JPS6314870A - Method for selective growth of thin metallic film - Google Patents

Abstract

PURPOSE:To maintain good selectivity and to form a thin metallic film at a high speed with good reproducibility by cooling parts such as the inside wall of a reaction vessel, substrate susceptor, and gas introducing pipe except the substrate exposed to gaseous raw materials. CONSTITUTION:WF6 and H2 are introduced from a WF6 cylinder 1 and H2 cylinder 2 through respective flow rate regulators 3, 4 and stop valves 5, 6 into the reaction vessel 8 cooled with water. Water-cooled light shielding plates 10, 11 are provided to the inside and outside of the reaction vessel 8 and air is blown from a direction B to cool a projection window 9 with the air. A halogen lamp 9 with a water-cooled reflection mirror is then lighted up to heat the vacuum vessel 12 through the projection window 9 and to cause the reaction of the introduced gases, by which the thin metallic film is selectively grown onto the substrate 12.

Description

[Detailed Description of the Invention] [Field of Sedentary Application] The present invention relates to a method for selectively forming a metal thin film by a vapor phase growth method, particularly for forming a metal thin film at high speed while maintaining high selectivity. According to a method suitable for b.

[Conventional technology]

Conventionally, the vapor phase growth method usually uses IEcVD equipment and low pressure CV.
D equipment has been used, but the low pressure CVD method, which has excellent film thickness distribution and construction coverage, has been used to form metal thin films. Among these methods, especially when gold xivg is selectively formed, it is necessary to take measures to avoid forming a metal thin film on the walls of the reaction vessel other than the wafer. As a true wall type low pressure CVD apparatus, the entire reaction vessel is heated with a heater as disclosed in US Pat. No. 4,547,404.
The reaction vessel has the advantage that infrared rays from the heater can pass therethrough and the interior of the reaction vessel can be heated uniformly. In addition, when forming a flora thin film using metal halide gas and hydrogen gas,
Selective film formation becomes possible by using gold, quartz, etc., on which it is difficult to form an A thin film, in the reaction vessel. However, even if the inner wall of the reaction vessel is rough, if there is dirt that becomes the core of film formation,
There is a problem in that the region in which the metal thin film is formed expands around the core, and eventually a metal thin film or imitation is formed on undesired portions of the substrate. On the other hand, as a cold wall type low pressure CVD device, JP-A-59-179775
As disclosed in No. 1, the entire reaction vessel is water-cooled, and there is a method in which the substrate is heated with an infrared rung from behind the basic surface on which the desired metal thin film is formed together with the basic support.

In this method, since almost nothing other than the substrate surface on which the desired metal thin film is formed is exposed to the raw material gas, there is no reaction between the reaction vessel wall and the raw material gas, and the film formation rate is 7: stable. be.

Furthermore, since the entire substrate is heated together with the substrate support, there is an advantage that the surface temperature of the substrate can be heated uniformly.

However, when the substrate support is also heated, a metal thin film is formed on the substrate support, and the area where the gold 4 thin film is formed expands, and eventually the gold 4 thin film is deposited on undesired parts of the substrate. The problem is that it forms.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional technology, it is difficult to control the temperature difference between the substrate on which a metal thin film is formed and something other than the substrate, such as a reaction vessel or a substrate support jig, and even if the desired metal g is There was no consideration given to the temperature difference between the part where the gold is selectively formed and the other parts, and there was a problem that it was not possible to maintain good selectivity and form a gold Y4 thin film at high speed with good progress. Ta.

The purpose of the present invention is to maintain good selectivity and perform gold metallization at high speed with good reproducibility. i4 i'J4 film.

[Solving the Problem/Step ζ] In order to achieve the above-mentioned object, in the present invention, the substrate material and the formed metal are exposed to light as a means for heating the substrate placed in the reaction vessel. Using a light source with absorption 2, the surface of the substrate 104 on which the desired metal i4 film is to be formed is irradiated with light from the light source, and further, the light from the light source is made such that it does not hit anything other than the substrate, or even if it does not hit anything other than the substrate. A thin metal film was formed by heating only the substrate to a predetermined temperature while using cooling means such as water cooling to prevent the temperature from rising, and by introducing metal halide gas and hydrogen gas into the ash stone container. Formation of a metal thin film by the vapor phase growth method is carried out by reduction of a metal halogenide with H2, and it is said that for this purpose, the presence of H atoms, which serve as a nucleus for film growth, is required. However, in the case of selective film formation, it is extremely bad if H atoms are generated for some reason or five atoms generated from the outside are attached to undesired portions.

Based on this idea, it is important to keep the polar resistance low in areas other than those where the desired metal thin film is to be formed, and to eliminate the cause of H atom generation. Therefore, in the present invention, a light source in which the substrate material and the formed metal absorb light is used as a means for heating the substrate, and the surface of the substrate on which the desired metal thin film is to be formed is irradiated with light from the light source. Further, the light from the light source is made so that it does not reach anything other than the base, or even if it hits, the temperature does not rise due to cooling means before water cooling.

Therefore, H atoms are not generated in parts other than the base. Also within the same substrate is the desired metal i? Since the light is irradiated from the basic surface side where the film is formed, the gold I on the substrate
Due to the difference in absorption coefficient due to the difference in material between the part where the j4 thin film is deposited and the other parts, the temperature is higher in the part where the metal is deposited than in the other parts. Therefore, the generation of H atoms from the portion of the substrate on which metal is not deposited can be suppressed to that extent.

〔Example〕

Next, the present invention will be explained according to examples. One implementation of the present invention
Tungsten hexafluoride (lIV14'4) as lJ
and hydrogen (H2) as raw material gas, thermal oxide film (SiO
2) on the surface, and there are many contact holes (0
, 6 .mu.m0 to 2 .mu.m', depth 1 .mu.m) in a silicon wafer (Si) with openings of 0 to 2 .mu.m' and a depth of 1 .mu.m). In FIG. 1, 1 and 2 indicate WFb and H cylinders, respectively, and 6,
4 is a Kukei regulator dedicated to each gas, and 5 and 6 are stosuge pulps dedicated to each gas. 7 is equipped with a water-cooled reflector.
- The light emitted from the rogen lamp heats the wafer 12 through the irradiation window 9 made of quartz. 87 shows a water-cooled reaction vessel, which suppresses the rise in the vessel wall by m degrees due to light irradiation. Further, this reaction vessel is connected to a vacuum exhaust system (not shown) in the inlet direction. ...Is the irradiation window 9 - when you turn on Rogenlang 7? In order to suppress the temperature rise on the inner wall of the reaction vessel 8, water-cooled light shielding plates 10 and 11 are provided both outside and inside the reaction vessel 8, and air is blown from direction B to close the irradiation window 9. It is air cooled. Furthermore, the wafer 12 is held by a water-cooled substrate support 16 in which three points are in substantially point contact so as not to cause a temperature drop. Note that a light shielding plate 111 provided in the reaction vessel 8 is designed so that four sources of the raw material gas are in contact with each other so that the two raw material gases can be effectively diffused into the wafer. In this example, vapor phase growth was performed using Experiment I equipment, so the wafer 1Q temperature was
, A 25p thermocouple was directly attached to the Que. In addition, to control the temperature of Way 12, the voltage output C from the above thermocouple is monitored, and the power controller 1
5, the output of the halogen rung 7 was varied. Is the pressure inside reaction vessel 8 measured by a capacitive pressure sensor? 14, and pressure control was performed by changing the conductance of an exhaust system (not shown) in the A direction.

Next, referring to FIG. 2, a description will be given of the temperature difference that occurs between the contact hole portion and other portions. Since the logen lamp 7 used as a heating means is made of quartz, it can be
There is a light emitting region up to the far infrared region of m. (However, since quartz has strong absorption at a wavelength of approximately 2.7 μm, the emission intensity is low at that position.) The materials of the irradiation window 9 and the thermal oxide film (SiO2) covering the surface of the Si Queno 1 are almost the same. It is thought that the light was irradiated through the entire irradiation window 9...
5iO215 on Pheno1 for Rogunra/Gua
It can be said that almost 100% of the light is transmitted through the lamp, and that there is no contribution to the temperature rise due to the lighting of the lamp. On the other hand, tungsten 17 has an absorption of 100 degrees for light in the above wavelength range.
Silicon wafer (5 wafers 5IJll [0,55 dragon)
In this case, it has only 70 degrees of absorption over the entire wavelength range. From this, it is expected that the temperature will be significantly different on the Pheno-12 surface where the reaction proceeds. In the embodiment of the present invention, it is very difficult to accurately know the surface temperature of the contact hole portion and other parts. The substrate temperatures were compared. W
The above 5.
When the substrate on which W was formed was heated under the same conditions as -C using the output of a halogen rung which heated the substrate on which 102 was formed to 550°C, the substrate temperature showed about 6500°C.

Next, the method 1 of forming W only in the contact hole part on the silicon wafer with the contact hole described above and filling the hole.
Explain the section. The reaction container 8 is evacuated to a vacuum of 10 -3'rorr or less, and after the evacuation, H2 gas is introduced into the reaction container 8, and the halogen lamp is turned on to start heating the substrate. The flow rate of H2 is maintained at 5003 CCm by the flow rate regulator 4. The pressure inside the reaction vessel 8 is set to 10 Torr by the conductance regulator 11 of the exhaust system (not shown), and the temperature of the substrate 12 is set to 550°0 by the power controller 15 of the halogen rung 7. When both pressure and temperature are stable, WF6 is introduced into the reaction vessel. The flow rate of WF'4 is maintained at 3 seconds by a flow rate regulator 6. Due to the introduction of WF4, slight fluctuations are seen in both the pressure and temperature, but the respective controllers restore them to predetermined values after a few seconds. After 30 seconds after the WF6 conductor, the supply of each gas is stopped by the stop pulp 5.6, and at the same time, the halogen lamp is turned off, substrate heating is stopped, and the residual gas in the reaction vessel is exhausted. After the substrate was cooled to below 100°, the reaction vessel 8 was leaked and the substrate was taken out. 1μm by the above operation
Tungsten was buried to a thickness of about 0.9 Am into the deep contact hole. To evaluate the selectivity, the wafer 12 was broken and the area around the contact hole was observed using a scanning electron microscope. Although the contact hole portion was almost completely filled with tungsten, there was no change in the 5iO215 around the hole, confirming that the selectivity was very good.

As is clear from the above examples, the present invention maintains high selectivity and forms metal thin films at high speed only on specific substrates (~
3500 A/ai+) It has 9 effects. In addition, the scope of use of the present invention is the film forming conditions described in Examples, yK
W as a metal halide gas, not only for raw materials and base materials.
Cl4, WCl5, MoF6. MoCl5T
iCl4. TaCl5, PtFi,
, ReF6, etc., kl, Cu, etc. as the base material.
Nl, Cr, Mo, Pi, Tiwsumx, MoSix, Ti5lx, PtEli
Corresponding metal thin films can be formed using materials such as x, TiNy, and WNy.

〔Effect of the invention〕

As described above, according to the present invention, a metal thin film can be formed selectively and at high speed only on a specific base on a substrate. Dogs contribute to improving yields, throughput, and product reliability in the manufacturing process of high-speed LSIs.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a step-up view of contact holes in an embodiment of the present invention. 1...WF4 cylinder 2...H2 cylinder 7...Halogen rung 8...Reaction vessel 12
...Substrate 13...Substrate support 14
...Pressure sensor -5...f9i0z1
6...S+wafer 17...Wt'>
. Representative Patent Attorney Katsutoshi Ogawa / Figure 1

Claims (1)

[Claims] 1. A method of selectively chemical vapor depositing a metal thin film only on a specific substrate on a substrate, 2. A metal halide gas of the metal and hydrogen gas are used as source gases; Place the substrate on top and heat at least the part on which you want to deposit the metal thin film to a temperature high enough for the above gas to react on the substrate, and (3) expose the inner wall of the reaction vessel, the substrate support, the gas introduction pipe, etc. to the above raw material gas. A method for selectively growing a metal thin film, which is characterized by cooling parts other than the substrate to prevent film formation from reacting with the raw material gas in areas other than the substrate. 2. The method for selectively growing metal thin films according to claim 1, wherein a light source in which the substrate material and the formed metal absorb light is used as the heating means. 3. The method for selectively growing a metal thin film according to claim 2, wherein the light from the light source is irradiated onto the surface of the substrate on which a desired metal thin film is to be formed. 4. The metal halide is WF_6, WCl_5, W
Cl_6MoF_6, MoCl_5, TiCl_4, T
aCl_5, NbCl_5, PtF_6, IrF_6,
The method for selectively growing a metal thin film according to claim 1, wherein the metal thin film is one of ReF_6. 5. The exposed underlying material of the portion on which the metal thin film is deposited reacts with the metal halide gas at a predetermined temperature to form a metal. Or, a patent claim characterized in that the material is a material that has a catalytic action to adsorb and dissociate hydrogen gas, and the material of the other parts on the substrate is a material that neither has the reaction nor the catalytic action at the same temperature. A method for selectively growing metal thin films according to scope 1. 6. The underlying exposed material of the part on which the metal thin film is deposited is silicon, metal, metal silicide, or metal nitride, and the exposed material of the other part of the base is silicon oxide, silicon nitride, alumina, diamond, 6. A method for selectively growing a metal thin film according to claim 5, wherein the method is an organic insulating film.