JP2006040936A - Method and apparatus of depositing insulating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which can deposit an insulating film, without using a plasma or without heating a substrate to a high temperature and which can further accelerate the depositing speed. <P>SOLUTION: The method of depositing the insulating film includes a step of containing a substrate to be treated in a chamber, a step of setting the substrate to be treated to a treating temperature of 0-120°C and setting the inner wall surface for specifying the chamber to a temperature higher than the treatment temperature, and a step of simultaneously supplying a first gas containing a precursor like, BTESE: bis (triethoxysilyl) ethane, a second gas containing water, a third gas containing oxygen which contains ozone, and a fourth gas containing acidic or alkaline catalyst, making oxygen containing the precursor react, water and ozone under the coexistence of the catalyst and forming the insulating film on the substrate to be treated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to an insulating film forming method and an insulating film forming apparatus, and more particularly to formation of an insulating film that can be used not only in the field of manufacturing semiconductor devices and electronic equipment but also in other fields such as the field of manufacturing optical devices. The present invention relates to a film method and an insulating film forming apparatus.

Chemical vapor deposition (CVD) is widely used to deposit an insulator thin film in an integrated circuit (IC) manufacturing process. A typical example of the insulator thin film is SiO ₂ . This SiO ₂ film is usually deposited by a method of reacting SiH ₄ with O ₂ (thermal SiH ₄ method). However, this method has a drawback that it is necessary to increase the temperature (400 ° C. to 500 ° C.) during film formation, and the step coverage is inferior particularly when the aspect ratio exceeds 1.

In order to solve these drawbacks, various SiO ₂ film forming methods have been developed. In order to avoid the problem of step coverage, TEOS (tetraethylorthosilicate: Si (OC ₂ H ₅ ) ₄ ) is used instead of SiH ₄ . This method using TEOS is called a thermal TEOS method and shows good step coverage, but it needs to be at a higher temperature (for example, 700 ° C.) than a thermal CVD method using SiH ₄ as a Si source.

In order to improve the reactivity of TEOS, it has been proposed to use ozone with oxygen. Ozone has a higher reactivity than O ₂ and film formation is achieved at a relatively low temperature (350 ° C. to 500 ° C.). However, film formation by this method is accompanied by stress and exhibits moisture absorption.

As another method for achieving film formation using TEOS at a lower temperature, a method using plasma called PECVD (plasma chemical vapor developing) is known. The film formation temperature by PECVD is 300 ° C. to 350 ° C. This method has better step coverage than the thermal SiH ₄ method, but is inferior to the thermal TEOS method, and additionally damages the plasma-generated film.

As another method using PECVD, a method of forming a film by reacting SiH ₄ and N ₂ O in plasma is known. This film formation method can achieve film formation at a low temperature of 200 ° C. to 400 ° C., although the step coverage is inferior to that of thermal SiH ₄ . However, this PECVD has the problem of damaging the film generated by plasma in the same manner as described above, in addition to the contamination of impurities by low molecular weight substances derived from the film.

Patent Document 1 discloses a CVD method for forming a SiO ₂ film on a substrate from TEOS, acetic acid and water under atmospheric pressure and low pressure. In this CVD method, the substrate is heated to, for example, 250 ° C. to 350 ° C. during film formation.

  Patent Document 2 discloses a thermal CVD method for forming a silicon oxide film from ozone, water vapor, and one of alkoxysilane and organosiloxane using a small amount of acid or alkali at atmospheric pressure. In this method, the substrate is heated to, for example, 400 ° C. during film formation.

  Patent Document 3 discloses a thermal CVD method for producing a thin layer made of ozone and an organosilane precursor, which is performed at 50 Torr to 450 Torr and 100 ° C. to 250 ° C.

In Patent Document 4, alkoxysilane (SiR ₄ , R is an alkoxy group or an alkylalkoxy group; for example, Si (O (CH ₂ ) ₂ O (CH ₂ ) ₂ OCH ₃ ) ₄ ) is cooled to 5 ° C. to 10 ° C. A method for condensing into a semiconductor substrate is disclosed. The condensed alkoxysilane is then exposed to steam under either steam or acid or base as a post-treatment to produce an alkoxysilane composition, and further undergoes post-treatment at 170 ° C. and heat treatment at 320 ° C., for example. The formation of the insulator film is completed. This patent document 4 also discloses a highly porous and low dielectric constant film.

  Patent Document 5 discloses a method in which a peroxide is first condensed on a substrate and then reacted with an organosilicon compound to deposit a low dielectric film. In this way, at least a porous silicon film is obtained after annealing at 400 ° C.

In Patent Document 6, from an alkyldisiloxane compound (HR ₁ R ₂ —O—SiR ₃ R ₄ R ₅ [R ₁ to R ₅ are hydrogen, methyl or ethyl]) and ozone at a temperature of 300 ° C. to 650 ° C. A thermal CVD method for forming a film is disclosed.
US Pat. No. 5,360,646 US Pat. No. 5,840,631 US Pat. No. 6,602,806 US Pat. No. 6,022,812 US Pat. No. 6,171,945 JP 2004-31482 A

  In the conventional techniques as described above, in order to form an insulator thin film, it is necessary to at least heat the substrate or use plasma during the film formation. However, film formation at a high temperature adds process restrictions in the production of semiconductor devices, for example, and restrictions in substrate materials in the production of liquid crystal display devices. Moreover, the film formation by plasma damages the formed film.

  The present invention provides a method and an apparatus that can form an insulator film without using plasma and without heating the substrate to a high temperature, and can further increase the film formation rate. .

  According to the present invention, the step of storing the substrate to be processed in the chamber, the substrate to be processed is set to a processing temperature of 0 to 120 ° C., and the inner wall surface defining the chamber is set to a temperature higher than the processing temperature. A first gas containing a precursor selected from the following general formulas (1) to (3) in the chamber, a second gas containing water, a third gas made of oxygen containing ozone, and an acidity Or simultaneously supplying a fourth gas containing an alkaline catalyst and reacting the precursor with oxygen containing water and ozone in the presence of the catalyst to form an insulating film on the substrate to be processed. A method for forming an insulating film is provided.

R ¹ _a (R ² O) _3-a SiR ³ _b Si (OR ⁴ ) _3-c R ⁵ _c (1)
Si (OR ⁶ ) ₄ (2)
R ⁷ _d Si (OR ⁸ ) _4-d (3)
However, each of R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ^{8 in} the formula represents an alkyl group, an allyl group, an acyl group, an acyloxy group and an alkenyl group, and R ³ represents an oxygen atom. , A phenylene group or C _n H _2n (where n is an integer of 1 to 5), a and c represent an integer of 0 to 2, b represents an integer of 0 or 1, and d represents Represents an integer of 1 or 2.

  According to the invention, the step of storing the substrate to be processed in the chamber, the substrate to be processed is set to a processing temperature of 0 to 120 ° C., while the inner wall surface defining the chamber is set to a temperature higher than the processing temperature. A step of setting, a first gas containing a precursor selected from the following general formulas (4) to (6) in the chamber, a second gas containing water, and a third gas made of oxygen containing ozone simultaneously. Supplying and reacting the precursor or oxygen containing water and ozone under the catalytic action of the precursor or the precursor and a catalyst component derived from water to form an insulating film on the substrate to be processed. An insulating film formation method is provided.

^{_{R 11 e (R 12 O)}} 3-e SiR 13 f Si (OR 14) 3-g R 15 g ... (4)
Si (OR ¹⁶ ) ₄ (5)
R ¹⁷ _h Si (OR ¹⁸ ) _4-h (6)
In the formula, R ¹¹ , R ¹² , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ each represents an acyl group and an acyloxy group, and R ¹³ represents an oxygen atom, a phenylene group, or C _m H _2m ( m represents an integer of 1 to 5, e and g represent an integer of 0 to 2, f represents an integer of 0 or 1, and h represents an integer of 1 or 2.

  Furthermore, according to the present invention, a chamber having temperature adjusting means for storing the substrate to be processed and setting the inner wall surface to a temperature higher than the processing temperature of the substrate to be processed, and the following general formulas (1) to (3) From a first supply means for supplying a first gas containing a precursor selected from the above, a second supply means for supplying a second gas containing water in the chamber, and oxygen containing ozone in the chamber An insulating film comprising: a third supply means for supplying a third gas, and a fourth supply means for supplying a fourth gas containing an acidic or alkaline catalyst in the chamber. A film forming apparatus is provided.

R ¹ _a (R ² O) _3-a SiR ³ _b Si (OR ⁴ ) _3-c R ⁵ _c (1)
Si (OR ⁶ ) ₄ (2)
R ⁷ _d Si (OR ⁸ ) _4-d (3)
However, each of R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ^{8 in} the formula represents an alkyl group, an allyl group, an acyl group, an acyloxy group and an alkenyl group, and R ³ represents an oxygen atom. , A phenylene group or C _n H _2n (where n is an integer of 1 to 5), a and c represent an integer of 0 to 2, b represents an integer of 0 or 1, and d represents Represents an integer of 1 or 2.

  According to the present invention, it is possible to provide a method for forming an insulating film under mild conditions in which plasma is not used at a relatively low temperature (0 ° C. to 120 ° C.).

  The present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic view showing a single-wafer type film forming apparatus used in the insulating film forming method according to the first embodiment of the present invention. The film forming container 1 includes an airtight chamber 2 that defines a processing space for storing and processing a substrate to be processed (semiconductor wafer W). The film forming container 1 is made of, for example, stainless steel or aluminum whose surface is anodized. A placement table (support member) 3 for placing the wafer W is disposed in the chamber 2. In the mounting table 3, a temperature controller 4 that combines a heater and a cooler is built in to bring the wafer W to a predetermined temperature. A temperature controller 5 that combines a heater and a cooler is installed around the inner periphery of the film forming container 1 in order to set a wall surface defining the chamber 2 to a predetermined temperature. An exhaust line 6 is connected to the lower part of the film formation container 1. The exhaust line 6 exhausts the gas in the chamber pressure control valve CCV and the chamber 2 from the film formation container 1 side to reduce the pressure and maintain a low pressure. The exhaust pump 7 and the abatement apparatus 8 are interposed in this order. This abatement device 8 is connected to the exhaust system of the factory. A shower head 9 for supplying a processing gas to the upper space of the mounting table 3 is disposed in the upper part of the chamber 2.

  The shower head 9 of the film forming container 1 includes a first source 10 of a first gas containing a precursor, a second source 11 of a second gas containing water, and a third source 12 of a third gas made of oxygen containing ozone. , And a fourth source 13 of a fourth gas containing a catalyst, respectively.

The first source 10 of the first gas has a container 15 in which a precursor 14 in a liquid state is accommodated. The container 15 is provided with a heater 16 for heating the entire container 15 to a predetermined temperature so as to cover the outer periphery including the lower part thereof to a height exceeding the liquid level of the precursor 14. One end (supply end) of the N ₂ line 17 for supplying an inert gas, for example, nitrogen (N ₂ ) is immersed in the liquid precursor 14 in the container 15. A mass flow controller MFC is interposed in the N ₂ line 17. One end of the first gas supply line 18 is positioned in the upper space of the precursor 14 in the container 15, and the other end is connected to the shower head 9. A back pressure control valve BCV is interposed in the first gas supply line 18. In the first source of the first gas having such a configuration, the precursor 14 in the container 15 is heated by the heater 16 and supplied from the N ₂ line 17 and bubbled with nitrogen whose flow rate is adjusted by the mass flow controller MFC. Is vaporized. The first gas containing the vaporized precursor 14 is supplied to the shower head 9 through the first gas supply line 18. The supply amount of the first gas is adjusted by a back pressure control valve BCV interposed in the MFC and the first gas supply line 18.

The second source 11 of the second gas has a container 19 in which liquid water 19 is accommodated. The container 20 is provided with a heater 21 for heating the entire container 20 to a predetermined temperature so as to cover the outer periphery including the lower part thereof to a height exceeding the water level of the water 19. One end of the N ₂ line 22 for supplying an inert gas, for example, nitrogen (N ₂ ), is immersed in the liquid water 19 in the container 20. A mass flow controller MFC is interposed in the N ₂ line 22. One end of the second gas supply line 23 is positioned in the upper space of the water 19 in the container 20, and the other end is connected to the shower head 9. In the second source 11 of the second gas having such a configuration, the water 19 in the container 20 is heated by the heater 21 and is bubbled with nitrogen supplied from the N ₂ line 22 and adjusted in flow rate by the mass flow controller MFC. To be vaporized. The second gas containing the vaporized water 19 is supplied to the shower head 9 through the second gas supply line 23. The supply amount of the second gas is adjusted by the back pressure control valve BCV interposed in the MFC and the second gas supply line 23.

  In the third source 12 of the third gas, an oxygen cylinder 24 is connected to the shower head 9 through a third gas supply line 25. In the third gas supply line 25, a pressure control valve PCV, a mass flow controller MFC, an ozonizer 26, a concentration detector 27, and a back pressure control valve BCV for keeping the pressure in the ozonizer 26 constant are arranged in this order from the oxygen cylinder 24 side. It is intervened in. The concentration detector 27 detects the ozone concentration in the third gas made of oxygen containing ozone that has flowed out of the ozonizer 26 to the third gas supply line. The controller 28 is connected to the ozonizer 26 and the concentration detector 27 through signal lines 29 and 30, respectively. The ozone concentration detection result by the concentration detector 27 is input to the controller 28 through the signal line 30, and based on this detection result, a control signal from the controller 28 is built in the ozonizer 26 through the signal line 29 (not shown). ) And the ozone generation amount by the ozonizer 26 is controlled to an appropriate value. When the oxygen cylinder 24 is opened in the third source of the third gas having such a configuration, the oxygen gas is supplied to the ozonizer 26 through the third gas supply line 25, and the mass flow controller MFC is passed through the line 25. To adjust the flow rate. In this ozonizer 26, ozone is generated and the ozone generation amount is controlled by the concentration detector 27 and the controller 28 described above, so that the third gas composed of oxygen containing ozone having an appropriate ozone concentration is discharged into the shower. It is supplied to the head 9.

  The fourth source 13 of the fourth gas has a catalytic gas cylinder 31 such as an acidic or alkaline catalyst gas, for example, an HCl gas cylinder. A fourth gas supply line 32 is connected to the catalyst gas cylinder 31, and the other end of the fourth gas supply line 32 is connected to the shower head 9. In the fourth gas supply line 32, a pressure control valve PCV and a mass flow controller MFC are interposed in this order from the cylinder 31 side. In the fourth source of the fourth gas having such a configuration, the flow rate of the fourth gas including the catalyst supplied from the catalyst gas cylinder 31 is controlled by the pressure control valve PCV and the mass flow controller MFC and supplied to the shower head 9.

  Next, a single wafer deposition method for an insulating film according to the first embodiment of the present invention will be described using the deposition apparatus shown in FIG.

  First, the semiconductor wafer W is carried into the chamber 2 of the film forming container 1 and placed on the mounting table 3 disposed in the chamber 2. Subsequently, after the chamber 2 is brought into an airtight state, the exhaust pump 6 is operated to set the chamber 2 to a desired pressure, and the pressure is maintained during the film forming process. Further, the wafer W is set to a desired processing temperature together with the mounting table 3 by the temperature controller 4 built in the mounting table 3, while the inner wall of the chamber 2 is moved by the temperature controller 5 disposed on the inner wall of the chamber 2. Set the temperature higher than the processing temperature.

  Thus, in the state which set the inner wall surface of the wafer W and the chamber 2 to the desired processing temperature and wall surface temperature, respectively, the first gas containing the precursor, the second gas containing water, and ozone by the above-described method. A third gas made of oxygen and a fourth gas containing a catalyst are simultaneously supplied to the shower head 9 in the chamber 2 through the supply lines 18, 23, 25, and 32. The shower head 9 discharges these gases through separate routes and mixes them in the chamber 2, so-called postmixing, whereby the precursors are produced under the oxidizing action of ozone in the third gas and the catalytic action in the fourth gas. An insulating film is deposited on the wafer W while reacting the body and water.

  Thus, after depositing an insulating film on the wafer W, you may perform the post-heating process for further hardening an insulating film as needed. The post heat treatment is performed by setting the wafer W to a temperature sufficiently higher than the vapor processing temperature by the temperature controller 4.

  In the method according to the first embodiment, a precursor selected from the substances represented by any one of the following three general formulas (1) to (3) is used.

R ¹ _a (R ² O) _3-a SiR ³ _b Si (OR ⁴ ) _3-c R ⁵ _c (1)
Si (OR ⁶ ) ₄ (2)
R ⁷ _d Si (OR ⁸ ) _4-d (3)
However, each of R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ^{8 in} the formula represents an alkyl group, an allyl group, an acyl group, an acyloxy group and an alkenyl group, and R ³ represents an oxygen atom. , A phenylene group or C _n H _2n (where n is an integer of 1 to 5), a and c represent an integer of 0 to 2, b represents an integer of 0 or 1, and d represents Represents an integer of 1 or 2. Particularly in the alkyl group, allyl group, acyl group, acyloxy group and alkenyl group represented by R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ in formulas (1) to (3), The number of carbon atoms is preferably 5 or less, more preferably 1 to 3 carbon atoms when aromatic (benzene ring) is not included. In the case of containing an aromatic (benzene ring), it is desirable to have 8 or less, more preferably 6 or 7 carbon atoms. Specifically, R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ are CH ₃ —, C ₂ H ₅ —, C ₃ H ₇ —, C ₆ H ₅ —, CH _{3. C 6 H 4 -, CH 3} CO-, C 2 H 5 CO-, C 3 H 7 CO-, CH 3 COO-, C 2 H 5 COO-, C 3 H 7 COO-, CH 2 = CH-, One of CH ₂ = CHCH _2- . In particular, R ² , R ⁴ , R ⁶ , R ⁸ are any of CH ₃ —, C ₂ H ₅ —, C ₆ H ₅ —, CH ₃ CO—, CH ₃ COO—, CH ₂ ═CH—. More preferably. R ¹ , R ⁵ , and R ⁷ are more preferably any of CH ₃ —, C ₂ H ₅ —, C ₆ H ₅ —, and CH ₂ = CH—. R _< ³ _{> in} Formula (1) is an oxygen atom, a phenylene group, or _CnH2n (n is an integer in any one of 1-5). However, the carbon number of R ³ is preferably 5 or less, more preferably any one of 1 to 3 carbon atoms, except for a phenylene group. In the case of a phenylene group, it is desirable that it has 8 or less carbon atoms, more preferably 6 or 7 carbon atoms. Specifically, R ³ is any one of an oxygen atom, —C ₆ H ₄ —, —C ₆ H ₃ (CH ₃ ) —, —CH ₂ —, —C ₂ H ₄ —, and —C ₃ H ₆ —. Preferably there is.

  The reaction on the wafer W when the precursors represented by the formulas (1) to (3) are used is as follows.

_{Si-OR + H 2 O →} Si-OH + R-OH ... (7)
Si—OH + HO—Si → Si—O—Si + H ₂ O (8)
Si-OH + RO-Si → Si-O-Si + ROH (9)
Here, R represents any of R ² , R ⁴ , R ⁶ , and R ⁸ . Ozone in the third gas has an oxidizing ability to extract R and hydrogen of Si—OR and Si—OH, and functions to promote the reactions (8) and (9).

  In particular, by using the precursor of the formula (1), it is possible to form an insulating film having a low dielectric constant due to an increase in the amount of carbon in the film derived from the structural formula.

  The first supply ratio that represents the amount of water supplied to the precursor and the second supply ratio that represents the total supply ratio of the precursor and water to the entire first and second gases also differ depending on the precursor. For example, the first supply ratio (water / precursor) is desirably set to 0.1 to 100, more preferably 10 to 100. The second supply ratio (precursor and water / total amount of the first and second gases) is desirably set to 0.001 to 0.5, more preferably 0.01 to 0.2. The supply amount of the precursor and water can be adjusted by controlling the heating temperature of the container, the internal pressure of the container, and the flow rate of nitrogen as the carrier gas.

  Note that a vaporizer or the like may be used when the bubbling method is not suitable for supplying the first gas and the second gas.

  The ozone contained in the third gas is desirably contained in oxygen at a concentration of 0.1 to 30% by volume, more preferably 1 to 10% by volume. The ozone concentration can be adjusted by controlling the amount of ozone generated by the ozonizer 26 by the concentration detector 27 and the control system 28 described above.

  The catalyst for promoting the above reaction is selected from the group consisting of hydrogen halide (eg, HCl), carboxylic acid, nitric acid, sulfuric acid, an acid typified by a simple halogen molecule, and an alkali typified by ammonia. Can be used. However, since an acidic substance such as HCl usually has a higher catalytic action, it is desirable to use an acidic substance as a catalyst. The catalyst is preferably a material that can be easily vaporized.

  In the method according to the first embodiment, the processing temperature (the temperature of the wafer W) varies depending on the precursors represented by the formulas (1) to (3) to be used. However, even in the use of all of the precursors, the processing temperature can be set to 0 ° C. to 120 ° C., more preferably 10 ° C. to 60 ° C., much lower than conventional CVD. In experiments to be described later, it was confirmed that the precursor and water can sufficiently react to form an insulating film by the oxidizing action of ozone in the third gas and the catalytic action in the fourth gas even at such a low temperature. .

  The wall surface temperature of the inner wall surface of the chamber 2 is set to be higher than the vaporization temperature of the precursor and higher than the processing temperature by, for example, 5 ° C. or more, preferably 30 ° C. or more. Thereby, it is possible to prevent the precursors from aggregating on the inner wall surface of the chamber 2 and to deposit the insulating film preferentially on the wafer W.

  The post heat treatment is preferably performed at a temperature of 150 ° C to 400 ° C.

  The pressure in the chamber 2 varies depending on the precursor to be used, but can be set relatively high because no plasma is used. The pressure in the chamber 2 is desirably set to, for example, 0.1 Torr to 760 Torr (atmospheric pressure), more preferably 10 Torr to 500 Torr.

(Second Embodiment)
In the method according to the second embodiment, a method similar to that of the first embodiment described above is used except that a precursor represented by any one of the following three general formulas (4) to (6) is used ( An insulating film is formed on a substrate to be processed such as a silicon wafer.

^{_{R 11 e (R 12 O)}} 3-e SiR 13 f Si (OR 14) 3-g R 15 g ... (4)
Si (OR ¹⁶ ) ₄ (5)
R ¹⁷ _h Si (OR ¹⁸ ) _4-h (6)
In the formula, R ¹¹ , R ¹² , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ each represents an acyl group and an acyloxy group, and R ¹³ represents an oxygen atom, a phenylene group, or C _m H _2m ( m represents an integer of 1 to 5, e and g represent an integer of 0 to 2, f represents an integer of 0 or 1, and h represents an integer of 1 or 2.

The general formulas (4) to (6) according to the second embodiment are expressed in the same manner as the general formulas (1) to (3) according to the first embodiment, respectively, but R ¹¹ , R ¹² , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ are different in that each is limited to an acyl group and an acyloxy group.

  In the method according to the second embodiment, a catalyst component derived from a precursor or a precursor and water is used instead of the catalyst in the fourth gas, that is, as shown in the general formulas (4) to (6). The catalyst component obtained from the acyl group or acyloxy group promotes the reaction between the precursor and water (autocatalysis).

In particular, in the formulas (4) to (6), R ¹¹ , R ¹² , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ are represented by acyl groups and acyloxy groups, and the number of carbon atoms is aromatic (benzene When it does not contain a ring), it is preferably 5 or less, more preferably 1 to 3 carbon atoms. In the case of containing an aromatic (benzene ring), it is desirable to have 8 or less, more preferably 6 or 7 carbon atoms. Specifically, R ¹¹ , R ¹² , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ are CH ₃ CO—, C ₂ H ₅ CO—, C ₃ H ₇ CO—, CH ₃ COO—, C ₂ H ₅ COO— or C ₃ H ₇ COO—. In particular, R ¹² , R ¹⁴ , R ¹⁶ , and R ¹⁸ are preferably CH ₃ CO— or C ₂ H ₅ CO—. R ¹¹ , R ¹⁵ and R ¹⁷ are preferably CH ₃ COO— or C ₂ H ₅ COO—. ^{R 13} in the formula (4) is an oxygen atom, a phenylene group or a _C m _{H 2m} (m is any of 1 to 5 integer). However, it is desirable that the carbon number of R ¹³ is 5 or less, more preferably any one of 1 to 3 carbon atoms other than the phenylene group. In the case of a phenylene group, it is desirable that it has 8 or less carbon atoms, more preferably 6 or 7 carbon atoms. Specifically, R ¹³ is any one of an oxygen atom, —C ₆ H ₄ —, —C ₆ H ₃ (CH ₃ ) —, —CH ₂ —, —C ₂ H ₄ —, and —C ₃ H ₆ —. It is preferable that

  Examples of the present invention will be described below.

Example 1
The following experiment was conducted using the film forming apparatus shown in FIG. As a precursor, BTESE (bis (triethoxysilyl) ethane: (C ₂ H ₅ O) ₃ Si—C ₂ H ₄ —Si (OC ₂ H ₅ ) belonging to the general formula (1) in the first embodiment of the present invention. ) ₃ ) was used. A 4-inch silicon wafer was used as the wafer W. A chamber 2 having a capacity of about 2 liters was used. The wafer was set to 25 ° C. as the processing temperature using the temperature controller 4. Further, the temperature of the inner wall of the chamber 2 is set to 106 ° C. by the temperature controller 5. BTESE is heated at 96 ° C. using the heater 16 in the container 15 and bubbled with 100 sccm of nitrogen, so that the vapor pressure of BTESE becomes 0. The first gas of 3 Torr was adjusted and the first gas was supplied. On the other hand, the water was heated to 50 ° C. using the heater 21 in the container 20 and bubbled with 100 sccm of nitrogen to adjust the second gas having a water vapor pressure of 92.6 Torr and to supply the second gas. . The third gas was adjusted to contain ozone at a concentration of 5% by volume in oxygen and supplied at 100 sccm. As the fourth gas, 10 sccm of hydrogen chloride (HCl) gas was supplied. Simultaneously with the supply of these gases, the pressure in the chamber 2 was maintained at 50 Torr by exhausting with the exhaust pump 7.

  Under such conditions, a treatment for 60 minutes was performed, and an insulating film was deposited on the wafer W.

  The deposited insulating film was heat-treated at 150 ° C. and 400 ° C. for 30 minutes in an inert gas atmosphere.

(Comparative Example 1)
An insulating film was deposited on the wafer W by performing the same treatment under the same conditions as in Example 1 except that 100 sccm of oxygen gas not containing ozone was supplied as the third gas.

The films deposited in Example 1 and Comparative Example 1 were uniform and had high adhesion to the wafer W. As a result of measurement using an optical spectrometer (Fourier Transform Infrared Absorption Spectroscopy (FTIR), Auger Electron Spectroscopy (AUGER), Spectroscopic Optical Thin Film Measuring Device), the deposited insulating film contains almost no impurities and is a precursor. It was found to be a low-density SiO ₂ film containing a CH ₂ group contained in the body in a network structure. The measured film thickness of the insulating film at this time is shown in the following table.

It was confirmed by capacitance measurement at 1 MHz that the deposited insulating film had a low dielectric constant due to the CH ₂ group introduced into the network structure. The dielectric constant values at this time are shown in Table 1 below.

Furthermore, about the insulating film after each heat processing, the elasticity modulus and hardness were calculated | required by the nanoindentation measurement. The results are shown in Table 1 below.

  As is apparent from Table 1, Example 1 and Comparative Example 1 show no change in the properties of the deposited insulating film with or without the addition of ozone as the third gas in the same processing time. Then, it turns out that it has a thick film thickness (about 680 nm) compared with the comparative example 1 (about 470 nm). That is, by adding ozone, the film formation rate can be increased in Example 1 as compared with Comparative Example 1.

(Example 2)
The following experiment was conducted using the film forming apparatus shown in FIG. As the precursor, TEOS (tetraethoxysilane: Si (OC ₂ H ₅ ) ₄ ) belonging to the general formula (2) in the first embodiment of the present invention was used. A 4-inch silicon wafer was used as the wafer W. A chamber 2 having a capacity of about 2 liters was used. The wafer was set to 13 ° C. as the processing temperature using the temperature controller 4. Further, the temperature of the inner wall of the chamber 2 is set to 85 ° C. by the temperature controller 5, TEOS is heated to 39 ° C. using the heater 16 in the container 15, and bubbled using 250 sccm of nitrogen, so that the vapor pressure of TEOS is 4. A first gas of 6 Torr was adjusted and the first gas was supplied. On the other hand, the water is heated to 60 ° C. using the heater 21 in the container 20, and the second gas having a water vapor pressure of 149.5 Torr is adjusted by bubbling using 195 sccm of nitrogen, and the second gas is supplied. did. The third gas was adjusted to contain ozone at a concentration of 5% by volume in oxygen and supplied at 100 sccm. As the fourth gas, 5 sccm of hydrogen chloride (HCl) gas was supplied. In addition, 290 sccm of nitrogen was also supplied into the chamber 2 (not shown). Simultaneously with the supply of these gases, the pressure in the chamber 2 was kept at 250 Torr by exhausting with the exhaust pump 7.

  Under such conditions, a treatment for 30 minutes was performed, and an insulating film was deposited on the wafer W.

(Comparative Example 2)
An insulating film was deposited on the wafer W under the same conditions as in Example 2 except that the third gas made of oxygen containing ozone was not supplied.

The films deposited in Example 2 and Comparative Example 2 were uniform and had high adhesion to the wafer W. As a result of measurement using an optical spectrometer, it was found that the deposited insulating film was a SiO ₂ film containing almost no impurities with no difference in film quality between them. When the thickness of the insulating film formed in the same processing time is measured, the insulating film formed in Example 2 has a thickness of about 650 nm, and the insulating film formed in Comparative Example 2 has a thickness of about 430 nm. Had.

  Therefore, although the film quality of the insulating film deposited in Example 2 and Comparative Example 2 did not change, it was found that the film formation rate was increased in Example 2 to which oxygen containing ozone was added compared to Comparative Example 2.

(Example 3)
The following experiment was conducted using the film forming apparatus shown in FIG. As the precursor, TAMS (triacetoxymethylsilane: CH ₃ —Si (OCOCH ₃ ) ₃ ) belonging to the general formula (3) in the first embodiment of the present invention was used. A 4-inch silicon wafer was used as the wafer W. A chamber 2 having a capacity of about 2 liters was used. The wafer was set to 42 ° C. as the processing temperature using the temperature controller 4. Further, the temperature of the inner wall of the chamber 2 was set to 120 ° C. by the temperature controller 5.

  The TAMS was heated to 87 ° C. using the heater 16 in the container 15 and bubbled using 120 sccm of nitrogen to adjust the first gas having a TAMS vapor pressure of 3 Torr, and the first gas was supplied. On the other hand, water was heated to 60 ° C. using the heater 21 in the container 20, and bubbling was performed using 355 sccm of nitrogen to adjust the second gas having a water vapor pressure of 149.5 Torr, and the second gas was supplied. The third gas was adjusted to contain ozone at a concentration of 5% by volume in oxygen and supplied at 100 sccm. Along with these, 200 sccm of nitrogen was also supplied into the chamber 2 (not shown). Simultaneously with the supply of these gases, the pressure in the chamber 2 was maintained at 15 Torr by exhausting using the exhaust pump 7. In this case, since TAMS has an autocatalytic action by acetic acid generated by reaction with water, hydrochloric acid (HCl) was not supplied.

  Under such conditions, a treatment for 15 minutes was performed, and an insulating film was deposited on the wafer W.

(Comparative Example 3)
An insulating film was deposited on the wafer W under the same conditions as in Example 3 except that the third gas composed of oxygen containing ozone was not supplied and the processing time was 20 minutes.

  The films deposited in Example 3 and Comparative Example 3 were uniform and had high adhesion to the wafer W. As a result of measurement using an optical spectrometer, it was found that the deposited insulating film was a low dielectric constant MSQ (methylsilsesquioxane) film with little difference in film quality and almost no impurities. When the film thickness of the formed insulating film is measured, the insulating film formed for 15 minutes in Example 3 has a film thickness of about 430 nm, and the insulating film formed in Comparative Example 3 for 20 minutes has a film thickness of about 400 nm. Had.

  Therefore, in Example 3 and Comparative Example 3, the film quality of the deposited insulating film was not changed, but it was found that Example 3 to which ozone was added increased the film formation rate compared to Comparative Example 3.

  As shown in Examples 1, 2, and 3, according to the present invention, it is not necessary to use plasma or heat the substrate to a high temperature, and the insulating film is formed at a temperature much lower than that of the conventional CVD method. Can be deposited. The resulting insulating film exhibits a very flat surface and good film quality.

  In addition, although only the oxygen (no ozone) as the third gas is supplied to the reaction system, the film forming speed is increased, but one of the features of the present invention is supplying oxygen containing ozone as the third gas to the reaction system. By doing so, as is clear from the comparison between Example 1 and Comparative Example 1, it has the effect of further promoting the deposition rate of the insulating film.

  Furthermore, using oxygen containing ozone as the third gas similarly has the effect of accelerating the deposition rate of the insulating film, as is apparent from the comparison between Examples 2 and 3 and Comparative Examples 2 and 3.

  Although FIG. 1 shows the case where the present invention is applied to a semiconductor device manufacturing process, the present invention can also be applied to other fields such as the field of optical device manufacturing. In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the single-wafer | sheet-fed insulation film forming apparatus used for the film-forming method which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Film-forming container, 2 ... Chamber, 3 ... Mounting stand, 4 ... Temperature controller, 5 ... Temperature controller, 9 ... Shower head, 10 ... 1st source of 1st gas containing a precursor, 11 ... Water A second source of a second gas containing, 12 a third source of a third gas composed of oxygen containing ozone, 13 a fourth source of a fourth gas containing a catalyst, 18 a first gas supply line, 23 a second gas Supply line, 25 ... third gas supply line, 32 ... fourth gas supply line

Claims (15)

Storing the substrate to be processed in the chamber;
Setting the substrate to be processed at a processing temperature of 0 to 120 ° C., while setting the inner wall surface defining the chamber to a temperature higher than the processing temperature;
A first gas containing a precursor selected from the following general formulas (1) to (3) in the chamber, a second gas containing water, a third gas comprising oxygen containing ozone, and an acidic or alkaline catalyst And a step of forming an insulating film on the substrate to be processed by reacting the precursor with oxygen containing water and ozone in the presence of the catalyst. A method for forming an insulating film.
R ¹ _a (R ² O) _3-a SiR ³ _b Si (OR ⁴ ) _3-c R ⁵ _c (1)
Si (OR ⁶ ) ₄ (2)
R ⁷ _d Si (OR ⁸ ) _4-d (3)
However, each of R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ^{8 in} the formula represents an alkyl group, an allyl group, an acyl group, an acyloxy group, and an alkenyl group,
R ³ represents an oxygen atom, a phenylene group or C _n H _2n (n is an integer of 1 to 5),
a and c represent any integer of 0 to 2;
b represents an integer of 0 or 1,
d represents an integer of 1 or 2.   The supply ratio of the water to the precursor is 0.1 to 100, and the total supply ratio of the precursor and the water to the whole of the first and second gases is 0.001 to 0.5. The method for forming an insulating film according to claim 1.   3. The method for forming an insulating film according to claim 1, wherein the ozone contained in the third gas is contained in the oxygen-containing oxygen at a concentration of 0.1 to 30% by volume. .   3. The method for forming an insulating film according to claim 1, wherein the ozone contained in the third gas is contained in oxygen containing the ozone at a concentration of 1 to 10% by volume.   The method for forming an insulating film according to claim 1, wherein the catalyst is acidic.   5. The method of forming an insulating film according to claim 1, wherein the catalyst is selected from the group consisting of hydrogen halide, carboxylic acid, nitric acid, sulfuric acid, halogen single molecule, and ammonia.   The method of forming an insulating film according to claim 1, wherein in the step of forming the insulating film, a processing pressure in the chamber is 0.1 Torr to 760 Torr. Storing the substrate to be processed in the chamber;
Setting the substrate to be processed at a processing temperature of 0 to 120 ° C., while setting the inner wall surface defining the chamber to a temperature higher than the processing temperature;
A first gas containing a precursor selected from the following general formulas (4) to (6), a second gas containing water, and a third gas made of oxygen containing ozone are simultaneously supplied into the chamber. Forming an insulating film on the substrate to be processed by reacting the precursor with oxygen containing water and ozone under the catalytic action of a catalyst component derived from the body or the precursor and water. A method for forming an insulating film.
_{^{R 11 e (R 12 O)}} 3-e SiR 13 f Si (OR 14) 3-g R 15 g ... (4)
Si (OR ¹⁶ ) ₄ (5)
R ¹⁷ _h Si (OR ¹⁸ ) _4-h (6)
However, each of R ¹¹ , R ¹² , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ^{18 in} the formula represents an acyl group and an acyloxy group,
R ¹³ represents an oxygen atom, a phenylene group or C _m H _2m (m is an integer of 1 to 5),
e and g each represent an integer of 0 to 2;
f represents an integer of 0 or 1,
h represents an integer of 1 or 2.   The supply ratio of the water to the precursor is 0.1 to 100, and the total supply ratio of the precursor and the water to the whole of the first and second gases is 0.001 to 0.5. The method for forming an insulating film according to claim 8.   The method for forming an insulating film according to claim 8 or 9, wherein the ozone contained in the third gas is contained in the oxygen-containing oxygen at a concentration of 0.1 to 30% by volume. .   10. The method for forming an insulating film according to claim 8, wherein the ozone contained in the third gas is contained in the oxygen-containing oxygen at a concentration of 1 to 10% by volume.   12. The method of forming an insulating film according to claim 8, wherein in the step of forming the insulating film, a processing pressure in the chamber is 0.1 Torr to 760 Torr.   The method for forming an insulating film according to claim 1, wherein a temperature difference between the processing temperature and the wall surface temperature is 5 ° C. or more.   14. The insulation according to claim 1, wherein the first gas contains an inert gas as a carrier gas, and the first gas is formed by bubbling the precursor with the inert gas. A film forming method. A chamber containing a substrate to be processed and having temperature adjusting means for setting the inner wall surface to a temperature higher than the processing temperature of the substrate to be processed;
First supply means for supplying a first gas containing a precursor selected from the following general formulas (1) to (3) into the chamber;
Second supply means for supplying a second gas containing water into the chamber;
Third supply means for supplying a third gas comprising oxygen containing ozone into the chamber;
A fourth supply means for supplying a fourth gas containing an acidic or alkaline catalyst into the chamber;
An insulating film forming apparatus comprising:
R ¹ _a (R ² O) _3-a SiR ³ _b Si (OR ⁴ ) _3-c R ⁵ _c (1)
Si (OR ⁶ ) ₄ (2)
R ⁷ _d Si (OR ⁸ ) _4-d (3)
However, each of R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ^{8 in} the formula represents an alkyl group, an allyl group, an acyl group, an acyloxy group, and an alkenyl group,
R ³ represents an oxygen atom, a phenylene group or C _n H _2n (n is an integer of 1 to 5),
a and c represent any integer of 0 to 2;
b represents an integer of 0 or 1,
d represents an integer of 1 or 2.

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