JPS63303073A - Photochemical reaction treatment device - Google Patents

Abstract

PURPOSE:To improve the intensity of short wavelength light, more particularly UV light near 185nm by erecting and providing a low pressure mercury lamp to be used for a titled device by positioning a temp. control part provided near the end of a coiled tube-like valve to the lower side. CONSTITUTION:The temp. control part 29 is provided to at least a part of the valve formed by using synthetic quartz as the valve 9 for a light source and sealing mercury and inert gas such as Ar into the valve. The temp. control part 29 controls the mercury vapor pressure in the valve 9 by passing cooling water through an inlet 30 and an outlet 31 to a heat exchanger 32 from the outside. This lamp 9 is erected and provided in a reaction chamber 2 or a light source chamber 5 adjacent to the chamber 2 by positioning the control part 29 to the lower side. The mercury vapor pressure in the valve 9 can be regulated by this device to the pressure under which the intensity of the light emission at about 185nm increases. The intensity of the light at about 185nm can be increased by applying high-frequency electric power to electrodes 33, 34 of the lamp.

Description

Detailed Description of the Invention (a) Field of Application of the Invention The present invention provides a semiconductor processing apparatus using an ultraviolet lamp that can be used in the industrial field, particularly in the field of ceramic coating and the field of semiconductor device manufacturing technology. be.

(b) Conventional technology The conventional ultraviolet light source lamps used in the technical field, particularly in the ceramic coating or semiconductor device manufacturing technology field, mainly include high-pressure mercury lamps and low-pressure mercury lamps. The present invention relates to improvements in light sources for optical processing apparatuses, such as optical CVD apparatuses, optical cleaning (UV cleaning) apparatuses, and optical plasma CVD apparatuses, and methods for using the same.

In conventional low-pressure mercury lamps, argon gas is sealed in the light source bulb at a pressure of several Torr, and mercury is also sealed at the same time.

Arc discharge is caused by applying alternating current power, generally at a commercial frequency (50 to 60 H2), through a pair of electrodes that generate arc discharge inside the bulb and an external electrode terminal led out from these electrodes through the glass bulb. The mercury atoms are excited by this externally applied electric power, and become mercury atoms in an excited state with various energy levels. Furthermore, the atoms in this excited state return to the next level due to the inner wall of the quartz bulb or collisions between atoms. At that time, it typically has a luminescence intensity distribution as shown in Figure 2, and has a luminescence intensity distribution of 254ns+
The emission intensity at a wavelength of 185 nm is the strongest, followed by the emission intensity at a wavelength around 185 nm.

However, recently in the field of semiconductor device manufacturing technology,
Optical processing equipment, especially photo-CVD method (decomposes reactive gases using ultraviolet light and causes them to react to form a film), UV cleaning (irradiates the substrate surface with ultraviolet light to remove dirt)
For example, in the method of manufacturing a semiconductor film using the photoCVO method, which is attracting attention, 5in)12□! (n = 1.2.
The silanes (3...) are decomposed and reacted with ultraviolet light to form a semiconductor film. At that time, short wavelength light, especially ultraviolet light around 185 nm, is particularly effective for the reaction, so in the conventional photoCVD method, which has a slow reaction rate using an ultraviolet light source,
It has been desired to increase the intensity of ultraviolet light around 185 ns+.

(c) Purpose of the invention The present invention satisfies these requirements, and uses short wavelength light,
In particular, the present invention provides a semiconductor processing apparatus having an ultraviolet light source with significantly increased ultraviolet light intensity near 185 nm.

(d) Structure of the Invention Therefore, the present invention provides a lamp for an ultraviolet light source having a temperature control section near the end of a serpentine bulb, and a temperature control section and power supply in a reaction chamber or a light source chamber provided adjacent to the reaction chamber. It has an upright structure with the inlet terminal facing downward.

As shown in the emission intensity distribution diagram of the low-pressure mercury lamp -a shown in FIG. 3, the light around 254 nm is the strongest.

When this 254 nm light transits from the 63Pt energy level to the ground state 61S0 level, energy corresponding to this wavelength is emitted.

General low pressure mercury lamps are 6'PI, 6'P6.6'p
Since the excitation probability for an energy level such as z is considerably higher than the excitation probability for a 61P1 level that emits light at around 185 nm, the intensity of light around 25 dnm is strong.

The present invention adds high frequency as a power supply in order to increase the intensity of short-wavelength light around 185 nm several times compared to conventional low-pressure mercury lamps, making it possible to simultaneously serve as a power source for plasma processing. Ta.

Since high-frequency power is used as the power supply, the probability of excitation of mercury atoms increases, the probability of excitation of the 6'PI energy level increases, and light emission around 185 nm becomes stronger.

Furthermore, a temperature control section is installed in at least one part of the ultraviolet light source lamp, and the temperature is controlled so that the intensity of ultraviolet light around 185 nm becomes strong, and the mercury vapor pressure inside the lamp bulb is reduced to 185 nm.
The pressure is adjusted so that the light emission around 5n- is strong, and the lamp is supplied with high-frequency power, for example, power with a frequency of 13.56 Ml+□, to make it emit light.

At this time, there is an optimum value for temperature control; if the temperature control is too low, the pressure of mercury in the lamp decreases, the number of mercury contributing to light emission decreases, and the light emission intensity weakens.

It has also been found that when the control temperature is too high, the pressure of mercury increases, the electron energy decreases, and the emission intensity around 185 nm becomes weaker.

In addition, it is necessary to introduce a medium for controlling the temperature into the temperature control section from the outside.Therefore, in the present invention, an ultraviolet light source lamp is placed upright in the reaction chamber or light source chamber in order to facilitate the introduction of the medium. This makes it easy to introduce the medium into a reaction chamber provided under reduced pressure.

The present invention will be explained below with reference to Examples.

〔Example〕

FIG. 2 schematically shows a lamp used in the apparatus of the present invention.

Synthetic quartz is used as the light source bulb (9), and a temperature control section (29) is provided in at least a portion of the bulb, which is filled with mercury and an inert gas such as Ar. Cooling water flows from the outside into the heat exchanger (32) from the inlet and outlet ports (30) and (31), and the valve (9)
) to control the mercury vapor pressure within.

Although the temperature control section (29) was controlled by adjusting the temperature of the cooling water, the method shown in this embodiment is not the only method, and other methods may be used as long as the temperature inside the lamp bulb (9') can be controlled.

1 through the electrodes (33) and (34) of this lamp (9).
A curve (35) in FIG. 4 shows the emission intensity of 185 nm light when 200 W of high frequency power of 3.56 MH2 was applied and the temperature of the temperature control section (29) was varied.

In the figure, the horizontal axis represents the temperature of the temperature control section, and the vertical axis represents the emission intensity of light with a wavelength of 185no+ on an arbitrary scale.

As is clear from the same curve (35), the intensity of 185 nm light was strong near 40 to 80°C, and the intensity was weak when the temperature was lower or higher than that range. For comparison, a lamp (9) exactly the same as in this example was used, and power at a frequency of 50 Hz was similarly applied to the electrodes (33),
200 W was applied through (34) to change the temperature of the temperature control section in the same way.

The results are shown in Figure 4, Song 1 (36).

Also, the scales are the same, so curves (35) and (36) can be compared.

As is clear from the curve (36), an optimum temperature also exists in the case of this comparative example, but the temperature was around 20°C, which was different from that in the case of the present invention. Furthermore, the strength was about half or less than that in the case of the present invention even near the optimum temperature.

Since the present invention uses such a lamp with a strong light intensity of 185nm, it is possible to emit light of 185nm without coating the window with oil or the like.
The critical thickness of the film that can be formed to allow a large amount of short-wavelength ultraviolet light to reach the surface on which the substrate is formed (in the case of silicon nitride film)
We were able to increase the number of employees from 1,000 to 3,000. For this reason, it is possible to create the necessary and sufficient film thickness for antireflection films for compound semiconductors such as InP, gate insulating films for thin-film silicon semiconductor devices, and passivation films for compound semiconductors such as GaAs using only the photoCVD method. obtain.

Furthermore, in the method of the present invention, since it is an oil-free reaction system that does not use Fomblin oil or the like at all in the window,
It was possible to reduce the background level of vacuum to 10-'torr or less.

Then, a photo-CVO coating is formed by photoexcitation of semiconductor coatings such as silicon, insulating coatings such as silicon oxide, silicon nitride, aluminum nitride, phosphorus glass, boron glass, etc., and conductive coatings of metals such as metal aluminum, titanium, tungsten, or their silicides. can be caused to form.

The details of the present invention will be described below using the apparatus of the present invention shown in FIG.

In FIG. 1, a substrate (4) having a surface to be formed is held on a substrate support (7) and held in a reaction chamber (2). A heater is provided adjacent to the interior of the substrate support. In addition, around the reaction chamber (2), a light source chamber (5) in which a large number of ultraviolet light ai (9) made of forced cooling low-pressure mercury lamps, which are supplied with electrical energy from a power source (13), are arranged upright.
). The light source chamber (5) and the reaction chamber (2) were maintained at approximately the same degree of vacuum with a pressure difference of 10 torr or less. For this reason, a non-product gas (nitrogen, hydrogen, helium, or argon) that did not interfere with the reaction and did not participate in the reaction was supplied to the light source chamber (5).

In order to emit electrons, the electrodes of this ultraviolet light lamp are made of a material with a small work function such as BaO (33) (
34) coated on top. Further, in order to sufficiently improve heat conduction between the temperature control section (29) and the heat exchanger (32) provided in this lamp, a thermally conductive paste is interposed between the temperature control section (29) and the heat exchanger (32).

By doing this, the temperature rise inside the pipe is controlled by the temperature control section (2).
9) can be controlled arbitrarily at 40 to 80
It became possible to control the temperature at ℃. Of course, in the gas phase reactor shown in Figure 1, the ultraviolet light source (9
) When the tube itself is heated, it is effective to provide a water-cooled tube in close linear contact with the outside of this tube.

In an example using the apparatus shown in FIG. 1, when a semiconductor such as silicon is produced as a reaction product, the product gas is silane (SinHtn**n≧2), halogenated silicon 01xSi, h- x(X-0~5)+H
XSizC1i-x(X”O~5)+HxSiiP
s-x (X=0-8).

11xSizC1m-x (X-0 to 8) was used. Furthermore, hydrogen, nitrogen, argon, or helium was used as a carrier gas for the non-product gas.

When producing nitrides (silicon nitride, aluminum nitride, gallium nitride, indium nitride, antimony nitride) as reaction products, 51 g of each product gas is used.
n5. AI(IIs)*+Ga(CHs)+, In(C
L)i.

5n(CHs)e, 5b(C)Irix were used, and ammonia or hydrazine was supplied as a non-product gas participating in the reaction. In addition, a non-product gas (hydrogen or helium) that does not participate in the reaction was supplied as a carrier gas.

When producing an oxide (silicon oxide, phosphorous glass, boron glass, aluminum oxide, indium oxide, tin oxide, antimony oxide, or a mixture thereof) as a reaction product, the oxide ( N
gO, Ot, NO or N02) were used. in this case,
Silicide (SiJi+ 5iz
Fi, 5ttC1i), aluminum compound (AI(C
Hs)s, ^1 (CzHs) s), indium compound (In(CH3)a+In(CJs)s), stannide (Sn(CHs)4.Sn(CJs)a), antimonide (Sb(CH3) +, 5b(C!Hs)s)
was used. Then, hydrogen or helium as a non-product gas not participating in the reaction was supplied as a carrier gas. Also, phosphin (pH 3) if necessary.

Diborane (Bgo, ) was fed.

When making conductors (aluminum, tungsten, molybdenum, titanium, or their silicides), hydrogen, argon, or helium was used as a non-product gas. AI(C113)3゜WF &1W as product gas respectively
(Ct)Is) s+ MoCl5. MO(CH3)
s 1TIC14+ T i (CHs) s or them and 5illi+5itPh+5iHzC1□, 5i
A mixture with Fa was supplied. Hydrogen, which is a non-product gas that does not participate in the reaction, was supplied as a carrier gas.

In the film formation process, first, the substrate (14) was placed on the substrate support (7), and then the inside of the reaction chamber (2) was initially evacuated to a vacuum state by the exhaust system (8).

After that, in order to prevent reactive gases from entering the light source chamber due to backflow, first add 100 to 150% of the non-product gas.
The light source was introduced into the light source chamber at a flow rate of 0.00 cc/min, and at the same time, a non-product gas, such as N113, participating in the reaction was similarly supplied to the reaction chamber. The substrate was left in this state for about 30 minutes, and active hydrogen and fluorine were generated by photolysis of the gas, and the surface of the substrate to be formed was photoetched. This removed the oxide on the surface to be formed, making etching possible by light irradiation and keeping the surface clean. Thereafter, the product gas of the reactive gases was fed.

The light source for the reaction is a low-pressure arc discharge mercury lamp made of synthetic quartz tube (9)
At least a portion of this mercury lamp is equipped with a temperature control section (
29) was established. The ultraviolet light source is 16 low-pressure mercury lamps made of synthetic quartz (emitting wavelengths of 185 nm and 254 nm, emission length 40cm, irradiation intensity 60 to 100 d/cm", lamp power 150 to 200 m2).

In this lamp, the temperature of the lamp tube wall rises due to self-heating due to light emission and radiant heat from the lamp plate, but the temperature control section (29
), the mercury vapor pressure inside the lamp remains at 185n even if the temperature of the lamp tube wall rises.
■The pressure is controlled to make the light emission the strongest.

This ultraviolet light passes through a light-transmitting shielding plate (6) made of synthetic quartz to the reactive gas and substrate (4) in the reaction space (2) of the reaction chamber.
irradiate the surface to be formed.

In addition, it is necessary to introduce a medium for controlling the temperature into the temperature control section from the outside.Therefore, in order to facilitate the introduction of this medium, the present invention incorporates an ultraviolet light source lamp into the reaction chamber or light source chamber. It is installed upright.

Furthermore, specific examples according to the present invention are shown in the following experimental examples.

Experimental example Formation example of silicon nitride film In FIG. 1, ammonia and disilane were supplied at 200 cc/min and disilane at 20 cc/min as reactive gases, and the substrate temperature was set at 350° C. to form a silicon nitride film. The substrates were four 5-inch diameter wafers. The pressure inside the reaction chamber was 10.0 torr.

Nitrogen is used as a non-product gas that does not participate in the reaction.
It was introduced at cc/min (15).

The relationship between the film thickness obtained at this time and time is shown in FIG.

The figure also shows the results obtained when a conventionally known mercury lamp was used instead of using the mercury lamp of the temperature control method of the present invention. In this case, the ultraviolet light intensity is 10 mW/cm on the substrate surface.
In that case, the curve in Figure 5 (38
), and the maximum film thickness was up to 1000 people.

On the other hand, the present invention obtained curve (37), and was able to achieve a high film formation rate and a maximum film thickness of 3,000, three times that of the conventional method.

(e) Effects As shown in Figure 4, the present invention can clearly obtain an ultraviolet light intensity with a short wavelength that is more than twice that of the conventional lamp, and the optimum temperature range for the intensity to be high is also from 40°C to It has a wonderful effect in that it has a wide temperature range of 80°C and is very easy to control.

Further, the configuration of the present invention has the feature that it is easy to introduce the medium into the temperature control section of the ultraviolet light source lamp, and the structure of the device is also very simple.

Note that the present invention shows the formation of silicon nitride as an example.

However, many types of semiconductors, insulators, and conductors, such as amorphous silicon films, silicon oxide, phosphorus glass containing impurities added thereto, boron glass, or aluminum, can be formed using the same technical idea. In addition, iron, nickel, and cobalt carbonyl compounds not shown in these examples are used as reactive gases, and iron, nickel, and cobalt carbonyl compounds are used as reactive gases.
It is effective to form a passivation film on a magnetic material of nickel, cobalt or a compound thereof.

In the experimental examples described above, dopants can be added at the same time when forming a silicon semiconductor.

In the present invention, if pollution problems are ignored, the film growth rate may be improved by passing through a mercury bubbler.

The shape of the mercury lamp in Figure 2 is not only a serpentine tube but also an annular shape.
Spirals, combs and other shapes are possible.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a semiconductor processing apparatus according to the present invention. FIG. 2 is a schematic diagram of a mercury lamp according to the present invention. FIG. 3 shows a luminous intensity distribution diagram of a conventional low-pressure mercury lamp. FIG. 4 shows the characteristics of the lamp of the invention. FIG. 5 shows the relationship between the film thickness and time of the film produced using the apparatus of the present invention. 2...Reaction chamber 4...Substrate 5...Light source chamber 7...Substrate support 9. ......Low pressure mercury lamp 29...Temperature control section 32...Heat exchanger

Claims (1)

[Claims] 1. An ultraviolet light source lamp in which mercury is sealed in a serpentine bulb and has a temperature control section near at least one end of the bulb that can control the mercury vapor pressure in the bulb is placed in or in the reaction chamber. A photochemical reaction processing apparatus characterized in that the temperature control section and the power introduction terminal are installed vertically in an adjacent light source chamber so that they are located on the lower side.