JP3376946B2 - Target replacement time determination method and computer-readable recording medium recording the program - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining a target replacement time suitable for maintenance of a sputtering apparatus and a computer-readable recording medium having the program recorded therein, and particularly when a plurality of sputterings under different conditions are performed. The present invention also relates to a target replacement timing determination method capable of highly accurate determination, and a computer-readable recording medium recording the program thereof.

[0002]

2. Description of the Related Art Conventionally, a sputtering apparatus has been used in a process of forming a metal film in manufacturing a semiconductor device. A target that is a raw material of a metal film is used in this sputtering apparatus. Since the target is a consumable member, it must be replaced before the usage limit is exceeded. Therefore, the replacement time is determined by the following method.

FIG. 4 is a flow chart showing a conventional target replacement timing determination method.

Here, the target is replaced and then n
The (n ≧ 2) -th operation will be described.

In the conventional determination method, first, the target integrated power up to the previous time is set to β _n-1 (step S2).
1). The target integrated power is an integrated value of power supplied to the target and supply time.

Next, the sputtering power is turned on for the nth sputtering (step S).
22). The power at this time is X _n (kW).

After Y _n seconds have passed since the sputter power (power) was turned on, the sputter power (power) is turned off (step S23). That is, X _n (kW)
Sputtering is performed for Y _n seconds with the power.

After that, the integrated power α _n in the n-th sputtering is calculated by the following formula 1 (step S2)
4).

[0009]

[Equation 1]

Next, the total target integrated electric power β _n at the time when the n-th sputtering is completed is calculated from (β _n-1 + α _n ) (step S25).

Then, it is determined whether the total target integrated power β _n is smaller than a predetermined value K (step S26).
At this time, if the total target integrated power β _n is smaller than the predetermined value K, n = n + 1 is set (step S27),
The (n + 1) th operation is performed.

On the other hand, when the total target integrated electric power β _n is not less than the predetermined value K, an alarm is generated at that time (step S28), the sputtering is stopped, and the target is replaced.

However, in this conventional target replacement timing determination method, when the sputtering conditions having different target erosion distributions are used together, an appropriate determination cannot be made unless a large margin is set.

FIGS. 5A to 5C are schematic views showing various sputtering conditions. There are various sputtering conditions. For example, as shown in FIG. 5 (a), four regions are concentrically formed in the target 11a so as to be deeper than other regions, and as shown in FIG. 5 (b). There are those in which the depth is increased toward the center of the target 11b, and those in which a region having a constant distance from the outer edge of the target 11c is deeper than other regions as shown in FIG. 5C.

In the above-mentioned conventional determination method, for example, FIG.
When the condition shown in (b) and the condition shown in FIG. 5 (c) are used together, and the usage ratio is unknown, the target exchange when sputtering is performed under all the conditions shown in FIG. 5 (b) It was necessary to set either the integrated power value or the target replacement integrated power value when sputtering was performed under the conditions shown in FIG. For this reason, when the above two conditions are used together at a certain ratio, the decrease in the central portion of the target is fast under one condition, and the decrease in the vicinity of the outer periphery of the target is fast under the other condition. It is obvious that the integrated power will last longer than in the case, but the advantage in that case cannot be utilized.

Therefore, there has been proposed a method of determining the target replacement time in consideration of different sputtering conditions (JP-A-10-330925). According to the determination method described in this publication, when calculating the total sputter integrated power after each sputtering, the ratio of the sputter rate and the sputter power at that time is taken into consideration to obtain the sputter integrated power at that time. ing.

[0017]

However, according to the above-mentioned Japanese Patent Laid-Open No. 10-330925, although the intended purpose could be achieved, the target replacement time is determined based on the total sputter integrated power. Because
There is a problem that delicate determination is difficult.

The present invention has been made in view of the above problems, and it is possible to determine the replacement time with high accuracy even when performing a plurality of sputterings under different conditions, and to reduce the cost. It is an object of the present invention to provide a target replacement timing determination method and a computer-readable recording medium recording the program thereof.

[0019]

A method for determining a target replacement time according to the present invention comprises a step of partitioning a target into a plurality of regions, and a step of obtaining an electric power used for each sputtering after each sputtering is completed. And, a step of determining the erosion depth in each region of the target by the sputtering in association with the power, and a step of determining the total erosion depth at the time when the sputtering of the target is finished for each region,
Determining whether or not the total erosion depth of at least one of the plurality of regions has reached a preset depth set for the region.

In the present invention, the erosion depth of each time is determined for each of the plurality of regions from the electric power used for each sputtering, and the total erosion depth is determined for each of the plurality of regions. Since it is judged whether or not the planned depth is reached, even if the conditions are different in multiple sputtering, it is higher than the conventional method that judges based on the total integrated power. It is possible to judge with accuracy.

In the present invention, the planned depth may be the same for a plurality of the areas.

The step of partitioning the target includes
It may be a step of partitioning the target into a plurality of concentric regions.

Further, the step of obtaining the erosion depth in each of the regions may include the step of multiplying the electric power by a coefficient associated with the condition of the current sputtering in each of the regions.

A computer-readable or recording medium in which a target replacement timing determination program according to the present invention is recorded is characterized by causing a computer to execute the above-mentioned steps (procedures).

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for determining a target replacement time according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 is a flow chart showing a target replacement timing determination method according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing a target to be sputtered.

Here, the target is replaced and then n
The (n ≧ 2) -th operation will be described.

In this embodiment, as shown in FIG.
The target 1 to be sputtered is divided into, for example, 26 areas A, B, ..., Z in concentric circles in advance. Then, in the n-th operation after replacing the target, first, the total erosion depths of the target 1 in the respective areas A to Z by the previous sputtering are set to A _{n-1 to} Z _n-1 respectively. (Step S1).

Next, the sputtering power is turned on for the nth sputtering (step S).
2). The power at this time is X _n (kW).

After Y _n seconds have passed since the sputter power (power) was turned on, the sputter power (power) is turned off (step S3). That is, sputtering is performed for Y _n seconds at a power of X _n (kW).

After that, the integrated power α _n in the n-th sputtering is calculated in the same manner as the equation 1 (step S4).

Next, the erosion depths A _n 'to Z _n ' of the target 1 by the n-th sputtering in the areas A to Z are calculated by the following equation 2 (step S5).

[0032]

[Equation 2]

However, γ _{am to} γ _zm are the areas A to Z, respectively.
Is a target erosion distribution coefficient for each area determined by the sputtering condition m.

Next, the total erosion depths A _{n to} Z _n of the target 1 at the time when the n-th sputtering in each area A to Z is completed is calculated by the following formula 3 (step S6).

[0035]

[Equation 3]

Then, it is determined whether the total erosion depths A _{n to} Z _n in all the areas A to Z are smaller than a predetermined value L (step S7). At this time, when the total erosion depths A _{n to} Z _n in all the areas A to Z are smaller than the predetermined value L, n = n + 1 is set (step S8), and the (n + 1) th operation is performed.

On the other hand, if the total erosion depth in any of the areas A to Z is greater than or equal to the predetermined value L, an alarm is generated at that point (step S9).
Stop sputtering and replace target.

In the first operation after replacing the target, the erosion depth up to the previous time may be regarded as 0 in the step S1.

As described above, in the present embodiment, the integrated electric power value of the sputtering at that time is multiplied by the target erosion distribution coefficient for each area which is different depending on the sputtering condition, and each erosion for each target area by the sputtering at that time is calculated. , The target replacement time is determined by accumulating it. That is, calculate the total erosion at that time for each target area,
The target replacement time is determined by taking into consideration the target erosion distribution which differs for each sputtering condition and the usage ratio of each sputtering condition.

Therefore, even when the sputtering conditions such as the position of the cathode magnet are different for each sputtering, the target replacement timing can be accurately determined. For example, even when two conditions are selected from FIGS. 5A to 5C, the target erosion depth that differs depending on the sputtering condition and the target area is taken into consideration. It is possible to make a decision on target replacement. Such an effect can be obtained not only when there are two conditions but also when more sputtering conditions are used together.

Although the target is divided into 26 areas A to Z in the above embodiment,
The number of sections is not particularly limited. The shape of the divided area is not particularly limited to the concentric donut shape. The concentric donut shape in the above-described embodiment is based on the assumption that the target erosion is distributed in the concentric shape.

Further, in the above-mentioned embodiment, in the process of step S7, the judgment standard of each area A to Z is the same predetermined value L, but the judgment standard may be different for each area. For example, the criterion for the area A is La,
The judgment criterion of the area Z can be set to Lz. By setting the determination criteria in this way, it is possible to apply the method when using a special target having a different thickness depending on the site, when using a target that has been used up again, and the like.

Further, the member for which the replacement time is determined is not particularly limited to the target as long as it is a consumable member such as a member worn out by use or a member whose material changes in position. FIG. 3 is a flowchart showing an embodiment of the present invention applied to consumable members in general.

In general application of the consumable member, the member 1 that is consumed by use is, for example, 26 areas A, B, ...
.., Z in advance, and in the n-th operation after exchanging the members, first, the total erosion depth of the members by the previous use in each of the areas A to Z is A respectively.
_{It is set to n-1 to} Z _n-1 (step S11).

Then, the discharge power is turned on for the n-th use (step S12). The power at this time is X _n (kW).

After Y _n seconds have passed since the discharge power (power) was turned on, the discharge power (power) is turned off (step S13). That is, discharging is performed for Y _n seconds with a power of X _n (kW).

After that, the integrated power α in the nth discharge
_{The n} is calculated in the same manner as the mathematical expression 1 (step S14).

Next, the erosion depths A _n ′ to Z _n ′ of the member due to the n-th discharge in each of the areas A to Z are calculated by the mathematical expression 2 (step S15).

Next, the total erosion depth A of the member at the time when the n-th discharge in each area A to Z is completed.
_{n to} Z _n are calculated by Equation 3 (step S16).

Then, it is determined whether the total erosion depths A _{n to} Z _n in all the areas A to Z are smaller than a predetermined value L (step S17). At this time, when the total erosion depths A _{n to} Z _n in all the areas A to Z are smaller than the predetermined value L, n = n + 1 is set (step S18), and the (n + 1) th operation is performed.

On the other hand, if the total erosion depth in any of the areas A to Z is greater than or equal to the predetermined value L, an alarm is generated at that point (step S1).
9) Stop the discharge and replace the member.

It should be noted that these target replacement timing determination methods are recorded on a computer-readable recording medium,
A computer may be made to perform this method.

[0053]

As described in detail above, according to the present invention,
The erosion depth of that time is obtained for each of the plurality of regions from the electric power used for each sputtering, and the total erosion depth is obtained for the plurality of regions, and whether or not this total erosion depth has reached the planned depth. Since it is determined whether or not the conditions are different in a plurality of sputterings, the determination can be performed with high accuracy. Therefore, the cost of the target can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing a target replacement timing determination method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a target to be sputtered.

FIG. 3 is a flowchart showing an embodiment of the present invention applied to a consumable member in general.

FIG. 4 is a flowchart showing a conventional target replacement timing determination method.

5A to 5C are schematic views showing various sputtering conditions.

[Explanation of symbols]

1, 11a, 11b, 11c; target A, B, Z; Area

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-63-83258 (JP, A) JP-A 8-260142 (JP, A) JP-A 9-176851 (JP, A) JP-A 10- 330925 (JP, A) JP-A-11-162851 (JP, A) Actual development Sho 59-157469 (JP, U) Japanese Patent Sho 62-15633 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 14/34 C23C 14/54

Claims (8)

(57) [Claims] 1. A step of partitioning a target into a plurality of regions, a step of obtaining electric power used for the sputtering of each time after each sputtering is finished, and an erosion in each region of the target by the sputtering of the time. Determining the depth in relation to the electric power, determining the total erosion depth for each region at the end of the sputtering of that time, and the total erosion depth of at least one region of the plurality of regions. And a step of determining whether the predetermined depth has reached a preset depth for the area, the target replacement timing determining method. 2. The target replacement timing determination method according to claim 1, wherein the planned depth is the same for a plurality of the regions. 3. The target replacement timing determination method according to claim 1, wherein the step of partitioning the target is a step of partitioning the target into a plurality of concentric regions. 4. The step of obtaining the erosion depth in each of the regions includes the step of multiplying the electric power by a coefficient associated with the condition of the current sputtering in each of the regions. 3. The target replacement timing determination method described in any one of 3 above. 5. A procedure for partitioning a target into a plurality of regions, a procedure for obtaining the electric power used for each sputtering at the end of each sputtering, and an erosion in each region of the target by that sputtering. A procedure for obtaining a depth in relation to the electric power, a procedure for obtaining a total erosion depth at the time when the sputtering of that time is completed for each of the regions, and a total erosion depth of at least one region of the plurality of regions. A computer-readable recording medium recording a target replacement timing determination program for causing a computer to execute a procedure for determining whether or not the predetermined depth has reached a preset depth for the area. 6. The computer-readable recording medium recording the target replacement timing determination program according to claim 5, wherein the predetermined depth is the same for a plurality of the areas. 7. The computer recording the target replacement time determination program according to claim 5, wherein the step of partitioning the target is a step of partitioning the target into a plurality of concentric areas. A readable recording medium. 8. The method for obtaining the erosion depth in each of the regions includes a step of multiplying the electric power by a coefficient associated with a condition of the current sputtering in each of the regions. A computer-readable recording medium in which the target replacement timing determination program according to any one of 7 is recorded.