JPH05160084A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To remove aluminum deposit so as to enable a board to be enhanced in contact characteristics by a method wherein a contact hole is provided to an insulating film formed on a treated board, and the treated board is subjected to a dry etching process by the use of specific gas plasma. CONSTITUTION:A contact hole is provided to an insulating film deposited on a treated board 7 through contact etching. At contact etching, a contact plane is covered with a film of carbon polymer, alumina, and the like. Then, alumina deposit is removed by vaporizing with plasma gas selected from CBr4, BCl3, CCl4, and BBr3. Furthermore, a contact plane is etched a little with fluorine gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to post-treatment after forming a contact hole.

As the integration and speed of semiconductor devices have increased, contact technology for connecting lower layer wiring and upper layer wiring has become more difficult. In particular, the contact surface after etching for forming the contact hole needs to be cleaned more than before.

[0003]

2. Description of the Related Art As a conventional post-etching post-treatment method for forming contact holes, a small amount of the contact surface is etched with a fluorine-based gas to deposit on the substrate surface or a damaged layer formed on the substrate surface Had been removed.

However, since alumina may be present as deposits after etching, it is difficult to remove this alumina by the conventional method. However, since the contact surface of the conventional semiconductor device is large, the alumina is removed by etching the contact surface. The deposit was removed by lift-off. However, as the contact surface becomes smaller with the miniaturization of semiconductor devices, it has become difficult to remove alumina deposits.

[0005]

Good contact characteristics cannot be obtained by the post-treatment of the conventional example, which hinders high integration and high speed of semiconductor devices.

An object of the present invention is to provide a post-treatment method for completely removing alumina deposits after contact etching to obtain good contact characteristics.

[0007]

[Means for Solving the Problems] 1)
Etching process to form contact holes in the insulating film deposited on the substrate to be processed, and then carbon tetrabromide (CBr ₄ )
Alternatively, a semiconductor device having a post-treatment step of dry etching the substrate to be treated using plasma of a gas containing boron trichloride (BCl ₃ ) or carbon tetrachloride (CCl ₄ ) or boron tribromide (BBr ₃ ). Or 2) a method of manufacturing a semiconductor device according to 1), wherein a mixed gas of the gas and a fluorine-based gas is used in the post-treatment step.
Alternatively, 3) it is achieved by the method of manufacturing a semiconductor device according to 1), in which dry etching is performed using the gas in the post-treatment step, and then dry etching is performed using a fluorine-based gas.

[0008]

In the present invention, by using a plasma of carbon tetrabromide (CBr ₄ ) or boron trichloride (BCl ₃ ) or carbon tetrachloride (CCl ₄ ) or boron tribromide (BBr ₃ ) as a post-treatment,
Alumina (Al ₂ O ₃ ) is removed as shown in the following reaction formula.

Al ₂ O ₃ + CBr ₄ → AlBr ₃ ↑ + CBr ₂ O ↑ Al ₂ O ₃ + BCl ₃ → AlCl ₃ ↑ + BCl ₂ O ↑ Al ₂ O ₃ + CCl ₄ → AlBr ₃ ↑ + (CCl ₃ ) ₂ O ↑ Al ₂ O ₃ + BBr ₃ → AlBr ₃ ↑ + Br ₂ O ↑ As in the above formula, the alumina deposits are vaporized and removed by the plasma such as CBr ₄ , and the contact surface is cleaned. A small amount of the contact surface is etched using a system gas.

[0010] etching this case, may be carried out at the same time the alumina removed and the contact surface etched with a mixed gas of CBr ₄ or the like and the fluorine-based gas, or CBr ₄ or the like and a fluorine-based gas in two steps using in this order You may go.

However, since CBr ₄ plasma is used in the present invention, the portion exposed to the plasma in the processing chamber is not made of aluminum (Al) or alumina material.

[0012]

EXAMPLE FIG. 1 is a schematic sectional view of a processing apparatus used in the example. In the figure, 1 is a processing chamber, 2 is a gas inlet,
3 is an exhaust port, 4 is a substrate side electrode, 5 is a counter electrode, 6 is RF
A power source, 7 is a substrate to be processed.

Example (1): Using the apparatus shown in the figure, contact etching for forming a contact hole was performed on an insulating film made of silicon dioxide (SiO ₂ ) deposited on a substrate to be processed by CH etching.
It is carried out by reactive ion etching (RIE) using F ₃ / CF ₄ / Ar.

During this etching, the contact surface is covered with a film of carbon-based polymer and alumina. Then, CBr ₄ / NF ₃ / Ar was added as a post-treatment at a flow rate of 20/20/60, respectively.
Flow with SCCM, RIE for 30 seconds under conditions of RF power of 50 W and gas pressure of 0.2 Torr.

At this time, the dug depth of the contact surface (silicon surface) was about 100Å. In the example, alumina removal and contact surface etching were performed simultaneously using a mixed gas of CBr ₄ and a fluorine-based gas.First, RIE was performed using CBr ₄ / Ar and then RIE was performed using NF ₃ / Ar. You may go.

Example (2): Using the apparatus shown in the figure, contact etching for forming contact holes was performed on the insulating film made of SiO ₂ deposited on the substrate to be processed, and CHF ₃ / CF ₄ / Ar was used. It will be done by RIE.

During this etching, the contact surface is covered with a film of carbon-based polymer and alumina. Then, as a post-treatment, BCl ₃ / Ar or CCl ₄ / Ar was made to flow at a flow rate of 20/80 SCCM, RF power of 50 W and gas pressure of 0.2 T.
RIE is performed for 30 seconds under the condition of orr.

At this time, the dug depth of the contact surface is about
It was 60Å. Example (3): Using the apparatus shown in the figure, contact etching for forming contact holes was performed on the insulating film made of SiO ₂ deposited on the substrate to be processed by RIE using CHF ₃ / CF ₄ / Ar. To do.

During this etching, the contact surface is covered with a film of carbon-based polymer, alumina or the like. Then, as a post-treatment, BBr ₃ / NF ₃ / Ar was used at a flow rate of 20/20/60, respectively.
Flow with SCCM, RIE for 30 seconds under conditions of RF power of 50 W and gas pressure of 0.2 Torr.

At this time, the dug depth of the contact surface is about
It was 80Å.

[0021]

According to the present invention, alumina deposits after contact etching can be completely removed, and good contact characteristics can be obtained. As a result, it became possible to make contact in a fine area and contribute to higher integration and higher speed of semiconductor devices.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a processing apparatus used in Examples.

[Explanation of symbols]

 1 processing chamber 2 gas inlet port 3 exhaust port 4 substrate side electrode 5 counter electrode 6 RF power source 7 substrate to be processed

Claims (3)

[Claims] 1. An etching process for forming a contact hole in an insulating film deposited on a substrate to be processed, and then carbon tetrabromide (CBr ₄ ) or boron trichloride (BCl ₃ ) or carbon tetrachloride (CCl 4). ₄ ) or a post-treatment step of dry etching the substrate to be treated using plasma of a gas containing boron tribromide (BBr ₃ ). 2. The method for manufacturing a semiconductor device according to claim 1, wherein a mixed gas of the gas and a fluorine-based gas is used in the post-treatment step. 3. The method of manufacturing a semiconductor device according to claim 1, wherein in the post-processing step, dry etching is performed using the gas, and then dry etching is performed using a fluorine-based gas.