JP2003297811A - Method of manufacturing semiconductor device, method of transferring semiconductor wafer, and transfer apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device which cancels the electrification of a wafer caused by plasma treatment and improves a yield and wafer quality. <P>SOLUTION: Oxygen gas is transformed into plasma and light etching is conducted to a damaged section at the bottom of a contact hole that has been formed (post treatment) (S105). The wafer is electrically charged at this point. Next, nitrogen gas purges the surface of the electrically charged wafer (S106). Consequently, the charge on the wafer is canceled, and pressure inside a post treatment chamber becomes atmospheric pressure. Then, lifter pins are elevated using air cylinders to hold the wafer by the lifter pins (S107), and a handling arm carries the wafer out of the post treatment chamber (S108). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing technique, and more particularly to a technique effective when applied to a technique for converting a semiconductor wafer (hereinafter also simply referred to as a wafer) into a plasma by converting oxygen gas into plasma.

[0002]

2. Description of the Related Art A conventional general process for forming a contact hole by dry etching an oxide film on a wafer using a dry etching apparatus will be briefly described.

[0003] First, on a wafer that is carried into the etching chamber, CF ₄ is introduced as an etching gas, CF ₄ by the high frequency power source is plasma. CF ₄ converted into plasma chemically reacts with the oxide film on the wafer, and the oxide film is dry-etched to form a contact hole on the wafer.

Next, the wafer having the contact holes formed therein is carried into the post-processing chamber and placed on a holding table having a temperature adjusting function. Since the silicon surface at the bottom of the contact hole has been damaged by the etching at the time of forming the contact hole, this damaged layer is removed by dry etching in the post-treatment chamber.

Dry etching in the post-treatment chamber is
Oxygen gas and CF as etching gas _FourMixed gas with
Used. This oxygen gas is plasma generated by a high frequency power source.
The oxygen gas that has been turned into plasma is converted into contact
The chemical reaction with the damage layer at the bottom of the
It

Next, after the post-treatment for removing the damage layer formed at the bottom of the contact hole, the wafer is held by the lifter pins by raising the lifter pins passing through the holding table.

Then, purging with nitrogen gas is carried out so that the pressure in the post-treatment chamber becomes atmospheric pressure. After that, the gate valve is opened, and the wafer held by the lifter pin is unloaded from the post-processing chamber by the handling arm.

Regarding dry etching technology using plasma, press journal company, 19
"Monthly Semiconductor World special edition", published in 1997 p
129-p143 etc.

[0009]

In the above-described conventional plasma etching process, oxygen gas is turned into plasma to light-etch the damaged portion formed at the bottom of the contact hole (post-treatment), and then the wafer is lifted by a lifter pin. It was then lifted up by the above, and then it was carried out of the processing chamber by the handling arm.

However, since the wafer immediately after the plasma etching process is charged by the ions in the plasma, it is attached to the surface of the holding table by electrostatic attraction. For this reason, the wafer sways when the lifter pin rises, and the wafer drops from the lifter pin or is transferred to the atmosphere while being charged. Therefore, there is a problem that dust is likely to adhere to the wafer.

It is an object of the present invention to provide a technique capable of discharging a charged wafer by plasma etching.

Another object of the present invention is to remove the charge on the wafer charged by plasma etching to prevent the wafer from being dropped and dust from being attached when the wafer is transferred, thereby improving the yield and quality of the semiconductor device. It is an object of the present invention to provide a wafer transfer method and a wafer transfer system.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0014]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

A method of manufacturing a semiconductor device according to the present invention is
(A) placing the wafer on the surface of a holding table provided inside the wafer processing chamber; and (b) etching the surface of the wafer by converting the oxygen gas supplied into the wafer processing chamber into plasma. And (c) after the step (b), purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure, and (d) after the step (c), the lifter penetrating the holding table. By raising the pin,
Holding the wafer with the lifter pins.

The semiconductor wafer transfer method according to the present invention comprises: (a) placing the wafer on the surface of a holding table provided inside the wafer processing chamber; and (b) supplying the wafer into the wafer processing chamber. Etching the surface of the wafer by converting oxygen gas into plasma; (c) purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure after step (b); and (d) After the step (c), the lifter pin penetrating the holding table is raised to hold the wafer by the lifter pin, and (e) the wafer held by the lifter pin is held in the wafer processing chamber. And the step of carrying it out to the outside.

Further, the semiconductor wafer transfer system according to the present invention has a wafer processing chamber provided with a holder for holding a wafer and a lifter pin penetrating the holder and movable up and down. The wafer is conveyed to the inside of the wafer processing chamber, the oxygen gas supplied to the inside of the wafer processing chamber is converted into plasma, the surface of the wafer is etched, and the inside of the wafer processing chamber is purged with nitrogen gas to bring the inside pressure to the atmospheric pressure. The wafer is carried out of the wafer processing chamber after the wafer is held by the lifter pin by raising a lifter pin passing through the wafer.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. Also, components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

FIG. 1 shows the structure of the dry etching apparatus according to the embodiment. The dry etching apparatus shown in FIG. 1 includes a load lock chamber 1, an etching processing chamber 2, a load lock chamber 3, and a post-processing chamber 4 (an example of a wafer processing chamber).

The load lock chamber 1 and the load lock chamber 3 are
The pressure is adjusted to reduce the pressure.

The etching chamber 2, CF ₄ is introduced as an etching gas, and is configured to allow plasma of CF ₄ by the high frequency power source. That is, it is configured such that CF ₄ which has been turned into plasma can be chemically reacted with the oxide film on the wafer under a predetermined pressure to dry-etch the oxide film.

As shown in FIG. 2, the post-processing chamber 4 includes a quartz bell jar 41, a high frequency introducing plate 42, a ground plate 43, and
The insulating ring 44 and the gas introducing portion 45 are external components.

A high frequency power source is connected to the high frequency introducing plate 42 so that a voltage can be applied. Further, the ground plate 43 is grounded. The insulating ring 44 is for electrically insulating the high frequency introduction plate 42 and the ground plate 43.

The gas introduction part 45 is for introducing oxygen gas, which is an etching gas, into the quartz bell jar 41.

Here, the introduced etching gas is turned into plasma by the voltage applied to the high frequency introduction plate 42.

As an example of the etching process by the dry etching apparatus having the above-mentioned structure, the oxide film 1 is formed after the MOS type element is formed by the substrate process as shown in FIG.
The process of forming the contact hole 12 as shown in FIG. 3 on the wafer 20 on which 0 and the resist film 11 are formed will be described as an example with reference to FIGS. 1 and 5. FIG. 5 is a flowchart illustrating a process of forming the contact hole 12 in the wafer 20.

First, as shown in FIGS. 1 and 5, the wafer 20 processed as shown in FIG. 2 is carried into the dry etching apparatus, and the wafer is positioned (S101).

Next, the wafer is transferred to the load lock chamber 1 and decompressed (S102). Then, the oxide film 10 is etched in the etching chamber 2 to form a contact hole 12 as shown in FIG. 3 (S
103). Specifically, in the etching processing chamber 2,
CF ₄ , Ar, C as etching gas for plasma conversion
HF ₃ or the like is used.

Next, the wafer 20 on which the contact holes 12 are formed by plasma etching is placed under a predetermined pressure in the load lock chamber 3 (S104), and is handled by a handling arm (not shown) in the post-treatment chamber 4 (LEC: Li).
ght Etch Chamber).

The internal structure of the post-processing chamber 4 is shown in FIG. In FIG. 6, the post-treatment chamber 4 includes a temperature adjustment plate 51, a lifter guide 52, a lifter pin 53, and a lifter support 5.
4, a spring 55, a stopper screw 56, and an air cylinder 57.

The temperature adjusting plate 51 is constructed so that the temperature of the wafer 20 placed on the surface can be adjusted to about 50 ° C. to 60 ° C., and the lifter pin 53 is also provided.
Through holes are formed so that the The temperature adjusting plate 51 is an example of a holding table and is made of aluminum.

The lifter guide 52 and the lifter support 54 are made of fluororesin, and the lifter pin 5
3 is made of stainless steel. Further, the tip end portion 53a of the lifter pin 53 is made of a fluororesin so as not to damage the back surface of the wafer 20.

The lifter guide 52, the lifter pin 53,
The lifter support 54, the spring 55, the stopper screw 56, and the air cylinder 57 are configured so that the lifter pin 53 can be moved up and down.

The wafer 20 transferred to the post-processing chamber 4 configured as described above is placed on the temperature adjusting plate 51 as shown in FIG. Then, oxygen gas and CF ₄
The gas mixture gas is turned into plasma, and the etching processing chamber 2
The damaged portion at the bottom of the contact hole 12 formed in step 3 is light-etched (post-processing (CDE: Chemical Dry Etch)
(S105). At this time, the wafer 20 is electrically charged by O ₂ plasma.

Next, the charged wafer 20 is purged with nitrogen gas (S106). Then, the charges on the wafer 20 are removed, and the inside of the post-processing chamber 4 becomes atmospheric pressure.

Thereafter, as shown in FIG. 7, the lifter pin 53 is raised by using the air cylinder 57 to hold the wafer 20 by the tip portion 53a of the lifter pin 53 (S107). At this time, the wafer 20 does not stick to the temperature adjustment plate 51, because the wafer 20 has been neutralized by purging with nitrogen gas. Therefore, when the lifter pins are raised, which is a problem of the prior art, the wafer does not shake and the wafer does not drop from the lifter pins. For this reason,
It is possible to improve the yield and the quality of the wafer. Further, as shown in FIG. 8, by providing unevenness on the surface of the temperature adjusting plate 51, the contact area between the wafer 20 and the temperature adjusting plate 51 may be reduced to prevent sticking.

Next, the gate valve is opened, and the wafer 20 is unloaded from the post-processing chamber 4 by a handling arm (not shown) (S108). At this time, since the wafer 20 is destaticized and is not transported to the atmosphere while being charged, dust is unlikely to adhere to the wafer.

In this way, the contact hole 12 can be formed on the wafer 20 by dry etching.

Although the invention made by the present inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the embodiments of the present invention, and does not depart from the gist of the invention. It goes without saying that various changes can be made with.

For example, in the embodiment, an example in which the charge of the wafer is eliminated in the post-treatment for forming the contact hole on the wafer, that is, the dry etching performed by converting the oxygen gas into plasma has been described. After the aluminum is embedded in the formed plug and the etch back process is performed, the charge on the wafer during the dry etching (dry etching performed by converting oxygen gas into plasma) to prevent cracks generated in the interlayer insulating film is eliminated. It may be applied in some cases.

Further, the present invention may be applied to dry etching which is carried out by converting oxygen gas into plasma which is carried out when ashing and removing the resist film.

[0042]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

Immediately after the oxygen gas is turned into plasma and the wafer is etched, purging with nitrogen gas is performed, and thereafter the lifter pin is raised so that the wafer is held by the lifter pin and conveyed. Thus, the effect of removing the electrostatic charge on the wafer can be obtained.

Therefore, since the charge on the wafer can be removed, it is possible to provide a method for manufacturing a semiconductor device which can prevent the sticking of the wafer and the holding table and the adhesion of foreign matter, and can improve the yield and the quality of the wafer. .

Further, it is possible to provide a carrying method and a carrying system capable of improving the yield and the quality of the wafer.

[Brief description of drawings]

FIG. 1 shows the configuration of a dry etching apparatus according to an embodiment.

FIG. 2 shows an external configuration of the post-treatment chamber shown in FIG.

FIG. 3 is a view showing a wafer on which an oxide film and a resist film are formed after forming a MOS type element.

FIG. 4 is a diagram showing a wafer having a contact hole formed therein.

FIG. 5 is a flowchart illustrating a process of forming a contact hole in a wafer.

FIG. 6 is a diagram showing a configuration of an inside of a post-treatment chamber.

FIG. 7 is a diagram showing a state in which a wafer is held by lifter pins.

FIG. 8 is a view in which unevenness is provided on the surface of the temperature adjustment plate.

[Explanation of symbols]

1 Road lock room 2 Etching chamber 3 Road lock room 4 Aftertreatment room 10 Oxide film 11 Resist film 20 wafers 41 Quartz bell jar 42 High frequency induction plate 43 ground plate 44 Insulation ring 45 gas inlet 51 Temperature control plate 52 Lifter Guide 53 lifter pins 53a Tip 54 lifter support 55 spring 56 Stopper screw 57 Air cylinder

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5F004 AA16 BA04 BB11 BB18 BB22                       BB24 BC06 BD01 CA01 DA01                       DA25 DA26 EB01                 5F031 CA02 HA02 HA08 HA33 HA37                       LA15 MA32 NA01 NA05 NA09                       PA21

Claims (5)

[Claims] 1. A step of: (a) placing a wafer on a surface of a holding table provided inside a wafer processing chamber; and (b) converting the oxygen gas supplied into the inside of the wafer processing chamber into a plasma to obtain a surface of the wafer. And (c) after the step (b), purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure, and (d) the step (c).
After the step, the step of holding the wafer by the lifter pin by raising a lifter pin penetrating the holding table is provided. 2. A step of: (a) placing a wafer on the surface of a holding table provided inside the wafer processing chamber; and (b) converting the oxygen gas supplied into the wafer processing chamber into a plasma to thereby make the surface of the wafer. And (c) after the step (b), purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure, and (d) the step (c).
After the step, a step of holding the wafer by the lifter pin by raising a lifter pin that penetrates the holding table, wherein the surface of the holding table is formed with unevenness. Of manufacturing a semiconductor device. 3. A step of: (a) placing a wafer on the surface of a holding table provided inside the wafer processing chamber; and (b) converting the oxygen gas supplied into the wafer processing chamber into a plasma to obtain the surface of the wafer. And (c) after the step (b), purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure, and (d) the step (c).
After the step, a step of holding the wafer by the lifter pin by raising a lifter pin passing through the holding table, and (e) carrying the wafer held by the lifter pin out of the wafer processing chamber. A method of transporting a semiconductor wafer, comprising: 4. A step of: (a) placing a wafer on a holding table provided inside the wafer processing chamber; and (b) etching the surface of the wafer by converting oxygen gas supplied into the wafer processing chamber into plasma. And (c) after the step (b), purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure, and (d) after the step (c),
A step of holding the wafer by the lifter pin by raising a lifter pin passing through the holding table; and (e) a step of unloading the wafer held by the lifter pin to the outside of the wafer processing chamber. A method of transporting a semiconductor wafer, characterized in that unevenness is formed on a surface of the holding table. 5. A wafer processing chamber having a holding table for holding a wafer and a lifter pin penetrating the holding table and movable up and down, and the wafer is transferred onto the holding table. By etching the surface of the wafer by plasmaizing the oxygen gas supplied to the inside of the wafer, purging with nitrogen gas to bring the inside of the wafer processing chamber to atmospheric pressure, and raising the lifter pin penetrating the holding table. A semiconductor wafer transfer system, wherein the wafer is carried out of the wafer processing chamber after being held by the lifter pins.