Method for improving target utilization in a sputtering system

Abstract

This disclosure provides a method for improving target utilization within a sputtering system. A plurality of targets are provided, each operatively connected to a central axis. An ion beam is generated within the sputtering system. During a first time period, the generated ion beam is guided to a first position on a first target. Each target is moved by rotating the central axis. During a second time period, the generated ion beam is guided to a second position on the first target.

Description

Technical Field

[0001] The present disclosure relates to the field of charged particle sources, including plasma sources for direct deposition, broad beam ion sources for ion beam deposition, and electron sources for surface modification. Background Art

[0002] Figure 1 Ion deposition (IBD) system is shown. In this IBD system 10, a plurality of targets 20 held on a target holder 25 are positioned on a support plate 50, which is connected to a motor at a center point. The target 20 is rotated around a central axis 30 by a motor. A target 20 is introduced and positioned so that it is placed in front of an ion source. The wafer can be exposed to sputtering material from the target 20. The ion source may include a plasma chamber and an ion extraction grid system. The plasma in the plasma source may be generated by methods known in the art including direct current (DC) and radio frequency (RF) inductively coupled plasma (ICP) coils. The energy of the ions extracted from the ion source is defined by the voltage applied to the grid system. Summary of the invention

[0003] According to an embodiment, the present disclosure is directed to offsetting targets relative to a central axis of a collimated ion beam in a multi-target ion beam deposition system so that a larger area of ​​the target is used.

[0004] According to one aspect of an embodiment of the present disclosure, a method for increasing target utilization within a sputtering system includes the following steps: providing a plurality of targets, each target being operably connected to a central axis; generating a first ion beam within the sputtering system; directing the generated first ion beam to a first position of a first target; interrupting the generation of the first ion beam; moving each target by rotating the central axis; generating a second ion beam within the sputtering system; and directing the generated second ion beam to a second position of the first target.

[0005] According to another aspect of an embodiment of the present disclosure, a method for increasing target utilization within a sputtering system includes the following steps: providing a plurality of targets, each target being operably connected to a central axis; generating an ion beam within the sputtering system; directing the generated ion beam to a first position of a first target within a first time period; moving each target by rotating the central axis; and directing the generated ion beam to a second position of the first target within a second time period.

[0006] According to another aspect of an embodiment of the present disclosure, a method for increasing target utilization within a sputtering system includes the following steps: providing a plurality of targets, each target being operably connected to a central axis; generating an ion beam within the sputtering system; guiding the generated ion beam to a first position of a first target; exposing a first substrate to sputtering material from the first position of the first target; moving each target by rotating the central axis; guiding the generated ion beam to a second position of the first target; and exposing a second substrate to the sputtering material from the second position of the first target.

[0007] Additional features and advantages of the present disclosure will be set forth in the following description, and in part will be apparent from the description, or can be learned by practicing the principles disclosed herein. The features and advantages of the present disclosure can be realized and obtained by the instruments and combinations particularly pointed out in the appended claims. These and other features of the present disclosure will become more apparent from the following description and the appended claims, or can be learned by practicing the principles set forth herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to describe the manner in which the above and other advantages and features of the present disclosure can be obtained, a more particular description of the principles briefly described above will be presented by reference to specific embodiments thereof shown in the accompanying drawings. It should be understood that these drawings depict only exemplary embodiments of the present disclosure and are not therefore to be considered limiting of its scope, the principles of the present invention are described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

[0009] Figure 1 An ion beam deposition system is shown;

[0010] Figure 2A An ion beam deposition system is shown with a target offset to the left of a nominal indexed position;

[0011] Figure 2B An ion beam deposition system is shown with a target at a nominal index position;

[0012] Figure 2C An ion beam deposition system is shown with a target offset to the right of a nominal indexed position;

[0013] Figure 3A An ion beam is shown hitting a target offset to the left of the nominal index position;

[0014] Figure 3B An ion beam is shown hitting a target offset to the right of the nominal index position;

[0015] Figure 4A shows target erosion when the ion beam hits the target offset to the left of the nominal position;

[0016] Figure 4B shows target erosion when the ion beam hits the target at a nominal location; and

[0017] Figure 4C Target erosion is shown when the ion beam hits the target offset to the right of the nominal positioning.

[0018] Like reference numerals refer to like parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0019] Target cost and target replacement frequency are the main drivers of the high cost of ownership of an ion beam deposition (IBD) system. Typically, 99.7% of the ion beam containment is within the center portion, which is half the diameter of the IBD target. Therefore, target utilization is very low, typically less than 15%. This low target utilization results in:

[0020] 1. Low mean time before maintenance and more frequent maintenance;

[0021] 2. Reduced tool utilization due to the time required to replace the target;

[0022] 3. Ultra-high vacuum recovery time; and

[0023] 4. Time for system re-qualification.

[0024] Enhanced target utilization provides significant cost of ownership benefits by:

[0025] 1. Lower target cost due to enhanced target utilization; and

[0026] 2. Increased tool availability.

[0027] In the present invention, target utilization is increased by deviating the target from the nominal positioning of the ion beam. This deviation of the ion beam on the target moves the maximum intensity of the sputtering plume symmetrically to the left or right of the center of the wafer. Due to the existence of the left-right symmetrical deviation, the deposition rate, deposition uniformity and other film properties are not affected by the target life enhancement method of the present invention.

[0028] The present invention for increasing target utilization does not require complex hardware. In the prior art, target positioning is continuously swept between offset positioning to enhance target life. However, this method causes premature failure of target indexing hardware and target cooling water dynamic seals. Unlike continuous sweeping of the target for increasing target life, the method of the present invention does not cause premature failure of target indexing hardware and target cooling water dynamic seals.

[0029] In one embodiment according to the invention, the controlled offset of the target index position in the direction opposite to the nominal index position runs continuously. The IBD system control can allow offset values ​​in steps of 0.025 inches or 0.1 degrees when measured at the target turret rotation axis.

[0030] In another embodiment of the invention, each deposition step may be divided into two equal parts, each part being at an offset value opposite to the nominal positioning.IBD system control may allow processing step sizes as small as 0.1 seconds.

[0031] In another embodiment of the present invention, the Kilow-Watt-Hour of the ion beam exposure on the target can be adjusted to match an offset in a direction opposite to the nominal index position of the target.

[0032] In one embodiment according to the present invention, a method is used to achieve increased target utilization within a sputtering system 10, wherein a plurality of targets 20 (each held by a target holder 25) are positioned along the exterior of a generally circular support plate 50 having a central axis 30, the central axis 30 being connected to a motor that rotates the support plate 50 in a generally circular motion, thereby rotating the plurality of targets 20 in a generally circular motion. A first ion beam directed to a first position of a first target 20 is generated within the sputtering system 10. The first position on the first target 20 can be nominal for the first ion beam, offset to the left of the nominal positioning of the first ion beam or offset to the right of the nominal positioning of the first ion beam. After a time period for which the first position of the first target 20 is exposed to the first ion beam, the first ion beam is turned off (interrupted). The time period can range from 0.5 seconds to any time period, wherein a time period of at least 1 to 5 seconds is preferred. After the first ion beam is turned off, the support plate 50 of the plurality of targets 20 is rotated by a motor that rotates the central axis 30 of the support plate 50, thereby moving each target 20 by rotating the central axis 30. A second ion beam directed to a second position of the first target 20 is generated within the sputtering system 10. The second position of the first target 20 may be offset from the first position of the first target 20 by a distance in the range of 1 mm to 50 mm. Alternatively, the rotational movement of the center axis 30 may be 0.16 degrees to 8 degrees. The generated first ion beam and the generated second ion beam may be applied to the first position of the first target 20 and the second position of the first target 20 in equal amounts of time, and may be applied with the same process conditions. Alternatively, the generated first ion beam and the generated second ion beam may be applied to the first position of the first target 20 and the second position of the first target 20 in different amounts of time, and may be applied with different process conditions.

[0033] In one embodiment according to the present invention, a method is used to achieve increased target utilization within a sputtering system 10, wherein a plurality of targets 20 (each held by a target holder 25) are positioned along the exterior of a generally circular support plate 50 having a central axis 30 connected to a motor that rotates the support plate 50 in a generally circular motion, thereby rotating the plurality of targets 20 in a generally circular motion. An ion beam directed at a first position of a first target 20 is generated within the sputtering system 10 during a first time period. The first position on the first target 20 may be nominal to the ion beam, offset to the left of the nominal position of the ion beam, or offset to the right of the nominal position of the ion beam. After the first time period of exposing the first position of the first target 20 to the ion beam, the support plate 50 of the plurality of targets 20 is rotated by a motor that rotates the central axis 30 of the support plate 50, thereby moving each target 20 by rotating the central axis 30. The first time period may range from 0.5 seconds to any time period, with a time period of at least 1 to 5 seconds being preferred. A second position of the first target 20 is exposed to the ion beam during a second time period. The second position on the first target 20 can be nominal to the ion beam, offset to the left of the nominal position of the ion beam or offset to the right of the nominal position of the ion beam. After exposing the second position of the first target 20 to the ion beam for a second period of time, the support plate 50 of the plurality of targets 20 is rotated by a motor that rotates the central axis 30 of the support plate 50, thereby moving each target 20 by rotating the central axis 30. The second period of time can range from 0.5 seconds to any period of time, wherein a period of at least 1 to 5 seconds is preferred. The second position of the first target 20 can be offset from the first position of the first target 20 by a distance ranging from 1 mm to 50 mm. Alternatively, the rotational movement of the central axis 30 can be 0.16 degrees to 8 degrees. The generated ion beam can be applied to the first position of the first target 20 and the second position of the first target 20 in equal time, and the same process conditions can be applied. Alternatively, the generated ion beam can be applied to the first position of the first target 20 and the second position of the first target 20 in different amounts of time, and different process conditions can be applied.

[0034] In one embodiment according to the invention, a method is used to achieve increased target utilization within a sputtering system 10, wherein a plurality of targets 20, each held by a target holder 25, are positioned along the exterior of a generally circular plate 50 having a central axis 30 connected to a motor that rotates the plate 50 in a generally circular motion, thereby rotating the plurality of targets 20 in a generally circular motion. An ion beam directed at a first position of a first target 20 is generated within the sputtering system 10 during a first time period. The first position on the first target 20 may be nominal to the ion beam, offset to the left of the nominal position of the ion beam, or offset to the right of the nominal position of the ion beam. During the first time period, a first substrate is exposed to sputtering material from the first position of the first target 20. After the first time period of exposing the first position of the first target 20 to the ion beam, the plate 50 of the plurality of targets 20 is rotated by a motor that rotates the central axis 30 of the plate, thereby moving each target 20 by rotating the central axis 30. The first time period may range from 0.5 seconds to any time period, with a time period of at least 1 to 5 seconds being preferred. After the first time period, the first substrate can be removed from the sputtering system 10 before any other substrate is exposed to the ion beam. The second position of the first target 20 is exposed to the ion beam during the second time period. The second position on the first target 20 can be nominal to the ion beam, offset to the left of the nominal position of the ion beam or offset to the right of the nominal position of the ion beam. During the second time period, the second substrate is exposed to the sputtered material from the second position of the first target 20. After the second time period of exposing the second position of the first target 20 to the ion beam, the support plate 50 of the plurality of targets 20 is rotated by a motor that rotates the central axis 30 of the support plate 50, thereby moving each target 20 by rotating the central axis 30. The second time period can range from 0.5 seconds to any time period, wherein a time period of at least 1 to 5 seconds is preferred. The second position of the first target 20 can be offset from the first position of the first target 20 by a distance ranging from 1 mm to 50 mm. Alternatively, the rotational movement of the central axis 30 can be 0.16 degrees to 8 degrees. The generated ion beam may be applied to the first position of the first target 20 and the second position of the first target 20 in equal amounts of time and may be applied with the same process conditions. Alternatively, the generated ion beam may be applied to the first position of the first target 20 and the second position of the first target 20 in different amounts of time and may be applied with different process conditions.

[0035] In any embodiment of the present invention, a stage holding a wafer during exposure to sputtered material from a target may rotate the wafer about a central axis. The stage may tilt the wafer relative to the sputtered material for at least a portion of the deposition process. The deposition plume of sputtered material from the target may be directed at any angle relative to the wafer surface by tilting the wafer stage. Provision may be made on the wafer stage to cool the wafer during the deposition process to prevent thermal damage to equipment on the wafer. The wafer may also be heated to a specific temperature to enhance the ion beam deposition process.

[0036] Although various examples and other information are used to explain various aspects within the field of the appended claims, limitations on the claims should not be implied based on specific features or arrangements in such examples, because a person of ordinary skill will be able to use these examples to derive a variety of implementations. In addition, although some subjects have been described in the language of examples specific to structural features and / or method steps, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the features or actions described. For example, such functions may be distributed differently or performed in components other than those identified herein. On the contrary, the described features and steps are disclosed as examples of components of systems and methods within the field of the appended claims. In addition, the claim language states that "at least one of" a set indicates that a member of the set or multiple members of the set satisfy the claim.

Claims

1. A method for improving target utilization in a sputtering system, comprising the steps of: providing a plurality of targets, each target of the plurality of targets being operatively connected to a target holder, each target of the plurality of targets being positioned along an exterior of a generally circular plate of the sputtering system, the circular plate having a central axis; generating a first ion beam within the sputtering system; directing the generated first ion beam to a first position of a first target; interrupting generation of the first ion beam; Rotating the central axis of the circular support plate; generating a second ion beam within the sputtering system; as well as The generated second ion beam is directed to a second position of the first target.

2. The method according to claim 1, wherein: The first position of the first target is offset from the second position of the first target by a distance in a range of 1 mm to 50 mm.

3. The method according to claim 1, wherein: The rotation of the central axis is 0.16 degrees to 8 degrees.

4. The method according to claim 1, wherein: The generated first ion beam and the generated second ion beam are applied to the first target at equal times.

5. The method according to claim 1, wherein: The generated first ion beam and the generated second ion beam are applied to the first target using the same process conditions.

6. The method according to claim 1, wherein: The first generated ion beam and the second generated ion beam are applied to the first target for different amounts of time.

7. The method according to claim 1, wherein: The generated first ion beam and the generated second ion beam are applied to the first target using different process conditions.

8. A method for improving target utilization in a sputtering system, comprising the steps of: providing a plurality of targets, each target of the plurality of targets being operatively connected to a target holder, each target of the plurality of targets being positioned along an exterior of a generally circular plate of the sputtering system, the circular plate having a central axis; generating an ion beam within the sputtering system; directing the generated ion beam to a first position of a first target during a first time period; Rotating the central axis of the circular support plate; as well as The generated ion beam is directed to a second location of the first target during a second period of time.

9. The method according to claim 8, wherein: The first position of the first target is offset from the second position of the first target by a distance in a range of 1 mm to 50 mm.

10. The method according to claim 8, wherein: The rotation of the central axis is 0.16 degrees to 8 degrees.

11. The method according to claim 8, wherein: The first time period is at least 0.5 seconds.

12. The method according to claim 11, wherein: The second time period is at least 0.5 seconds.

13. The method according to claim 8, wherein: The first time period is at least 1 second.

14. The method according to claim 13, wherein: The second time period is at least 1 second.

15. The method according to claim 8, wherein: The first time period is at least 2 seconds.

16. The method according to claim 15, wherein: The second time period is at least 2 seconds.

17. A method for improving target utilization in a sputtering system, comprising the steps of: providing a plurality of targets, each target of the plurality of targets being operatively connected to a target holder, each target of the plurality of targets being positioned along an exterior of a generally circular plate of the sputtering system, the circular plate having a central axis; generating an ion beam within the sputtering system; directing the generated ion beam to a first position of a first target; exposing a first substrate to sputtered material from the first position of the first target; Rotating the central axis of the circular support plate; directing the generated ion beam to a second position of the first target; as well as A second substrate is exposed to sputtered material from the second location of the first target.

18. The method according to claim 17, wherein: The first position of the first target is offset from the second position of the first target by a distance in a range of 1 mm to 50 mm.

19. The method according to claim 17, wherein: The rotation of the central axis is 0.16 degrees to 8 degrees.

20. The method of claim 17, further comprising removing the first substrate from the sputtering system before exposing the second substrate to the sputtered material from the second position of the first target.

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