottom of the buried wiring line
53
. However, in this case, the unburied though hole under the bottom of the semiconductor substrate penetrative conductor
52
is exposed because the buried metal that makes up the bottom of thereof is removed. If the through hole remains without being buried when the back surface metal
55
is formed, a solder material is sucked up by the through hole and enters it when the semiconductor chip is bonded to a package etc. with the solder material, and a situation occurs in which the penetrative conductor
52
of the substrate
51
first cracks, for example, because of the difference in the coefficient of thermal expansion between the semiconductor substrate
51
and the solder material. Accordingly, disadvantageously, the crack causes the breakage or deterioration of the semiconductor elements or circuit wiring lines disposed on the front surface of the substrate.
As a countermeasure against this, the inside of the penetrative conductor
52
can be completely buried by the plating of Au. However, it was confirmed that cracks appeared in the semiconductor substrate
51
because of the difference in the coefficient of thermal expansion between Au and the semiconductor substrate
51
from the heat history during the manufacturing. Especially, when a lot of semiconductor substrate penetrative conductors
52
were disposed in a row keeping them near each other for grounding, the substrate between the penetrative conductors
52
was noticeably damaged. Therefore, trouble also occurred in completely burying the penetrative conductors
52
with metal.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a semiconductor device having a stable conductor which penetrates a semiconductor substrate, wherein the semiconductor device does not cause cracks etc. in a semiconductor substrate and exerts no influence upon semiconductor elements etc. on the front surface of the substrate, and provide a method of forming the penetrative conductor.
The semiconductor device of the present invention comprises a semiconductor substrate having an opening penetrating from the front surface to the back surface of the semiconductor substrate at a predetermined position thereof; a semiconductor element formed on the front surface of the semiconductor substrate and a circuit therearound; a conductive film (back surface conductive film) formed on the back surface of the semiconductor substrate; a metal film (through metal film) formed on an inner wall of the opening and connected electrically to the conductive film; and resin with which space enclosed by the metal film formed in the opening is filled.
The conductive film may be a pad processed to cover the opening. The conductive film can cover the entire back surface of the semiconductor substrate. Preferably, the conductive film is formed to be electrically connectable by solder to a conductor disposed in any one of a package and a mounting substrate for mounting the semiconductor device.
A method of manufacturing a semiconductor device according to the present invention comprises the steps of forming a non-through hole with a predetermined diameter, the non-through hole passing from a front surface of a semiconductor substrate on which a semiconductor element and a circuit thereof are formed halfway to a back surface of the semiconductor substrate at a predetermined position thereof; forming a metal film at a predetermined region of the front surface of the semiconductor substrate and on an inner wall of the non-through hole; filling a space enclosed by the metal film formed on the inner wall of the non-through hole with resin; and grinding the back surface of the semiconductor substrate until the metal film and the resin are exposed.
There can be further included a step of forming a conductive layer at a predetermined region covering the metal film and the resin exposed on the back surface of the semiconductor substrate.
A method of manufacturing a semicond
Chu Chris
Hayes & Soloway P.C.
Lee Eddie
NEC Corporation
LandOfFree
Semiconductor device and method for manufacturing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device and method for manufacturing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device and method for manufacturing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2957824