Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Groove formation
Reexamination Certificate
1999-04-14
2001-08-28
Christianson, Keith (Department: 2813)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Groove formation
Reexamination Certificate
active
06281032
ABSTRACT:
RELATED APPLICATION DATA
The present application claims priority to Japanese Application No. P10-112569 filed Apr. 22, 1998 which application is incorporated herein by reference to the extent permitted by law.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a semiconductor device and its manufacturing method especially suitable for application to semiconductor lasers, light emitting diodes or electron mobility devices using nitride III-V compound semiconductors.
2. Description of the Related Art
GaN semiconductors are direct transition semiconductors having forbidden band widths ranging from 1.9 eV to 6.2 eV and enabling realization of light emitting devices capable of emitting light over a wide range from the visible region to the ultraviolet region. For these properties, they have become of interest recently, and are placed under active developments. Additionally, GaN semiconductors have a large possibility as material of electron transport devices. Saturation electron velocity of GaN is approximately 2.5×10
7
cm/s, which is larger than those of GaAs and SiC, and its breakdown electric field is as large as approximately 5×10
6
V/cm next to the intensity of diamond. For these reasons, GaN semiconductors have been expected to be greatly hopeful as materials of electron transport devices for high frequencies, high temperatures and high power.
There is a semiconductor laser called LOP (laser on photo diode) in which a laser chip is mounted on a sub mount having formed a photo diode for monitoring light output. LOP is packaged in the following manner.
As shown in
FIG. 1A
, first made is a Sn solder layer (not shown) on a surface of a Si substrate
101
having formed light output monitoring photo diodes (not shown) in individual pellets by vacuum evaporation, for example. Next, as shown in
FIG. 1B
, the Si substrate
101
is half-cut between individual pellets by dicing. Next, as shown in
FIG. 1C
, separately prepared laser chips
102
are mounted on respective pellets on the Si substrate
101
in a predetermined positional relation therewith. After that, by heating the Si substrate
101
, the Sn solder layer formed thereon is welded to the bottom surface of the laser chips
102
. Then, after the Si substrate
101
is fully cut between respective pellets, here again by dicing, it is pulled and broken into chips. As a result, a LOP chip
103
as shown in
FIG. 1D
is obtained. The LOP chip
103
is thereafter mounted on a heat sink of a package, not shown. Further, a cap with a window is applied onto the package to seal it. Thus, assembling is completed.
The conventional method of semiconductor lasers explained above was certainly more rationalized than methods relying on individually welding each laser chip. However, it was not a so-called batch process, but still needed a number of steps for assembling. Therefore, its productivity was not satisfactory. This problem also lies when manufacturing a semiconductor laser using GaN semiconductors.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a semiconductor device manufacturing method capable of manufacturing devices using nitride III-V compound semiconductors, such as semiconductor lasers or light emitting diodes, and electron transport devices like FET, with a high productivity, and provide a semiconductor device made by the manufacturing method.
According to the invention, there is provided a method for manufacturing a semiconductor device comprising the steps of:
bonding a surface of a nitride III-V compound semiconductor layer of a first substrate to one of major surfaces of a second substrate, the first substrate having the nitride III-V compound semiconductor layer on one of major surfaces thereof to form a plurality of devices; and
dividing the first substrate and the second substrate bonded together into a plurality of portions.
According to the invention, there is further provided a method for manufacturing a semiconductor device comprising the steps of:
bonding a surface of a nitride III-V compound semiconductor layer of a first substrate to one of major surfaces of a second substrate, the first substrate having the nitride III-V compound semiconductor layer on one of major surfaces thereof to form a plurality of devices separated from each other by grooves deep enough to reach the first substrate, the nitride III-V compound semiconductor layer having on a surface thereof first projections and second projections extending in parallel with the grooves and separated from each other; and
dividing the first substrate and the second substrate bonded together into a plurality of portions.
In a typical version of the present invention, the first substrate and the second substrate bonded together are divided into discrete devices on the first substrate. However, the substrates may be divided into units each including two or more devices, if so desired. Division of the substrates is typically effected by dicing these bonded first substrates and second substrates.
In the present invention, a plurality of devices on the first substrate are typically separated from each other by grooves deep enough to reach the first substrate. Typically, the bonded first substrate and second substrate are divided into discrete devices on the first substrate typically by lapping the first substrate from the other major surface thereof at least deep enough to reach the grooves, or by dicing the first substrate from the other major surface thereof at least deep enough to reach the grooves.
In the present invention, electrodes of devices are typically made on the nitride III-V compound semiconductor layer of the first substrate, and solder electrodes are formed on a major surface of the second substrate at positions corresponding to the electrodes of devices. In this case, the first substrate and the second substrate are bonded together by bonding the electrodes of devices on the first substrate to the solder electrodes on the second substrate.
In the present invention, the device made of nitride III-V compound semiconductor layers on the first substrate may be essentially any. Preferably, however, it is of a type made by face-down mounting. More specifically, the device may be a semiconductor laser, light emitting diode or electron transport device such as FET, for example. Formed on the second substrate is any required device.
In the present invention, materials of the first substrate and the second substrate may be chosen as desired. Examples of the material of the first substrate are sapphire substrate, SiC substrate, Si substrate, spinel substrate and ZnO substrate, and so on. Examples of the material of the second substrate are Si substrate, SiC substrate, diamond substrate, AlN substrate, GaN substrate (including those made by growing a GaN layer on a sapphire substrate or any other appropriate substrate), and so on. The first substrate and the second substrate are typically wafer-shaped. However, one or both of the first substrate and the second substrate may be bar-shaped, having a plurality of device structures are aligned in one or more rows. In the case where an electrically insulating substrate is used as the second substrate, wiring from the solder electrodes formed on one major surface thereof may be brought out via through holes made in the second substrate, for example.
According to the invention, there is further provided a method for manufacturing a semiconductor device comprising the steps of:
bonding a surface of a nitride III-V compound semiconductor layer of a first substrate to one of major surfaces of a second substrate, the first substrate having the nitride III-V compound semiconductor layer on one of major surfaces thereof to form a device; and
dividing the first substrate and the second substrate bonded together into a plurality of portions.
The projection is typically formed on a side opposite from taller one of the p-side electrode and the n-side electrode with respect to lower one of the p-side electrode and the n-side electrode. T
Kawai Hiroji
Kobayashi Toshimasa
Matsuda Osamu
Nakayama Norikazu
Christianson Keith
Sonnenschein Nath & Rosenthal
Sony Corporation
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