JP2003179225A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the punch through of boron to a silicon substrate that is generated in the activation RTA treatment of a transistor without increasing the number of processes. <P>SOLUTION: In the semiconductor device, at least one of an offset film 14 formed on a gate electrode 13, a sidewall film 15 formed at the sidewall section of the gate electrode 13, and an etching stopper film 18 used when forming a connection hole 22 for connecting a wiring layer that is not illustrated and a silicon substrate 11 is formed by a silicon nitride film. For the amount of combination hydrogen in the silicon nitride film, when the amount is determined by a peak area value obtained from an infrared absorption spectrum, the peak area ratio of Si-H combination to Si-N bonding is preferably 0.3% or less. In addition, for the nitride silicon film, the ratio of nitride to silicon is preferably 1:1 or more and 1:3 or less. Further, the nitride silicon film is preferably formed at a film-forming temperature of 200°C or more and 600°C or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and
For details of the manufacturing method, refer to P of the gate electrode portion. ⁺Type
Penetration of boron from the crystalline silicon film to the silicon substrate side
Semiconductor with a silicon nitride film to prevent scratches
A body device and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, the demand for higher integration and miniaturization of semiconductor devices has led to a dual gate type MISFE.
In T (metal-insulator-semiconductor FET), thinning of the gate insulating film progresses, and boron in the P ⁺ -type polycrystalline silicon film of the gate electrode portion penetrates through the gate insulating film and diffuses into the silicon substrate. , The problem that the current drive capability of the PMOS transistor is lowered has become apparent. Although the detailed mechanism of the diffusion of boron into the silicon substrate has not yet been clarified, the need for a technique for suppressing boron penetration is rapidly increasing.

In order to solve this problem of boron penetration, for example, as disclosed in Japanese Patent Laid-Open No. 2000-216156, a silicon oxide film is formed by nitriding a silicon oxide film in a nitrogen oxide gas atmosphere at 800 ° C. or higher. There is a technique of using a silicon nitride oxide film as a gate insulating film. In this technique, since high-temperature heat treatment is performed, there remains a problem that the impurities doped in the channel region for adjusting the threshold voltage are redistributed. Moreover, since the nitrogen concentration on the interface side between the silicon oxynitride film and the silicon substrate is high, NB
There arises a problem that reliability such as T (Negative Bias Temperature) characteristics deteriorates. Therefore, there is a demand for development of a technique for forming a gate insulating film capable of achieving both suppression of boron penetration and reliability.

On the other hand, the penetration of boron is caused by an etching stopper used in the step of forming a silicon nitride film (eg, the step of forming a gate electrode offset film, the step of forming a sidewall film, and the step of forming a contact hole reaching a substrate). It is said that it is caused by the formation process). Thermal stress (that is,
Film forming temperature) is reduced, so-called as-deposit
Various attempts have been made to solve the problem of boron penetration during ed. For example, it has been reported that a low pressure CVD method uses a halogen-based silicon source gas to lower the film formation temperature or single-wafer the low pressure CVD apparatus. In either case, RTA (Rapid of 1000 ° C.) is used. When thermal annealing is performed, boron penetration occurs, and as a technique for forming a silicon nitride film, a technique capable of solving the problem of boron penetration after activation RTA treatment of a transistor has not been established.

[0005]

When the activation RTA process of the transistor is performed, the penetration of boron occurs.
As a known finding, it is said that it is caused by hydrogen in the silicon nitride film. However, there is no disclosure or suggestion of a case in which the amount of hydrogen contained in the silicon nitride film is rigorously quantified and used as a solution to the penetration of boron. In addition, in Japanese Patent Laid-Open No. 2000-315791,
A technique for forming a silicon nitride film using a source gas containing deuterium has been disclosed, but this technique results in high manufacturing cost and is not practical. Also, JP-A-10-2239
No. 6, after adding boron into the silicon nitride film,
Although a technique of removing hydrogen in the film by performing heat treatment is disclosed, this method has a problem that the number of steps is increased.

[0006]

SUMMARY OF THE INVENTION The present invention is a semiconductor device and a method of manufacturing the same which are made to solve the above problems.

The semiconductor device of the present invention is used for forming the offset film formed on the gate electrode, the sidewall film formed on the side wall of the gate electrode, and the connection hole for connecting the wiring layer and the substrate. In a semiconductor device in which at least one of the etching stopper films is formed of a silicon nitride film, the amount of bound hydrogen in the silicon nitride film is Si-when quantified by a peak area value obtained from an infrared absorption spectrum. The peak area ratio of H bond to Si—N bond is 0.3% or less.

In the above semiconductor device, the amount of bonded hydrogen in the silicon nitride film is quantified by the peak area value obtained from the infrared absorption spectrum, and Si-N of Si-H bond is contained.
Since the peak area ratio to the coupling is 0.3%, the RT of 1000 ° C. is required for activation of the transistor.
Even if the A treatment is performed, the penetration of boron is suppressed. If the peak area ratio of Si—H bond to Si—N bond exceeds 0.3%, boron penetration is likely to occur when RTA treatment at 1000 ° C. is performed to activate the transistor.

According to the method of manufacturing a semiconductor device of the present invention, an offset film formed on the gate electrode, a sidewall film formed on the side wall of the gate electrode, and a connection hole for connecting the wiring layer and the substrate are formed. In the method for manufacturing a semiconductor device in which at least one of the etching stopper films used in the case is formed of a silicon nitride film, the amount of bonded hydrogen in the silicon nitride film was quantified by a peak area value obtained from an infrared absorption spectrum. At this time, the peak area ratio of Si—H bond to Si—N bond is set to 0.3% or less.

In the method of manufacturing a semiconductor device described above, when the amount of bonded hydrogen in the silicon nitride film is quantified by the peak area value obtained from the infrared absorption spectrum, the peak area ratio of Si--H bond to Si--N bond is 0. Since the silicon nitride film is formed so as to have a content of 0.3% or less, boron penetration is suppressed even if the RTA treatment at 1000 ° C. is performed for activation of the transistor. Note that when the peak area ratio of Si—H bond to Si—N bond exceeds 0.3%, the R of 1000 ° C. is increased for transistor activation.
When TA treatment is performed, boron penetration easily occurs.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of a semiconductor device of the present invention will be described with reference to the schematic cross-sectional view of FIG. In FIG. 1, the PMOS of the dual gate type MISFET is shown.
Shows a transistor.

As shown in FIG. 1, a gate electrode 13 is formed on a silicon substrate 11 via a gate insulating film 12, and an offset film 14 is formed on the gate electrode 13.
Further, a sidewall film 15 is formed on the sidewall of the stripped electrode 13. Further, source / drain regions 16 and 17 are formed on the silicon substrate 11 on both sides of the gate electrode 13. Further, an interlayer insulating film 18 is formed on the silicon substrate 11 so as to cover the offset film 14, and the wiring 31 formed on the interlayer insulating film 21 and the silicon substrate 11 (source / drain regions 17) are connected. An etching stopper film 18 serving as an etching stopper when forming the connection hole 22 is formed between the interlayer insulating film 21 and the semiconductor substrate 11.

At least one of the offset film 14, the sidewall film 15 and the etching stopper film 18 is formed of a silicon nitride film. In this silicon nitride film, when the amount of bonded hydrogen in the film was quantified by the peak area value obtained from the infrared absorption spectrum, the peak area ratio of Si—H bond to Si—N bond was 0.3% or less. It is what In addition, Si-N of Si-H bond
If the peak area ratio to the bond exceeds 0.3%, boron will penetrate into the silicon substrate 11 after the activation RTA treatment at 1000 ° C. for 10 seconds, as will be described later. Note that, ideally, the Si-H bond is 0. However, since hydrogen is contained in the source gas component, Si--H in the silicon nitride film is
It is difficult to set the bond to 0.

The silicon nitride film preferably has a nitrogen: silicon ratio of 1: 1 or more and 1: 3 or less, and is formed at a film forming temperature of 200 ° C. or more and 600 ° C. or less. It is preferable that If the ratio of nitrogen: silicon is out of the above range, the performance as a silicon nitride film is not sufficiently exhibited. The film forming temperature is 2
If the temperature is lower than 00 ° C., it takes a long time to form the film, and the film forming state is deteriorated or the film is not formed. On the other hand, when the film forming temperature exceeds 600 ° C., boron penetration is likely to occur.

Next, the amount of boron penetrated after the RTA treatment at 1000 ° C. for 10 seconds and the S content in the silicon nitride film.
The correlation with the i-H binding amount is shown by FIG. In Figure 2,
Black circles indicate the present invention, and other marks indicate conventional art. The amount of boron penetration (unit: atoms)
/ Cm ² ) is a value obtained by determining the SiO / Si interface assumed from the concentration distribution of boron in the silicon substrate by SIMS (Secondary Ion Mass Spectroscopy) measurement on the back surface of the substrate and performing area integration. Further, the Si-H bond amount means the peak area of the Si-H bond peak (near 2200 cm ^-2 ) obtained from the infrared absorption spectrum of the silicon nitride film, and the peak area of the Si-N bond peak (near 830 cm ^-2 ). The value is standardized by dividing by (unit is%).

As shown in FIG. 2, if a silicon nitride film is formed with a Si--H bond amount of 0.3% or less, boron penetration will occur even if RTA treatment is performed at 1000 ° C. for activation of the transistor. It can be seen that can be suppressed. Although the detailed mechanism of the effect of the Si-H group on the boron penetration phenomenon is not clear,
It is presumed that the Si-H group produces a reactive hydrogen radical after the RTA treatment at high temperature, which causes the diffusion rate of boron in the gate insulating film to be accelerated. In the silicon nitride film, unbonded free hydrogen, which is easily desorbed by heating, is usually present. It is speculated that this free hydrogen has little relation to the phenomenon of boron penetration.

In the silicon nitride film, nitrogen: silicon is set to 1: 1 or more and 1: 3 or less. By selecting the film formation conditions as described above, it becomes possible to adjust the refractive index to a desired value of about 2.0, and a silicon nitride film with excess nitrogen can obtain good electrical characteristics and workability. Therefore, the offset film of the gate electrode and the sidewall film,
Also, it can be applied as an etching stopper film used when forming a connection hole that connects a wiring layer and a substrate without impairing the processing margin of the etching step and the subsequent processing steps.

Next, the relationship between the amount of penetration of boron and the film formation temperature of the silicon nitride film at the time of as-deposited will be described with reference to FIG. In FIG. 3, black circles indicate the present invention, and other marks indicate the prior art.

As shown in FIG. 3, the silicon nitride film is
It can be seen that by forming at a film forming temperature of 00 ° C. or more and 600 ° C. or less, penetration of boron during as-deposited is suppressed. As a means for forming the silicon nitride film at a low temperature in this way, a low pressure CVD method (or a thermal CVD method: the source gas may be supplied after decomposing and activating radicals), a plasma CVD method, a so-called catalyst C
Any film forming method such as a VD method or an ADL (Atomic Layer Deposition) method may be used.

As described above, according to the present invention,
The silicon nitride film, which is one of the causes of boron penetration, has a film structure such that the Si-H bond amount is 0.3% or less, and the nitrogen: silicon ratio is 1: 1 or more and 1: 3 or less. Film composition temperature is 200 ° C to 600 ° C
By the following, boron penetration does not occur during as-deposited or after the activation RTA process of the transistor, and the dual gate type with high performance and small variation without lowering the current drive capability of the PMOS transistor. It becomes possible to easily form the MISFET.

Next, as one example for realizing the manufacturing method of the present invention, catalytic CVD as shown in the schematic sectional view of FIG.
A method for manufacturing a silicon nitride film using an apparatus (also referred to as hot wire CVD) will be described below.

As shown in FIG. 4, the catalytic CVD apparatus 101
Is a CV in which a tungsten wire, which is a catalyst body 119, is installed in the chamber 111 so as to face the substrate 117.
D device, the raw material gas 120 is 1800 ° C to 2000
It is characterized in that reaction active species such as radicals are generated by coming into contact with the catalyst body 119 heated to ° C, and film formation is performed at a low temperature without damaging the substrate 117.

The chamber 111 is a single-wafer type chamber, and the inside of the chamber 111 is exhausted from the exhaust unit 113 by a turbo molecular pump (not shown) via a throttle valve (not shown) for adjusting pressure. It is kept in a low pressure atmosphere of 0.1 Pa or less. It is possible to form a film in this state.

The susceptor 115 installed in the chamber 111 can be moved up and down by, for example, driving a cylinder, and the slit valve 1 provided in the chamber 111 can be moved.
2 is opened and the substrate 117 is transferred, the susceptor 115 is
When the film is formed by closing the slit valve 112 so that the lift pin 116 rises above the substrate mounting surface of the lift pin 11 below the substrate mounting surface of the susceptor 115.
The susceptor 15 is driven so that 6 is retracted. Further, during film formation, the substrate 17 is heated by the heater 114 embedded in the susceptor 15, and at that time, the substrate 117 is heated.
The substrate temperature is monitored by measuring the backside temperature of the substrate using an optical fiber thermometer (not shown).

The source gas 2 is provided above the chamber 111.
A blocker plate 122 for blowing out 0 and a catalyst body 119 made of a tungsten wire are installed.
The catalyst body 119 is heated to 1800 ° C. to 2000 ° C. by the electric power supplied from the AC power source 118, and the temperature thereof is monitored by, for example, an infrared radiation thermometer (not shown). Further, the raw material gas 120 has a flow rate adjusting valve 121.
It is supplied above the blocker plate 122 via a through hole and is sprayed onto the catalyst body 119 through a plurality of holes provided in the blocker plate 122.

Next, an example of forming a silicon nitride film by the manufacturing method of the present invention using the above catalytic CVD apparatus 101 will be described below.

For example, when the silicon nitride film used as the gate current offset film has a thickness of 170 nm,
The film thickness when used as an etching stopper film is 25 n
m.

As an example of film forming conditions, ammonia (NH ₃ ) and monosilane (SiH ₄ ) were used as source gases, and the flow rate ratio was NH ₃ : SiH ₄ = 1: 261. The pressure inside the chamber was set to 1.1 Pa, the distance between the catalyst body and the substrate was set to 40 mm, the temperature of the catalyst body was set to 2000 ° C, and the substrate temperature was set to 405 ° C.

When a silicon nitride film was formed under the above conditions, a silicon nitride film having N / Si of 1.22 and a refractive index of 1.95 was obtained. Also, the substrate temperature is 405 ° C.
Since it was low, penetration of boron did not occur at the time of as-deposited. Furthermore, the Si—H bond amount of the film injection was as low as 0.1%, and no boron penetration occurred even after RTA treatment at 1000 ° C. for 10 seconds.

Therefore, for example, 0.18 is formed by using the silicon nitride film formed by the manufacturing method of the present invention.
The μm generation PMOS transistor becomes a high-performance transistor that has a high current driving capability and a small variation in threshold voltage without increasing the concentration of nitrogen in the silicon nitride oxide film formed as the gate insulating film. . Therefore, by using this PMOS transistor, a high performance dual gate type MISFET can be manufactured.

As described above, the silicon nitride film, which is one of the causes for the penetration of boron, is formed at a temperature of 200 ° C. or higher 60
Since the film is formed at a low temperature of 0 ° C. or less, as-depos
It is possible to reliably prevent the penetration of boron during iteding. Further, since it has a film structure such that the Si—H bond amount is 0.3% or less, even if the activation RTA process of the transistor is performed at, for example, 1000 ° C. for 10 seconds, penetration of boron occurs. Is definitely blocked. Therefore, without lowering the temperature of the activation RTA process of the transistor and sacrificing the capability of the NMOS transistor of the dual gate type MISFET, a gate insulating film (for example, a high nitrogen concentration) that retains a high blocking capability against the penetration of boron is obtained. Even if the silicon nitride oxide film or the insulating film having a higher dielectric constant than the silicon oxide film) is not used, the problem that the current driving capability of the PMOS transistor is deteriorated is avoided, and the offset film of the gate electrode, the sidewall film, and the etching film are removed. It can be widely used in the step of forming a stopper film and the like.

Therefore, it becomes possible to manufacture a dual gate type MISFET having higher performance and higher reliability than conventional ones at low cost, which greatly contributes to higher integration and higher performance of semiconductor devices.

[0033]

As described above, according to the semiconductor device of the present invention, the problem that the current driving capability of the PMOS transistor is lowered is avoided, and the offset film of the gate electrode, the sidewall film, the etching stopper film, etc. A silicon nitride film can be used for the structure. Therefore, it is possible to obtain higher performance and reliability than ever before.

According to the semiconductor device and the method of manufacturing the same of the present invention, the problem that the current driving capability of the PMOS transistor is lowered is avoided, and the silicon nitride film is used as the offset film of the gate electrode, the sidewall film, the etching stopper film and the like. Can be formed by using. Therefore, a semiconductor device having higher performance and reliability than ever before can be formed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of an embodiment of a semiconductor device of the present invention.

FIG. 2 is a diagram showing a relationship between a penetration amount of boron and a Si—H bond amount in a silicon nitride film after RTA treatment at 1000 ° C. for 10 seconds.

FIG. 3 is a diagram showing a relationship between a penetration amount of boron and a deposition temperature of a silicon nitride film at the time of as-deposited.

FIG. 4 is a schematic cross-sectional view showing an example of a catalytic CVD apparatus that realizes the manufacturing method of the present invention.

[Explanation of symbols]

11 ... Silicon substrate, 13 ... Gate electrode, 14 ... Offset film, 15 ... Sidewall film, 18 ... Etching stopper film

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5F058 BC08 BF02 BF04 BF07 BF23                       BF30 BJ01 BJ02 BJ07                 5F140 AA28 AB03 AC01 BA01 BD09                       BG14 BG22 BG52 BK21 BK26                       CC01 CC08 CC12 CC13

Claims (6)

[Claims] 1. An offset film formed on a gate electrode, a sidewall film formed on the side wall portion of the gate electrode, and an etching stopper film used when forming a connection hole connecting a wiring layer and a substrate. In a semiconductor device in which at least one of them is formed of a silicon nitride film, the amount of bound hydrogen in the silicon nitride film is quantified by a peak area value obtained from an infrared absorption spectrum,
A semiconductor device having a peak area ratio of Si-H bonds to Si-N bonds of 0.3% or less. 2. The semiconductor device according to claim 1, wherein the nitrogen: silicon ratio in the silicon nitride film is 1: 1 or more and 1: 3 or less. 3. The silicon nitride film has a temperature of 200.degree.
The semiconductor device according to claim 1, wherein the semiconductor device is formed at a film forming temperature of 00 ° C. or less. 4. An offset film formed on a gate electrode, a sidewall film formed on the side wall portion of the gate electrode, and an etching stopper film used when forming a connection hole connecting a wiring layer and a substrate. In a method of manufacturing a semiconductor device in which at least one of them is formed of a silicon nitride film, when the amount of bound hydrogen in the silicon nitride film is quantified by a peak area value obtained from an infrared absorption spectrum, S
The peak area ratio of the i-H bond to the Si-N bond is 0.
A method of manufacturing a semiconductor device, characterized in that the silicon nitride film is formed so as to be 3% or less. 5. The method of manufacturing a semiconductor device according to claim 4, wherein the silicon nitride film is formed with a nitrogen: silicon ratio of 1: 1 or more and 1: 3 or less. 6. The silicon nitride film is formed at a temperature of 200.degree.
The method of manufacturing a semiconductor device according to claim 4, wherein the film is formed at a film forming temperature of 00 ° C. or less.