JP3038827B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Regarding a pretreatment method for forming a wiring, the object of the present invention is to provide a pretreatment method that stabilizes film formation and optimizes a treatment container. Exposure to an excited gas atmosphere containing at least one of CO, COCl ₂ and HCN as
A treatment for removing hydrocarbons present on the surface of the object; and treating the surface of the object with H ₂ , NF ₃ , SF ₆ , BCl ₃ ,
A treatment for removing an oxide present on the surface of the object by exposing to an excited gas atmosphere containing at least one of BF ₃ and, after the completion of the two treatments, an exposure to an excited gas atmosphere containing hydrogen. The above-mentioned 2 existing on the surface of the object to be treated
A process of removing the residue resulting from the process, and a step of cleaning the surface of the object to be processed.

2) Each of the above-described processes is configured to be performed by using a means for exciting a process gas by heat, light, or plasma.

3) After the cleaning step 1) or 2), a film is formed on the surface of the workpiece.

4) The object to be processed is a processing chamber or a film forming chamber for performing the cleaning step.

[Industrial applications]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a pre-processing method for forming a wiring.

In the manufacture of semiconductor devices, it is necessary to optimize the film interface, stabilize film formation, and achieve high mass productivity. For this purpose, a pretreatment method for the underlying material of metal wiring such as silicon (Si) substrates and aluminum (Al) The present invention can be applied as

[Conventional technology]

Conventionally, as a pretreatment of a base material before film formation, a wet treatment using dilute hydrofluoric acid and a dry treatment using SF ₆ , NF ₃ , and BCl ₃ have been basically performed.

However, in the wet processing, there is a problem that it is difficult to re-form the underlying natural oxide film or to simultaneously treat, for example, Si and metal when the underlying layer is made of a different kind.

In dry processing using SF ₆ , NF ₃ , or BCl ₃ , or in film formation using WF ₆ or TiCl ₄ as a raw material gas, impurities caused by these gases (for example, F, Cl or by-products containing these (SF _x , NF _x , WF _x , SiF _x , AlF _x , BC
L _x , SiCl _x , AlCl _x , HF, HCl, etc.) and hydrocarbons resulting from resists, etc.] remain.

[Problems to be solved by the invention]

Therefore, the reproducibility of the process of the processing substrate is reduced, and an abnormal film formation, an increase in the contact resistance of the wiring, and a purification of the leak current after the formation of the element occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pretreatment method that stabilizes film formation and optimizes a processing container.

[Means for solving the problem]

To solve the above problems: 1) Exposing the surface of an object to be treated to an excited gas atmosphere containing at least one of CO, COCl ₂ , and HCN as a processing gas;
A treatment for removing hydrocarbons present on the surface of the object; and treating the surface of the object with H ₂ , NF ₃ , SF ₆ , BCl ₃ ,
A treatment for removing an oxide present on the surface of the object by exposing to an excited gas atmosphere containing at least one of BF ₃ and, after the completion of the two treatments, an exposure to an excited gas atmosphere containing hydrogen. The above-mentioned 2 existing on the surface of the object to be treated
A method of manufacturing a semiconductor device having a step of cleaning the surface of the object to be processed, including a step of removing residues caused by the processing; or 2) the excited gas atmosphere is at least one of heat, light, and plasma. A method for manufacturing a semiconductor device according to the above 1), wherein the semiconductor device is formed by excitation means; or 3) a method for manufacturing a semiconductor device, wherein a film is formed on the surface of the workpiece after the cleaning step according to the above 1) or 2). Or 4) The semiconductor device manufacturing method according to 1) or 2), wherein the object to be processed is a processing chamber or a film forming chamber for performing the cleaning step.

[Action]

The present invention provides a method for forming a film on the surface of an object to be processed by removing hydrocarbons on the surface of the object to be processed, removing a natural oxide film, and removing a residue by the above-described method. Is obtained by experimentally confirming that the stabilization is achieved (see the data of contact resistance in FIG. 2).

In addition, it is possible to perform a series of continuous processes, and when there is no substrate in the processing chamber, or after performing the above-described cleaning process on the substrate, the same cleaning process is performed in the processing chamber to further improve the effect of the present invention. Can be increased.

〔Example〕

1 (a) and 1 (b) are cross-sectional views of a substrate for explaining an embodiment of the present invention.

In the figure, 1 is a base material of a silicon substrate or a metal film such as Al, tungsten (W), titanium (Ti) or a silicide film of these metals, and 2 is an insulating film having a contact hole formed therein, which is silicon dioxide (SiO ₂ ). The film, 3 is a hydrocarbon and oxide deposited on the substrate surface, and 4 is an oxide of SiO _x or A
lO _x , WO _{x and the} like.

Next, film formation including pre-treatment by plasma of a processing gas generated by high frequency (RF) power will be described in the order of steps.

(1) Treatment Removal of hydrocarbons (see Fig. 1 (a)) COCl ₂ : 5SCCM Gas pressure: 0.05Torr RF power: 50W / substrate RF frequency: 13.56MHz Chemical formula of hydrocarbon (C _m H _n ) removal process: _{C m H n + COCl 2 →} CCl 4 + H 2 O + ··· (2) if the removal of the treated oxide (FIG. 1 (b) refer) i) underlying Si, of _{W NF 3: 5SCCM H 2:} 500SCCM gas Pressure: 0.02 Torr RF power: 20 W / substrate RF frequency: 13.56 MHz Processing time: 5 to 30 sec Chemical formula of oxide removal process: SiO _x + NF ₃ → SiF ₄ + NO ₂ + ・ ・ ・ WO _x + NF ₃ → WF ₆ + NO ₂ Ii) When the base is Al BCl ₃ : 5 SCCM H ₂ : 500 SCCM Gas pressure: 0.02 Torr RF power: 20 W / substrate RF frequency: 13.56 MHz Processing time: 5 to 30 sec Chemical formula of oxide removal process: AlO _x + BCl ₃ → AlCl _y + BO _z + ... After the above processing, the substrate is replaced with H ₂ if necessary.
Heat at 800 ° C for 2 minutes in. However, at no heating row is a material of Al Hitoshihiku melting point, may be performed with H ₂ treatment is excited plasma or the like as the next process instead.

(3) treatment process, removing H of the residual impurities resulting from the process gas _2: 500 SCCM Gas pressure: 0.01～0.1Torr RF Power: 300 W / substrate RF frequency: 13.56 MHz processing time: 20～60Sec impurity removal process of the formula: F (Cl, B) + H ₂ → HF (HCl, B ₂ H ₆ ) As an impurity resulting from the processing gas in the above processing, there is F, Cl, etc. as described above, but can be removed by this processing.

(4) Wiring film formation This film formation is performed by, for example, the following method that is usually performed depending on the type of the film.

i) Sputtering of Al Ar gas pressure: 0.001 Torr RF power: 200 W / substrate RF frequency: 13.56 MHz ii) Vapor phase growth of W (CVD) WF ₆ and SiH ₄ or H ₂ were used as source gases. W is deposited by thermal decomposition on the substrate.

iii) Using TiCl ₄ and NH ₃ or N ₂ H ₄ as the source gas for CVD of TiN,
Thermal decomposition is performed on the substrate to deposit Tin.

Organic compounds of Ti such as (C
₂ H ₅₎ is sometimes used ₂ iTi (N _{3) 2.}

Here, the W film and the TiN film are used, for example, as follows.

First, W is selectively grown and embedded in the contact hole.
In order to improve the adhesiveness between the layers, a TiN film is interposed and W is grown on the TiN film on the front surface.

 FIG. 2 shows the contact resistance in this case.

FIG. 2 is a diagram showing the contact resistance of the embodiment in comparison with the conventional example.

In the figure, the horizontal axis shows the number of times of growth, and the vertical axis shows the contact resistance standardized by the value of the embodiment.

 The dotted line indicates the time when the apparatus was cleaned.

As a result, it can be seen that in the example, the contact interface is stabilized.

(5) Processing chamber cleaning i) Al sputter chamber The processing chamber is cleaned in the order of processing, processing using BCl ₃ or BF ₃ , and processing.

ii) W-CVD chamber treatment, treatment with NF ₃ or SF _6, the order of processing, cleaning the process chamber.

iii) Cleaning treatment (pretreatment) room The treatment room is cleaned in the order of treatment, treatment, and treatment.

FIG. 3 is a schematic sectional view of a pretreatment device used in the embodiment.

In the figure, 11 is a processing chamber, 12 is a gas inlet, 13 is an exhaust port,
14 is the substrate holder / ground electrode, 15 is the RF electrode, 16 is the RF power supply, 17
Numeral 19 denotes a mass flow controller (MFC).

Further, as shown in FIG. 4, an apparatus in which a pretreatment chamber and each growth chamber are connected in a vacuum-transportable manner as shown in FIG.

FIG. 4 is a schematic plan view of a continuous processing apparatus capable of carrying a vacuum between a pretreatment chamber and two growth chambers.

The arrows in the figure show the flow of the process, (A) shows the pretreatment chamber,
(B) and (C) show the growth chamber.

FIGS. 5 (a) and 5 (b) show examples of a time chart of the processing of the continuous processing apparatus.

In the figure, arrows indicate the flow of each processing substrate, and oblique lines indicate conditioning (cleaning processing of the pre-processing chamber and the growth chamber).

In the embodiment, the processing gas is excited by plasma, but the same effect can be obtained by heat or light instead of this. In this case, ordinary substrate heating means and means for irradiating the substrate with light may be used.

〔The invention's effect〕

As described above, according to the present invention, a pretreatment method that stabilizes film formation and optimizes a processing container is obtained.

As a result, cleaning of the processing substrate and the processing chamber could be achieved, stabilization of the blocking characteristics, and high reproducibility of a plurality of processes were obtained.

[Brief description of the drawings]

1 (a) and 1 (b) are cross-sectional views of a substrate for explaining one embodiment of the present invention, FIG. 2 is a diagram showing contact resistance of the embodiment in comparison with a conventional example, and FIG. 3 is an embodiment. FIG. 4 is a schematic plan view of a continuous processing apparatus in which a vacuum transfer can be performed between the preprocessing chamber and two growth chambers, and FIGS. 5 (a) and 5 (b) are continuous views. 4 shows an example of a time chart of processing of the processing device. In the figure, 1 is a base material of a metal film such as an Si substrate or Al, W, 2 is an SiO ₂ film which is an insulating film having a contact hole opened, 3 is a hydrocarbon and an oxide deposited on the substrate surface, and 4 is an oxidized film. SiO _x or AlO _x , WO _x , 11 are processing chambers, 12 is a gas inlet, 13 is an exhaust port, 14 is a substrate holder / ground electrode, 15 is an RF electrode, 16 is an RF power source, and 17 to 19 are It is a mass flow controller (MFC).

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuhiro Misawa 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-63-215037 (JP, A) JP-A-63-267430 (JP, A) JP-A-1-152274 (JP, A) JP-A-63-76333 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/304, 21 / 88

Claims (4)

(57) [Claims] 1. A pre-process for forming a wiring in a semiconductor device, wherein a surface of an object to be processed is exposed to an excited gas atmosphere containing at least one of CO, COCl ₂ , and HCN as a process gas. , A treatment for removing hydrocarbons present on the surface of the object, and H ₂ , NF ₃ , SF ₆ , BCl ₃ , BF ₃
A treatment for removing oxides present on the surface of the workpiece by exposing to an excited gas atmosphere containing at least one of the following: A method of cleaning a surface of the object to be processed, the method including a step of removing a residue resulting from the processing. 2. The method according to claim 1, wherein the excited gas atmosphere is formed by at least one of heat, light, and plasma. 3. A method for manufacturing a semiconductor device, comprising, after the cleaning step according to claim 1 or 2, forming a film on the surface of the object to be processed. 4. The method for manufacturing a semiconductor device according to claim 1, wherein the object to be processed is a processing chamber or a film forming chamber for performing the cleaning step.