JPH03286531A - Formation of silicon oxide film - Google Patents

Abstract

PURPOSE:To improve a film-formation speed and a film quality by a method wherein, when an organic silane compound and ozone are supplied to the inside of a container which has housed a substrate and a silicon oxide film is formed on the substrate, the substrate is heated and the substrate is irradiated with ultraviolet rays. CONSTITUTION:It is preferable that an organic silane compound is an organic silane compound provided with an alkoxyl group. It is preferable to execute this method in the following manner: a silicon oxide film is formed on a substrate; after that, the supply of the organic silane compound to the inside of a container is stopped; while ozone is being supplied, the substrate is heated and the substrate is irradiated with ultraviolet rays; and the silicon oxide film is annealed. In addition, it is preferable to execute the method in the following manner: the silicon oxide film is formed on the substrate; the substrate is once taken out from the container; after that, the substrate is housed again in the container; while ozone is being supplied to the inside of the container, the substrate is heated and irradiated with the ultraviolet rays; and the silicon oxide film is annealed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for forming a silicon oxide film on a substrate such as a silicon wafer. The method of the present invention includes photo-CVD
belongs to the law.

<Prior Art> Manufacturing of semiconductor devices includes a process of forming wiring layers. Then, an insulating layer is formed around the wiring layer and between the layers to prevent electrical leakage. A silicon oxide film is often used as such an insulating layer, and known methods for forming it include CVD, PVD, and SOI.

Among the methods for forming silicon oxide films, the CVD method is the most common method, and the CVD methods that have been put into practical use include the following methods ("Fundamentals of VLSI Material Processing")
, Ohmsha, supervised by Ito, written by Kishino).

■5iH4-0□Normal pressure CVD method ■5iH4-02 Plasma CVD method ■TEOS (Tetraethoxysilane) -02 Reduced pressure C
In the VD method (■), a silicon oxide film is quickly formed, but the filling shape between wiring layers tends to have an overhang shape, and therefore voids are likely to occur in the hole area. This causes a decrease in yield.

In the method (2), although the overhang was improved, there was a tendency for the film thickness of the sidewall portion to become smaller, which often caused problems with the insulation of the sidewall portion. That is, step coverage tends to deteriorate as the aspect ratio increases.

Method (2) overcomes the drawbacks of (2) and (2), but the film forming temperature is around 740°C, which is 450°C (450°C) and 400°C (400°C).
℃, and cannot be used in the process after Aj2 wiring.

Therefore, in order to overcome these problems of conventional CVD techniques, a method using light irradiation has been proposed.

For example, as an improvement method limited to SiH4 materials, a method of increasing the film formation rate by irradiating ozone-added SiH4 gas with visible or short wavelength light is disclosed in JP-A-1-1.
It is disclosed in Japanese Patent No. 29420. However, since this method also uses SiH4 as the material,
The problem of (2), such as overhang, cannot be improved significantly, and the generation of particles that cause deterioration of film quality is significant. Therefore, this method is not necessarily suitable for semiconductor manufacturing processes that require even finer structures.

Separately, a film is formed on the substrate by coating liquid organosilicon on the substrate, which is then transported into a processing chamber and exposed to ozone-containing gas before being irradiated with ultraviolet rays. A method for forming a film of 5i02 is disclosed in Japanese Patent Application Laid-Open No. 63-248710.

However, according to this method, although the reaction progresses well on the outermost surface, the reaction does not progress sufficiently deep in the thickness direction of the film.
Therefore, the 111i of the formed film was insufficient.

More recently, as a way to overcome the shortcomings mentioned here,
A method of forming a silicon oxide film by a CVD method at normal pressure using ozone and TE01, which is classified as an organic silane compound and is a type of alkoxysilane, has been attracting attention. This method achieves prevention of overhang, prevention of side wall thinning, and low-temperature acid @ (film-forming temperature of 450° C. or less), and overcomes the drawbacks of the prior art.

<Invention or problem to be solved> As mentioned above, the ozone-TEO5 normal pressure CVD method is attracting attention from the viewpoint of good step coverage and film formation temperature for forming silicon oxide films, especially interlayer insulating films. It has been done. In particular, practical use is being considered for memories of 4M DRAM or larger, where the design rule is 0.8 μm or less.

However, the silicon oxide film formed by this ozone-TEO3 atmospheric pressure CVD method also has the following drawbacks, and therefore it cannot be considered to be used alone as an interlayer insulating film.

■The film formation speed is slow. Under normal conditions it is 0.2 μm/min.

At the same time as memories are becoming more highly integrated, substrates are becoming larger in diameter, and a method of sequentially processing each substrate (patterning) is becoming mainstream in devices. At this time, in order to ensure a throughput comparable to the conventional batch method that processes many sheets at the same time, it is necessary to significantly improve the film formation rate.

■Crank occurs.

Residual stress is normal (2-5) x 109dyn/cm2
Due to compression, cracks occur when the film thickness is 1.2 μm or more. Furthermore, if it is directly attached to a wiring pattern made of aluminum or the like, cracks will occur in both the metal and the silicon oxide film.

(2) When the aspect ratio is 0.5 or more, voids or regions with poor density tend to occur between horizontal wirings.

■The dielectric strength is 5 to 6 MV/cm, which is (3 to 4) MV/cm smaller than that of a thermal oxide film.

The present invention takes advantage of the characteristics (good step coverage) of the silicon oxide film formed by the ozone-TEO3 normal pressure CVD method described here, while improving the film formation speed and improving the current problems of this method. The aim is to provide a technology to improve film quality.

Means for Solving the Problems〉 The inventors took advantage of the good step coverage of the silicon oxide film formed by the ozone-TEOS atmospheric pressure CVD method and applied it to the glabella insulating film that is essential for LSI. We have carried out various studies on the possibilities of this.
In particular, regarding the film formation rate, currently it is at most 0.2μm/
Therefore, in order to maintain the same level of throughput as batch-type devices in pattern-type devices, which will become the mainstream of LSI manufacturing equipment in the future, it is necessary to increase the film-forming speed by approximately 2 to 5 times, which requires improvement. I felt the need.

In addition, when a thick silicon oxide film is deposited on a substrate by the ozone-TEO3 normal pressure CVD method, the silicon oxide film is cranked, and if it is directly attached to a wiring layer at A℃,
After examining the characteristics related to the film quality of the silicon oxide film, such as cracks appearing in the n wiring layer and silicon oxide film at the same time, and the poor dielectric strength of the formed silicon oxide film, the cause was found to be It was found that this was due to the fact that the silicon oxide film was not formed densely. Elemental analysis of the silicon oxide film revealed that the silicon oxide film is not dense. That is, the silicon oxide film contained carbon or hydrogen up to nearly 1% in some cases, and this was thought to be because the ozone-TEO5 reaction had not completely progressed to the final point.

From these facts, it has become clear that in order to further increase the film formation rate and improve the film quality, it is sufficient to finally complete the reaction efficiently. In order to carry out the reaction efficiently, attention should be paid to the following two points.

(2) Completely react the TE01 introduced into the device with ozone, that is, increase the decomposition reaction efficiency.

■Through the ozone-TEOS reaction, all ethyl groups (C2H5) or ethoxy groups (C2H50) are removed from the four ethoxy groups (C2H2O) bonded to - Si, creating a compound that is stable in the gas phase and producing exhaust gas. These are removed from the chamber as possible to minimize their incorporation into the silicon oxide film.

The present invention is a method for realizing such an efficient ozone-TEOS reaction, in which an organic silane compound and ozone are supplied into a container containing a substrate to form a silicon oxide film on the substrate. The present invention provides a method for forming a silicon oxide film, which comprises heating the substrate and irradiating the substrate with ultraviolet rays.

The organic silane compound is preferably an organic silane compound having an alkoxyl group.

Further, after forming a silicon oxide film on the substrate by the above method, stopping the supply of the organic silane compound into the container, heating the substrate and irradiating the substrate with ultraviolet rays while supplying ozone, It is preferable to anneal the silicon oxide film.

Furthermore, after forming a silicon oxide film on the substrate by the method described above, once taking out the substrate from the container, storing the substrate in the container again, and supplying ozone into the container,
It is preferable to heat the substrate and irradiate the substrate with ultraviolet rays to anneal the silicon oxide film.

The present invention will be explained in detail below.

First, the principle of forming a silicon oxide film by the conventional ozone-TEOS atmospheric pressure CvD method and the method of the present invention and the reaction rate at that time will be described.

TEOS is represented by the chemical formula 5i(OC*H6)4. The mechanism by which a silicon oxide film (Stow) is formed by the reaction between this compound and ozone (03) is not yet fully known, but thermal decomposition of a mixed gas of TEOS and oxygen requires a temperature of 740°C. In the ozone-TEO5 reaction, the growth temperature of silicon oxide film is 400℃.
Considering that the temperature is around .degree. C., it is thought that oxygen atoms are generated by thermal decomposition of ozone, and the oxygen atoms attack and decompose TEOS, that is, the reaction proceeds according to the following formulas (1) and (2).

03 → 02+o(1)SiCO
C2H5)a +O→ = = SiO2
(2) Considering this, in order to efficiently advance the reactions shown in equations (1) and (2) to the final point, it is necessary to maintain a high concentration of oxygen atoms in the gas phase or on the growth surface of the substrate. I know what to do.

Here, the ozone decomposition reaction and recombination reaction due to thermal decomposition when ozone is mixed in oxygen gas are shown in equations (3) to (6).

0, + M −h O2+ 0 (3) 0
+ O, -o, + 02 (4) 0
+ o2+M → Os+M(5)0+O+M
→ 02+M (6) However, M in the above formula is a third body.

Here, assuming a steady state regarding the oxygen atom concentration ([○ko, hereinafter [] represents the concentration of the specified species), d[o ko /dt=ks[os ko [M]-
k 4 [o ko [03ko ks co
:] [O0ko [M]-ni6 [0]
It can be considered that [O0ko [Mko(7)] holds true. Here, the fourth term on the right side is the square of the oxygen atom concentration, which has a small concentration, multiplied by the concentration of the third body, so it can be considered to be small compared to the other terms. If ignored, [0ko = (ks[os] [M] )/(
k4[os]+ks[o2] [M] ) (8) is induced.

From this equation (8), in order to maintain a high concentration of oxygen atoms in ozone gas diluted with oxygen molecules, the following steps are taken: - Increase the ozone concentration - ■ Increase the size of the molecule on the right side of equation (8) is possible. In order to achieve (2), in addition to the ozone thermal decomposition reaction, other ozone decomposition processes need to be added.

From this point of view, the present invention aims to improve the ozone-EOS normal pressure CVD method.

That is, in order to stably decompose ozone and maintain a high concentration of oxygen atoms, ozone gas diluted with oxygen molecules is irradiated with ultraviolet rays that have an ozone-decomposing effect, and the photostationary state is maintained.
).

Thereby, a reaction system in which formula (9) is added to formulas (3) to (6) is established.

03 + M -02+ O(3) 03+UV light -02+0(9) o + o, -o, + 02 (4
)o + 020 M -403+ M(5)0
+ O+ M −02+ M (6) Here, assuming steady state regarding oxygen atoms, d [O] / d t = k s
[Os ko [M] + lc9 [0, 4 to ko [0] [03 ko 1 k 5 [0 ko [02] [M] - 6 to
[0] [Oko [M] (10) It can be considered that the following holds true. Here, the fifth term on the right side is the square of the oxygen atom concentration, which has a small concentration, multiplied by the concentration of the third body, so it can be considered to be small compared to the other terms. If ignored, [○] = Ncs[o 31 [M co + k 9[03])/ (k4[0,l+ks[o
z] [M] ) (11) is induced.

As is clear from comparing equations (8) and (11), by irradiating ultraviolet rays, the oxygen atom concentration under steady state becomes [o3
] [It will be M times more expensive. And this is
This is the rationale supporting the advantage of the method of the present invention.

Furthermore, we will provide additional explanation regarding the reaction rate.

In order to estimate the rate of photodecomposition due to ultraviolet irradiation, it is first necessary to know the absorption spectrum and absorption coefficient of ozone.

FIG. 1 shows the absorption spectrum of ozone in the wavelength range of 200 to 300 nm. In addition, FIG. 1 is based on the literature () 1.0kabe.

”Photochemistry of Small
Molecules, Wiley.

New York, 1978. This is quoted from p239). According to Figure 1, ozone is 200-30
Since it has strong absorption at 0 nm, if we use a low-pressure mercury lamp as the ultraviolet light source and emit light at 253.7 nm, the absorption coefficient at this wavelength position is 120 atm-'cm-' ( b a se is 10). If we change this unit to display the absorption cross section, a = 1, 1 x 10-” cm2/m
It can be seen that it becomes an olecule.

Here, kg=1. X (7XΦ. However, Io
is the photon density, σ is the absorption cross section, and Φ is the quantum yield of unreacted (9).

It is well known that the quantum yield of the decomposition reaction of ozone by ultraviolet light (unreacted (9)) is 1 (H, 0 kab
e, already mentioned). Furthermore, since the photon density of a low-pressure mercury lamp for optical processing is 10'' to 1019 pieces/cm'-5 ec, kg = 11 to 110 sec-'.
Of course, if the light is condensed, the photon density can be further increased, and it is also possible to reach about kg=1000 sec-'.

On the other hand, according to the literature, the reaction rate constant of pure thermal decomposition reaction equation (3) is 7.55 x 1O-9exp (-24000/RT
) cm3・molecule-'・5ec-'teal (
S? 1'1. BENSON, “FOI]NDATION
OF CHEMICAL KINETIC5”, WIL
EY, 1960. NEW YORK). This is 2
Although it is a molecular reaction, when the reaction is carried out under 1 atm, the pseudo-unimolecular decomposition reaction of ozone decomposition is expressed as the product of k3 and the number of molecules contained in a unit volume of gas at that temperature. Ru.

It was set as 2-3, and the 2-3 calculated at each temperature is shown in Table 1.

Thermal Decomposition Rate Constant (k'k3) As is clear from Table 1, the ozone decomposition reaction has extremely high temperature dependence. Therefore, increasing the reaction temperature significantly increases the reaction rate. However, when forming a silicon oxide film, the temperature of the reaction system cannot be unconditionally increased. In addition, normal ozone-TEO3 Jooh Cv
Since method D uses a so-called cold wall type CVD device that heats only the substrate, the gas temperature does not reach the specified temperature, and the actual reaction rate in the CVD chamber is shown in Table 1. It is thought that this is considerably smaller than that due to the reaction rate constants at each temperature shown.

Here, the photodecomposition rate of ozone due to ultraviolet irradiation and the thermal decomposition rate of ozone will be compared. In the case of thermal decomposition, the formation of a good quality silicon oxide film by ozone-TEOS is usually observed at around 350 to 400°C, but for example,
Taking 0℃ as an example, the thermal decomposition rate constant of ozone is 342s
ec-'. This value and the previously estimated photodecomposition rate constant of ozone due to ultraviolet irradiation are, for example, 1000 se.
When compared with the case where the irradiation conditions are c-', the photodecomposition rate of ozone is approximately four times the thermal decomposition rate at 350°C.

In other words, since the ozone concentration under steady state conditions can be maintained four times as high, the decomposition rate of EO3 also increases approximately four times, and therefore the film formation rate also increases approximately four times, which is one of the objectives of the present invention. It is possible to improve the film speed.

Furthermore, the formation of silicon oxide films at lower temperatures will also be described.

When the substrate temperature is 250° C. or less, as is clear from Table 1, the thermal decomposition reaction of ozone is very slow at 10 sec-'. Therefore, with the conventional ozone-TEO3 normal pressure CVD method, it is not practical to form a silicon oxide film at such a low temperature. However, even if the substrate temperature is 250° C. or lower, the decomposition rate can be expected to improve by two to three orders of magnitude by irradiating the substrate with ultraviolet rays. Therefore, it is possible to reduce the film forming temperature.

In addition to the above, in the conventional ozone-TEO3 normal pressure CVD method, the thermal decomposition reaction occurred only near the boundary around the substrate, whereas in the method of the present invention, the reaction progresses within the optical path along which the light travels. Therefore, it should be added that there is a possibility that a reaction enhancement effect higher than that described above can be obtained. However, this is of course subject to various conditions such as the shape of the reaction vessel and the density of photons reaching the irradiation surface from the light source.

The above-mentioned matters are the theoretical background why the method of the present invention can improve the film formation rate compared to the conventional ozone-TEO3 normal pressure CVD method using only a thermal decomposition reaction.

Next, the reason why the film quality of the silicon oxide film is improved by the present invention will be described.

TEOS is produced by the following formula (12) due to the action of oxygen atoms derived from ozone.
), but irradiation of ultraviolet rays on the silicon oxide film growth surface or near the growth surface accelerates the decomposition of ozone in the gas phase or on the substrate surface.
The disassembly of the OS will proceed to the final point. Therefore, a silicon oxide film with very high purity and excellent film quality can be obtained.

S i (OC28s) 4→Si (OC2Ha
)3→Si (OC2H8)2→5iOC2H.

→Sin, (12) On the other hand, when the series of reactions does not proceed to the final point, the formula (12
), 5i(OC2H5), S l
Carbon-containing hydrogen intermediates such as (OC2H5)SiOC2H are incorporated into the silicon oxide film. the result,
The concentration of residual carbon and residual hydrogen in the silicon oxide film increases, causing a decline in film quality.

Next, the method of the present invention will be specifically explained.

The substrate used in the present invention is a material used as a semiconductor material such as polycrystalline silicon or single crystal silicon.

The container used in the present invention is equipped with a heating device, an ultraviolet irradiation device, an ozone generator, an organic silane compound vaporization device, and the like.

The heating device may be a known heater or the like;
It must be able to be heated to a temperature (approximately 100 to 600° C.) suitable for forming a silicon oxide film.

The ultraviolet irradiation device may be any device as long as it has a light source that can efficiently decompose ozone. An example of such a light source is a low-pressure mercury lamp. Alternatively, KrF248 nm excimer laser light or triple harmonic light of Ar ion laser may be used. These emit light with a wavelength near the peak of the ozone absorption spectrum shown in the ¥S1 diagram.

Rather than directly causing the decomposition of ozone, a light source may be used that decomposes an oxygen molecule into two oxygen atoms and reacts the oxygen atoms with the oxygen molecules to produce ozone. Examples of such a light source include Ar1 light (193 nm) of an excimer laser or a low-pressure mercury lamp of 184.9 nm.

The ozone generator may be of any known type, but it is preferable that the principle of ozone generation is based on silent discharge.In order to generate high concentration ozone, it is particularly important to use an ozone generator for semiconductor manufacturing in which the discharge part is covered with high-purity ceramics. Preferably a container.

The organic silane compound vaporization device may also be a known device.

In the present invention, the substrate is housed in the container, a gaseous organic silane compound and ozone are supplied into the container, and ultraviolet rays are irradiated while heating the substrate.

The organic silane compound is not particularly limited, but one having an alkoxyl group is preferable. Examples of such organic silane compounds include TEOS (tetraethoxysilane), tetramethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. The organosilane compound is supplied into the container in gaseous form, but usually He
, A r % N 2 or the like. The flow rate at that time is 0.1 to IOS
LM grade is preferable.

In addition, trimethylborate (B(OCHs) is a doping gas for reflow glass PSG and BPSG.
Organic boron such as s), trimethyl phosphate (P
O(CHs)s), trimethylphosphite (p
An organic phosphorus compound such as (oc Hs) slihJ may be added to the organic silane compound. In such a case, the amount added is preferably about 2 to 10%. These compounds are also attacked by oxygen atoms generated by the photodecomposition reaction of ozone, and their decomposition is accelerated.

Ozone is usually supplied as a mixed gas with oxygen, and the ozone concentration is preferably about 0.5 to 7%. Further, the flow rate is preferably about 0.5 to IO5LM.

The heating conditions for the substrate are limited by the type of metal used for the wiring layer. For example, when the wiring layer is made of aluminum, the temperature is about 350 to 450°C, and when it is made of poly-51, a higher temperature is possible, and about 350 to 600°C is preferable.

The ultraviolet rays may be irradiated from outside the reactor through a synthetic quartz window plate, or a light source may be placed inside the reactor.

Note that in the present invention, the pressure inside the container is not limited, but is usually 1 atm.

When a silicon oxide film is formed on the substrate under the above conditions,
For the reason explained above in the case where the organic silane compound is TEOS, a silicon oxide film with excellent film quality can be obtained in a short time.

For example, a silicon oxide film with a thickness of about 1 μm is formed in about 1 minute at a heating temperature of about 350° C., and about 2 minutes at a heating temperature of 450° C.

The film quality of the silicon oxide film formed according to the present invention is excellent, or even better film quality may be required depending on the application.

In such cases, annealing is recommended.

Specifically, after forming a silicon oxide film on a substrate using the method and conditions described above, only the supply of the organic silane compound into the container is stopped, and other operations are continued to anneal the silicon oxide film. It is. Alternatively, the substrate that has been taken out of the container after the formation of the silicon oxide film is completed is placed back into the container, and the same operation as in the case of forming the silicon oxide film is performed except that the organic silane compound is not supplied. The oxide film is annealed.

As a result, photodecomposition of ozone progresses, and the generated oxygen atoms react with carbon, hydrogen, etc. remaining in the film and become gas phase components, reducing their residual concentration in the film.
The residual stress and dielectric strength of the silicon oxide film are further improved.

<Example> EXAMPLES The present invention will be specifically explained below with reference to Examples.

(Example 1) Ozone and TE01 can be introduced into the vicinity of the substrate independently, and the temperature is variable. A container was prepared in which a low-pressure mercury lamp in the form of was installed.

Inside this container is a Si with a test pattern of aluminum wiring.
A substrate is stored, and ozone and EO are placed in the container under the following conditions.
5 was introduced, the substrate was heated to 350°C, and a low-pressure mercury lamp was turned on to irradiate it with ultraviolet rays to form a film with a film thickness of 1.
A 5 μm silicon oxide film was formed.

TEO3 vaporizer temperature = 65℃ TEOS carrier gas flow rate: 120sec 02 (including ozone) flow rate near, 5SLM ozone concentration・
The deposition rate of silicon dioxide during film formation at 3.5% was measured. Further, the formed silicon oxide film was tested and evaluated using the following method.

The results are shown in Table 2.

■Dielectric strength voltage: An AJZ electrode was formed on the back surface of the Si oxide film and the St substrate in an area of 1 mm2 by sputtering, a voltage was applied, and the accompanying change in current was measured. The dielectric strength voltage was calculated from the voltage and film thickness at the point where the current significantly increased.

(2) Aspect ratio: Determined from a SEM photograph of a cross section after forming a test pattern on a Si base.

■Step coverage: After the coating was performed, the substrate was cut, an SEM image of the cross section was taken, and the film thickness on the side wall portion was divided by the film thickness on the flat portion, and the ratio was determined as the step coverage. A ratio of about 1.0 was marked as ◎, a ratio of 0.8 to about 1.0 was marked as ○, and a ratio of less than O or a was marked as △.

(2) The warpage of the residual silicon substrate was measured and calculated from this.

(2) Residual carbon and hydrogen were measured by SIMS.

(Example 2) A silicon oxide film having a thickness of 1.5 μm was formed under the same conditions as in Example 1. Next, the introduction of TE01 into the container was stopped, the substrate heating temperature was set to 450° C., and annealing was performed for 30 minutes under the same conditions as those used for forming the silicon oxide film.

Regarding this, the same tests and evaluations as in Example 1 were conducted.

The results are shown in Table 2.

(Comparative Example 1) Using a container for normal pressure CVD method, SiH
A silicon oxide film with a thickness of 1.5 μm was formed using No. 4 and oxygen as raw materials.

N2 dilution S i H4 gas (0.1%) flow rate/100s
100 5c flow rate: 101000se Pressure = 1 atm Substrate temperature: 450°C Regarding this, the same tests and evaluations as in Example 1 were performed.

The results are shown in Table 2.

(Comparative Example 2) Using a container for plasma method, Si
A silicon oxide film with a thickness of 1.5 μm was formed using H and N20 as raw materials.

N2 diluted SiH4 gas (0.1%) flow rate: 500sec
m N20 flow rate: 101000sc Plasma power source: RF (13,56MHz), 00
W Pressure crab ITorr Substrate temperature: 380°C Regarding this, the same tests and evaluations as in Example 1 were conducted.

The results are shown in Table 2.

(Comparative Example 3) Using a container for plasma method, TEOS was
A silicon oxide film with a thickness of 1.5 μm was formed using this as a raw material.

TEO3 vaporizer vaporizer temperature above 65°C S Bubbling N2 dose 2 Flow rate 0 sec ○2 flow rate: 500 sec Total pressure ITorr TEO3 partial pressure: 0.38 Torr Plasma power source: RF (13,56MHz), 25
0 W Substrate temperature: 400°C Regarding this, the same tests and evaluations as in Example 1 were performed.

The results are shown in Table 2.

(Comparative Example 4) Using a container for low pressure thermal CVD method, TE was carried out under the following conditions.
A silicon oxide film with a thickness of 1.5 μm was formed using OS as a raw material.

TEOS vaporizer temperature near 0°C TEOSEOS bubbling flow i-: 400sec O2 flow rate: 400sccm Total pressure 0.6 Torr TEO3 partial pressure: 0.3 Torr Substrate temperature = 740°C Regarding this, the same tests and evaluation as in Example I were conducted. Ta.

The results are shown in Table 2.

(Comparative Example 5) The same container as in Example 1 was used. Set the substrate heating temperature to 38
Example 1 except that the temperature was 0°C and the low pressure mercury lamp was not turned on.
A silicon oxide film with a thickness of 1.5 μm was formed under the same conditions as described above.

Regarding this, the same tests and evaluations as in Example 1 were conducted.

The results are shown in Table 2.

The results shown in Table 2 revealed the following matters.

First, a comparison of raw materials is made with SiHd-based oxide film (
Compared to Comparative Example 1.2), the oxide film using TEOS (
In Comparative Example 3.4.5), despite the large aspect ratio, no overhang shape was observed and the step coverage was good. Also, T.E.O.
The dielectric strength voltage and film formation speed when using S are as follows: SiH4
The result was comparable to that obtained using the system oxide film formation method. However, when TEOS was used, the residual stress in the oxide film was quite large, and it was thought that cranking would occur if the film was formed thickly.

In Example 1, the raw material is TEOS, but ozone-TEO
Since the three reactions were carried out using both heat and ultraviolet light, silicon dioxide was deposited with good sticker coverage even with an aspect ratio of 1.2, and the deposition rate was about three times that of the conventional method (comparative example). In addition, in the silicon oxide film of Example 1,
No residual carbon or hydrogen was observed, suggesting that the decomposition of TEOS proceeded efficiently to the final point. Furthermore, the dielectric strength was 8 MV/cm, reaching the level of a thermal oxide film, and the residual stress, which is important for preventing cracks, was also low. When a silicon oxide film with a thickness of 2 μm was formed using the same method,
No cranking was observed (data omitted).

Regarding Example 1, the properties of the silicon oxide film were examined in more detail, and the silicon oxide film was subjected to post-processes (up to etching) during semiconductor device manufacturing, but no voids were observed, and wet etching was performed. As a result, it was confirmed that the film had uniform density.

In Example 2, after film formation was performed in the same manner as in Example 1, annealing was performed. Note that the characteristics of the silicon oxide film before annealing were similar to those of the silicon oxide film obtained in Example 1 (data omitted).

As shown in Table 2, compared to Example 1, the residual stress and dielectric strength of the silicon oxide film were further improved.

As described above, the film formation rate of the method of the present invention is significantly higher than that of the conventional silicon oxide film formation method.

Furthermore, the quality of the silicon oxide film formed is also superior to that obtained by conventional methods.

Since the oxide film has excellent film quality in terms of dielectric strength, residual stress, etc., the yield when forming a silicon oxide film during the semiconductor device manufacturing process is greatly improved.

[Brief explanation of drawings]

FIG. 1 is an absorption spectrum of ozone. <Effects of the Invention> The present invention provides a method for forming a silicon oxide film that provides a silicon oxide film with a high film formation rate and excellent film quality. Since the present invention is a method that enables the formation of a silicon oxide film at a lower temperature, it can also be applied to the case where a metal with a low melting point is used for the wiring layer of a semiconductor device. Furthermore, since the film forming rate of the present invention is high, a practical manufacturing time can be secured even when applied to a pattern pattern device.

Claims (4)

[Claims] (1) When supplying an organic silane compound and ozone into a container containing a substrate to form a silicon oxide film on the substrate, the substrate is heated and the substrate is irradiated with ultraviolet rays. Method of forming silicon oxide film. (2) The method for forming a silicon oxide film according to claim 1, wherein the organic silane compound is an organic silane compound having an alkoxyl group. (3) Forming a silicon oxide film on a substrate by the method according to claim 1 or 2, then stopping the supply of the organic silane compound into the container, and heating the substrate while supplying ozone. A method for forming a silicon oxide film, comprising irradiating the substrate with ultraviolet rays to anneal the silicon oxide film. (4) Forming a silicon oxide film on a substrate by the method according to claim 1 or 2, once taking out the substrate from the container, storing the substrate in the container again, and supplying ozone into the container. A method for forming a silicon oxide film, which comprises heating the substrate and irradiating the substrate with ultraviolet rays to anneal the silicon oxide film.