JPH07130922A - Semiconductor device fitted with cooler - Google Patents

Abstract

PURPOSE:To make heat conductivity small and cool a semiconductor with a small current by charging at least one kind out of xenon, krypton, and argon into the package of a semiconductor device fitted with a cooler. CONSTITUTION:For the Peltier element 31 of a semiconductor device fitted with a cooler, the coldness is controlled electrically by an external controller which has referred to the temperature information from a thermistor 31. At this time, for the Peltier element 12, the topside is cooled, and the bottom heats. The heat generated from the Peltier element at the bottom is conducted to the case, and the heat of a chip is conducted as the conductive heat from the case, and besides the heat is conducted by the convection of the gas inside a package. But, since xenon is charged in the package, the conductivity of the heat inside the heat circuit becomes small, and the chip is hardly affected by the heat from a cooler, so it can be cooled with a current smaller than before, therefore the power consumption can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a cooling device. In recent years, semiconductor devices have become
It is used in various harsh temperature environments such as the seabed and underground.

[0002]

2. Description of the Related Art Some semiconductor chips have characteristics that change sensitively with temperature, and changes in the characteristics may seriously affect their functions. For example, in a semiconductor laser chip, since the efficiency is not 100%, a loss of injection current occurs and heat generation of about several degrees Celsius to 100 degrees Celsius occurs. This heat generation changes the oscillation wavelength of the semiconductor laser chip,
This may cause a change in threshold current.

Also in semiconductor chips other than semiconductor laser chips, it is preferable to suppress heat generation and keep the temperature constant in order to stabilize the operation. Therefore, various semiconductor devices having a cooling device have been manufactured.
In a conventional semiconductor device having a cooling device, a gas having an inert property is sealed to prevent a reaction between the semiconductor chip and the atmosphere in the package. As the gas to be sealed, nitrogen that is stable, inexpensive, and easily available is used.

[0004]

In a semiconductor device having a cooling device, when the ambient temperature is very high, the output of a thermistor for detecting the temperature of the semiconductor chip (or the temperature in the vicinity thereof) is used to control the cooling device. Increases the injection current into the cooling device to provide further cooling. As a result, the amount of heat generated by the cooling device itself increases and the cooling effect of the cooling device is reduced, so that more current is required for cooling to achieve a predetermined temperature. The increase in the current causes further increase in heat generation of the cooling device itself, and an endless vicious cycle occurs. As mentioned above, when a vicious circle occurs, the cooling system itself becomes uncontrollable and thermal runaway occurs. That is, when the temperature inside the package is low, there is no problem because the load of the cooling device is small, but when the temperature is high, the thermal runaway as described above occurs. Therefore, the guaranteed temperature of a general semiconductor device is set so as not to exceed the temperature that causes the thermal runaway.

Further, since the cooling device consumes a large amount of electric power, it is required to reduce the power consumption of the cooling device especially when the outside air temperature is high. In order to meet these demands, it is desired to reduce the influence of the temperature outside the package or the heat generation from the cooling device to the periphery of the chip, and conventionally, attempts have been made mainly to improve the structure of the package. (See, for example, Japanese Patent Application Laid-Open No. 2-299281) However, the atmosphere has not been examined. The present invention expands the guaranteed temperature range of a semiconductor device having a cooling device by changing the enclosed atmosphere and reduces power consumption.

[0006]

FIG. 1 shows the principle of the present invention. In order to expand the above-mentioned guaranteed temperature range and reduce power consumption, the present invention provides:
A semiconductor chip (1), a cooling device (2) for cooling the semiconductor chip (1), and a temperature control device for measuring the temperature around the semiconductor chip (1) and controlling the cooling temperature of the cooling device (2). In a semiconductor device with a cooling device provided with a temperature detecting means (3) for outputting, at least one of xenon, krypton, or argon is enclosed in the package of the semiconductor device with a cooling device.

[0007]

As shown in FIG. 1, the two paths shown in FIG. 1 are mainly considered as the conduction paths for the heat generated from the cooling device to the chip. 1 as indicated by the arrow in FIG.
One is heat conducted from the heat source of the heat generating part of the cooling device to the case and then conducted from the case through the gas, and the other is heat conducted from the heat source of the heat generating part of the cooling device to the gas and conducted by gas convection. It is the heat that is done.

Both of the two heat conduction paths include a portion through which heat is conducted by the sealing gas, and the thermal conductivity of the sealing gas has an important meaning for the amount of heat conducted to the chip. The present inventor has found that he has. In the present invention, based on this finding, xenon gas, krypton, or argon, which has a low thermal conductivity, is sealed in so that the heat outside the package is less likely to be transferred to the chip inside the package.

According to the present invention, the thermal conductivity as a sealing gas is
Uses low xenon, krypton, argon
It Thermal conductivity at 100 ° C is 3.09 for nitrogen
(10 ^-2Wm^-1・ K^-1), For which xeno
0.70 (10^-2Wm^-1・ K^-1), Krip
1.15 (10 tonnes)^-2Wm^-1・ K^-1), Al
2.12 (10^-2Wm^-1・ K^-1), And
It That is, these, xenon, krypton, algo
To replace the nitrogen used previously with nitrogen.
Thus, the thermal conductivity of the above two heat conduction paths can be lowered, and
The heat conduction to the periphery of the cup is reduced.

For example, when xenon is used as the sealing gas, the thermal conductivity at around 100 ° C. is about 1/4 of that of nitrogen, so that heat is conducted to the case out of the two paths and emitted from the case. The conduction of heat to the chip by heat is ¼ that of nitrogen. Similarly, when krypton or argon is used, the thermal conductivity to the chip can be reduced by the same ratio of the thermal conductivity with nitrogen.

In addition to the above-mentioned two typical heat conduction paths, regarding the heat circuit in which the heat conduction of the sealing gas is involved, the heat conducted to the chip by the heat circuit uses the previous nitrogen. It can be less than what you have.

[0012]

EXAMPLE An example of the present invention will be described below. 2 and 3 are diagrams for explaining an embodiment in which the present invention is applied to a butterfly type laser module. FIG. 2 is a side sectional view of a butterfly type laser module showing one embodiment of the present invention, and FIG. 3 is a plan sectional view of a butterfly type laser module showing one embodiment of the present invention.

In the figure, 11 is a semiconductor laser chip that emits laser light, 12 is a Peltier element for cooling the chip, 31 is a thermistor for measuring the temperature on the chip, and 14 is a semiconductor laser chip. 11 is a submount that is connected to the semiconductor laser chip 11 by a gold wire, 13 is a carrier that mounts the submount 14 on which the semiconductor laser chip 11 is mounted, and the thermistor 31, and 15 is the light from the semiconductor laser. A tapered tip spherical fiber for transmission, 16 a coating covering the tapered tip spherical fiber, 17 a side plate, 18 a bottom plate, 19 a sealed xenon (Xe), 20
Is a top lid, 21 is a rubber tube for covering the coating,
Numeral 22 is a solder for fixing the tapered spherical fiber, and 3
Reference numeral 0 is an electrode connected to the outer lead, 32 is an outer lead, and 33 is a bonding wire connecting each element to the electrode.

The side plate 17 is joined to the bottom plate 18 to form a case. The submount 14 and the thermistor 31 on which the semiconductor laser chip 11 is mounted and which are connected by a gold wire are connected to the carrier 1
Put on 3. The carrier 13 mounted on the Peltier element 12 is attached to a desired position of the case. After wire-bonding each part, the optical fiber 15 inserted in the case and the semiconductor laser chip 11 are optically coupled.

The upper lid 20 is placed in an atmosphere of xenon before being attached, and then the upper lid 20 is placed and seam-welded to seal the xenon. Also,
Alternatively, xenon may be sprayed and seam welded before the top lid 20 is attached. The semiconductor device with a cooling device is completed as described above. Peltier element 31 (cooling device) of a semiconductor device with a cooling device according to this embodiment
The degree of cooling is electrically controlled by an external control device (not shown) that refers to the temperature information from the thermistor 31. At this time, the upper surface of the Peltier element 12 is cooled, and the lower surface generates heat. The heat generated from the Peltier element on the bottom surface is conducted to the case, and is transferred to the chip as conduction heat from the case. In addition, heat is transferred to the chip by convection of gas inside the package.In this example, xenon is sealed in the package. Since it is stopped, the thermal conductivity in the thermal circuit becomes small, and the guaranteed temperature range (high temperature side) can be expanded.

Of course, similar effects to xenon can be obtained by sealing krypton or argon. Although the Peltier element is used as the cooling device in the present embodiment, the cooling device is not limited to this, and other cooling devices may be used.

[0017]

According to the present invention, since at least one gas of xenon, krypton, or argon is sealed in the package of the semiconductor device, the thermal conductivity is lower than that of nitrogen which has been conventionally sealed. As a result, the chip is less likely to be affected by heat generated by the cooling device, so that the chip can be cooled with a smaller current than in the past, and power consumption is reduced. Therefore, the temperature causing thermal runaway becomes high, and the semiconductor device with a cooling device can be provided in a wide guaranteed temperature range.

[Brief description of drawings]

FIG. 1 is a principle diagram showing a configuration of a semiconductor device with a cooling device of the present invention.

FIG. 2 is a side sectional view of an embodiment in which the present invention is applied to a butterfly type laser module.

FIG. 3 is a plan sectional view of an embodiment in which the present invention is applied to a butterfly type laser module.

[Explanation of symbols]

 1 Semiconductor laser chip 2 Peltier element 3 Thermistor 4 Xe atmosphere

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical indication H01S 3/18

Claims (3)

[Claims] 1. A semiconductor chip (1), a cooling device (2) for cooling the semiconductor chip (1), a temperature around the semiconductor chip (1) is measured, and a cooling temperature of the cooling device (2) is measured. A temperature detecting means (3) for outputting temperature information to a temperature control device for controlling, a semiconductor device with a cooling device, comprising: at least one of xenon, krypton, or argon in a package of the semiconductor device with a cooling device. A semiconductor device with a cooling device, in which a semiconductor device is enclosed. 2. The semiconductor device with a cooling device according to claim 1, wherein the semiconductor chip (1) is a semiconductor light emitting element. 3. The semiconductor device with a cooling device according to claim 1, wherein the cooling device (2) is a Peltier element.