Semiconductor device manufacturing: process – Coating of substrate containing semiconductor region or of...
Reexamination Certificate
1999-05-20
2001-07-24
Picardat, Kevin M. (Department: 2823)
Semiconductor device manufacturing: process
Coating of substrate containing semiconductor region or of...
C438S022000, C438S584000
Reexamination Certificate
active
06265324
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device and a mask used to form a thin film pattern.
2. Description of the Related Art
A semiconductor light-emitting element (LED) is generally used which includes an N-type GaP layer and a P-type Gap layer stacked in order on a semiconductor, e.g. GaP substrate and an electrode of e. g. Au formed on the P-type GaP layer. Such a semiconductor light-emitting element can be manufactured as follows. First, a semiconductor wafer (hereinafter also referred to as “semiconductor substrate”) is prepared by stacking the N-type GaP layer and P-type GaP layer in order on the surface of the GaP substrate. In this state, electrodes each having a prescribed diameter are arranged at a prescribed pitch on the front surface of the semiconductor substrate on the side of the P-type GaP layer. Electrodes are also arranged on the back surface of the semiconductor substrate. The semiconductor substrate is diced into plural pieces each having a single (P-type) electrode on the front surface and plural electrodes on the back surface. The electrodes are formed with a mask having through-holes mounted on the semiconductor substrate within a metallic vacuum.
FIG. 21
shows a schematic configuration of a vacuum deposition apparatus for forming electrodes. Within a bell jar (deposition vessel) with an evaporation source such as a pot arranged at a predetermined position, a fixed stand
3
is arranged so that it can swing within a prescribed angle with respect to the deposition source
2
. A semiconductor substrate
4
and a metallic mask
5
are mounted on the fixed stand
3
. The evaporated metal having flied from the evaporation source is deposited on the surface of the semiconductor substrate
4
exposed within through-holes. In the above process, the semiconductor substrate
4
is placed on the fixed stand
3
and the metallic mask
5
having a diameter equal to that of the semiconductor substrate and through-holes each having a prescribed shape made at a prescribed pitch is arranged on the semiconductor substrate
4
. Using pins or the like, the metallic mask
5
and semiconductor substrate
4
are fixed on the fixed stand
3
at plural positions in the vicinity of the edge of the metallic mask
5
. Although not shown, a spacer is arranged between the metallic mask
5
and semiconductor substrate
4
as occasion demands.
In this state, when the evaporation source
2
is heated, metallic atoms
7
evaporated from the evaporation source
2
fly toward the metallic mask
5
. As seen from
FIG. 22
which is a partially enlarged sectional view of the metallic mask
5
and semiconductor substrate
4
, the metallic atoms are deposited on the semiconductor substrate
4
through through-holes
8
made in the metallic mask
5
. Thus, the electrodes
9
each having a prescribed shape are formed at a prescribed pitch on the semiconductor substrate
4
.
In the case of the LED element, each of the through-holes
8
of the metallic mask
5
corresponds to the electrode of each LED element. In the case of an IC, a plurality of electrodes are often formed on a single chip. In this case, several through-holes of the metallic mask
5
are formed within a single IC element so as to correspond to its electrodes.
The metallic mask
5
is as thin as several tens of &mgr;m so that it expands owing to heat from the evaporation source
2
. Thus, it becomes deformed in various shapes, for example, its central portion swells. If the metallic mask
5
becomes deformed, the semiconductor substrate
4
may be greatly separated from the metallic mask
5
and the locations of the through-holes of the metallic mask
5
may vary momently. Therefore, it is difficult to form electrodes precisely so that they are located at prescribed positions so as to have prescribed shapes.
During the deposition, the metallic mask
5
is liable to suffer from heat. The metallic mask
5
, which has a larger thermal expansion coefficient than that of the semiconductor substrate
4
, is apt to expand. If it has a large size to provide a wide free region, it is more likely to become deformed. In order to minimize such a deformation of the metallic mask
5
, the metallic mask
5
is commonly formed to have a size equal to that of the semiconductor substrate
4
Therefore, when the metallic mask
5
is fixed, in alignment with the semiconductor substrate
4
, on the fixed stand
3
, the fixing pins
6
are also located on the semiconductor substrate
4
. Thus, no deposition is made on the surface of the semiconductor substrate
4
where the pins
6
are located. This leads to reduction in the production yield in the electrodes. The present invention has been accomplished in order to solve the problem described above.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method of manufacturing a semiconductor device which can easily form a thin film pattern for an electrode with high precision on a semiconductor substrate surface to improve the production yield of the electrode, and a deposition mask used for this method.
In order to attain the above object, in accordance with a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device comprising the steps: fixing a glass mask having a though-hole superposed on a surface of a semiconductor substrate; and arranging the glass mask and semiconductor substrate within a material gas containing material particles so that the material gas is passed through the through-hole and brought into contact with the surface of the semiconductor substrate to form a thin film pattern.
In accordance with the present invention, a through-hole each having a prescribed shape is formed at a prescribed position of a glass plate to form a glass mask. The glass mask superposed on a semiconductor substrate for forming a semiconductor device is fixed and arranged within an atmosphere of a material gas such as metal vapor. The material gas containing at least material particles is passed through the through-hole of the glass mask so that it is deposited in a prescribed shape at a prescribed position of the semiconductor substrate. In this way, a thin film pattern such as an electrode can be formed at a necessary position of the semiconductor device.
In this method, the glass plate with the through-hole having a prescribed shape at a prescribed position is used as a material of the mask for forming a thin film pattern. The mask has a very small thermal expansion coefficient so that its shape is not almost changed. For this reason, a precise electrode having a prescribed shape can be easily formed at a prescribed position. The glass mask, which has a very small thermal expansion coefficient, is difficult to warp. Therefore, the glass mask can have a larger size than that of the semiconductor substrate. Where the glass mask as well as the semiconductor substrate is fixed on a fixed stand for vapor deposition, it is not necessary to attach any fixing means on the semiconductor substrate, thereby improving the production yield of the semiconductor device.
In accordance with the second aspect of the present invention, the method of manufacturing a semiconductor device according to first aspect is characterized in that the material gas is metal vapor and the metal vapor is brought into contact with the surface of the semiconductor substrate through the glass maskto form a thin film pattern.
In accordance with the third aspect of the present invention, the method of manufacturing a semiconductor device according to the first aspect is characterized in that the material gas is refractory metal vapor and the refractory metal vapor is brought into contact with the surface of the semiconductor substrate through the glass mask to form a refractory metal thin film pattern.
Where a film of metal, particularly refractory metal is formed, the mask is likely to become deformed due to the high temperature of the semiconductor device. The thin film pattern co
Miyano Yasuo
Nakata Shunji
Ogura Koutarou
Tsutsui Tsuyoshi
Collins D. M.
Morgan & Lewis & Bockius, LLP
Picardat Kevin M.
Rohm & Co., Ltd.
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