JP2003007640A - Cleaning method and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method and a semiconductor device manufacturing method, where short circuit is restrained from occurring between a gate electrode and a contact plug, by removing fine projections on a silicide gate. SOLUTION: This semiconductor device manufacturing method comprises a Ti film forming process of forming a Ti film on a gate electrode 3 and diffusion layers 6 and 7 in source/drain regions, a silicide process of forming Ti silicide films 9a to 9c on the gate electrode 3 and the diffusion layers 6 and 7 in the source/drain regions by making the Ti film undergo a thermal treatment, a cleaning process of removing the Ti film left unchanged in the silicide process by carrying out a cleaning operation, while ultrasonic waves are added to a cleaning solution, containing ammonia water and hydrogen peroxide water, a film-forming process of forming an interlayer insulating film 10 on the Ti silicide film, and a connection hole boring process of boring a first and a second connection hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning method and a method for manufacturing a semiconductor device, and more particularly to a cleaning method and a method for manufacturing a semiconductor device in which a short circuit between a gate electrode and a contact plug is suppressed.

[0002]

2. Description of the Related Art FIG. 9 is a sectional view for explaining a conventional method for manufacturing a semiconductor device. First, the silicon substrate 10
A gate oxide film 102 is formed on the surface of No. 1, and a gate electrode 103 is formed on the gate oxide film 102. Next, using the gate electrode 103 as a mask, the silicon substrate 10
Impurity ions are implanted at 1. As a result, the low concentration impurity layer 104 is formed in the LDD region of the silicon substrate 101.
Is formed. After that, a sidewall (sidewall material) 105 is formed on the sidewall of the gate electrode 103.

After that, impurity ions are ion-implanted into the silicon substrate 101 by using the gate electrode 103 and the side wall 105 as a mask, and the silicon substrate 101 is heat-treated. As a result, the diffusion layers 106 and 107 of the source / drain regions are formed in the source / drain regions of the silicon substrate 101 in a self-aligned manner. Next, the gate electrode 1
03, the side wall 105, the diffusion layers 106 and 107 of the source / drain regions, and the element isolation film, a Ti film is formed on the entire surface by sputtering.

Next, the Ti film, the gate electrode 103, and the diffusion layers 106 and 107 in the source / drain regions are heat-treated. By this heat treatment, the gate electrode 103 and the diffusion layer 1
By reacting the silicon in 06 and 107 with the Ti film, Ti silicide films 109a to 109c are formed on the surfaces of the gate electrode 103 and the diffusion layers 106 and 107, respectively.

After that, the Ti film remaining on the sidewalls 105 without being silicidized is removed. Then
The interlayer insulating film 1 made of SiO _{2 is} formed on the entire surface including the Ti silicide films 109a to 109c and the sidewalls 105.
10 is deposited by the CVD method. After that, a photoresist film is applied on the interlayer insulating film 110, and the photoresist film is exposed and developed to form the interlayer insulating film 1.
A resist pattern is formed on the surface 10.

Then, the interlayer insulating film 110 is etched by using this resist pattern as a mask to form contact holes on the Ti silicide films 109a to 109c in the interlayer insulating film. Then, after removing the resist pattern, the W film 12 is embedded in the contact hole. As a result, the W
The plugs 112a to 112c are formed. Next, on the W plugs 112a to 112c, Al alloy wirings 113a to 11c are formed.
3c is formed.

[0007]

By the way, in the above-described conventional method for manufacturing a semiconductor device, the Ti silicide film 109a formed on the surface of the gate electrode 103 may grow laterally, and the Ti silicide film 109a may grow on the gate electrode 103. In some cases, a fine protrusion 114 in which the Ti silicide film 109a extends laterally may be formed. The minute protrusions 114 cause a short circuit between the gate electrode 103 and the contact plugs 112b and 112c. That is, as the semiconductor element becomes finer and the gap between the gate electrode and the contact plug is shortened, a short defect between the gate electrode and the contact plug may occur due to minute protrusions on the silicide gate.

The present invention has been made in consideration of the above circumstances, and an object thereof is to remove short protrusions on a silicide gate to prevent a short circuit between a gate electrode and a contact plug. An object of the present invention is to provide a suppressed cleaning method and a semiconductor device manufacturing method.

[0009]

In order to solve the above-mentioned problems, a cleaning method according to the present invention is a cleaning method for removing a metal film which is not silicided and remains in a sidewall in a salicide process. It is characterized in that cleaning is performed while applying ultrasonic waves to a cleaning solution containing hydrogen oxide water.

According to the above-mentioned cleaning method, ultrasonic waves are applied to the cleaning solution containing ammonia water and hydrogen peroxide solution when selectively removing the metal film remaining on the sidewalls without being silicided in the salicide process. By cleaning, minute protrusions on the silicide gate can be removed. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

The cleaning method according to the present invention is a cleaning method for removing a metal film remaining without silicidation on sidewalls in a salicide process, in which a cleaning solution containing ammonia water and hydrogen peroxide water is used, And a step of washing with water while applying a sound wave.

According to the above cleaning method, when the metal film remaining on the sidewalls without being silicided is selectively removed in the salicide process, after cleaning with a cleaning solution containing ammonia water and hydrogen peroxide solution, By washing with water while applying a sound wave, minute protrusions on the silicide gate can be removed. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

A method of manufacturing a semiconductor device according to the present invention comprises a step of forming a gate electrode on a semiconductor substrate, a step of forming a diffusion layer in source / drain regions of the semiconductor substrate, and the step of forming the gate electrode and the source / drain. A step of forming a metal film on the diffusion layer in the region, and a silicidation step of forming a metal silicide film on the gate electrode and on the diffusion layer in the source / drain region by subjecting this metal film to a heat treatment; In the cleaning step of removing the metal film remaining without being silicidized in the oxidization step, the step of cleaning while applying ultrasonic waves to a cleaning solution containing ammonia water and hydrogen peroxide solution, and the step of cleaning the insulating film on the metal silicide film A step of forming the first insulating film and a first connection hole and a source / drain region located above the gate electrode in the insulating film by etching the insulating film; And a step of burying a contact plug in each of the first and second connection holes, and a step of forming a second connection hole located above the diffusion layer.

According to the method of manufacturing a semiconductor device described above, when the metal film remaining without being silicidized in the silicidation process is selectively removed, ultrasonic waves are applied to the cleaning liquid containing ammonia water and hydrogen peroxide water. By washing
It is possible to remove minute protrusions on the silicide gate. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

A method of manufacturing a semiconductor device according to the present invention comprises a step of forming a gate electrode on a semiconductor substrate, a step of forming a diffusion layer in a source / drain region of the semiconductor substrate, and the step of forming a gate electrode and a source / drain. A step of forming a metal film on the diffusion layer in the region, and a silicidation step of forming a metal silicide film on the gate electrode and on the diffusion layer in the source / drain region by subjecting this metal film to a heat treatment; A cleaning step of removing the metal film remaining without being silicidized in the oxidization step, the step of cleaning with a cleaning solution containing ammonia water and hydrogen peroxide solution, and then rinsing with water while applying ultrasonic waves; A step of forming an insulating film on the insulating film, and by etching the insulating film, a first connection hole and a saw located above the gate electrode are formed in the insulating film. Forming a second connection hole located above the diffusion layer in the drain / srain region, and first and second
And embedding a contact plug in each of the connection holes.

According to the above method of manufacturing a semiconductor device, when the metal film remaining without being silicidized in the silicidation process is selectively removed, after cleaning with a cleaning liquid containing aqueous ammonia and hydrogen peroxide, By washing with water while applying a sound wave, minute protrusions on the silicide gate can be removed. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 are cross-sectional views showing a method for manufacturing a semiconductor device according to the first embodiment of the present invention. FIG. 8 is a configuration diagram showing an example of the RCA cleaning device.

First, as shown in FIG. 1, a silicon substrate 1
An element isolation film (not shown) is formed on the surface of, and a gate oxide film 2 which is a gate insulating film is formed on the silicon substrate 1 between the element isolation films by a thermal oxidation method. A structure such as LOCOS, semi-recessed LOCOS, and shallow trench can be used as the element isolation film.

After that, CVD (Che
A polycrystalline silicon film is deposited by the mical vapor deposition method. Next, a photoresist film (not shown) is applied on this polycrystalline silicon film, and this photoresist film is exposed and developed to form a resist pattern on the polycrystalline silicon film. Then, the polycrystalline silicon film is etched by using this resist pattern as a mask to form the gate electrode 3 made of polycrystalline silicon on the gate oxide film 2.

Next, impurity ions are ion-implanted into the silicon substrate 1 using the gate electrode 3 and the element isolation film as a mask. As a result, the LDD (Lightly Dop
The low concentration impurity layer 4 is formed in the ed drain region. Then, for example, a silicon nitride film is deposited on the entire surface including the gate electrode 3 by the CVD method. Next, by etching back this silicon nitride film, a side wall (side wall material) 5 is formed on the side wall of the gate electrode 3.

After that, impurity ions are ion-implanted into the silicon substrate 1 using the gate electrode 3 and the side walls 5 as a mask, and the silicon substrate 1 is heat-treated. As a result, the diffusion layers 6 and 7 of the source / drain regions are formed in the source / drain regions of the silicon substrate 1 in a self-aligned manner. Next, a Ti film 8 is formed by sputtering on the entire surface including the gate electrode 3, the sidewall 5, the diffusion layers 6 and 7 of the source / drain regions, and the element isolation film.

Next, as shown in FIG. 2, the Ti film 8, the gate electrode 3, and the diffusion layers 6 and 7 in the source / drain regions are heat-treated. By this heat treatment, the silicon in the gate electrode 3 and the diffusion layers 6 and 7 reacts with the Ti film 8 to form Ti silicide films 9a to 9c on the surfaces of the gate electrode 3 and the diffusion layers 6 and 7, respectively. At this time,
Ti silicide film 9a formed on the surface of the gate electrode 3
May grow laterally, and the Ti silicide film 9a
A microprojection 14 extending in the lateral direction above the gate electrode 3 is formed.

After that, the Ti film 8 which is not silicided and remains on the sidewall 5 and the element isolation film is removed by the RCA cleaning device shown in FIG. This cleaning device
An apparatus for performing an RCA cleaning process, for example, an R filled with an RCA cleaning liquid obtained by adding hydrogen peroxide solution to ammonia water.
The CA cleaning tank 21, a water washing tank 22 for performing a water washing treatment, a rinse tank 23 for performing a rinse treatment, a dryer 24 for performing a drying treatment, and the like. An ultrasonic wave generation device 25 for generating ultrasonic waves in the cleaning liquid is connected to the RCA cleaning tank 21.
Hereinafter, a specific method of cleaning the silicon substrate using this cleaning apparatus will be described.

The silicon substrate 1 is transferred to the RCA cleaning tank 21 by a transfer machine (not shown), and the silicon substrate is cleaned in the RCA cleaning tank 21 for about 35 minutes.
After that, the silicon substrate is transferred to the RCA cleaning tank 21 by a carrier.
From the above to the washing tank 22 and the silicon substrate is washed in the washing tank 22 for a predetermined time. Then, the silicon substrate is transferred from the water washing tank 22 to the rinse tank 23 by the transfer machine, and the silicon substrate is rinsed in the rinse tank 23 for a predetermined time. After that, the silicon substrate is transferred from the rinse tank 23 to the dryer 24 by the transfer machine, and the silicon substrate is dried in the dryer 24 for a predetermined time.

Next, the silicon substrate is transferred from the dryer 24 to the RCA cleaning tank 21 by the transfer machine, and ultrasonic waves are applied to the cleaning liquid in the RCA cleaning tank 21 by the ultrasonic wave generator 25. As a result, the RCA cleaning process is performed for about 10 minutes while ultrasonically cleaning the silicon substrate. Then, the silicon substrate is transferred from the RCA cleaning tank 21 to the water washing tank 22 by a carrier, and the silicon substrate is subjected to a water washing treatment for a predetermined time in the water washing tank 22. Next, the silicon substrate is transferred from the washing tank 22 to the rinse tank 23 by a transfer machine,
The silicon substrate is rinsed in the rinse tank 23 for a predetermined time. After that, the silicon substrate is transferred from the rinse tank 23 to the dryer 24 by the transfer machine, and the dryer 24
A silicon substrate is subjected to a drying process for a predetermined time inside. By performing the RCA cleaning while performing the ultrasonic cleaning in this way, the Ti silicide protrusions 14 formed on the gate electrode 3 can be removed.

After that, as shown in FIG. 3, S is formed on the entire surface including the Ti silicide films 9a to 9c and the sidewalls 5.
The interlayer insulating film 10 made of iO ₂ is deposited by CVD. After that, a photoresist film is applied on the interlayer insulating film 10, and the photoresist film is exposed and developed to form a resist pattern 11 on the interlayer insulating film 10.
Is formed.

Next, as shown in FIG. 4, the inter-layer insulating film 10 is etched by using this resist pattern 11 as a mask to form a Ti silicide film 9 on the inter-layer insulating film.
Contact holes 10a to 10c located on a to 9c
Is formed.

Next, as shown in FIG. 5, after removing the resist pattern 11, contact holes 10a to 10c are formed.
The W film 1 is formed on the inner and interlayer insulating films 10 by sputtering.
Form 2.

After this, as shown in FIG.
CMP (Chemica) until the surface of the interlayer insulating film 10 is exposed.
l Mechanical polishing) or polishing back. As a result, the contact holes 10a-
W film is embedded in 10c, and W plugs 12a to 12c
Is formed.

Next, as shown in FIG. 7, the W plug 12a
Al alloy films 13a to 13c are formed on the W plug by depositing an Al alloy film on the entire surface including .about.12c by sputtering and patterning the Al alloy film. The Al alloy wiring 13a is electrically connected to the gate electrode 3 via the W plug 12a.
b is electrically connected to the diffusion layer 6 via the W plug 12b, and the Al alloy wiring 13c is electrically connected to the diffusion layer 7 via the W plug 12c.

According to the first embodiment described above, ultrasonic waves are used for RCA cleaning when selectively removing the Ti film 8 which is not silicided and remains on the sidewall 5 and the element isolation film in the salicide process. By adding cleaning, minute protrusions on the silicide gate can be removed. Therefore, it is possible to suppress the occurrence of a short circuit defect between the silicide gate and the contact plugs 12b and 12c.

Next, a second embodiment according to the present invention will be described. The description of the same parts as those in the first embodiment will be omitted.

In the first embodiment, the RCA cleaning tank 21 is used.
While ultrasonic cleaning is performed by applying ultrasonic waves to the cleaning liquid of No. 2, in the second embodiment, ultrasonic cleaning is performed while applying ultrasonic waves to the washing tank 22 shown in FIG.

That is, after the silicon substrate 1 is cleaned in the RCA cleaning tank 21, it is rinsed in the rinse tank 22 and then rinsed in the rinse tank 23.
Next, after performing a drying treatment in the dryer 24, the silicon substrate is subjected to a washing treatment in the washing bath 22 while applying ultrasonic waves to the washing bath 22. Next, the silicon substrate is rinsed in the rinse tank 23 and dried in the dryer 24.

In the second embodiment, as in the first embodiment, it is possible to remove the protrusion 14 above the gate electrode to some extent. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

Next, a third embodiment according to the present invention will be described. The description of the same parts as those in the first embodiment will be omitted.

In the first embodiment, the RCA cleaning tank 2
1, the washing tank 22, the rinse tank 23, and the dryer 24 are processed in this order, then ultrasonic cleaning is performed in the RCA cleaning tank 21, and then the washing tank 22, the rinse tank 23, and the dryer 24 are processed in this order. In the third embodiment, the RCA cleaning tank 21
Ultrasonic cleaning with, and then rinse tank 22, rinse tank 2
3 and the dryer 24 are processed in this order.

In the third embodiment as well, it is possible to remove the protrusion 14 above the gate electrode as in the first embodiment. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

Next, a fourth embodiment according to the present invention will be described. The description of the same parts as those in the first embodiment will be omitted.

In the first embodiment, the RCA cleaning tank 2
1, the washing tank 22, the rinse tank 23, and the dryer 24 are processed in this order, then ultrasonic cleaning is performed in the RCA cleaning tank 21, and then the washing tank 22, the rinse tank 23, and the dryer 24 are processed in this order. In the fourth embodiment, the RCA cleaning tank 21
After the cleaning process is performed, the ultrasonic cleaning is performed while applying ultrasonic waves to the pure water in the water washing tank 22 to wash with water, and then the rinse tank 23 and the dryer 24 are sequentially processed.

In the fourth embodiment, the protrusion 14 on the gate electrode can be removed to some extent as in the first embodiment. Therefore, the occurrence of a short circuit between the silicide gate and the contact plug can be suppressed.

The present invention is not limited to the above embodiment, and can be implemented with various modifications. For example,
In the above-described embodiment, the Ti silicide films 9a to 9c are formed on the gate electrode 3 and the diffusion layers 6 and 7 in the source / drain regions, respectively, but not limited to the Ti silicide film, other silicide films are formed. For example, a W silicide film, a Co silicide film or a Ni film may be formed on each of the diffusion layers of the gate electrode and the source / drain regions.
It is also possible to form a silicide film.

[0043]

As described above, according to the present invention, a cleaning liquid containing ammonia water and hydrogen peroxide water is used when selectively removing a metal film which is not silicided and remains on the sidewall in the salicide process. Wash while applying ultrasonic waves. Therefore, it is possible to provide the cleaning method and the semiconductor device manufacturing method in which the minute protrusions on the silicide gate can be removed, thereby suppressing the occurrence of a short circuit defect between the gate electrode and the contact plug.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the method of manufacturing a semiconductor device according to the first embodiment of the invention, and showing the next step of FIG.

FIG. 3 is a cross-sectional view showing the method of manufacturing the semiconductor device according to the first embodiment of the invention, and showing the next step of FIG. 2.

FIG. 4 is a sectional view showing the method of manufacturing the semiconductor device according to the first embodiment of the present invention, showing the step subsequent to that of FIG. 3;

FIG. 5 is a sectional view showing the method of manufacturing the semiconductor device according to the first embodiment of the present invention, showing the step subsequent to that of FIG. 4;

FIG. 6 is a cross-sectional view showing the method of manufacturing the semiconductor device according to the first embodiment of the present invention, showing the step subsequent to FIG. 5;

FIG. 7 is a cross-sectional view showing the method of manufacturing the semiconductor device according to the first embodiment of the invention, and showing the next step of FIG. 6.

FIG. 8 is a configuration diagram showing an example of an RCA cleaning device.

FIG. 9 is a cross-sectional view for explaining the conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

1, 101 ... Silicon substrate 2, 102 ... Gate oxide film 3, 103 ... Gate electrode 4, 104 ... Low concentration impurity layer 5, 105 ... Side walls 6, 7, 106, 107 ... Diffusion layer 8 of source / drain region ... Ti films 9a-9c, 109a-109c ... Ti silicide films 10, 110 ... Interlayer insulating films 10a-10c ... Contact holes 11 ... Resist pattern 12 ... W films 12a-12c, 112a-112c ... W plugs 13a-13c, 113a- 113c ... Al alloy wiring 14, 114 ... Micro projection 21 ... RCA cleaning tank 22 ... Water cleaning tank 23 ... Rinse tank 24 ... Dryer 25 ... Ultrasonic generator

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/336 H01L 21/88 C 29/43 29/78 301P 29/78 F term (reference) 4M104 AA01 BB01 BB02 BB18 BB20 BB21 BB25 BB28 BB40 CC05 DD04 DD16 DD22 DD37 DD43 DD64. BB15 BB27 5F140 AA14 BA01 BE07 BF04 BF11 BF18 BF60 BG08 BG14 BG28 BG30 BG34 BG37 BG45 BG52 BG53 BH15 BJ08 BJ11 BJ17 BJ18 BJ27 BK02 CF13 CB03 CB13 CB01 CB34 CB01 CB40 CB34 CB01 CB40 CB39 CE04

Claims (4)

[Claims] 1. A cleaning method for removing a metal film remaining without silicidation on sidewalls in a salicide process, characterized in that cleaning is performed while applying ultrasonic waves to a cleaning liquid containing ammonia water and hydrogen peroxide water. Cleaning method. 2. A cleaning method for removing a metal film remaining without being silicided in sidewalls in a salicide process, a step of cleaning with a cleaning solution containing ammonia water and hydrogen peroxide solution, and a method of cleaning with ultrasonic waves. A cleaning method comprising the steps of: 3. A step of forming a gate electrode on a semiconductor substrate, a step of forming a diffusion layer in a source / drain region of the semiconductor substrate, and a metal film on the diffusion layer of the gate electrode and the source / drain region. A step of forming, a silicidation step of forming a metal silicide film on the gate electrode and the diffusion layers of the source / drain regions by performing a heat treatment on the metal film, and a step of remaining without being silicidized in the silicidation step. Which is a cleaning step for removing the metal film, which is performed by applying ultrasonic waves to a cleaning solution containing ammonia water and hydrogen peroxide solution, a step of forming an insulating film on the metal silicide film, and a step of forming the insulating film. By etching, the insulating film is provided with a first contact hole located above the gate electrode and a second contact hole located above the diffusion layer of the source / drain region. Forming a connection hole, the semiconductor device manufacturing method characterized by comprising the step of filling a contact plug within the respective first and second connection holes, a. 4. A step of forming a gate electrode on a semiconductor substrate, a step of forming a diffusion layer in a source / drain region of the semiconductor substrate, and a metal film on the diffusion layer of the gate electrode and the source / drain region. A step of forming, a silicidation step of forming a metal silicide film on the gate electrode and the diffusion layers of the source / drain regions by performing a heat treatment on the metal film, and a step of remaining without being silicidized in the silicidation step. A cleaning step for removing the metal film, which comprises: cleaning with a cleaning solution containing ammonia water and hydrogen peroxide solution, followed by washing with ultrasonic waves; and a step of forming an insulating film on the metal silicide film, By etching the insulating film, the insulating film is formed above the first connection hole located above the gate electrode and above the diffusion layer in the source / drain region. Process and method of manufacturing a semiconductor device characterized by comprising a step of filling a contact plug within the respective first and second connection holes, the forming the second connecting hole located.