Electric heating – Metal heating – Wire – rod – or bar bonding
Reexamination Certificate
2002-07-31
2004-09-28
Shaw, Clifford C. (Department: 1725)
Electric heating
Metal heating
Wire, rod, or bar bonding
Reexamination Certificate
active
06797910
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a production apparatus of a planer type semiconductor device welding an interconnector to a planer type semiconductor element, and a method of fabricating a planer type semiconductor device.
2. Description of the Background Art
An example of a production apparatus of a planer type semiconductor device having an interconnector to lead out an output of a conventional planer type semiconductor element connected by parallel gap welding, and a method of fabricating a planer type semiconductor device will be described with reference to
FIGS. 12 and 13
. A planer type semiconductor element
105
is placed and fixed on a weld bed
106
. An interconnector
103
is disposed on an electrode
104
of planer type semiconductor element
105
. Weld electrodes
101
and
102
are abutted against interconnector
103
. Load is applied on weld electrodes
101
and
102
, and a current is conducted across weld electrodes
101
and
102
. Welding is effected by the resistance heat generated here. Welding is repeatedly conducted by moving weld electrodes
101
and
102
corresponding to the width of interconnector
103
.
In the above-described conventional production apparatus, aluminum is generally used for the material of weld bed
106
on which planer type semiconductor element
105
is placed. Aluminum is used by virtue of its workability and low cost. It is to be noted that aluminum has an extremely high thermal conductivity. When aluminum is used for weld bed
106
, the heat generated for welding will escape through weld bed
106
. There was a problem that sufficient welding cannot be achieved, resulting in degradation of the weld strength.
According to a welding method using the conventional production apparatus of a planer type semiconductor device, welding is repeatedly conducted when there are a plurality of welding positions P for one interconnector
103
. Therefore, the temperature of weld electrodes
101
and
102
and weld bed
106
of interconnector
103
sequentially rises from the first site of welding to the second site, third site, and on, and is not stable. Also, the escaping manner of heat during welding differs depending upon weld position P. By this difference in temperature, sufficient welding may not be achieved at some parts. There is a problem that weld strength is degraded. Likewise, in the case where the welding operation is carried out continuously for two times or more, the temperature of weld electrodes
101
and
102
and weld bed
106
will sequentially rise from the first welding operation, and is not stable.
In a welding method using a conventional production apparatus of a planer type semiconductor device, a current is conducted across weld electrodes
101
and
102
to generate resistance heat for welding. At this stage, weld electrodes
101
and
102
glow and attain a high temperature to react with oxygen in the air. As a result, weld electrodes
101
and
102
will be oxidized. Nitrogen gas is blown out through a nozzle to weld electrodes
101
and
102
to minimize such oxidation (refer to FIG.
12
). However, oxidation cannot be prevented sufficiently by just this blowing measure. As oxidation proceeds, the resistance of weld electrodes
101
and
102
becomes higher to shorten the lifetime. Increasing this lifetime is one issue from the standpoint of cost.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a planer type semiconductor device production apparatus that can effect favorable welding, and a method of fabricating a planer type semiconductor device using such a production apparatus.
According to the present invention, a planer type semiconductor device production apparatus electrically connects an interconnector to lead out an output of a planer type semiconductor element with an external output electrode of the planer type semiconductor element through parallel gap welding. A weld bed on which is placed the planer type semiconductor element that is to be welded is formed of a material with stainless steel as the main component.
By employing a weld bed with stainless steel as the main component in the planer type semiconductor device production apparatus of the present aspect, the thermal conductivity becomes lower than the thermal conductivity of the generally used aluminum weld bed. Therefore, the heat generated for welding will not escape through the bed. Thus, favorable welding can be conducted.
According to a planer type semiconductor device production apparatus of another aspect of the present invention that electrically connects an interconnector to lead out an output of a planer type semiconductor element with an external output electrode of the planer type semiconductor element through parallel gap welding, a weld bed on which is placed a planer semiconductor element to be welded is formed of a material with ceramics as the main component.
By using a weld bed with ceramics as the main component in the planer type semiconductor device production apparatus of the present aspect, the thermal conductivity becomes lower than the thermal conductivity of the generally used aluminum weld bed. Therefore, the heat generated for welding will not escape through the bed. Thus favorable welding can be conducted. Furthermore, the apparatus of the present aspect with a weld bed formed mainly of ceramics is higher in performance than the apparatus with a weld bed formed mainly of stainless steel since ceramics has a lower thermal conductivity than stainless steel.
According to a planer type semiconductor device production apparatus of a further aspect of the present invention that electrically connects an interconnector to lead out an output of a planer type semiconductor element with an external output electrode of the planer type semiconductor element through parallel gap welding, a weld bed temperature control mechanism is provided to control the temperature of the weld bed on which is placed a planer type semiconductor element to be welded.
By having the weld bed hold heat in advance through the control of the temperature of the weld bed by the planer type semiconductor device production apparatus of the present aspect, the heat generated for welding will not be depleted by the bed. Thus, favorable welding can be conducted.
Preferably in the planer type semiconductor device production apparatus of the present invention, the area of the plane of the weld bed where the planer type semiconductor element to be welded is placed is set to be not more than the area of the planer type semiconductor element in contact with the plane of the weld bed.
By such a planer type semiconductor device production apparatus, the heat quantity depleted by the weld bed among the heat generated for welding is reduced. Thus, favorable welding can be conducted.
In the planer type semiconductor device production apparatus of the present invention, the thickness of the weld bed may be not more than 3 mm.
By using a weld plate set as thin as possible in structure in such a planer type semiconductor device production apparatus, the heat capacity can be reduced to the best possible degree. Therefore, the heat quantity depleted by the weld bed among the heat generated for welding is reduced. Thus, favorable welding can be conducted.
According to still another aspect of the present invention, a planer type semiconductor device fabrication method electrically connect an interconnector to lead out an output of a planer type semiconductor element with an external output electrode of the planer type semiconductor element through parallel gap welding. When there are at least two welding positions in one interconnector in the welding process through parallel gap welding, the power for welding is set for each welding position.
Accordingly, the power at the position where the welding strength was low can be increased whereas the power at the welding position where excessive power was applied can be reduced. Thus, favorable welding can be conducted.
In a planer type semiconductor d
Nixon & Vanderhye P.C.
Sharp Kabushiki Kaisha
Shaw Clifford C.
LandOfFree
Production apparatus of planer type semiconductor device and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Production apparatus of planer type semiconductor device and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Production apparatus of planer type semiconductor device and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3227913