JPH10340901A - Semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent losses due to moisture-caused corrosion of metal wiring by controlling the formation of a reflow SiON film on a semiconductor substrate while causing a mixture of NH4 OH and H2 O2 to react with SiH4 gas under a predetermined degree of vacuum within a predetermined temperature range in a vacuum chamber where the semiconductor substrate is placed. SOLUTION: An H2 O2 -and-NH4 OH-mixed solution contained in a raw material tank 306 is caused to react with SiH4 gas under a degree of vacuum smaller than about 1000 Pa, or more preferably under 665 Pa at a temperature ranging from -10 deg.C to +10 deg.C to form a reflow SiON film having a reflow shape on a semiconductor substrate 311 contained in a vacuum chamber 301. Reacting conditions such as the degree of vacuum and the temperature range within the chamber 301 are controlled by a control means 312. Losses and the like due to the corrosion of metal wiring caused by moisture within the reflow SiON film can be prevented, so that an interlayer insulating film having excellent planarization can be formed inexpensively without involving a planarization step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus, and more particularly, to a semiconductor manufacturing apparatus for forming an interlayer insulating film by a CVD method.

[0002]

2. Description of the Related Art The prior art of the present invention will be described with reference to FIGS.

FIG. 1 shows a conventional CVD apparatus for forming an insulating film on a semiconductor substrate. In FIG. 1, a semiconductor substrate 1
A vacuum chamber 101 accommodating the vacuum chamber 11, an exhaust line 105 for exhausting a reaction gas, a lower electrode 102 provided in the vacuum chamber 101, and an upper electrode 103 provided opposite the lower electrode 102. , RF power supply 1 for applying RF electromagnetic waves
And _04, a raw material tank 106 accommodating the H 2 _{O 2} solution, from a raw material tank 106 and a pump 107 for sucking the _H 2 _{O 2} solution, and vaporizer 107 for spraying the _H 2 _{O 2} solution sucked up, spray The converted H ₂ O ₂ into the vacuum chamber 1
01, gas pipe 109, SiH ₄ gas, N ₂
A gas pipe 110 for guiding the O gas and the N ₂ gas to the vacuum chamber 101;

In a CVD apparatus for forming an insulating film on a semiconductor substrate, as shown in FIG. 2, a first insulating film 202 is formed on a metal wiring 201, and the metal wiring 201 and the first insulating film are formed. The reflow SiON film 20 is formed on the first insulating film 202 in order to eliminate the step formed at 202.
3 is formed, and a second insulating film 204 is formed on the reflow SiON film 203 with a substantially uniform thickness without being affected by a step of a lower layer.

Conventionally, a SiH ₄ gas and H ₂ O ₂ are introduced into a vacuum chamber 101 containing a semiconductor substrate 111 and the
H ₄ gas and H ₂ O ₂ have been reacted with each other in a predetermined temperature range within a predetermined vacuum to form a reflow SiO ₂ film having a reflow shape on a semiconductor substrate.

[0006] Here, the term "reflow" refers to an attempt to self-flatten, and the term "reflow shape" refers to a shape formed by a reflow action. The reflow SiO ₂ film functions to eliminate steps formed in the lower layer as much as possible and to form the second insulating film 204 formed on the reflow SiO ₂ film with a constant film thickness.

[0007]

Problems of the prior art will be described with reference to FIGS. 1 and 2. FIG.

When the reflow SiO ₂ film 203 is formed by the reaction between SiH ₄ and H ₂ O ₂ as in the prior art, H ₂ O is generated as a by-product of the reaction. Therefore, the reflow SiO ₂ film 203 has a large amount of moisture in the film. Therefore, as shown in FIG. 2, the metal wiring 201 and the reflow SiO ₂
A first insulating film 202 having a high ability to prevent downward diffusion is provided between the films 203. In this case, considering the embedding property between the metal wirings 201, the first insulating film 202 is formed of 1
It is necessary to control the thickness to be equal to or less than 00 nm. here,
The embedding property between the metal wirings 201 means that the distance between the wirings of the metal wiring 201 is narrowed by being sandwiched from both sides by the thickness of the first insulating film 202. This relates to the problem that the reflow SiO ₂ film 203 is not stably fixed between the metal wirings 201 when the valley becomes shallow.

Since it is necessary to reduce the thickness of the first insulating film 202, the first insulating film 202 becomes thinner particularly on the side surfaces of the metal wiring 201, thereby deteriorating the film quality, and also has the ability to prevent the downward diffusion of moisture. descend. Therefore, the metal wiring 201 made of aluminum or the like may be corroded and, in the worst case, disappear. Further, the reduction in the ability of the first insulating film 202 to prevent the downward diffusion of moisture also affects the quality of the device, and causes a problem that the yield of the device is reduced and the reliability is also reduced.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to solve the problem of the conventional reflow SiO ₂ film 203.
The reflow SiO ₂ film obtained when a mixed solution of H ₂ O ₂ and NH ₄ OH is used to reduce the water content in the film. An object of the present invention is to provide a semiconductor manufacturing apparatus capable of realizing an interlayer insulating film having excellent flatness at a low cost without performing a flattening step, based on the knowledge of the present inventor that the present invention can be performed.

[0011]

To achieve the above object, according to the Invention The semiconductor manufacturing apparatus of the present invention includes a vacuum chamber in which the semiconductor substrate is mounted, SiH ₄ for supplying the SiH ₄ gas into the vacuum chamber Gas supply means, and a mixture supply means for supplying a mixture of NH ₄ OH and H ₂ O ₂ into the vacuum chamber;
The mixture and the SiH ₄ gas are reacted at a predetermined degree of vacuum at a predetermined temperature range to form a reflow Si0 having a reflow shape.
Control means for controlling an N film to be formed on the semiconductor substrate.

Preferably, the mixture is supplied to the vacuum chamber in the form of a liquid in the form of a spray. The predetermined degree of vacuum is:
It is preferably at most 1,000 Pa, more preferably at most 665 Pa.

The predetermined temperature range is -10 ° C. or more and + 10 ° C.
It is preferable that the temperature range is not higher than ° C.

In the present invention described above, H ₂ O ₂ and NH ₄
By reacting a mixture of OH with SiH ₄ ,
Since Si—N and Si—H increase, the ratio of Si—OH decreases. For this reason, the OH groups serving as water in the reflow SiON film are reduced, and the water content is reduced. Reflow SiO
Due to the decrease in the amount of moisture in the N film, the amount of downward diffusion into the metal wiring also decreases.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 3 is a diagram showing a C according to the semiconductor manufacturing apparatus of the present invention.
It is a schematic structure figure showing one embodiment of a VD device. FIG.
, A vacuum chamber 301 for accommodating a semiconductor substrate 311 to be processed, an exhaust line 305 formed below the vacuum chamber 301 for exhausting a reaction gas, and a semiconductor substrate 311 disposed in the vacuum chamber 301 are mounted. A lower electrode (heater plate) 302, an upper electrode (shower head) 303 disposed opposite to the lower electrode 302, and an RF power source for applying an RF electromagnetic wave between the lower electrode 302 and the upper electrode 303. 304, a raw material tank 306 containing a mixed liquid of H ₂ O ₂ and NH ₄ OH,
A pump 307 for sucking a mixed solution of ₂ O ₂ and NH ₄ OH, and H ₂ O ₂ and N sucked by the pump 307
Vaporizer 3 to which a mixed solution of H ₄ OH is supplied and atomized
08, a gas pipe 309 for guiding a mixture of H ₂ O ₂ and NH ₄ OH atomized into liquid particles by a vaporizer 308 to a vacuum chamber 301, and a SiH ₄ gas, a N ₂ O gas and a N ₂ gas. A gas pipe 310 for guiding to the vacuum chamber 301;
A control means 312 for reacting a mixture of H ₂ O ₂ and NH ₄ OH with a SiH ₄ gas or the like at a predetermined degree of vacuum in a predetermined temperature range to control a reaction condition so as to form a reflow SiON film on the semiconductor substrate 311; It has.

As described above, the mixed liquid of H ₂ O ₂ and NH ₄ OH is guided to the vacuum chamber 301 in a state of being atomized into liquid particles by the vaporizer 308. H ₂ O ₂ and NH
_The reason why the mixture of ₄ OH is sent to the vacuum chamber 301 in the form of a spray is that the mixture of H ₂ O ₂ and NH ₄ OH retains the properties of a liquid so that the mixture of H ₂ O ₂ and NH ₄ OH can be mixed. This is because the reaction between the gas and the gas such as the SiH ₄ gas is reliably performed, and the reflow film is easily formed uniformly on the semiconductor substrate 311.

The conventional apparatus shown in FIG. 1 is different from the conventional apparatus shown in FIG. 1 in that a raw material tank 3 containing a mixed solution of H ₂ O ₂ and NH ₄ OH is used.
06 is different.

A mixture of H ₂ O ₂ and NH ₄ OH is converted to SiH ₄
A gas and the like are reacted with each other at a predetermined degree of vacuum and a predetermined temperature, and a reflow SiON film 403 having a reflow shape is formed on the semiconductor substrate housed in the vacuum chamber 301 as shown in FIG.

The reaction conditions such as the degree of vacuum and the temperature range in the vacuum chamber 301 are controlled by the control means 312. Also, R
The application condition of the F electromagnetic wave can also be controlled by the control unit 312.

Here, the predetermined degree of vacuum is about 1000 P
a, and more preferably 665 Pa or less. When the degree of vacuum in the vacuum chamber 301 is higher than about 1000 Pa, the reaction rate between the mixture of H ₂ O ₂ and NH ₄ OH and the SiH ₄ gas or the like becomes slow, and the reflow SiON film 4
03 hardly reflows on the semiconductor substrate 311. Further, by setting the predetermined degree of vacuum to a degree of vacuum of 665 Pa or less, the reflow Si
The ON film 403 is more easily reflowed on the semiconductor substrate 311.

The predetermined temperature is -10 ° C. or higher and + 10 ° C.
The temperature is within a temperature range of not more than 0 ° C, for example, 0 ° C. In such a temperature range, the reflow SiON film 403
Are efficiently formed.

In FIG. 4, a first insulating film 402 having a thickness of about 100 nm or less is formed on a metal wiring 401, and then a reflow SiON film 403 is formed on the first insulating film 402. A second insulating film 404 is formed on the reflow SiON film 403. First insulating film 40
2 is thinned to a thickness of about 100 nm or less because the distance between the metal wirings 401 is narrowed by being sandwiched by the first insulating film 402 from both sides by the thickness of the first wiring.
This is to prevent the embedding property of the O ₂ film 403 from being lowered. Note that since the thickness of the first insulating film 402 is small, the first insulating film 402 which prevents moisture from diffusing downward is used.
Tend to have a lower ability to prevent downward diffusion. However, as described later, the decrease in the ability of the first insulating film 402 to prevent the downward diffusion of moisture is compensated for by reducing the moisture in the reflow SiO ₂ .

By mixing NH ₄ OH with H ₂ O ₂ and reacting the mixture with SiH ₄ , Si—
Since N and Si-H increase, the ratio of Si-OH decreases. For this reason, it is considered that the OH groups serving as moisture in the reflow SiON film 403 decrease, and the moisture amount decreases.

In this way, when a mixture of H ₂ O ₂ and NH ₄ OH is formed and this mixture is reacted with SiH ₄ to form a reflow SiON film 403, a metal wiring made of aluminum metal is formed. It was confirmed that corrosion did not occur in 401 and the loss of the metal wiring 401 caused by the corrosion was prevented.

According to the above-described embodiment, the semiconductor substrate 3
For forming an insulating film having a reflow shape on silicon 11
In the apparatus, a mixture formed by mixing NH ₄ OH with H ₂ O ₂ and SiH ₄ gas are mixed in a predetermined vacuum, for example, at about 1000 Pa or less, more preferably 665 Pa
By forming a reflow SiON film 403 having a reflow shape by reacting with each other within a temperature range of −10 ° C. or more and + 10 ° C. or less at the following degree of vacuum, metal wiring due to moisture in the film, which is a problem in the prior art, It is possible to prevent disappearance due to corrosion of 401 and the like. That is, it is possible to solve the problem of a large amount of moisture in the conventional reflow SiO 2 film, and to realize an interlayer insulating film having excellent flatness at a low cost without performing a flattening step.

As a result, the following effects can be obtained. (1) The amount of downward diffusion of the reflow SiON film 403 into the metal wiring 401 also decreases due to a decrease in the amount of water in the film. For this reason, the thickness of the first insulating film 402 is reduced in order to secure the burying property of the reflow SiON film 403, and even if the ability of the first insulating film 402 to prevent the downward diffusion of moisture is reduced. In addition, loss due to corrosion of the metal wiring 401 can be prevented, the yield is improved, and the reliability of the wiring is also improved. (2) The film structure of the reflow SiON film 403 is SiON
Therefore, the blocking ability of heavy metal contaminants such as Na is improved as compared with the conventional SiO ₂ film, so that the reliability of the device is improved. (3) Since the water content in the film after the formation of the reflow SiON film 403 is reduced, the pre-bake time after the formation of the reflow SiON film 403 can be shortened, so that the productivity is improved.

[0028]

As described above, according to the structure of the present invention, a mixture of H ₂ O ₂ and NH ₄ OH reacts with SiH ₄ gas to form a reflow SiON having a reflow shape on a semiconductor substrate. Since the film is formed, loss due to corrosion of the metal wiring due to moisture in the film of the reflow SiON film can be prevented.

As a result, (1) the amount of downward diffusion into the metal wiring is also reduced due to the reduction in the amount of water in the film, so that the loss due to corrosion of the metal wiring can be prevented, the yield is improved, and the wiring reliability is improved. (2) Since the film structure is SiON, the blocking ability of heavy metal contaminants such as Na is improved as compared with the conventional SiO ₂ film, so that the reliability of the device can be improved. Since the amount of water in the film afterwards decreases, the pre-bake time after the formation of the reflow SiON film can be shortened, so that the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a conventional semiconductor manufacturing apparatus.

FIG. 2 is a sectional view of a semiconductor device manufactured by a conventional semiconductor manufacturing apparatus.

FIG. 3 is a cross-sectional view of the semiconductor manufacturing apparatus of the present invention.

FIG. 4 is a sectional view of a semiconductor device manufactured by the semiconductor manufacturing apparatus of the present invention.

[Explanation of symbols]

 301 vacuum chamber 302 lower electrode (heater plate) 303 upper electrode (shower head) 304 RF power supply 305 exhaust line 311 semiconductor substrate 306 material tank 307 pump 308 vaporizer 309 gas pipe 310 gas pipe 312 control means 401 metal wiring 402 first Insulating film 403 Reflow SiON film 404 Second insulating film

Claims (5)

[Claims] 1. A vacuum chamber in which a semiconductor substrate is mounted, a SiH ₄ gas supply means for supplying a SiH ₄ gas into the vacuum chamber, and a mixture of NH ₄ OH and H ₂ O ₂ is vacuum-evaporated. A mixture supply means for supplying the mixture into the room;
a semiconductor manufacturing apparatus comprising: control means for causing an iH ₄ gas to react with a predetermined degree of vacuum in a predetermined temperature range to control a reflow SiON film having a reflow shape on the semiconductor substrate. 2. The semiconductor manufacturing apparatus according to claim 1, wherein said mixture is supplied to said vacuum chamber in a sprayed liquid state. 3. The semiconductor manufacturing apparatus according to claim 1, wherein the predetermined degree of vacuum is 1000 Pa or less. 4. The semiconductor manufacturing apparatus according to claim 3, wherein the predetermined degree of vacuum is 665 Pa or less. 5. The predetermined temperature range is from -10 ° C. to + 10 ° C.
2. The semiconductor manufacturing apparatus according to claim 1, wherein the temperature is in a temperature range of not more than C.