JPH11340235A - Semiconductor device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device, which is capable of maintaining gettering effects and can suppress the increase in the number of phosphorus implanting steps, without deteriorating the reliability of the semiconductor device. SOLUTION: The method comprises a step of forming an insulating film 102 on an upper surface of a semiconductor element 11 on a semiconductor substrate 10, a step of making a contact hole 104 in the insulating film 102, and a step of implanting ionic species having gettering effects in the film 102 and semiconductor substrate 10 at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a semiconductor device and a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device using a phosphorus-implanted oxide film as an interlayer insulating film and a semiconductor device.

[0002]

2. Description of the Related Art In MOS devices, it is desired to improve long-term reliability of transistors. for that reason,
2. Description of the Related Art Phosphorus-doped oxide films (BPSG, PSG) are used as interlayer insulating films on semiconductor elements. The reason for this is that impurities such as sodium can be captured in the insulating film by the gettering effect of phosphorus, so that an adverse effect on the element can be prevented.

Japanese Patent Application Laid-Open No. Sho 61-26767 discloses a technique for obtaining a gettering effect by implanting phosphorus ions after forming a gate oxide film on a semiconductor substrate. In Japanese Patent Application Laid-Open No. 2-18738, since the plasma phosphorus glass film (P-PSG film) contains phosphorus, alkali ions can be fixed and inactivated by the gettering effect, and the MOS interface (Si- SiO ₂ interface)
Can be stabilized. Further, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 3-102325 describes that a phosphorus-treated film is formed on a silicon oxide film by depositing POCl ₃ at a temperature of 800 to 1000 ° C., thereby enabling gettering of the silicon oxide film. .

As means for forming a phosphorus-doped film,
Generally, a chemical vapor deposition (CVD) method is used. Re
Can be used on semiconductor devices.
As a method of forming at a temperature as low as possible, SiH₄/ PH
₃/ O₂Or SiH ₄/ PH₃/ N₂Using O
It is known that

However, when these are used, a large amount of moisture (H ₂ O) is generated, which causes a problem that the moisture diffuses into the semiconductor element, and the moisture deteriorates the hot carrier resistance of the MOS transistor.

Therefore, a method is conceivable in which a silicon oxide film is formed as an insulating film on a semiconductor element by a CVD method at a low temperature and a small amount of water is mixed therein, and phosphorus is doped into the film by ion implantation.

A plasma CVD method using SiH ₄ / O ₂ as a raw material is an example of a CVD method in which water is hardly mixed. In recent years, a method of obtaining an excellent step coverage performance by using an apparatus capable of generating high-density plasma such as electron cyclotron resonance (ECR) as a plasma source has been widely used.

According to the above method, the gettering effect of the insulating film can be maintained without deteriorating the hot carrier resistance of the MOS transistor.

[0009]

However, in the above method, it is necessary to add a step of implanting phosphorus into the interlayer insulating film to a normal step, and shortening of the step period and reduction of the step cost are important issues. In the method of manufacturing a semiconductor device, it cannot be easily adopted.

The present invention has been made in view of the above circumstances, and can maintain a gettering effect, does not degrade reliability such as hot carrier resistance, and can suppress an increase in the number of steps. It is an object of the present invention to provide a method for manufacturing a semiconductor device.

[0011]

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an insulating film on an upper surface of a semiconductor element on a semiconductor substrate; forming a contact hole in the insulating film; Simultaneously ion-implanting ion species having a gettering action into the film and the semiconductor substrate.

According to a method of manufacturing a semiconductor device of the present invention, in the method of manufacturing a semiconductor device according to claim 1, the insulating film is formed by a high-density plasma CVD method (HDP CVD method).

In the method of manufacturing a semiconductor device according to the present invention, the insulating film is a silicon oxide film, and the ionic species having a gettering action is phosphorus. is there.

According to the method of manufacturing a semiconductor device of the present invention, a step of forming an etching stopper on an upper surface of a semiconductor element on a semiconductor substrate, a step of forming an insulating film on the etching stopper, and stopping by the etching stopper Forming a contact hole in the insulating film by performing an etching process as described above, and simultaneously ion-implanting an ion species having a gettering action into the insulating film and the semiconductor substrate. The ion implantation is performed via the etching stopper.

According to the method of manufacturing a semiconductor device of the present invention, a first insulating film is formed on an upper surface of a semiconductor element on a semiconductor substrate, and a second insulating film is formed on the first insulating film. Forming a contact hole in the second insulating film by etching the second insulating film using the first insulating film as an etching stopper; and forming a contact hole in the second insulating film and the semiconductor substrate. Simultaneously ion-implanting an ion species having a gettering action, wherein the ion implantation into the semiconductor substrate is performed through the first insulating film.

In the method of manufacturing a semiconductor device according to the present invention, the second insulating film is formed by a high-density plasma CVD method.

According to a method of manufacturing a semiconductor device of the present invention, in the method of manufacturing a semiconductor device according to claim 5 or 6, the second insulating film is a silicon oxide film, and the ionic species having the gettering action is , Is phosphorus.

In the method for manufacturing a semiconductor device according to the present invention, in the method for manufacturing a semiconductor device according to any one of claims 5 to 7, the first insulating film is a silicon nitride film.

In the method of manufacturing a semiconductor device according to the present invention, in the method of manufacturing a semiconductor device according to any one of claims 5 to 8, the first insulating layer exposed by the contact hole after the ion implantation step. And selectively etching the film.

According to a method of manufacturing a semiconductor device of the present invention, a step of forming an insulating film on an upper surface of a semiconductor element on a semiconductor substrate; a step of forming a pair of contact holes in the insulating film; At the same time on the substrate
Performing ion implantation of an ion species having a gettering action, and after the phosphorus ion implantation, masking one of the contact holes of the pair of contact holes, and simultaneously in the insulating film and the semiconductor substrate, Performing boron ion implantation.

According to a method of manufacturing a semiconductor device of the present invention, in the method of manufacturing a semiconductor device according to claim 10, the insulating film is formed by a high-density plasma CVD method.

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising:
The insulating film is a silicon oxide film, and the ion species having the gettering action is phosphorus.

According to the method of manufacturing a semiconductor device of the present invention, a step of forming an etching stopper on an upper surface of a semiconductor element on a semiconductor substrate, a step of forming an insulating film on the etching stopper, and stopping by the etching stopper Forming a pair of contact holes in the insulating film by performing an etching process as described above, simultaneously ion-implanting an ion species having a gettering action into the insulating film and the semiconductor substrate, Later, the method includes a step of masking one of the contact holes of the pair of contact holes, and a step of simultaneously implanting boron ions into the insulating film and the semiconductor substrate, wherein the gettering action on the semiconductor substrate is provided. Ion implantation of certain ion species
This is performed via the etching stopper.

According to the method of manufacturing a semiconductor device of the present invention, a first insulating film is formed on an upper surface of a semiconductor element on a semiconductor substrate, and a second insulating film is formed on the first insulating film. Forming a pair of contact holes in the second insulating film by etching the second insulating film using the first insulating film as an etching stopper; and forming the second insulating film and the semiconductor. At the same time on the substrate
Ion-implanting an ion species having a gettering action; masking one of the pair of contact holes after the ion implantation; and simultaneously forming boron in the insulating film and the semiconductor substrate. Performing an ion implantation, wherein the ion implantation of the ion species having the gettering action to the semiconductor substrate is performed through the first insulating film.

According to a method of manufacturing a semiconductor device of the present invention, in the method of manufacturing a semiconductor device according to claim 14, the second insulating film is formed by a high-density plasma CVD method.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
The second insulating film is a silicon oxide film, and the ionic species having a gettering action is phosphorus.

According to a method of manufacturing a semiconductor device of the present invention, in the method of manufacturing a semiconductor device according to any one of claims 14 to 16, the first insulating film is a silicon nitride film.

In the method of manufacturing a semiconductor device according to the present invention, in the method of manufacturing a semiconductor device according to any one of claims 14 to 17, after the step of ion-implanting the ion species having the gettering action, Prior to the step of masking the contact hole, the method further includes the step of selectively etching the first insulating film exposed to the pair of contact holes.

A semiconductor device according to the present invention includes a semiconductor substrate, a semiconductor element formed on the semiconductor substrate, a first insulating film formed on the semiconductor element, and a semiconductor element formed on the semiconductor element. A second insulating film formed thereon, a contact hole penetrating the first insulating film and the second insulating film and exposing a part of the semiconductor substrate, and a second insulating film formed on the second insulating film. A first phosphorus-doped layer doped with phosphorus ions, and a second phosphorus-doped layer formed at a portion of the semiconductor substrate exposed by the contact hole and doped with phosphorus ions, The phosphorus-doped layer has a lower concentration of phosphorus ions than the first phosphorus-doped layer.

A semiconductor device according to the present invention includes a semiconductor substrate, a semiconductor element formed on the semiconductor substrate, a silicon nitride film formed on the semiconductor element, and a semiconductor element formed on the silicon nitride film. A silicon oxide film, a contact hole penetrating through the silicon nitride film and the silicon oxide film to expose a part of the semiconductor substrate, and a first phosphorus doped film formed in the silicon oxide film and doped with phosphorus ions. A second phosphorus-doped layer formed in a portion of the semiconductor substrate exposed by the contact hole and doped with phosphorus ions, wherein the second phosphorus-doped layer is more than a first phosphorus-doped layer. The concentration of phosphorus ions is low.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a semiconductor device according to the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 to 6 show the steps of the method for fabricating the semiconductor device according to the present embodiment. In FIG.
Reference numeral 10 denotes a semiconductor substrate, and 11 denotes a semiconductor element formed of a MOS formed on the semiconductor substrate 10.

First, as shown in FIG.
On a semiconductor substrate 10 containing
An iN film 101 is deposited to a thickness of 50 nm.

Next, as shown in FIG.
On the upper surface of the layer 101, a high-density plasma CVD method (High Density Pla
The plasma oxide film 102 is
It is formed to a thickness of 200 nm. Next, the surface is flattened by a chemical mechanical polishing method so that the total thickness of the insulating films 101 and 102 on the semiconductor substrate 10 becomes 1 μm.

Next, as shown in FIG. 3, after forming a photoresist 103 on the upper surface of the plasma oxide film 102,
The photoresist 103 is opened in the contact pattern by a normal exposure method. Next, the contact holes 104 are formed in the plasma oxide film 102 by etching the plasma oxide film 102 by an anisotropic dry etching method.
This etching stops on the plasma SiN layer 101.

As the etching gas in this case, C ₄ F
₈ / CO / Ar / O ₂ = 6/30/180 / 1sccm
Using a pressure of 40 mtorr and RF 650 W.

Next, as shown in FIG. 4, after removing the photoresist 103, monovalent phosphorus ions are implanted.
The condition in that case is 40 KeV and 1E16. Phosphorus ions are deposited on the plasma oxide film 102 and the semiconductor substrate 10.
To form a phosphorus-doped region 105. That is, the region 105a in the plasma oxide film 102 and P
Phosphorus is doped into the contact portions 105b of both the N-type and N-type regions.

Next, as shown in FIG. 5, the plasma SiN layer 101 remaining at the bottom of the contact hole 104 is selectively etched to expose the connection region of the semiconductor element 11. The etching gas is CHF ₃ / O ₂ = 25/10
(Sccm) at a pressure of 40 mtorr.
r, RF400W.

Next, as shown in FIG. 6, after forming a pattern so that the resist 106 is opened only in the P-type region of the semiconductor element 11 by a normal exposure method, BF ₂ ions are implanted at 40 KeV 5E14. The previously doped phosphorus is returned to form a boron-doped region 107 in the contact hole of the P-type region.

By doping phosphorus and boron into the contact, the contact hole deviates from the connection region of the element due to misalignment at the time of exposure of the contact pattern.
No leak current flows through the semiconductor substrate 10 even when the semiconductor substrate 10 passes through the isolation region or becomes excessively etched.

Next, after removing the resist 106, a buried wiring for the contact hole 104 is formed by a usual method.

According to the present embodiment, the deterioration of the reliability of the semiconductor element 11 is suppressed by forming the interlayer insulating film on the semiconductor element 11 by the plasma oxide film 102 with a small amount of moisture. Further, by implanting phosphorus into the plasma oxide film 102, the impurity gettering effect of the insulating film can be maintained. In addition, this phosphorus injection
Since it also serves as normal contact ion implantation, the number of steps does not increase.

In this embodiment, first, BP is used as the insulating film.
By using the non-doped plasma oxide film 102 without using SG, the amount of water that enters a large amount during the formation of BPSG is reduced, and then phosphorus ions are implanted into the plasma oxide film 102 to improve the gettering effect of impurities. It is what we decided to get.

Second, the phosphorus implantation also serves as contact ion implantation. Third, an etching stopper is used in contact etching, and phosphorus is implanted at a stage where etching of the contact is stopped by the etching stopper.

That is, in the present embodiment, after forming an insulating film (plasma SiN layer 101) serving as a stopper at the time of contact etching on the gate electrode, plasma is formed by high-density plasma CVD or the like in which water is little mixed into the film. An oxide film 102 is formed. The contact hole 104 is formed by an ordinary method, but the etching is temporarily stopped by a stopper film. This step is similar to the contact formation method using a normal etching stopper.

Next, phosphorus ions are implanted into the entire surface of the substrate 10. This step is a normal contact ion implantation, but is performed at a higher concentration than usual. The gettering effect is obtained by implanting phosphorus into the plasma oxide film 102, and a stable contact resistance is obtained by the phosphorus implanted into the contact portion.

Further, since ions are implanted through the etching stopper film, even if a sufficient amount is implanted for gettering, it is not excessively implanted into the contact portion, and does not affect the characteristics of the semiconductor element 11. . next,
Boron is implanted into the P-type region using a normal photoresist process. Subsequently, the nitride film 101 is etched to completely open a contact hole.

In the present embodiment, phosphorus is ion-implanted as an ion species having a gettering action, but a gettering action is also observed for chlorine ions, hydrogen ions, and the like.

[0049]

According to the method of manufacturing a semiconductor device of the present invention, a step of forming an insulating film on an upper surface of a semiconductor element on a semiconductor substrate, a step of forming a contact hole in the insulating film, Simultaneously ion-implanting an ion species having a gettering action into the semiconductor substrate, so that the gettering effect can be maintained and the reliability such as hot carrier resistance is not deteriorated. An increase in the number can be suppressed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first step in one embodiment of a method for manufacturing a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view showing a second step in the present embodiment.

FIG. 3 is a cross-sectional view showing a third step in the present embodiment.

FIG. 4 is a cross-sectional view showing a fourth step in the present embodiment.

FIG. 5 is a cross-sectional view showing a fifth step in the present embodiment.

FIG. 6 is a cross-sectional view showing a sixth step in the present embodiment.

[Explanation of symbols]

 Reference Signs List 10 semiconductor substrate 11 semiconductor element 101 plasma SiN layer 102 plasma oxide film 104 contact hole 105 phosphorus-doped region 107 boron-doped region

Claims (20)

[Claims] A semiconductor device (1) on a semiconductor substrate (10).
1) forming an insulating film (102) on the upper surface of (1); forming a contact hole (104) in the insulating film (102); and simultaneously forming the insulating film (102) and the semiconductor substrate (10) in the insulating film (102). Implanting ion species having a gettering action. 2. The method according to claim 1, wherein the insulating film is formed by a high-density plasma CVD method. 3. The method of manufacturing a semiconductor device according to claim 1, wherein said insulating film is a silicon oxide film, and said ionic species having a gettering action is phosphorus. Method. 4. A semiconductor device (1) on a semiconductor substrate (10).
Forming an etching stopper (101) on the upper surface of (1); and forming an insulating film (10) on the etching stopper (101).
Forming a contact hole (104) in the insulating film (102) by performing an etching process so as to be stopped by the etching stopper (101); Simultaneously implanting ion species having a gettering action into the semiconductor substrate (10), wherein the ion implantation into the semiconductor substrate (10) is performed via the etching stopper (101). Manufacturing method. 5. A semiconductor device (1) on a semiconductor substrate (10).
Forming a first insulating film (101) on the upper surface of (1); and forming a second insulating film (10) on the first insulating film (101).
Forming the second insulating film, etching the second insulating film using the first insulating film as an etching stopper, and forming a contact hole in the second insulating film. Forming the second insulating film (102) and the semiconductor substrate (1).
0) simultaneously with the step of ion-implanting an ion species having a gettering action, wherein the ion implantation into the semiconductor substrate (10) is performed through the first insulating film (101). A method for manufacturing a semiconductor device. 6. The method for manufacturing a semiconductor device according to claim 5, wherein the second insulating film is formed by high-density plasma CVD.
A method for manufacturing a semiconductor device formed by a method. 7. The semiconductor device manufacturing method according to claim 5, wherein said second insulating film is a silicon oxide film, and said ionic species having a gettering action is phosphorus. Device manufacturing method. 8. The method for manufacturing a semiconductor device according to claim 5, wherein said first insulating film (101) is a silicon nitride film. 9. The method of manufacturing a semiconductor device according to claim 5, wherein said first insulating film exposed by said contact hole after said ion implantation step.
1) A method for manufacturing a semiconductor device, comprising a step of selectively etching (1). 10. An insulating film (102) is formed on an upper surface of a semiconductor element (11) on a semiconductor substrate (10); and a pair of contact holes (10) are formed in the insulating film (102).
4) forming, simultaneously ion-implanting an ion species having a gettering action into the insulating film (102) and the semiconductor substrate (10); and forming the pair of contact holes after the phosphorus ion implantation. A method of manufacturing a semiconductor device, comprising: masking one of the contact holes of (104); and simultaneously implanting boron ions into the insulating film (102) and the semiconductor substrate (10). 11. The method for manufacturing a semiconductor device according to claim 10, wherein said insulating film is formed by a high-density plasma CVD method. 12. The method of manufacturing a semiconductor device according to claim 10, wherein said insulating film is a silicon oxide film, and said ionic species having a gettering action is phosphorus. Method. 13. An etching stopper (101) on an upper surface of a semiconductor element (11) on a semiconductor substrate (10); and an insulating film (10) on the etching stopper (101).
Forming a pair of contact holes (104) in the insulating film (102) by performing an etching process so as to be stopped by the etching stopper (101); and forming the insulating film (102). ) And simultaneously ion-implanting ion species having a gettering action into the semiconductor substrate (10); and after the ion implantation, one of the contact holes (10) of the pair of contact holes (104).
4) masking the insulating film (102) and the semiconductor substrate (10) simultaneously with boron ion implantation, wherein the ion species having the gettering action on the semiconductor substrate (10) is provided. The method of manufacturing a semiconductor device, wherein the ion implantation is performed via the etching stopper (101). 14. A step of forming a first insulating film (101) on an upper surface of a semiconductor element (11) on a semiconductor substrate (10), and a second insulating film on the first insulating film (101). Membrane (10
Forming the second insulating film, and etching the second insulating film using the first insulating film as an etching stopper to form a pair of contact holes in the second insulating film. 10
4) forming the second insulating film (102) and the semiconductor substrate (1);
0) at the same time, ion-implanting an ion species having a gettering action; and, after the ion implantation, the contact hole (10) of one of the pair of contact holes (104).
4) masking the insulating film (102) and the semiconductor substrate (10) simultaneously with boron ion implantation, wherein the ion species having the gettering action on the semiconductor substrate (10) is provided. The ion implantation is performed by the first insulating film (1).
01). 15. The method for manufacturing a semiconductor device according to claim 14, wherein the second insulating film is formed by high-density plasma CVD.
A method for manufacturing a semiconductor device formed by a method. 16. The method according to claim 14, wherein the second insulating film is a silicon oxide film, and the ionic species having a gettering action is phosphorus. Device manufacturing method. 17. The method of manufacturing a semiconductor device according to claim 14, wherein the first insulating film (101) is a silicon nitride film. 18. The method for manufacturing a semiconductor device according to claim 14, wherein after the step of ion-implanting the ion species having the gettering action, the one of the contact holes (10).
Before the step of masking 4), the first insulating film (10) exposed to the pair of contact holes (104) is formed.
1) A method for manufacturing a semiconductor device, comprising a step of selectively etching (1). 19. A semiconductor substrate (10), a semiconductor element (11) formed on the semiconductor substrate (10), and a first insulating film (101) formed on the semiconductor element (11). ), A second insulating film (102) formed on the first insulating film (101), and penetrating the first insulating film (101) and the second insulating film (102). A contact hole (104) for exposing a part of the semiconductor substrate (10), a first phosphorus-doped layer (105a) formed in the second insulating film (102) and doped with phosphorus ions, A second phosphorus-doped layer (105b) formed in a portion of the semiconductor substrate (10) exposed by the contact hole (104) and doped with phosphorus ions, wherein the second phosphorus-doped layer (105b) Than one phosphorus-doped layer (105a), the concentration of phosphorus ions is lower semiconductor device. 20. A semiconductor substrate (10), a semiconductor element (11) formed on the semiconductor substrate (10), and a silicon nitride film (101) formed on the semiconductor element (11). A silicon oxide film (102) formed on the silicon nitride film (101); and a part of the semiconductor substrate (10) penetrating the silicon nitride film (101) and the silicon oxide film (102). A first phosphorus-doped layer (105a) formed in the silicon oxide film (102) and doped with phosphorus ions
And a second phosphorus-doped layer (105b) formed in a portion of the semiconductor substrate (10) exposed by the contact hole (104) and doped with phosphorus ions. 4) is a semiconductor device having a lower concentration of phosphorus ions than the first phosphorus-doped layer (105a).