Method and apparatus for modifying lithographic patterns to adjust plating uniformity - Patents.com

Abstract

A method and apparatus for electroplating a substrate incorporates aspects of digital lithography and feedback from the electroplating process to improve characteristics of plating a material based on a die pattern. In some embodiments, a method of electroplating a substrate may include receiving a die design, forming a first lithographic pattern for a first substrate based on the die design, using a digital lithography process to pattern the first substrate with the first lithographic pattern, using an electroplating process to deposit material on the first substrate, using a metrology process to determine at least one parameter of the deposited material on the first substrate, and forming a second lithographic pattern for the second substrate from the first lithographic pattern based at least in part on the at least one parameter received directly from the metrology process for the first substrate by the digital lithographic process for the second substrate.

Description

[Technical field]

[0001] FIELD OF THE PREFERRED EMBODIMENTS Embodiments of the present principles relate generally to semiconductor processing of semiconductor substrates. [Background technology]

[0002] A die is designed and then multiple patterns of the die are copied onto a substrate. Often the die pattern does not completely fill the available surface area of ​​the substrate. When the substrate undergoes a plating process, the thickness of the deposited plating material may vary depending on the underlying die pattern on the substrate. In traditional processes, extra copies of the die pattern, or so-called dummy patterns, may be placed in unused areas of the substrate to enhance plating uniformity. However, the inventors have discovered that dummy patterns may not provide optimal plating thickness uniformity and are costly to manufacture with traditional stepper-based lithography processes.

[0003] Accordingly, the inventors have provided a method and apparatus for improving plating thickness uniformity. Summary of the Invention

[0004] SUMMARY OF THE DISCLOSURE Provided herein are methods and apparatus for modifying plating thickness uniformity based on metrology data.

[0005] In some embodiments, a method of electroplating a substrate may include receiving a die design, forming a first lithographic pattern for a first substrate based on the die design, using a digital lithography process to pattern the first substrate with the first lithographic pattern, using an electroplating process to deposit material on the first substrate with a first electroplating deposition uniformity, using a metrology process to determine at least one parameter of the deposited material on the first substrate, and altering the first lithographic pattern to form a second lithographic pattern that adjusts the first electroplating deposition uniformity to match a second electroplating deposition uniformity of an electroplating process for a second substrate based at least in part on the at least one parameter of the deposited material from the metrology process for the first substrate.

[0006] In some embodiments, the method further includes using a substrate plating model based on metrology data associated with deposition by electroplating to facilitate forming a first lithographic pattern for the first substrate or forming a second lithographic pattern for the second substrate, the substrate plating model including pattern density data of a die design in forming the first lithographic pattern for the first substrate or forming the second lithographic pattern for the second substrate; incorporating the metrology data from the electroplating process into the die design prior to receiving the die design, the first lithographic pattern including an active die pattern and a first set of dummy patterns, and the second lithographic pattern including an active die pattern and a first set of dummy patterns, the second lithographic pattern including at least a portion of a density of deposited material on the second substrate compared to the first substrate. and a second set of dummy patterns that vary at least one parameter of the deposited material on the second substrate compared to the first substrate, wherein the first lithographic pattern includes an active die pattern, and the second lithographic pattern includes an active die pattern with at least one active die pattern in a different orientation that varies at least one parameter of the deposited material on the second substrate compared to the first substrate, wherein the at least one parameter of the deposited material is a thickness of the deposited material at a particular location on the first substrate, and wherein the first lithographic pattern or the second lithographic pattern has an edge region pattern that differs from a pattern used in a center region of the first substrate or the second substrate. Prior to receiving the die design, the method may include incorporating metrology data from the electroplating process into the die design and / or varying the first lithographic pattern or the second lithographic pattern based on a current flow of a plating bath used in the electroplating process.

[0007] In some embodiments, a non-transitory computer readable medium having instructions stored thereon that, when executed, cause a method of electroplating a substrate to be performed, the method may include receiving a die design; forming a first lithographic pattern for a first substrate based on the die design; using a digital lithography process to pattern the first substrate with the first lithographic pattern; using an electroplating process to deposit material on the first substrate with a first electroplating deposition uniformity; using a metrology process to determine at least one parameter of the deposited material on the first substrate; and altering the first lithographic pattern to form a second lithographic pattern that adjusts the first electroplating deposition uniformity to match a second electroplating deposition uniformity of an electroplating process for a second substrate based at least in part on the at least one parameter of the deposited material from the metrology process for the first substrate.

[0008] In some embodiments, the method of the non-transitory computer readable medium further includes using a substrate plating model based on metrology data associated with deposition by electroplating to facilitate forming a first lithographic pattern for a first substrate or forming a second lithographic pattern for a second substrate, incorporating metrology data from the electroplating process into the die design prior to receiving the die design, wherein the first lithographic pattern includes an active die pattern and a first set of dummy patterns, and the second lithographic pattern includes an active die pattern and a second set of dummy patterns that alter at least one parameter of the deposited material on the second substrate compared to the first substrate, and the first lithographic pattern includes the active die pattern and a second set of dummy patterns that alter at least one parameter of the deposited material on the second substrate compared to the first substrate. Prior to receiving the die design, the method may include incorporating metrology data from the electroplating process into the die design and / or altering the first lithographic pattern or the second lithographic pattern based on a current flow of a plating bath used in the electroplating process, wherein the second lithographic pattern includes an active die pattern with at least one active die pattern in a different orientation that alters at least one parameter of the deposited material on the second substrate compared to the first substrate, the at least one parameter of the deposited material being a thickness of the deposited material at a particular location on the first substrate, and the first lithographic pattern or the second lithographic pattern has an edge region pattern that differs from a pattern used in a center region of the first substrate or the second substrate.

[0009] In some embodiments, an apparatus for electroplating a substrate may include a substrate plating model on a processing unit configured to determine a digital lithographic pattern that alters deposition characteristics of an electroplating process based on a die design; a digital lithography patterning tool configured to interact with at least the substrate plating model to form a lithographic pattern of an active die pattern and a dummy pattern on a first substrate based on the die design and the deposition characteristics of the electroplating process; an electroplating tool configured to deposit a first plating material on the first substrate; and a metrology tool configured to determine deposition parameters of the first plating material on the first substrate, where the metrology tool interacts with the substrate plating model or the digital lithography patterning tool to provide deposition parameters that alter the dummy pattern to change at least one parameter of a second plating material deposited on a second substrate.

[0010] In some embodiments, the apparatus may further include the processing unit being part of a digital lithography patterning tool and / or the metrology tool being part of an electroplating tool.

[0011] Other and further embodiments are disclosed below.

[0012] Embodiments of the present principles, briefly summarized above and described in more detail below, can be understood by reference to exemplary embodiments of the present principles, which are illustrated in the accompanying drawings, which, however, illustrate only general embodiments of the present principles, and therefore should not be considered limiting in scope, since the present principles may admit of other equally effective embodiments. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram of a method for adjusting electroplating uniformity, according to some embodiments of the present principles; [Diagram 2]1 is a plan view of an active die pattern on a substrate, in accordance with some embodiments of the present principles; [Diagram 3] 1 is a plan view of an active die pattern with the active die pattern reoriented on a substrate, in accordance with some embodiments of the present principles; FIG. [Figure 4] 1 is a plan view of an active die pattern and a dummy die pattern on a substrate, in accordance with some embodiments of the present principles; [Diagram 5] 1 is a plan view of an active die pattern and a dummy die pattern with the dummy die pattern reoriented on a substrate, in accordance with some embodiments of the present principles; [Figure 6] 1A-1C are plan views of different active and dummy die patterns on a substrate based on central or edge regions, in accordance with some embodiments of the present principles; [Figure 7] 1 is a cross-sectional view of an integrated toolset for adjusting electroplating uniformity, in accordance with some embodiments of the present principles; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] For ease of understanding, the same reference numbers have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0015] The method and apparatus provide the ability to optimize both the patterning and plating processes, improving deposition uniformity and film quality. The method and apparatus incorporate maskless digital lithography and the ability to create customized dummy patterning (outside of the active die). Modeling for plating uniformity provides customized design pattern files (e.g., Graphic Data System (GDS) files, etc.) for patterning in near real time. The principles allow for feedback from metrology with extremely fast learning cycle times for the next iteration. In traditional processes, the ability to create dummy patterns is limited to production mask patterns or other designed dummy masks. The techniques of the principles greatly improve the flexibility and speed of substrate patterning. The techniques provide extremely rapid learning (e.g., completed in hours versus weeks for building new masks) by incorporating metrology results directly into the next pattern iteration, significantly reducing costs by eliminating multiple mask sets per product. The technique also has the advantage of making it easier to dial in new products by using internal modeling capabilities to define next steps (e.g., pattern or tool parameters, etc.) Also, the high level of uniformity allows for the elimination of planarization processes during manufacturing.

[0016] Electroplating is often used to provide a base material for conductive pathways to form redistribution layers and other structures. During electroplating, a uniform electric field is created on the substrate, and areas with smaller pattern density will have the same current flow as areas with higher pattern density. Areas with smaller pattern density will be plated more heavily than areas with higher pattern density (more patterns to plate using the same amount of current means less plating on high density patterns). Traditional processes use dummy patterning to improve plating uniformity by using the same product mask or simple uniform array pattern repetition to fill edge dead spaces on the substrate, resulting in thick plating due to current crowding during plating deposition. The method and apparatus of the present principles have the advantage of being able to create dummy patterns that accommodate density variations and die asymmetries on the substrate to enhance plating thickness uniformity and quality. Unlike traditional processes where patterning is predefined and rarely modified after the initial mask build, the present principles have the benefit of flexibility and easy pattern correction of observed problems. The method and apparatus of the present principles allows for co-optimization of the process, leveraging lithography and plating as a whole. Moving pattern modeling optimization down the process line allows for faster learning cycles and much greater flexibility in creating and validating new solutions. The ability to input metrology results for the next patterning step is a significant advantage over legacy processes that do not have this capability.

[0017] In some embodiments, starting with a base die design (e.g., a GDS file), the process substrate plating model lays out the substrate configuration of active die and dummy patterning to compensate for pattern density variations, pattern asymmetries, substrate or die layout asymmetries, and / or edge dead spaces. The digital lithography tool then exposes the active die on the substrate in a defined array and adds dummy patterning to the substrate as determined by the substrate plating model and / or another input. The first wafer is then processed, i.e., developed, plated, stripped, and metrology is then performed to determine the quality and uniformity of the plating deposit. The metrology data is then input into the substrate plating model and / or the digital lithography tool, and subsequent iterations of the patterning / layout are performed for subsequent substrates.

[0018] FIG. 1 is a method 100 of adjusting electroplating uniformity according to some embodiments. In block 102, an active die design is received that is to be used in a photolithography process to print a pattern of a die or "active die" on a first substrate. As used herein, an "active die" is a die or die pattern that is formed on a substrate to create an actual semiconductor device, structure, conductive path, or the like. A dummy die or dummy pattern is a simulated circuit pattern of a complete or partial die that is not intended to be a practical or active die. In block 104, the active die design 204 is used to form a first lithographic pattern 206 for a first substrate 202, as shown in view 200 of FIG. 2. In block 106, the first substrate 202 is patterned with the first lithographic pattern 206 having a first electroplating deposition uniformity. At block 108, the first substrate 202 with the first lithographic pattern 206 is electroplated, for example, in a plating tank using an electric current and a bath solution. At block 110, the plating deposit from the electroplating process, after the masking material is removed, is subjected to metrology testing to determine at least one metrology data point for the electroplated deposit material. In some embodiments, the metrology data may include one or more locations where the electroplating thickness is measured. The metrology data may also include an average or mean thickness of the plating material in a particular area of ​​a surface across multiple points on the first substrate. The metrology data may be measured in situ with the electroplating chamber and / or in a separate process or chamber. In block 112, the first lithographic pattern is modified from at least one metrology data point acquired from the first substrate 202 to form a second lithographic pattern 350, 450, 550, 650 (see Figures 3-6) having a second electroplating deposition uniformity formed on a second substrate.

[0019] In some embodiments, the method 100 may be iterative and include several cycles to enhance the electroplating uniformity to a predefined level. Thus, the second lithographic pattern 350, 450, 550, 650 may be the initial or first lithographic pattern from which metrology data is collected and fed back into the process. Several examples of pattern expansion are shown in FIGS. 3-6, which are described as "second lithographic patterns." The second lithographic pattern may also be the "first lithographic pattern" for the method 100 when several iterations are performed to optimize the electroplating uniformity. Those examples are selected for simplicity and are not limiting in any manner. In some embodiments, based on feedback from metrology data acquired through the method 100, the second lithographic pattern 350 on the second substrate 330 may be as shown in the view 300 of FIG. 3, with the active die design 204 flipped and / or rotated to form a new orientation of the active die design 306. By varying the design orientation, variations in pattern density can be balanced to optimize plating uniformity for the active die design 204. For example, but not limited to, different pattern density areas of a die design can be located adjacent to one another (high density area next to low density area, and low density area next to high density area) to increase electroplating uniformity on the active die design 204.

[0020] In some embodiments, based on feedback from metrology data acquired through method 100, second lithographic pattern 450 may be as shown in view 400 of FIG. 4. Dummy replicate pattern 410 of active die design 204 is used to form second lithographic pattern 450 on second substrate 330 along with active die design 204. Added dummy replicate pattern 410 facilitates maintaining similar density across the surface of second substrate 330 to improve electroplating uniformity. In some embodiments, based on metrology data, reoriented dummy replicate pattern 512 may be used along with active die design 204 as shown in view 500 of FIG. 5. As explained above, the patterns, whether active or dummy, may be reoriented to position similar or different pattern density areas adjacent to each other to enhance electroplating uniformity. In some embodiments, the surface area of ​​second substrate 330 may be divided into center region 616 and edge region 620 as shown in view 600 of FIG. 6. The second substrate 330 may also be divided into three or more regions. A center region dummy pattern 618 may be used in the center region 616 of the second substrate 330, and an edge region dummy pattern 614 may be used in the edge region 620 of the second substrate 330. Using different dummy patterns in different regions of the substrate allows for greater flexibility in fine-tuning the electroplating uniformity.

[0021] In the view 700 of FIG. 7, an integrated apparatus for adjusting electroplating on a substrate is shown. An active die design 702 (e.g., a GDS format file) is introduced to a digital lithography patterning tool 706 and / or a substrate plating model 704. The active die design 702 may also include dummy files, etc., for modifying electroplating uniformity at the beginning of the process. The substrate plating model 704 may reside on a processing unit 712 configured to determine a digital lithographic pattern that modifies deposition characteristics of the electroplating process based on the die design and / or prior knowledge. The substrate plating model 704 may utilize machine learning and / or a set of rules to help establish a lithographic pattern that optimizes electroplating on a substrate based on previous electroplating metrology data and / or lessons learned, etc. The substrate plating model 704 may also incorporate electroplating process time, type of deposition material, solutions used in the plating bath during plating, electroplating hardware details (current values, plating speed, etc.), etc., to enhance the modeling process. In some embodiments, the substrate plating model 704 may be standalone and have portions that reside in or entirely within the digital lithography patterning tool 706. The digital lithography patterning tool 706 uses any prior knowledge and / or rule sets, if available, to form the first lithographic pattern and then process the pattern onto the first substrate 202. The digital lithography patterning tool 706 may also accept user input to facilitate forming the first lithographic pattern. In some embodiments, the digital lithography patterning tool 706 is configured to interact with at least the substrate plating model 704 to form a lithographic pattern of the active die pattern and a dummy pattern on the first substrate based on the die design and the deposition characteristics of the electroplating process.

[0022] The first substrate 202 then moves to an electroplating tool 708 configured to deposit a plating material on the first substrate 202. In some embodiments, the electroplating tool 708 may be in communication with the substrate plating model 704 and / or the digital lithography patterning tool 706 to account for operational parameters such as deposited material, current settings, solutions used, etc. After the electroplating process, the first substrate 202 undergoes metrology testing. In some embodiments, the metrology testing may be performed in situ within the electroplating chamber or tool. The metrology tool 710 is configured to determine deposition parameters of the plating material on the first substrate 202. In some embodiments, the metrology tool 710 may interact with the substrate plating model 704 and / or the digital lithography patterning tool to provide deposition parameters to alter the dummy pattern and / or the active pattern to alter at least one parameter of a subsequent plating material deposited on a second substrate (not shown). The use of digital lithography allows for near real-time feedback of plating process quality to the substrate plating model 704 and / or digital lithography patterning tool 706 to allow for fast changes in subsequent substrate patterning without the cost of expensive and time-consuming masks.

[0023] A single digital pattern may be used in place of the active die mask and dummy mask, eliminating mask alignment errors and costs associated with multiple masks. Additionally, the ability to improve the substrate plating model 704 with each run or iteration allows plating uniformity to be improved to high levels not easily achievable with traditional processes. The apparatus and method of the present principles also allows for improved plating uniformity beyond just the feedback of metrology data to the substrate plating model 704 and digital lithography patterning tool 706. Information gathered from modeling and lessons learned may also be used to improve plating uniformity by modifying the active die design to improve plating. Also, the die designer may use the acquired metrology data to not only design the active die for the GDS file, but also the pattern for the entire substrate to provide optimal plating uniformity in the first iteration of the method described herein. To further improve plating uniformity, changes in plating contact location on the substrate, etc. may also be incorporated into the process. In some embodiments, the contact location may be matched to improve current flow across the substrate based on the density of the lithographic pattern.

[0024] Embodiments according to the present principles may be implemented in hardware, firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored using one or more computer-readable media, which may be read and executed by one or more processors. A computer-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing platform, or a "virtual machine" running on one or more computing platforms). For example, a computer-readable medium may include any suitable form of volatile or non-volatile memory. In some embodiments, a computer-readable medium may include a non-transitory computer-readable medium.

[0025] While the forgoing is directed to embodiments of the present principles, other and further embodiments of the present principles may be devised without departing from the basic scope thereof.

Claims

1. 1. A method for electroplating a substrate, comprising: Receiving a die design; forming a first lithographic pattern for a first substrate based on the die design; using a digital lithography process to pattern the first substrate with the first lithographic pattern; using an electroplating process to deposit a material on the first substrate with a first electroplating deposition uniformity; using a metrology process to determine at least one parameter of a deposited material on the first substrate; altering the first lithographic pattern by the digital lithographic process to form a second lithographic pattern for the second substrate based at least in part on the at least one parameter of deposited material received directly from the metrology process for the first substrate by the digital lithographic process, the second lithographic pattern adjusting the first electroplating deposition uniformity to match a second electroplating deposition uniformity of the electroplating process for the second substrate; A method comprising:

2. Using a substrate plating model based on metrology data associated with deposition by electroplating to facilitate forming the first lithographic pattern for the first substrate or forming the second lithographic pattern for the second substrate. The method of claim 1 further comprising:

3. 3. The method of claim 2, wherein the substrate plating model includes pattern density data of the die design in forming the first lithographic pattern for the first substrate or in forming the second lithographic pattern for the second substrate.

4. Prior to receiving the die design, incorporating metrology data from an electroplating process into the die design. The method of claim 1 further comprising:

5. 2. The method of claim 1 , wherein the first lithographic pattern includes an active die pattern and a first set of dummy patterns, and the second lithographic pattern includes the active die pattern and a second set of dummy patterns that alter at least one parameter of a deposited material on the second substrate compared to the first substrate.

6. 2. The method of claim 1, wherein the first lithographic pattern includes an active die pattern and the second lithographic pattern includes the active die pattern with at least one active die pattern in a different orientation that alters at least one parameter of the deposited material on the second substrate compared to the first substrate.

7. The method of claim 1 , wherein the at least one parameter of the deposited material is a thickness of the deposited material at a particular location on the first substrate.

8. The method of claim 1 , wherein the first lithographic pattern or the second lithographic pattern has an edge region pattern that is different from a pattern used in a central region of the first substrate or the second substrate.

9. Varying the first lithographic pattern or the second lithographic pattern based on a current flow in a plating bath used in the electroplating process. The method of claim 1 further comprising:

10. A non-transitory computer readable medium having stored thereon instructions that, when executed, perform a method for electroplating a substrate, the method comprising: Receiving a die design; forming a first lithographic pattern for a first substrate based on the die design; using a digital lithography process to pattern the first substrate with the first lithographic pattern; using an electroplating process to deposit a material on the first substrate with a first electroplating deposition uniformity; using a metrology process to determine at least one parameter of a deposited material on the first substrate; altering the first lithographic pattern by the digital lithographic process to form a second lithographic pattern for the second substrate based at least in part on the at least one parameter of deposited material received directly from the metrology process for the first substrate by the digital lithographic process, the second lithographic pattern adjusting the first electroplating deposition uniformity to match a second electroplating deposition uniformity of the electroplating process for the second substrate; A non-transitory computer readable medium comprising:

11. The method further comprising: Using a substrate plating model based on metrology data associated with deposition by electroplating to facilitate forming the first lithographic pattern for the first substrate or forming the second lithographic pattern for the second substrate.

11. The non-transitory computer-readable medium of claim 10, further comprising:

12. The method further comprising: Prior to receiving the die design, incorporating metrology data from an electroplating process into the die design.

11. The non-transitory computer-readable medium of claim 10, further comprising:

13. 11. The non-transitory computer-readable medium of claim 10, wherein the first lithographic pattern includes an active die pattern and a first set of dummy patterns, and the second lithographic pattern includes the active die pattern and a second set of dummy patterns that alter the at least one parameter of the deposited material on the second substrate compared to the first substrate.

14. 11. The non-transitory computer readable medium of claim 10, wherein the first lithographic pattern includes an active die pattern and the second lithographic pattern includes the active die pattern with at least one active die pattern in a different orientation that alters the at least one parameter of the deposited material on the second substrate compared to the first substrate.

15. 11. The non-transitory computer readable medium of claim 10, wherein the at least one parameter of the deposited material is a thickness of the deposited material at a particular location on the first substrate.

16. 11. The non-transitory computer readable medium of claim 10, wherein the first lithographic pattern or the second lithographic pattern has an edge region pattern that is different from a pattern used in a central region of the first substrate or the second substrate.

17. The method further comprising: Varying the first lithographic pattern or the second lithographic pattern based on a current flow in a plating bath used in the electroplating process.

11. The non-transitory computer-readable medium of claim 10, further comprising:

18. 1. An apparatus for electroplating a substrate, comprising: a substrate plating model on the processing unit configured to determine a digital lithographic pattern that modifies deposition characteristics of an electroplating process based on the die design; a digital lithography patterning tool configured to interact with at least the substrate plating model to form a lithographic pattern of an active die pattern and a dummy pattern on a first substrate based on the die design and deposition characteristics of the electroplating process; an electroplating tool configured to deposit a first plating material on the first substrate; a metrology tool configured to determine deposition parameters of the first plating material on the first substrate, the metrology tool interacting directly with the substrate plating model or the digital lithography patterning tool to provide the deposition parameters for altering the dummy pattern to change at least one parameter of a second plating material deposited on a second substrate; An apparatus comprising:

19. The apparatus of claim 18 , wherein the processing unit is part of the digital lithography patterning tool.

20. The apparatus of claim 18 , wherein the metrology tool is part of the electroplating tool.

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