JP2000265269A - Target exchange timing judging method, and computer- readable recording medium with its program recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a target exchange timing judging method capable of judging an exchange timing with excellent accuracy even when a plurality of sputtering of different conditions is achieved and reducing the cost, and a computer-readable recording medium with its program recorded therein. SOLUTION: A target is demarcated into a plurality of areas, and the power used for each sputtering is obtained every time when each sputtering is completed. The erosion depth in each area of the target by each sputtering is obtained with relation to the power, and the total erosion depth is obtained for each area when each sputtering is completed. Whether or not the total erosion depth of at least one area among the plurality of areas reaches the depth preset for the area is judged.

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 storing the program, and more particularly to a method for performing a plurality of sputterings under different conditions. The present invention also relates to a target replacement time determination method capable of determining with high accuracy and a computer-readable recording medium on which the program is recorded.

[0002]

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

FIG. 4 is a flowchart showing a conventional method for determining a target replacement time.

Here, after replacing the target, 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 the power supplied to the target and the supply time.

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

[0007] After a lapse of sputtering power Y _n seconds after the (power) and the on-state to the sputtering power (electric power) and off state (step S23). That is, X _n (kW)
The sputtering is performed for Y _n seconds with the power of.

Thereafter, the integrated power α _n in the n-th sputtering is calculated by the following equation (step S2).
4).

[0009]

(Equation 1)

Next, the total target integrated 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 or not 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, if the total target integrated power β _n is equal to or larger 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 the conventional method for determining the target replacement time, when using sputtering conditions having different target erosion distributions together, an appropriate determination cannot be made unless a large margin is set.

FIGS. 5A to 5C are schematic diagrams showing various sputtering conditions. There are various sputtering conditions. For example, as shown in FIG. 5 (a), four regions are concentrically formed on the target 11a to be deeper than other regions, as shown in FIG. 5 (b). 5A. As shown in FIG. 5C, a region having a certain distance from the outer edge of the target 11c is made deeper than other regions.

In the above-described conventional determination method, for example, FIG.
In the case where the conditions shown in FIG. 5B and the conditions shown in FIG. 5C are used in combination, and when the usage ratio is unknown, all targets are replaced when sputtering is performed under the conditions shown in FIG. It was necessary to set the smaller of the integrated power value and the target replacement integrated power value when sputtering was performed under the conditions shown in FIG. Therefore, when the above two conditions are used together in a certain ratio, the reduction in the central portion of the target is rapid under one of the conditions, and the reduction near the outer periphery of the target is rapid under the other condition. Although it is clear that the integrated power lasts longer than the case, the advantage in that case cannot be utilized.

Therefore, there has been proposed a method of judging the replacement time of a target in consideration of the sputter conditions when the sputtering conditions are different (Japanese Patent Laid-Open No. 10-330925). According to the determination method described in this publication, when calculating the total sputter power after each sputtering, the total sputter power is calculated in consideration of the ratio between the sputter rate and the sputter power. ing.

[0017]

However, according to the above-mentioned Japanese Patent Application Laid-Open No. H10-330925, although the intended purpose has been achieved, the target replacement timing is determined based on the total sputter integrated power. So
There is a problem that delicate judgment is difficult.

The present invention has been made in view of such a problem, and it is possible to determine the replacement time with high accuracy even when performing a plurality of sputterings under different conditions, thereby reducing the cost. It is an object of the present invention to provide a target replacement time determination method and a computer-readable recording medium on which the program is recorded.

[0019]

According to the present invention, there is provided a method of determining a target replacement time, comprising the steps of dividing a target into a plurality of regions, and obtaining power used for the sputtering each time the sputtering is completed. And the step of determining the erosion depth in each region of the target by the current sputtering in association with the power, and the step of determining the total erosion depth at the time when the current sputtering is completed for each of the regions,
Determining whether or not the total erosion depth of at least one of the plurality of regions has reached a predetermined planned depth for the region.

In the present invention, the erosion depth of each time is obtained for a plurality of regions from the electric power used for each sputtering, and the total erosion depth is obtained for a plurality of regions. Since it is determined whether or not the scheduled depth has been reached, even if the conditions are different in a plurality of sputtering, it is higher than the conventional method in which the determination is based on the total integrated power. Judgment with accuracy is possible.

In the present invention, the predetermined depth may be the same for a plurality of the regions.

Further, the step of partitioning the target includes:
The step of partitioning the target into a plurality of concentric regions may be performed.

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

A computer readable or non-transitory computer readable recording medium having recorded thereon the target replacement time judging program according to the present invention is characterized by causing a computer to execute the above-mentioned steps (procedures).

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for determining a target replacement time according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a flowchart illustrating a target replacement timing determination method according to the embodiment of the present invention.
FIG. 2 is a schematic diagram showing a target to be sputtered.

Here, after replacing the target, n
The (n ≧ 2) -th operation will be described.

In this embodiment, as shown in FIG.
The target 1 to be sputtered is previously concentrically partitioned into, for example, 26 areas A, B,..., Z. Then, in the n-th operation after exchanging the target, first, the total erosion depth of the target 1 by the previous sputtering in each of the areas A to Z is set to An _{-1 to} Zn _-1 respectively. (Step S1).

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

[0029] After a lapse of sputtering power Y _n seconds after the (power) and the on-state to the sputtering power (electric power) and off state (step S3). That is, the sputtering of Y _n seconds at a power of X _n (kW).

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

Next, the erosion depth of the target 1 A _n 'to Z _n' by n-th sputtering in each area A to Z is calculated by the following equation 2 (step S5).

[0032]

(Equation 2)

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

[0034] Then, compute the total erosion depth A _n to the following Equation 3 Z _n of the target 1 at the time of n-th sputtering in each area A to Z has been completed (step S6).

[0035]

(Equation 3)

[0036] Then, the total erosion depth A _n to Z _n in all areas A to Z determines whether the difference is less than a predetermined value L (step S7). At this time, if the total erosion depth A _n to Z _n in all areas A to Z smaller than the predetermined value L, and n = n + 1 (step S8), performs (n + 1) -th operation.

On the other hand, if the total erosion depth in any of the areas A to Z is equal to or more than the predetermined value L, an alarm is generated at that time (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 power value of the current sputtering is multiplied by the target erosion distribution coefficient for each of a plurality of areas which varies depending on the sputtering conditions, and each erosion for each target area by the current sputtering is calculated. The target replacement time is determined by integrating the values. That is, the total erosion at that time is calculated for each target area,
The target replacement time is determined in consideration of the target erosion distribution that 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, it is possible to accurately determine the target replacement time. For example, even when two conditions are selected from FIGS. 5A to 5C, since different target erosion depths are considered depending on the sputtering conditions and the target area, it is necessary to select a proper timing. It is possible to determine the target exchange. Such an effect can be obtained not only when there are two conditions but also when a combination of more sputtering conditions is used.

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

In the above-described embodiment, in the process of step S7, the criterion for each of the areas A to Z is set to the same predetermined value L. However, the criterion may be different for each area. For example, the criterion of the area A is La,
.., The determination criterion for the area Z can be set to Lz. By setting the determination criterion in this way, it is possible to apply the present invention to a case where a special target having a different thickness depending on a part is used, or a case where a used target is used again.

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 that is worn by use or a member whose material changes in different parts. FIG. 3 is a flowchart showing an embodiment of the present invention applied to a general consumable member.

When generally applied to a consumable member, the member 1 consumable by use is divided into, for example, 26 areas A, B,.
, Z, and beforehand, in the n-th operation after the replacement of the member, first, the total erosion depth of the member in each of the areas A to Z by the previous use is A
_{n-1 to} Zn _-1 (step S11).

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

[0046] After a lapse of a discharge power (electric power) from the ON state Y _n seconds, discharge power (electric power) and off state (step S13). That is, the discharge of Y _n seconds at a power of X _n (kW).

Thereafter, the integrated power α in the n-th discharge
_n is calculated in the same manner as Expression 1 (step S14).

Next, the erosion depths A _n ′ to Z _n ′ of the members caused by the n-th discharge in the areas A to Z are calculated by Expression 2 (step S15).

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

[0050] Then, the total erosion depth A _n to Z _n in all areas A to Z determines whether the difference is less than a predetermined value L (step S17). At this time, if the total erosion depth A _n to Z _n in all areas A to Z smaller than the predetermined value L, and n = n + 1 (step S18), performs the (n + 1) -th operation.

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

Note that these target replacement time determination methods are recorded on a computer-readable recording medium,
A computer may perform this method.

[0053]

As described in detail above, according to the present invention,
For each sputtering, the erosion depth of the current time is determined for a plurality of regions from the power used for the sputtering, and the total erosion depth is determined for a plurality of regions. Whether or not the total erosion depth has reached a predetermined depth Therefore, even when 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 the drawings]

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

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

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

FIG. 4 is a flowchart illustrating a conventional target replacement time determination method.

FIGS. 5A to 5C are schematic diagrams showing various sputtering conditions.

[Explanation of symbols]

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

Claims (8)

[Claims] 1. A step of dividing a target into a plurality of regions, a step of obtaining power used for each sputtering each time a sputtering is completed, and an erosion of the target in each region by the sputtering. Determining a depth in association with the power, determining a total erosion depth at the time of completion of the current sputtering for each of the regions, and determining the total erosion depth of at least one of a plurality of the regions. Determining whether or not the target depth has reached a predetermined scheduled depth for the area. 2. The method according to claim 1, wherein the predetermined depth is the same depth for a plurality of the regions. 3. The 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 method according to claim 1, wherein the step of determining the erosion depth in each of the regions includes a step of multiplying the power by a coefficient associated with a condition of the current sputtering in each of the regions. 3. The method for determining a target replacement time according to any one of 3. 5. A step of partitioning a target into a plurality of regions, a step of obtaining power used for each sputtering every time each sputtering is completed, and an erosion of the target in each region by the sputtering each time. A procedure for determining a depth in association with the power, a procedure for determining a total erosion depth at the time when the current sputtering is completed for each of the regions, and a procedure for determining the total erosion depth of at least one of a plurality of the regions. And a computer-readable recording medium for recording a target replacement time determination program for causing a computer to execute a procedure for determining whether or not a predetermined depth has been reached for the area. 6. The computer-readable recording medium according to claim 5, wherein the predetermined depth is the same for a plurality of the areas. 7. The computer according to claim 5, wherein the step of partitioning the target is a step of partitioning the target into a plurality of concentric regions. A readable recording medium. 8. The method according to claim 5, wherein the step of obtaining the erosion depth in each of the regions includes a step of multiplying the power by a coefficient associated with a condition of the current sputtering in each of the regions. A computer-readable recording medium recording the target replacement time determination program according to any one of claims 7 to 13.