JPH01112732A - Ashing or resist - Google Patents

Abstract

PURPOSE:To improve characteristics of constituents by adding H2 to O2 gas as a sub-constituent to change impurities such as B, P, and As which have been implanted into the resist layer in the ion implantation process to a volatile substance for removing it along with the resist layer. CONSTITUTION:A substrate to be treated 1 where a resist layer implanted with relatively high dose of impurities ion such as B, P, and As is plated on a stage 13. Then, the inside of a vacuum container 1 is evacuated through an exhaust pipe 10 and then a mixture gas of O2+H2 including approximately 1-10% H2 is introduced at a specified flow rate through a introduction pipe 5. A microwave generation source 6 is activated and microwave is irradiated to the mixed gas within a plasma generation room 3 through a microwave penetration window 8 to generate plasma. Neutral hydrogen atoms (H), etc., which are generated due to dissociation of neutral oxygen atoms (O) and H2 molecules within plasma thus generated dissipate and enter a treatment room 4 through a small hole 12 of a shower head 2. Then, they react with the resist layer which is applied to a substrate to be treated 11 and impurities ions such as B, P, and As implanted to the resist layer and the impurity ions are removed through a discharge pipe as a volatile substance along with the resist layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] This invention relates to a down-flow ashing method used in the manufacturing process of semiconductor devices.

The object of the present invention is to provide a method that allows a resist layer to be removed by ashing without leaving impurity ions implanted in the resist layer.

A mixed gas containing 02 gas as a main component and Hl as a subcomponent is introduced into the plasma generation chamber of a down-flow one-type ashing apparatus, and a plasma of the mixed gas is generated to form a resist layer and a resist layer coated on a substrate to be processed. It consists of selectively removing impurity ions implanted into the

[Industrial application field]

The present invention relates to a method for removing a resist coating layer used in the manufacturing process of a semiconductor device, and particularly relates to a down-flow one-type ashing method.

[Conventional technology]

With the miniaturization of semiconductor devices, the manufacturing process is becoming increasingly dry. Regarding the removal of the resist layer used as a mask in the phosphorography process, instead of wet removal using a solvent, a dry method called ashing is used in which the resist layer is removed by solid phase/vapor phase reaction.

In the dry removal method, an oxygen gas plasma is generated and a reaction between atomic oxygen contained in the plasma and the resist layer is utilized. Among this ashing method,
In order to avoid damage to the substrate due to collisions with charged particles, the place where the substrate to be processed is installed is separated from the place where the plasma is generated, and measures are taken to prevent ions, electrons, etc. in the plasma from reaching the substrate to be processed. There is a so-called down-flow one-way method that uses a similar device.

[Problem that the invention seeks to solve]

The reactive gas in resist layer removal using the down-flow one-way method generally has oxygen gas as its main component, but neutral oxygen atoms (0)
In order to increase the production efficiency, small amounts of subcomponent gases are added. In this down-flow type ashing, the organic resist layer undergoes a chemical reaction with oxygen atoms, is converted into volatile substances such as COt and 20, and is removed.

On the other hand, 1. In the normal semiconductor device manufacturing process.

Impurity ions to be implanted into the substrate to be processed are simultaneously implanted into a resist layer coated on the substrate to be processed, such as a silicon wafer. Generally, boron (B), ta (P), arsenic (83), etc., which are implanted as impurities, form nonvolatile oxides in the ashing process.
Not removed at the same time as the resist layer.

It remains on the surface of the substrate to be processed after the resist layer is removed. Such residual impurities diffuse into the substrate to be processed in the subsequent heat treatment process, and have an undesirable effect on the characteristics of devices such as transistors formed therein.

In particular, there is a tendency for high-dose ion implantation to be performed as semiconductor devices become smaller, and the influence of residual impurities after ashing increases.

An object of the present invention is to provide a method that does not cause the above-mentioned problems in resist ashing using a down-flow method.

[Means for solving problems]

The above purpose is to install a substrate on which a resist layer is formed in a processing chamber in a down-flow one-type resist ashing method, and to supply a mixed gas containing 0□ gas as a main component and H2 as a subcomponent in a plasma generation chamber. This is achieved by the resist ashing method according to the present invention, which is characterized in that the resist layer and the impurity ions implanted into the resist layer are selectively removed by introducing the mixed gas and generating plasma of the mixed gas.

[For production]

In the down-flow one-type ashing, B is implanted into the resist layer in the ion implantation process by adding H2 as a subcomponent to the 0□ gas.

Impurities such as P+As are converted into volatile substances and removed at the same time as the resist layer.

〔Example〕

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

FIG. 1 is a schematic cross-sectional view of a down-flow type ashing device used to carry out the present invention. The inside of the vacuum container 1 is separated into a plasma generation chamber 3 and a processing chamber 4 by a shower head 2. Plasma generation chamber 3
An introduction pipe 5 for introducing a reaction gas and a microwave introduction pipe 7 connected to a microwave generation source 6 for generating plasma of the reaction gas are provided.

The microwave introduction tube 7 is provided with a microwave transmission window 8 made of, for example, a quartz glass plate, and a water cooling flange 9 for cooling the microwave transmission window 8. on the other hand,
The processing chamber 4 is provided with an exhaust pipe 10 connected to an exhaust system for maintaining the inside of the vacuum container 1 at a predetermined low pressure, and the bottom of the processing chamber 4 is equipped with a silicon wafer coated with a resist layer. A temperature controllable stage 13 is installed on which a substrate 11 to be processed such as the like is placed. The shower head 2 is held at ground potential and has a small hole 1 passing through it.
2 are provided in large numbers.

Ashing is performed using the above-mentioned apparatus according to the following steps.

■2 such as 1xlO” or 1x10 on stage 13
A substrate 1 to be processed, such as a silicon wafer, is placed on which a resist layer in which impurity ions such as B, P, and As are implanted at a relatively high dose of ``atoms/d'' is formed.

■After evacuating the inside of the vacuum container 1 through the exhaust pipe 10, O2 containing about 1 to 10% H
2+H, system mixed gas is introduced at a predetermined flow rate.

At this time, the gas pressure in the plasma generation chamber 3 is approximately 1.0
Torr.

(2) Start up the microwave source 6 and irradiate the mixed gas in the plasma generation chamber 3 with microwaves through the microwave transmission window 8 to generate plasma. Note that examples of the frequency and power of the micro are 2.45 GHz and 1.5 KM, respectively.

The ions and electrons in the plasma generated as described above collide with the shower head 2 and lose their charge, so the ions and electrons do not enter the processing chamber 4, causing undesirable damage to the substrate to be processed. do not have. On the other hand, neutral oxygen atoms (o) in the plasma, neutral hydrogen atoms (H) generated by dissociation of 82 molecules, etc. diffuse into the small hole 1 of the shower head 2.
2 and enters the processing chamber 4, the resist layer coated on the substrate 11 to be processed and the B and P injected into the resist layer.

Reacts with impurity ions such as As. As a result, the impurity ions mentioned above are removed together with the resist layer as volatile substances through the exhaust pipe 10.

0! It has been confirmed that when H2 is added to the gas, the amount of neutral oxygen atoms in the plasma increases compared to when Ot gas is used alone, and the ashing rate of the resist increases. On the other hand, impurity ions such as B, P, and As are converted into volatile substances when neutral hydrogen atoms (H) generated from H2 in the plasma react with these impurity ions.
This is thought to be due to the generation of gas molecules such as RtHb*PHz+ASH3.

〔Effect of the invention〕

According to the present invention, in the ashing process of a resist layer formed on a substrate to be processed such as a silicon wafer, impurity ions implanted into the resist layer can be removed at the same time, resulting in a highly integrated semiconductor device having desired characteristics. This has the effect of making it possible to manufacture with high yield.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the structure of a down-flow type ashing device used in carrying out the present invention. In fig. 1 is a vacuum container. 2 is the shower head. 3 is the plasma generation chamber. 4 is the processing room. 5 is the introduction pipe. 6 is a microwave generation source. 7 is a microwave introduction tube. 8 is a microwave transmission window. 9 is a water cooling flange. 10 is the exhaust pipe. 11 is a substrate to be processed. 12 is a small hole. 13 is by the stage.

Claims (1)

[Claims] A plasma generation chamber into which a reactive gas is introduced and generates a plasma of the reactive gas, a processing chamber which is evacuated to vacuum and where a substrate to be processed is installed, and a process chamber in which neutral species in the plasma are removed from the plasma generation chamber to the processing chamber. A substrate to be processed on which a resist layer implanted with impurity ions is formed is installed in the processing chamber of an ashing apparatus equipped with a means for selectively passing through the ashing chamber, and O_2 gas as a main component is placed in the plasma generation chamber. Toshi H_
1. A method for ashing a resist, which method comprises introducing a mixed gas containing 2 as a subcomponent to generate plasma of the mixed gas to selectively remove the resist layer and impurity ions implanted into the resist layer.