JPH1088348A - Sputtering method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain highly precise thickness distribution and film thickness over the period from the initial stage to the final stage in the use of a target. SOLUTION: Over the period from the initial stage to the final stage in the use of a target 2, the film thickness distribution of the film formed on a substrate 5 and the variation of the film forming rate are measured by a film thickness measuring means 9. Based on the variation, at every time of film formation in a primary vacuum vessel 1 being the film forming part, the inverval between the target 2 and the substrate 5 is regulated optimumly by an interval regulating means 6, and the film forming time is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering method and apparatus for depositing and forming a thin film on a substrate, and more particularly to a sputtering method and apparatus capable of forming a film with a stable film thickness distribution and film thickness accuracy.

[0002]

2. Description of the Related Art Conventionally, in a sputtering method, a method of forming a film by rotating or revolving a substrate holding portion provided opposite to a target has been used as a method for ensuring a highly accurate film thickness distribution. .

[0003]

In recent years, due to the miniaturization and high performance of products such as electronic parts, high-precision film forming performance is required even in film forming by a sputtering method. However, even in the above-described conventional method, there is a problem that the film thickness distribution and the film forming speed vary depending on the consumption state of the target, and the required high-precision film forming performance cannot be obtained.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a sputtering method and apparatus capable of stably realizing a more accurate film thickness distribution and film thickness from the early stage to the last stage of use of a target.

[0005]

Means for Solving the Problems A substrate and a target are placed in a vacuum vessel so as to face each other, a gas is introduced while maintaining a predetermined vacuum pressure in the vacuum vessel, and a voltage is applied between the vacuum vessel and the target. It has already been known that, in a sputtering method in which a film is formed by applying a pressure, when the distance between the target and the substrate is changed, the film thickness distribution and the film forming speed change. Therefore, the present invention measures the target film thickness distribution by measuring the film thickness distribution of the substrate when the target is continuously formed from the early stage to the end stage of use, thereby obtaining the target film thickness distribution required. The distance between the substrates can be determined, and at the same time, the amount of change in the deposition rate due to the change in the distance between the target and the substrate can be determined to determine the deposition time for obtaining the required film thickness. It is the thing which paid attention to.

That is, according to the sputtering method of the present invention, the change in the film thickness distribution and the film formation rate of the film formed on the substrate is obtained from the initial stage to the end stage of use of the target, and the change amount is determined based on the change amount Each time the film is formed, the optimum distance between the target and the substrate and the film formation time are determined and the film is formed, whereby a more accurate film thickness distribution and film thickness can be stably obtained. .

Preferably, the optimum distance between the target and the substrate and the film formation time in the subsequent film formation are determined based on the measurement results of the film thickness distribution and the film thickness during the film formation on the preceding substrate. Since the film formation conditions are determined by feeding back the measurement results while sequentially forming the films and determining the film formation conditions for the next film formation, it is possible to obtain a film thickness distribution and film thickness with extremely high accuracy. .

[0008] The sputtering apparatus of the present invention includes a film forming unit capable of changing the distance between the target and the substrate and a film thickness measuring unit for measuring the film thickness of the film formed on the substrate. The method can be performed.

Preferably, the substrate is placed on a first vacuum vessel in which a substrate holding portion, an electrode and a target are provided, and a distance adjusting means for varying a distance between the target and the substrate is provided. A stage and a second vacuum vessel in which the film thickness measuring means are disposed are connected to the first vacuum vessel and the second vacuum vessel via a gate valve, and the first vacuum vessel is connected to the second vacuum vessel. A third unit provided with a transfer unit for transferring a substrate;
And a film formed earlier in the third vacuum vessel is measured while sequentially forming a film in the first vacuum vessel, and the measurement result is stored in the first vacuum vessel. Film formation can be performed by feeding back to film formation conditions, and highly accurate and accurate film thickness distribution and film thickness can be stably realized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sputtering apparatus according to one embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, an electrode 3 to which a target 2 is fixed is fixed in a first vacuum vessel 1.
A substrate holding portion 4 is provided opposite to the substrate 1 and on which the substrate 5 can be placed and fixed. A high frequency voltage or a DC voltage is supplied to the electrode 3 from a power supply (not shown).

The substrate holding section 4 is provided with an electrode 3
Is adjustable so that the distance between the target 2 and the substrate 5 can be arbitrarily varied. Although not shown, the vacuum vessel 1 is provided with a vacuum exhaust unit and a gas introduction unit, and is configured so that the pressure in the vacuum vessel 1 can be adjusted.

The second vacuum vessel 7 contains a substrate 5 on which a film has been formed.
And a film thickness measuring means 9 facing the stage 8. Between the first vacuum vessel 1 and the second vacuum vessel 7, a third vacuum vessel 10 provided with a substrate transfer means 11 is provided.

A gate valve 12 is connected between the first vacuum vessel 1 and the third vacuum vessel 10, and between the third vacuum vessel 10 and the second vacuum vessel 7, respectively. Second
Although not shown, each of the vacuum vessel 7 and the third vacuum vessel 10 is provided with a vacuum exhaust unit.

A description will now be given of the sputtering operation performed by the apparatus configured as described above. First, as conditions, a target film thickness distribution A ₀ , a target film thickness B ₀ , and a film forming time T ₀ are determined. The deposition time is empirically determined by the magnitude of the voltage supplied to the electrode 3. First, the first substrate 5 is placed on the substrate holding unit 4 by using a substrate transfer unit (not shown), and a film is formed with the distance between the target 2 and the substrate 5 set to L ₁ and the film formation time T ₀ . After the film formation, the substrate 5 is transferred onto the stage 8 in the second vacuum container 7 by using the substrate transfer means 11 disposed in the third vacuum container 10. Next, the film thickness distribution and thickness of the substrate 5 are measured by the film thickness measuring means 9. The measurement results of the film thickness distribution and the film thickness of the substrate 5 are denoted by A ₁ and B ₁ , respectively. The measured substrate 5 is carried out of the apparatus by using a substrate carrying means (not shown).

Next, the second substrate 5 is placed in the same manner as the first substrate.
Placed on a substrate holder 4, is the distance between the target 2 and the substrate 5 and L ₁ and a minute amount of a different L _2, deposition time T _0, a film is formed. After the film formation, the substrate 5 is transferred onto the stage 8 in the second vacuum container 7 by using the substrate transfer means 11 disposed in the third vacuum container 10. Next, the film thickness distribution and thickness of the substrate 5 are measured by the film thickness measuring means 9. The measurement results of the film thickness distribution and the film thickness of the substrate 5 are defined as A ₂ and B ₂ , respectively.
The measured substrate 5 is transported out of the apparatus using a substrate transport unit (not shown).

Next, similarly to the first substrate 5, the third substrate 5 is
It is placed on the substrate holder 4. Here, the distance L ₃ between the target 2 and the substrate 5, which are the film forming conditions of the substrate 5, and the film forming time T
Figure 2 a method of determining ₃ will be described with reference to FIG. FIG. 2 is a diagram showing an example of a relationship between a target-substrate distance and a film thickness distribution in a target in an early stage of use, and FIG. 3 is an example of a relationship between a target-substrate distance and a film thickness in a target in an early stage of use. FIG. As shown in FIG. 2, the change amount E of the film thickness distribution due to the change of the target-substrate distance is obtained from the measurement results of the first and second substrates.
It is expressed by the following equation (1).

E = (L ₂ −L ₁ ) / (A ₂ −A ₁ ) (1) Therefore, the optimal target satisfying the target film thickness distribution A ₀ −
Substrate distance L ₃ is obtained by the following equation (2).

L ₃ = E (A ₀ −A ₂ ) + L ₂ (2) As shown in FIG. 3, the amount of change F in the film thickness due to the change in the distance between the target and the substrate is the first sheet. And the measurement result of the second substrate, the following expression (3) is obtained.

F = (B ₂ −B ₁ ) / (L ₂ −L ₁ ) (3) The film thickness B _L3 that satisfies the target-substrate distance L ₃ is obtained by the following equation (4).

B _L3 = F (L ₃ −L ₂ ) + B ₂ (4) Since the film formation time of the first and second substrates 5 is T ₀ ,
The film forming time T ₃ is obtained by the following equation (5).

T ₃ = (B ₀ / B _L3 ) · T ₀ (5) From the above, the film forming condition of the third substrate 5 is determined, the distance between the target and the substrate is L ₃ , and the film forming time is Is formed under the condition of T ₃ to obtain a target film thickness distribution and a target film thickness. After the film formation, the substrate 5 is transferred to the second vacuum container 7 using the substrate transfer means 11 provided in the third vacuum container 10.
Is transferred onto the stage 8 located inside. Next, the film thickness distribution and the film thickness of the substrate 5 are measured by the film thickness measuring means 9. The measurement result of the substrate is similarly fed back to the film formation conditions of the substrate 5. That is, the optimum target-substrate distance Ln of the n-th sheet is obtained by the following equation (6), and the optimum film formation time Tn of the n-th sheet is obtained by the following equation (7).

Ln = {(L _n−1 −L _n−2 ) / (A _n−1 −A _n−2 )} · (A ₀ −A _n−1 ) + L _N−1 (n ≧ 3) _{·· (6) Tn = B 0} T 0 (L n-1 -L n-2) / {(L n-1 -L n-2) B n-1 + (B n-1 -B n-2 ) (L _n −L _n−1 )｝ (n ≧ 3) (7) As described above, by repeating the same operation sequentially, a more accurate film thickness distribution can be obtained from the beginning to the end of use of the target. And a stable film thickness.

Incidentally, the configuration of the apparatus, the method of processing the film thickness distribution and the film thickness data are not limited to the above-described embodiment.

[0025]

According to the sputtering method of the present invention,
As is clear from the above description, the change in the film thickness distribution and the film formation rate of the film formed on the substrate is obtained from the initial use period to the end use of the target, and the change amount is determined based on the change amount. Each time the film is formed, the optimum distance between the target and the substrate and the film formation time are determined to form the film, so that a more accurate film thickness distribution and film thickness can be stably obtained.

Further, the optimum distance between the target and the substrate and the film formation time in the subsequent film formation are determined based on the film thickness distribution and the film thickness measurement result during the film formation on the preceding substrate. When the film is formed, the measurement result is fed back while sequentially forming the film, and the film forming conditions at the time of the next film formation are determined, so that a highly accurate film thickness distribution and film thickness can be obtained.

Further, according to the sputtering apparatus of the present invention, there is provided a film forming section for changing the distance between the target and the substrate and a film thickness measuring section for measuring the film thickness of the film formed on the substrate. The above sputtering method can be performed.

Also, a first vacuum vessel provided with a substrate holder, an electrode and a target therein, and provided with a distance adjusting means for varying a distance between the target and the substrate, a stage on which the substrate is placed, and a film. A thickness measurement unit is communicated with a second vacuum vessel provided therein, the first vacuum vessel and the second vacuum vessel via a gate valve, and the substrate is transferred from the first vacuum vessel to the second vacuum vessel. And a third vacuum vessel provided with a transfer means for performing the measurement, the film formed earlier in the third vacuum vessel is measured while forming the film sequentially in the first vacuum vessel, and the The measurement results can be fed back to the film formation conditions in the first vacuum vessel to form a film, and highly efficient and accurate film thickness distribution and film thickness can be stably realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a sputtering apparatus of the present invention.

FIG. 2 is a diagram showing a correlation between a target-substrate distance and a film thickness distribution in an early stage of use of a target.

FIG. 3 is a diagram illustrating a correlation between a target-substrate distance and a film thickness in an early stage of use of a target.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first vacuum vessel 2 target 3 electrode 4 substrate holding unit 5 substrate 6 interval adjusting means 7 second vacuum vessel 8 stage 9 film thickness measuring means 10 third vacuum vessel 11 substrate transport means 12 gate valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Maruyama 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. 72) Inventor Susumu Takeyama 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture, Japan Matsushita Electric Industrial Co., Ltd. 1006 Kadoma, Kadoma City Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A substrate and a target are placed in a vacuum vessel so as to face each other, a gas is introduced while maintaining a predetermined vacuum pressure in the vacuum vessel, and a voltage is applied between the vacuum vessel and the target. In the sputtering method for forming a film,
From the initial use to the end of use of the target, the change in film thickness distribution and film formation rate of the film formed on the substrate is determined, and based on the change, the optimal target and substrate A sputtering method wherein a film is formed by determining a distance between the films and a film forming time. 2. An optimum distance between a target and a substrate during a subsequent film formation and a film formation time are determined based on a film thickness distribution and a film thickness measurement result at the time of film formation on a preceding substrate. The sputtering method according to claim 1, wherein the film is formed. 3. A substrate and a target are placed in a vacuum vessel so as to face each other, a gas is introduced while maintaining a predetermined vacuum pressure in the vacuum vessel, and a voltage is applied between the vacuum vessel and the target. In a sputtering apparatus for forming a film,
A sputtering apparatus, comprising: a film forming unit that can change a distance between a target and a substrate; and a film thickness measuring unit that measures a film thickness of a film formed on the substrate. 4. A first vacuum vessel in which a substrate holder, an electrode, and a target are provided, and a distance adjusting means for varying a distance between the target and the substrate is provided, a stage on which the substrate is mounted, and a film. A thickness measurement unit is communicated with a second vacuum vessel provided therein, the first vacuum vessel and the second vacuum vessel via a gate valve, and the substrate is transferred from the first vacuum vessel to the second vacuum vessel. 4. The sputtering apparatus according to claim 3, further comprising a third vacuum vessel provided with a transfer unit that performs the transfer.