JPS631382Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a light irradiation device, particularly an ultraviolet light irradiation device used for industrial purposes.

In order to efficiently generate ultraviolet rays in a light irradiation device, the coldest point temperature of the discharge lamp is controlled to an appropriate temperature in order to control the light emission conditions of the built-in discharge lamp. For example, in the case of a low-pressure mercury lamp, it is desirable to maintain the coldest point temperature inside the discharge lamp at 40 to 45 degrees Celsius in order to efficiently emit ultraviolet rays with a wavelength of 254 nm, but in the case of industrial use,
Due to the high power consumption of discharge lamps and the fact that the light emitting opening of the lamp body is covered with a front glass, making the lamp body almost closed, the coldest point temperature of the discharge lamp is In order to prevent this temperature rise, light irradiation devices equipped with various cooling mechanisms have already been proposed.

By the way, conventional cooling mechanisms are broadly classified into air-cooled types and water-cooled types. Among these, the wind-cooled type uses forced air or natural convection to flow a specified amount of cooling air inside the device to cool the glass envelope of the discharge lamp, but it depends on factors such as the outside temperature and the environment where the device is installed. The cooling effect is influenced by the temperature of the lamp, and because the glass enclosure has poor thermal conductivity, air cooling from the outside of the glass enclosure does not efficiently cool the inside of the discharge lamp, and its response is also low. There is a point. Furthermore, recently, light irradiation equipment is often used in the semiconductor manufacturing process.
Semiconductors need to be protected from dust and other tiny foreign objects as much as possible, but there has been a problem in which dust and other tiny foreign objects floating in the cooling air tend to adhere to semiconductors.

In order to solve these problems, a metal block with good thermal conductivity is brought into contact with the glass enclosure.
A method of cooling this metal block with water has been proposed. Compared to the above-mentioned air-cooled type, this type is less affected by the external environment and can be controlled more accurately, but it has the problem of a complicated structure and an increase in the size of the device. Since cooling was still performed through a poor glass enclosure, there was a limit to its control efficiency.

Therefore, the purpose of the present invention is to provide a light irradiation device that has a simple structure and can accurately control the temperature of the coldest point of a discharge lamp with a fast response speed. This is a light irradiation device in which a discharge lamp is placed in a lamp body having an irradiation opening, and a metal rod is inserted into a predetermined position near the coldest point of the glass enclosure of the discharge lamp to seal it. This is achieved by a light irradiation device characterized in that the temperature of the portion protruding outward from the glass enclosure is controlled by a thermomodule or the like using a Peltier effect element or the like.

The present invention will be specifically described below based on embodiments shown in the drawings.

The drawing is a cross-sectional view of a light irradiation device used in the baking process of semiconductor wafers.A reflective mirror 2 with a mirror finish is placed horizontally in the center of the device box 1, and a mirror 2 is placed below the periphery. A vertical sub-reflection mirror 3 is arranged to form a mirror box. The ultraviolet lamp 4 is held by a lamp holder 1a such that its light emitting part 4a is located within a mirror box and a glass enclosure 4c surrounding its electrode part 4b is located above the back of the reflecting mirror 2. This ultraviolet lamp 4 has an arc length of 100cm.
Although this is a low-pressure mercury lamp that mainly emits ultraviolet rays with a wavelength of 254 nm, the glass enclosure 4c surrounding the electrode part 4b is arranged in a vertical position, and the light emitting part 4a
is bent in a meandering substantially W-shape to form a horizontal surface light source. A pocket-shaped mercury reservoir portion 4d is provided protruding from the glass enclosure 4c surrounding the electrode portion 4b. A light irradiation opening is provided below the light emitting section 4a, and a front glass 5 made of quartz glass is provided in this opening, and the ultraviolet rays from the ultraviolet lamp 4 are transmitted through the front glass 5 and directed downward. irradiated. The semiconductor wafer which is the object 6 to be irradiated is a large one with a diameter of 6 inches (approximately 153 mm), and is supported by a support 7 approximately 2.5 cm below the light emitting section 4a.

Next, a metal rod 8 made of tungsten is inserted into the mercury reservoir 4d of the ultraviolet lamp 4 and sealed. The metal rod 8 is not limited to being made of tungsten, but is preferably a metal that can be easily sealed in quartz glass and has good thermal conductivity. Furthermore, the shape is not limited to a round bar, but may be a square bar or even a flat plate. The temperature of the part of the metal rod 8 that protrudes outside is controlled in the control box 9, and this part has a flat plate shape, and a control metal plate with many thermomodules bonded to the upper and lower surfaces thereof. 10 is closely attached. A thermomodule that uses a Peltier effect element generates heat on one side and absorbs heat on the other side depending on the current value when current is passed in one direction, and when current is passed in the opposite direction, the heat-absorbing and heat-generating surfaces are reversed. However, it has small thermal inertia and
Precise control is possible with low power consumption. Then, the temperature of the metal rod 8 is actually measured, and this actual temperature and a preset target cooling temperature (for example,
Current is applied to the Peltier effect element whose size and direction correspond to the difference between the temperature and the temperature (40°C). Note that if a cooling block is brought into contact with the control metal plate 10 so that the lower surface of the thermomodule can be cooled, the upper surface of the thermomodule absorbs heat and conversely the lower surface absorbs heat in order to lower the temperature of the metal rod 8. When heat is generated, the heat generating surface is cooled and the thermo module can be operated effectively.

When the target cooling temperature is set in the control box 9 and the ultraviolet lamp 4 is turned on, the irradiated object 6
However, since the ultraviolet lamp 4 is placed in a substantially closed space, the temperature rises to a higher temperature than the target cooling temperature of, for example, 40° C. within a short time. The metal rod 8 also tries to rise in temperature, but
When the temperature rises above the target cooling temperature, the thermomodule absorbs heat and lowers the temperature. From then on, the thermomodule repeatedly generates and absorbs heat in a small range to maintain the target cooling temperature. At this time, since the metal rod 8 has high thermal conductivity, when the part protruding to the outside is maintained at the target cooling temperature, the tip part sealed inside the ultraviolet lamp 4 immediately reaches a temperature almost equal to this, and the ultraviolet rays The coldest point temperature of the lamp 4 is precisely controlled to be equal to the target cooling temperature. Therefore, the ultraviolet lamp 4 can operate efficiently and generate a large amount of ultraviolet light with a wavelength of 254 nm.

In this way, the present invention involves inserting a metal rod into a predetermined position near the coldest point of the glass enclosure of a discharge lamp and enclosing it.
Since the temperature of the part of the metal rod that protrudes outside the glass enclosure is controlled by a thermomodule such as a Peltier effect element, it is possible to use a highly thermally conductive metal without going through a glass enclosure with similar thermal conductivity. The temperature inside the discharge lamp can be directly controlled using the rod as a medium. Therefore, control efficiency is good and response is fast.
Since the temperature of the coldest spot can be accurately maintained at an appropriate temperature, very favorable results can be obtained for controlling the discharge lamp. Since thermomodules such as Peltier effect elements are used, a simple structure is required without the need for air cooling or water cooling equipment.
Accurate control with low power consumption. Furthermore, since the cooling air does not hit the irradiated object, it is also suitable for semiconductor manufacturing processes where minute foreign matter such as dust is to be avoided as much as possible. As explained above, according to the present invention, it is possible to provide a light irradiation device that has a simple structure and is capable of controlling the coldest point temperature of a discharge lamp accurately and with a fast response speed. .

[Brief explanation of drawings]

FIG. 1 is a front sectional view of an embodiment of the present invention, FIG. 2 is a side sectional view, and FIG. 3 is an enlarged sectional view of the main parts. 1... Equipment box, 2... Reflection mirror, 3... Sub-reflection mirror, 4... Ultraviolet lamp, 4a... Light emitting section, 4b... Electrode section, 4c... Glass enclosure, 4d
...Mercury reservoir, 6...Irradiated object (semiconductor wafer), 8...Metal rod, 9...Control box, 10
...Control metal plate.

Claims (1)

[Scope of utility model registration request] A light irradiation device in which a discharge lamp is disposed in a lamp body having an opening for light irradiation, in which a metal rod is inserted into a predetermined position of the glass enclosure of the discharge lamp and the metal rod is enclosed in the glass enclosure. A light irradiation device characterized in that the temperature of a portion protruding to the outside is controlled by a thermo module using a Peltier effect element or the like.