JPH0766125A - Reduced pressure processing system - Google Patents

Abstract

PURPOSE:To achieve good processing by setting the weight of a member for pressing an object to be processed on the front thereof higher than the lifting force of gas pressure thereby setting an arbitrary gas pressure being employed for ensuring thermal conductivity. CONSTITUTION:A heating plate 3 mounting an Si wafer 4 is lifted to cause lifting of a presser ring 8 placed on a separating plate 7 thus pressing the Si wafer 4. A weight 9 is placed on the presser ring 8. When the pressure on the rear surface is 1300Pa, the force for pushing up the wafer is 2.30kg in case of a 6 inch wafer. Consequently, when the total weight of the presser ring 8 and the weight 9 is 2.30kg for a 6 inch wafer, gas pressure of 1300Pa is obtained on the rear surface and thereby the thermal conductivity is enhanced and quick temperature rise/cooling characteristics are obtained, resulting in a good filling of a contact hole using high temperature sputtering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduced pressure processing apparatus,
In particular, the present invention relates to a depressurization processing apparatus configured to process an object to be processed under reduced pressure, receive the gas pressure from the rear surface of the object, and press the front surface thereof with a pressing member. INDUSTRIAL APPLICABILITY The present invention can be used as, for example, an apparatus for processing an electronic material such as a semiconductor substrate under reduced pressure, for example, a sputtering apparatus, a deposition or etching apparatus under reduced pressure, or the like.

[0002]

2. Description of the Related Art Conventionally, a processing apparatus for processing an object to be processed under reduced pressure has been used in various fields. For example, a high-temperature sputtering apparatus used for manufacturing a semiconductor element performs film formation by sputtering on a semiconductor substrate while heating the semiconductor substrate to be processed under reduced pressure.

A high temperature sputtering technique, for example, a high temperature Al sputtering technique has been attracting attention as a promising technique. That is, L
With the miniaturization of elements such as SI, the technique of burying metal in the fine connection hole has become important, and blanket CVD tungsten, selective CVD tungsten, etc. have been proposed as the technique of burying metal in the fine connection hole. ,
Al embedding by high-temperature sputtering that can realize embedding at low cost and high throughput is considered to be promising.

In the high temperature sputtering method, the substrate to be processed is
By sputter depositing an Al-based material such as Al or an Al alloy in a state of being heated at a high temperature of 500 ° C., the Al-based material is fluidized or brought into a state close to that, and the Al-based material is filled in the connection hole. This is a flattening technique. In this case, as a base of the Al-based material, for example, Al such as Ti
It is known that when a material having a good wettability with is used, the interfacial reaction between the Al-based material and the underlying Ti during film formation proceeds favorably, so that the burying property is greatly improved.

It is known to use a multi-chamber sputtering apparatus as shown in FIG. 6 for film formation by high temperature sputtering. In this apparatus, a plurality of chambers (etching chamber 14, sputtering chambers 15 to 17, load chamber 18) are formed around a transfer chamber 12 via a gate valve 13, and all the chambers are in a reduced pressure atmosphere. is there. The reason why such a multi-chamber system is used is that when Ti is oxidized, the wettability with the upper Al-based material is deteriorated, and therefore it is necessary to continuously form a film in a vacuum. The wafer transfer arm 11 that transfers the wafer W that is the object to be processed receives the wafer W in the load lock chamber 18 and places it on the heating plate of the sputtering chamber. A metal is formed on the wafer W simultaneously with heating.
First, Ti is used in the sputtering chamber 15, Al is used in the sputtering chamber 16, and the antireflection film T is used in the sputtering chamber 17.
Deposit iON. In the figure, 20a to 20c are intake / exhaust and gas introduction systems, 21 is a supply cassette, and 22 is a recovery cassette. Reference numeral 11a denotes a transfer arm joint, and 19 denotes its axis.

7 and 8 are sectional views of the sputtering chamber. A target 2 is arranged above the vacuum chamber 1. First, as shown in FIG. 7, the wafer transfer arm 1
1. The Si wafer 4 transferred by
Can be placed on.

Next, the heating plate is lifted as shown in FIG. At this time, the pressing ring 8 placed on the deposition-inhibiting plate 7 is lifted, and the Si wafer 4 is pressed by its own weight. That is, the pressing ring 8 serves as a pressing member that presses the target object (substrate wafer 4). Next, gas is introduced through the gas introduction pipe 6, and the introduced gas such as Ar acts as a heat conduction medium between the heating plate 3 and the Si wafer 4. The substrate wafer 4, which is the object to be processed, receives the Ar gas pressure from the back surface. The bellows 5 is used so that the vacuum can be maintained even when the heating plate moves up and down.

[0008]

However, in the above heating mechanism, the wafer to be processed is lifted by the Ar gas introduced as a heat transfer medium to the back surface of the wafer to be processed. There was a problem that I could not raise it. For example, the backside gas pressure needs to be about 600 Pa or more in order to secure the thermal conductivity. In this case, the backside gas pushing up the wafer is about 6 g / cm ² . Therefore, the wafer is lifted with a force of 1.06 kg for a 6-inch wafer and 1.88 kg for an 8-inch wafer. Therefore 1k
There is a problem in that the gas pressure cannot be raised to the required gas pressure with a holding ring of about g.

Further, the conventional pressing ring presses the circumference of the wafer by surface contact. For this reason, heat escapes to the ring, making it difficult to make the heating temperature uniform within the surface of the wafer that is the object to be processed.

The present invention solves the above problems by treating the object to be treated under reduced pressure, and the object to be treated receives gas pressure from its back surface, and its front surface is held by a holding member. With regard to the depressurization processing device, the gas pressure used for ensuring thermal conductivity can be set arbitrarily, and the object is to provide a technology that can achieve good processing. Also, uniform in-plane processing of the object to be processed. It aims at providing the technology which can achieve.

[0011]

The present invention has been proposed to solve the above problems. That is, according to the invention of claim 1 of the present application, the object to be processed is processed under reduced pressure, the object to be processed receives gas pressure from the back surface thereof, and the front surface thereof is pressed by the pressing member. In the apparatus, the weight of the pressing member is set to be larger than the force by which the gas pressure lifts the object to be processed, which achieves the above-mentioned object.

The invention according to claim 2 of the present application is the depressurization processing apparatus according to claim 1, wherein the pressing member comprises a pressing member main body and a replaceable weight adjusting additional member. By doing so, the above-mentioned object is achieved.

According to the invention of claim 3 of the present application, the object to be processed is processed under reduced pressure, the object to be processed receives gas pressure from its rear surface, and its front surface is pressed by a pressing member. In the processing apparatus, the pressure-reducing processing apparatus is characterized in that the pressing member and the object to be processed are in contact with each other at a plurality of points, and thereby the above-mentioned object is achieved.

The invention according to claim 4 of the present application is the depressurization processing apparatus according to claim 3, wherein the pressing member comprises a pressing member main body and a replaceable weight adjusting additional member. By doing so, the above-mentioned object is achieved.

[0015]

According to the invention of claim 1 of the present application, the weight of the pressing member (pressing ring or the like) is set to be greater than the force with which the backside gas lifts the object (wafer or the like) to be processed. Improve characteristics (wafer heating characteristics, etc.). In addition to the body of the pressing member,
By providing a replaceable additional member for weight adjustment, for example, the pressing ring may be composed of a plurality of parts and used in combination as necessary.

That is, by making the weight of the pressing member (pressing ring or the like) more than the lifting force of the backside gas, the gas pressure on the backside of the object to be processed (substrate or the like) is increased to improve the thermal conductivity. In this way, it is possible to improve the processing such as increasing the temperature of the wafer and increasing the cooling rate.

According to the invention of claim 3 of the present application, the contact of the pressing member (pressing ring or the like) with the object to be processed (wafer to be processed, etc.) is set at a plurality of points, so that the inside of the wafer to be processed is By improving the temperature distribution of
Uniform processing can be achieved. That is, by reducing the contact area of the pressing member with the object to be processed, the heat escape from the periphery of the object (wafer) to the pressing member (holding ring) is reduced, and the temperature around the object (wafer) is reduced. By reducing the decrease, it becomes possible to improve the temperature uniformity within the surface of the object (wafer) to be processed, and the processing can be made uniform.

[0018]

EXAMPLES Specific examples of the present invention will be shown and described below. However, it should be understood that the present invention is not limited to the embodiments.

Example 1 In this example, the present invention is applied to a high temperature sputtering apparatus, and in particular, by increasing the weight of a pressing ring which is a pressing member for pressing a wafer which is an object to be processed, this pressing is performed. The weight of the member is larger than the gas pressure from the back surface of the object to be processed and the force for lifting the object to be processed. This embodiment will be described with reference to FIG.

The structure of the processing apparatus of this embodiment is the same as that of the prior art shown in FIGS. 7 and 8 except for the holding ring 8 which is a holding member. The Si wafer 4 transferred by the wafer transfer arm is placed on the heating plate 3. Then the heating plate 3 is lifted. Protective plate 7
At this time, the pressing ring 8 placed on the
The Si wafer 4 is pressed down.

In the case of this embodiment, a weight 9 for a retaining ring is placed on the retaining ring 8 in an overlapping manner. For this reason, a greater weight is applied to the wafer 4, which is the object to be processed, than in the conventional technique. In this way, the weight 9 for the pressing ring is added to the pressing ring 8 which is the main body of the pressing member, and serves as an additional member for adjusting the weight. It was replaceable and could be adjusted to different weights.

The required total weight of the pressing ring 8 to which the weight 9 is added can be calculated as follows. Back side
In order to ensure the gas pressure up to 1300 Pa with a margin to ensure the thermal conductivity of the gas,
The weight of the ring may be set as follows. 1300
In the case of Pa, the force of the backside gas pushing up the wafer is about 13g
/ Cm ² . Therefore, in the case of a 6 inch wafer, 2.
In the case of a 30 kg 8-inch wafer, the wafer is lifted by a force of 4.08 kg.

Therefore, if the total weight of the press ring 8 and the press ring weight 9 is 2.30 kg for a 6-inch wafer and 4.08 kg for an 8-inch wafer, a backside gas pressure of 1300 Pa is obtained. Since the thermal conductivity is increased, rapid temperature rising and cooling characteristics can be obtained, and good filling of contact holes using high temperature sputtering can be achieved.

Next, a process of filling the connection hole by high temperature sputtering using the above apparatus will be described with reference to FIG.

After forming the first-layer Al wiring 1a, an interlayer insulating film SiO ₂ 2a is formed, and a normal photoresist,
The connection hole is opened by the RIE process. Here, the film thickness of the interlayer film was 500 nm, and the diameter of the connection hole was 0.6 μm.

Next, using a single-wafer multi-chamber sputtering apparatus, Ti3a is deposited to a thickness of 100 nm under the above conditions. Ti film forming condition DC power 4 kW process gas Ar 100 SCCM sputter pressure 3 mTorr substrate heating temperature 150 ° C.

Subsequently, the substrate is transferred to another chamber and Al-1 wt% Si5a is deposited to a thickness of 600 nm.
At this time, it is important to form a film while maintaining the substrate temperature at 500 to 600 ° C. Deposition rate is 600 nm / min
Therefore, the film formation time is 1 minute. The film forming conditions were as follows. AlSi film forming conditions DC power 5 kW Process gas Ar 100 SCCM Sputtering pressure 3 mTorr Substrate heating temperature 550 ° C.

The back side (back side) gas pressure is, for example, 400 Pa.
If it is low, it takes about 40 seconds to raise the temperature, so it is practically 500 ° C.
The holding time is about 20 seconds, and Al does not flow sufficiently in this case, and good embedding characteristics cannot be obtained.

On the other hand, the back side (back side) gas pressure is 100
In the case of 0 Pa, it takes about 15 seconds to raise the temperature, so it is practically 500
The time to be kept above ℃ is about 45 seconds,
Flow, and good embedding characteristics are obtained.

Example 2 Next, the contact between the pressing member and the object to be processed was changed to point contact, and
An example in which the contact area of the pressing member (pressing ring) is reduced will be described with reference to FIG.

The structure is shown in FIGS. 7 and 8 except for the holding ring.
It is the same as the prior art of. The Si wafer 4 transferred by the wafer transfer arm is placed on the heating plate 3. Then the heating plate is lifted. At this time, the pressing ring 8 placed on the adhesion-preventing plate 7 is lifted, and S
The i-wafer 4 is pressed down.

In the case of this embodiment, the pressing ring 8 has a plurality of protrusions 10 as shown in FIG. 4 which is a perspective view (enlarged view of portion A in FIG. 3) from below. Therefore, when the heating plate 3 is lifted, only the tip of the protrusion 10 contacts the wafer 5. That is, it becomes point contact. In addition,
The material of the ring and the protrusion in this embodiment is stainless steel.

Therefore, the escape of heat from the wafer 4 to the ring 8 is reduced, the temperature uniformity in the wafer 4 is improved,
The Al filling uniformity is improved. In the case of an 8-inch wafer, the temperature distribution within the wafer is about 60 ° C. in surface contact.
In this case, even if the central portion of the wafer is 550 ° C., the peripheral portion has a temperature of 490 ° C., which means that the filling characteristics in the peripheral portion are insufficient. However, when the point contact is used as in the present embodiment, the temperature distribution becomes about 30 ° C., and good embedding characteristics can be secured in the entire area of the wafer.

Embodiment 3 In this embodiment, as shown in FIG. 5, the contact between the pressing ring 8 which is a pressing member and the wafer 5 which is the object to be processed is point contact (the pressing ring 8 which makes point contact is The weight of the pressing member (pressing ring 8) and the pressing member (pressing ring 8) is made larger than the force by which the backside gas pressure lifts the wafer 5 by the weight 9 which is an exchangeable additional member.

It can be said that this embodiment has the advantages of the first and second embodiments.

[0036]

According to this embodiment, an object to be processed such as a wafer is processed under a reduced pressure, the object to be processed receives gas pressure from its back surface, and its front surface is pressed by a pressing member. With regard to the decompression processing device, the gas pressure used for ensuring thermal conductivity etc. can be arbitrarily set appropriately, so that it is possible to provide a technology capable of achieving good processing, and also the in-plane processing of the object to be processed. It was possible to provide a technique capable of achieving homogenization.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a decompression processing apparatus according to a first embodiment.

FIG. 2 is an explanatory diagram of an embedding process in the first embodiment.

FIG. 3 is a configuration diagram showing a decompression processing apparatus according to a second embodiment.

FIG. 4 is a partially enlarged view of the device according to the second embodiment.

FIG. 5 is a configuration diagram showing a decompression processing apparatus according to a third embodiment.

FIG. 6 is a diagram showing a configuration example of a multi-chamber processing apparatus.

FIG. 7 is a diagram showing a conventional technique.

FIG. 8 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Target 3 Heating plate 4 Processing target (wafer) 5 Bellows 6 Gas introduction tube 7 Adhesion prevention plate 8 Pressing member / pressing member main body (pressing ring) 9 Additional member (weight) 10 Protrusion

Claims (4)

[Claims] 1. A depressurization processing apparatus configured to process an object to be processed under reduced pressure, receive the gas pressure from the back surface of the object, and press the front surface thereof with a pressing member. A depressurization processing apparatus, wherein a weight of the gas is set to be larger than a force of lifting an object to be processed. 2. The depressurization processing apparatus according to claim 1, wherein the pressing member includes a pressing member main body and a replaceable weight adjusting additional member. 3. A depressurization processing apparatus configured to process an object to be processed under reduced pressure, receive the gas pressure from the back surface of the object, and press the front surface of the object with a pressing member. A decompression processing apparatus, wherein the contact with the object to be processed is a plurality of point contacts. 4. The depressurization processing apparatus according to claim 3, wherein the pressing member includes a pressing member body and a replaceable weight adjusting additional member.