Method for adjusting stress transition of a film on a substrate

Abstract

The present disclosure relates to a method for adjusting stress transition of a film on a substrate. The method includes: forming a stress adjustment layer on the substrate, wherein the stress adjustment layer includes a first region formed of a first material and a second region formed of a second material, wherein the first material includes a first internal stress and the second material includes a second internal stress, and wherein the first internal stress is different from the second internal stress; and forming a transition region between the first region and the second region, wherein the transition region includes an interface between the first material and the second material, the interface having a predetermined slope greater than zero and less than 90 degrees.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims the benefit of U.S. Provisional Application No. 62 / 876,372, filed on July 19, 2019, and U.S. Application No. 16 / 922,809, filed on July 7, 2020, which are incorporated herein by reference in their entireties. Technical Field

[0003] The present disclosure relates to a semiconductor device manufacturing method, and more particularly to a method for adjusting stress transition of a film on a substrate. Background Art

[0004] The purpose of the background description provided herein is to generally present the context of the present disclosure. To the extent that the work of the presently named inventors is described in this background section, as well as aspects of this specification that may not be identified as prior art at the time of filing, no admission is made, either explicitly or implicitly, as prior art against the present disclosure.

[0005] Semiconductor manufacturing involves a number of different steps and processes. One typical manufacturing process is called photolithography (also known as microlithography). Photolithography uses radiation such as ultraviolet or visible light to create fine patterns in semiconductor device designs. Many types of semiconductor devices such as diodes, transistors, and integrated circuits can be constructed using semiconductor manufacturing techniques including photolithography, etching, film deposition, surface cleaning, metallization, etc.

[0006] An exposure system (also referred to as a tool) is used to implement photolithography. The exposure system typically includes an illumination system, a mask (also referred to as a photomask) or a spatial light modulator (SLM) for generating a circuit pattern, a projection system, and a wafer alignment stage for aligning a semiconductor wafer covered with a photoresist. The illumination system illuminates an area of ​​the mask or SLM with an illumination field (such as a rectangular groove illumination field). The projection system projects an image of the illuminated area of ​​the mask pattern onto the wafer. In order to achieve accurate projection, it is important to expose the light pattern on a relatively flat or flat wafer (preferably, with a height deviation of less than 10 microns). Summary of the invention

[0007] This summary is provided to introduce some aspects of the disclosure in a simplified form that are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0008] Aspects of the present disclosure provide a method for regulating stress on a substrate. The method includes: depositing a first layer of a first material on the substrate; depositing a second layer of a second material on the first layer; changing the solubility of the second layer at one or more coordinate locations on the substrate, wherein the solubility of the second layer is changed at each of the one or more coordinate locations from a top surface of the second layer down to a predetermined depth in the second layer, and wherein changing the solubility of the second layer includes creating a transition region that defines a predetermined slope of solubility change across the transition region; and removing a soluble portion of the second layer using a developer so that the remaining portion of the second layer includes the predetermined slope from a first z-height of the second layer to a second z-height of the second layer in the transition region, wherein the first z-height of the second layer is less than the second z-height of the second layer.

[0009] According to one aspect, the method further includes performing an etching process that simultaneously etches the first material and the second material to transfer the predetermined slope to the first layer.

[0010] According to another aspect, the method further comprises depositing a third material on the substrate, thereby producing a planar surface of the substrate, the third material filling a region of the substrate to a maximum z-height of the first layer.

[0011] In an example, changing the solubility of the second layer includes creating a second transition region defining a second predetermined slope of solubility change across the second transition region.

[0012] According to yet another aspect, the method further comprises depositing a third material on the substrate, thereby creating a planar surface of the substrate, the third material filling a region of the substrate to a maximum z-height of the second layer.

[0013] According to yet another aspect, the method further includes: depositing a third material on the substrate; and planarizing the substrate to remove excess portions of the third material, the third material having the predetermined slope in the transition region.

[0014] In an example, the transition region defining the predetermined slope of the solubility change is created based on a desired stress transition in the transition region.

[0015] According to yet another aspect, the method further includes: depositing a third material on the substrate, the third material filling an area of ​​the substrate with a smaller z-height; depositing a fourth material on the substrate, the fourth material filling an area of ​​the substrate with a smaller z-height; and planarizing the fourth material by changing the solubility of the fourth material at a relatively larger z-height position and removing a soluble portion of the fourth material using a developer.

[0016] In an example, the first material has a different internal stress than the second material.

[0017] In another example, the first material has a different internal stress compared to the third material.

[0018] In yet another example, the predetermined slope is selected based on a design stress transition.

[0019] In yet another example, the first layer and the second layer are deposited on a backside surface of the substrate, the backside surface being opposite to a frontside surface of the substrate, the frontside surface of the substrate including the semiconductor device.

[0020] Aspects of the present disclosure also provide another method for regulating stress on a substrate. The method includes: depositing a first layer of a first material on the substrate; changing the solubility of the first layer at one or more coordinate locations on the substrate, wherein the solubility of the first layer is changed at each of the one or more coordinate locations from the top surface of the first layer down to a predetermined depth in the first layer, and wherein changing the solubility of the first layer includes creating a transition region, the transition region defining a predetermined slope of solubility change across the transition region, the predetermined slope being greater than zero and less than 90 degrees; and removing a soluble portion of the first layer using a specific developer so that the remaining portion of the first layer includes the predetermined slope from a first z-height of the first layer to a second z-height of the first layer in the transition region, wherein the first z-height of the first layer is less than the second z-height of the first layer.

[0021] According to one aspect, the method further includes: depositing a second layer of a second material on the substrate, the second material and the first material forming an interface having the predetermined slope, the second material and the first material having different internal stresses.

[0022] Aspects of the present disclosure also provide a method for regulating stress on a substrate. The method includes: forming a stress regulating layer on the substrate, wherein the stress regulating layer includes a first region formed of a first material and a second region formed of a second material, wherein the first material includes a first internal stress and the second material includes a second internal stress, and wherein the first internal stress is different from the second internal stress; and forming a transition region between the first region and the second region, wherein the transition region includes an interface between the first material and the second material, the interface having a predetermined slope greater than zero and less than 90 degrees.

[0023] In an example, the predetermined slope is greater than 15 degrees and less than 75 degrees.

[0024] According to one aspect, the method further includes forming transition regions having different interface slopes based on coordinate positions on the substrate.

[0025] In an example, the first internal stress is a compressive stress and the second internal stress is a compressive stress.

[0026] In another example, the first internal stress is a tensile stress, and the second internal stress is a tensile stress.

[0027] In yet another example, the first internal stress is compressive stress, and the second internal stress is tensile stress.

[0028] In yet another example, the first internal stress is a tensile stress, and the second internal stress is a compressive stress.

[0029] In yet another example, the first material and the second material have the same molecular composition and different internal stresses.

[0030] It should be noted that the Summary of the Invention section does not specify every aspect and / or incremental novel aspect of the disclosure or the claimed subject matter. Instead, the Summary of the Invention only provides a preliminary discussion of different aspects and corresponding points of novelty. For additional details and / or possible viewpoints of the disclosure and various aspects, the reader should consult the Detailed Description section and corresponding drawings of the disclosure as further discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate various aspects consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0032] Figure 1 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0033] Figure 2 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0034] Figure 3 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0035] Figure 4 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0036] Figure 5A Cross-sectional configurations based on selection of specific slope angles according to exemplary aspects of the present disclosure are shown.

[0037] Figure 5B Cross-sectional configurations based on selection of specific slope angles according to exemplary aspects of the present disclosure are shown.

[0038] Figure 5C Cross-sectional configurations based on selection of specific slope angles according to exemplary aspects of the present disclosure are shown.

[0039] Figure 6 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0040] Figure 7 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0041] Figure 8 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0042] Fig. 9 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0043] Fig.10 Cross-sectional configurations during various steps in a cyclic planarization process according to exemplary aspects of the present disclosure are shown.

[0044] Fig.11 A cross-sectional configuration is shown during one of the steps of a stress adjustment process according to an exemplary aspect of the present disclosure.

[0045] Fig. 12A A cross-sectional configuration according to an exemplary aspect of the present disclosure is shown.

[0046] Fig. 12B The present disclosure shows an exemplary aspect of Fig. 12A Membrane stress graph for the construction shown in .

[0047] Fig.13A A cross-sectional configuration according to one aspect of the present disclosure is shown.

[0048] Fig. 13B The present disclosure shows an exemplary aspect of Fig.13A Membrane stress graph for the construction shown in .

[0049] Fig.14A A cross-sectional configuration according to an exemplary aspect of the present disclosure is shown.

[0050] Fig. 14BThe present disclosure shows an exemplary aspect of Fig.14A Membrane stress graph for the construction shown in .

[0051] Fig.15A A cross-sectional configuration according to an exemplary aspect of the present disclosure is shown.

[0052] Fig. 15B The present disclosure shows an exemplary aspect of Fig.15A Membrane stress graph for the construction shown in .

[0053] Fig.16 A flow chart of a method of stress tuning a substrate according to an exemplary aspect of the present disclosure is shown.

[0054] The specific aspects of the present disclosure shown in the above-mentioned drawings will be described in detail below. These drawings and descriptions are not intended to limit the scope of the present disclosure in any way, but are intended to explain the concept of the present disclosure to those skilled in the art by referring to specific aspects. DETAILED DESCRIPTION

[0055] The following disclosure provides a number of different aspects or examples for implementing the different features of the provided subject matter. A number of specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are only examples and are not intended to be limiting. For example, forming a first feature above or on a second feature in the following description may include aspects in which the first feature and the second feature are directly contacted and formed, and may also include aspects in which additional features may be formed between the first feature and the second feature so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may reuse reference numerals and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various aspects and / or configurations discussed. Further, for ease of description, spatially related terms such as "top", "bottom", "below", "below", "lower", "above", "upper" may be used herein to describe the relationship between an element or feature and other (multiple) elements or (multiple) features as shown in the accompanying drawings. In addition to the orientations depicted in the accompanying drawings, spatially related terms are also intended to cover different orientations of the device in use or operation. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0056] For the sake of clarity, the discussion order of the different steps described herein has been given. Generally, these steps can be performed in any suitable order. In addition, although each different feature, technology, configuration, etc. in this article may be discussed in different places of the present disclosure, it is intended that each concept can be performed independently of each other or in combination with each other. Accordingly, the present disclosure can be implemented and viewed in many different ways.

[0057] As semiconductor device manufacturing technology develops, the demand for lithography systems and coaters / developers used to manufacture semiconductor devices is increasing. This includes an increasing demand for substrate alignment accuracy. The substrate is typically mounted on a chuck, also known as a wafer stage. During exposure, the features exposed on the substrate need to cover existing features on the substrate. In other words, pattern B needs to be aligned with pattern A. The alignment of subsequent layers is called coverage. Overlay error means that one layer is offset relative to the layer below (or above). In order to obtain the desired coverage performance, the substrate is aligned with the substrate stage before exposure. However, any movement of the substrate relative to the substrate stage after alignment may result in coverage error. Conventional tools for measuring coverage error already exist, such as by using a scatterometer.

[0058] Various manufacturing process steps (material deposition, etching, curing, etc.) can cause expansion and / or contraction of the substrate, resulting in a warped or bent substrate. For example, during exposure to actinic radiation, the substrate is locally heated due to the energy transferred from the exposure beam to the substrate. The substrate is also heated during the annealing process. This heating causes the substrate to expand. If the substrate expansion is not checked, the expansion may exceed the overlay error tolerance. In addition, if the clamping force between the substrate and the substrate chuck is not sufficient to prevent the substrate from expanding, the substrate will slide on the substrate chuck and greater substrate expansion will occur, resulting in greater overlay errors. In certain processes, such as extreme ultraviolet ("EUV") systems, sliding may be more significant because the environment surrounding the substrate during exposure is a vacuum. Therefore, vacuum clamping is not always possible, and weaker electrostatic clamping must be used instead of vacuum clamping.

[0059] Other manufacturing steps can also cause the substrate to expand and contract. For example, deposited films can cause the substrate to shrink. Moreover, various annealing and doping steps can produce considerable curvature in a given substrate. Annealing steps, in particular, can create overlay challenges. The result of these various manufacturing steps is an uneven or uneven substrate. For example, the back side of the substrate will have a z height difference (the difference in vertical height or distance perpendicular to the substrate surface) with high points and low points. The height difference caused by such curvature can be on the order of about one micron to about 500 microns or more. This fluctuation is significant because the semiconductor devices or structures exposed by the respective exposure tools are exposed on a scale of tens of nanometers to hundreds of nanometers. Therefore, having deviation variations of thousands of nanometers to 10,000 nanometers will greatly reduce the yield because it is difficult to correctly align the two patterns.

[0060] Various techniques for addressing substrate bow and uneven curvature on partially processed substrates focus on clamping techniques that clamp (or clamp or adsorb) the substrate on a substrate holder to flatten the curvature. However, due to such significant curvature, it is difficult or impossible to accurately flatten the substrate by simply clamping the substrate. Therefore, it is desirable to have a substrate overlay correction technique to improve and / or correct the overlay before being sent or returned to the scanner / stepper for additional exposure.

[0061] Wafer coverage can be corrected or improved by measuring the curvature of the substrate to map the z-height variation on the substrate, and then generating a coverage correction pattern based on the initial curvature measurement of the substrate, which defines an adjustment to the internal stress at a specific location on the substrate. In the coverage correction pattern, a first given location on the substrate has a different defined internal stress adjustment compared to a second given location on the substrate in the coverage correction pattern. Then, according to the coverage correction pattern, the internal stress on the substrate is modified at a specific location on the substrate, thereby modifying the curvature of the substrate. The substrate that has been subjected to the bending modification has a second coverage error. The coverage error of the second coverage error is reduced compared to the initial coverage error. Other techniques can also be used to determine the position on the substrate, thereby correcting the two errors with compensating internal stress. A specific stress correction layer can have a sudden transition between multiple materials with different internal stresses (e.g., a compression to tension interface). However, the technology in the present disclosure provides a gradual transition between materials with different internal stresses. The interface transition herein can be formed to have different interface slopes. A steeper slope will have a shorter transition, while a gentler slope will have a gradual transition. The sloped transition of the stress-correcting film can be patterned using location-specific development of the film and vertical acid diffusion length.

[0062] The technology herein may further enhance the subject matter of U.S. patent application serial number 15 / 695,966, entitled “Location-Specific Tuning of Stress to Control Bow to Control Overlay In Semiconductor Processing,” which is incorporated herein by reference in its entirety.

[0063] The technology disclosed in the present disclosure provides a method for adjusting the transition of a film on a substrate, which provides a gradual transition between films with different internal stresses by using position-specific development of the film. This can include using a direct-write projection system that performs exposure control by position, including changing the intensity of different positions. A solubility modifier (such as a photoacid generator) can be deposited on a given developable film. The light from the patterned exposure can generate more or less acid at the coordinate position. Through the baking step, the generated acid diffuses to a predetermined depth in the underlying film. The depth is a function of the amount of acid generated by the amount or intensity of the radiation exposure and the baking time and temperature.

[0064] For example, the substrate has a film with a photoacid generator, or an acid coating or other reagent coating is deposited on the developable layer. A given location on the substrate receives 100% of the available radiation, another location receives 50% of the available radiation, and another location receives no radiation. No acid diffuses at the location that does not receive radiation. At the location that receives 50% of the radiation energy (or energy equal to half of the solubility changing compound that can be generated), the solubility changing reagent diffuses to a first depth in the layer. At the location that receives 100% of the available energy, the solubility changing reagent diffuses to a second depth in the layer that is twice as deep as the first depth. Therefore, depending on the dose and baking, the layer can be dissolved to different depths. During the development step, different amounts of material are removed.

[0065] By transitioning or gradually exposing in a specific transition region, a physical slope can be formed in a given material. The effect from a given film on the substrate is a function of the internal stress of the film and the thickness at a given location. Therefore, by having a gradual change in thickness in the stress boundary region, a gradual stress transition is provided to the corresponding substrate.

[0066] Figures 1 to 11 Various cross-sectional configurations are shown during various steps of a stress adjustment process in accordance with aspects of the present disclosure.

[0067] Figure 1 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Figure 1 As shown in the configuration 101, a substrate 110 may be provided. The substrate 101 may be mounted on a chuck, also referred to as a wafer stage.

[0068] Figure 2 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Figure 2 As shown in the structure 102, a film can be coated or deposited on the substrate 110 to form a first layer 120 of a first material A. For example, the first layer 120 can be formed by spin coating, chemical vapor deposition (CVD), atomic layer deposition (ALD), stamping, roller, tube extrusion, spraying, printing, or any suitable method for coating or depositing a film on the substrate 110. The first material A can be one or a combination of SoC, PR, SiARC, SiO, SiN, HfO, TiO, AlO, TiN, or any other suitable material. The first layer 120 can cover the substrate 110, which can have a flat top surface. Further, it should be noted that the side of the substrate 101 on which the first layer 120 is deposited can be the back side surface of the substrate 101, which is opposite to the front side surface of the substrate 101 that can include a semiconductor device.

[0069] Figure 3 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Figure 3 As shown in the structure 103, the second layer 130 second material B can then be deposited on the first layer 120. The second layer 130 can be a film that provides the desired stress, or the second layer 130 can be a patterned layer that defines the tilt transition discussed later. For example, the second layer 130 can be formed by spin coating, chemical vapor deposition (CVD), stamping, roller, tube extrusion, spray coating, printing or any suitable method for coating or depositing a film on the first layer 120. The second material B can be one or a combination of acid-sensitive polymer PTDPR, acid-sensitive polymer NTDPR, acid-sensitive polymer DARC, acid-sensitive polymer DBARC, acid-sensitive monomer acid catalyst crosslinking (H+) or any other suitable material. The second layer 130 can have a flat top surface. The material A of the first layer 120 and the material B of the second layer 130 can be selected to directly amplify the amplitude of z height control. For example, the material can be selected so that the material A has a greater etching rate than the material B.

[0070] The solubility of the second layer 130 can be varied by coordinate position on the substrate 110. In addition, the solubility of the second layer 130 can be varied from the top surface of the second layer 130 down to a predetermined depth in the second layer 130 at each coordinate position. Varying the solubility of the second layer 130 can include creating a transition region that defines a predetermined slope of solubility change across the transition region. This can be created by a gradient exposure to actinic radiation.

[0071] Figure 4 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Figure 4 As shown in the structure 104 of the substrate 110, a soluble portion of the second layer 130 can be removed using a specific developer. The remaining portion of the second layer 130 can have a slope 410 from a first z-height 411 of the second layer 130 to a second z-height 412 of the second layer 130 in the transition region. The first z-height 411 of the second layer 130 can be less than the second z-height 412 of the second layer 130. The angle of the slope 410 can be selected, and the corresponding light exposure can then provide a grayscale exposure to produce the desired slope 410. Selecting the angle of the slope 410 provides the ability to adjust the stress transition in various layers on the substrate 110. The selected angle of the slope 410 can be greater than zero and less than 90 degrees, or greater than 15 degrees and less than 75 degrees, or any other suitable angle value that is used to promote stress transition between adjacent materials in the formed structure.

[0072] Figure 5A , Figure 5B and Figure 5C Examples of cross-sectional configurations based on selection of different slope angles for adjustable slopes in transition regions between various z-heights in accordance with aspects of the present disclosure are shown.

[0073] like Figure 5A As shown in the configuration 501 of FIG. 5 , the soluble portion of the second layer 130 may be removed so that the remaining portion of the second layer 130 may have a slope 510 in the transition region from a first z-height 511 of the second layer 130 to a second z-height 512 of the second layer 130. The first z-height 511 may be slightly smaller than the second z-height 512, and the angle of the slope 510 may be relatively gentle. For example, the height difference between the first z-height 511 and the second z-height 512 may be between 1% and 30% of the film thickness of the second layer 130 (i.e., Δh=1% to 30%), and the angle of the slope 510 may be less than or equal to 30° (i.e., θ≤30°).

[0074] like Figure 5BAs shown in the configuration 502 of FIG. 5 , the soluble portion of the second layer 130 may be removed so that the remaining portion of the second layer 130 may have a slope 520 in the transition region from a first z-height 521 of the second layer 130 to a second z-height 522 of the second layer 130. The first z-height 521 may be moderately smaller than the second z-height 522, and the angle of the slope 520 may be relatively moderate. For example, the height difference between the first z-height 521 and the second z-height 522 may be between 30% and 70% of the film thickness of the second layer 130 (i.e., Δh=30% to 70%), and the angle of the slope 520 may be between 30° and 60° (i.e., 30°<Θ<60°).

[0075] like Figure 5C As shown in the configuration 503 of , the soluble portion of the second layer 130 can be removed so that the remaining portion of the second layer 130 can have a slope 530 from a first z-height 531 of the second layer 130 to a second z-height 532 of the second layer 130 in the transition region. The first z-height 531 can be significantly smaller than the second z-height 532, and the angle of the slope 530 can be relatively steep. For example, the height difference between the first z-height 531 and the second z-height 532 can be between 70% and 100% of the film thickness of the second layer 130 (i.e., Δh=70% to 100%), and the angle of the slope 530 can be between 60° and 90° (i.e., 60°<Θ<90°).

[0076] Apart from Figure 5A , Figure 5B and Figure 5C In addition to the above-described examples of different slope transitions in the second layer 130, other slope transitions having slopes with angles varying from very gentle to very steep may be formed in the second layer 130.

[0077] Figure 6 1 shows a cross-sectional configuration during one of the multiple steps of a stress adjustment process according to one aspect of the present disclosure. As previously described, the second layer 130 can be a film that provides the desired stress and can be used as a first stress control film. The second layer 130 can also be a patterned layer that defines a sloped transition. Some desired stress adjustment materials may not be developable, so the developable layer can be patterned first. Figure 6As shown in the configuration 105 of FIG. 1 , an etching process may be performed that simultaneously etches the first material of the first layer 120 and the second material of the second layer 130. The etching process transfers the slope 410 formed in the configuration 104 of the second layer 130 to the first layer 120, thereby forming a slope 610 in the second layer 130 and a slope 620 in the first layer 120. More specifically, the first and second materials of the respective first and second layers 120 and 130 may be etched at an equal rate, so that the angle of the slope in the transition region may be transferred from the second layer 130 to the first layer 120.

[0078] Figure 7 A cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure is shown. Specifically, Figure 7 Structure 106 is shown, which is an example result after the etching process transfers the slope from the second layer 130 into the first layer 120, completing the pattern transfer as shown in structure 105. Figure 7 As shown, the second layer 130 can be completely removed, and its slope can be completely transferred to the first layer 120, thereby forming a slope 710 in the first layer 120. The first layer 120 can provide tensile stress or compressive stress, and has a gradual stress reduction at the inclined region with the slope 710. In other words, the pulling force or pushing force from the film on the wafer gradually decays at the inclined region, which provides a technical advantage of smooth stress transition of the film on the substrate 110.

[0079] like Figure 7 As shown, after forming a membrane with intrinsic stress and a sloped transition region, more membranes can be added. Figure 8 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Figure 8 As shown in the structure 107, the third layer 140 of the third material C can be deposited on the first layer 120 and the exposed portion of the substrate 110 to form a second stress control film and provide the desired stress. For example, the third layer 140 can be formed by spin coating, chemical vapor deposition (CVD), atomic layer deposition (ALD), stamping, roller, tube extrusion, spraying, printing or any suitable method for coating or depositing a film on the first layer 120 and the substrate 110. The third material C can be one or a combination of SoC, PR, SiARC, SiO, SiN, HfO, TiO, AlO, TiN or any other suitable material. The third material C of the third layer 140 can be deposited only in the opening or area without the first material A, and only on the top surface of the first layer 120. The third material C of the third layer 140 can also be conformally deposited and then planarized. Figure 8 Conformal deposition of the third layer 140 is shown.

[0080] Fig. 9 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Fig. 9 As shown in the structure 108, the fourth layer 150 fourth material D can be deposited on the third layer 140. The fourth material D can be developable. For example, the fourth layer 150 can be formed by spin coating, chemical vapor deposition (CVD), embossing, roller, tube extrusion, spraying, printing or any suitable method for coating or depositing a film on the third layer 140. The fourth material D can be one or a combination of acid-sensitive polymer PTD PR, acid-sensitive polymer NTD PR, acid-sensitive polymer DARC, acid-sensitive polymer DBARC, acid-sensitive monomer acid catalyst crosslinking (H+) or any other suitable material. The fourth material D can then be exposed in a region of greater z height, thereby directly or after the vertical diffusion of the solubility-changing reagent to change the solubility of the fourth layer 150.

[0081] Fig.10 1 shows a cross-sectional structure during one of the multiple steps of the stress adjustment process according to one aspect of the present disclosure. Specifically, after the top portion of the fourth layer 150 is made soluble, the soluble portion of the fourth material D of the fourth layer 150 can then be developed to remove it. Fig.10 As shown in the structure 109 , removing the soluble portion of the fourth material D of the fourth layer 150 can obtain a planarized top surface 1001 .

[0082] Fig.11 1 shows a cross-sectional configuration during one of the steps of a stress adjustment process according to one aspect of the present disclosure. Fig.11 As shown in the structure 110 of FIG. 1 , the third material C and the fourth material D of the third layer 140 and the fourth layer 150 are then planarized, respectively, leaving only the first material A and the third material C of the corresponding first layer 120 and the third layer 140. Specifically, the third material C and the fourth material D of the third layer 140 and the fourth layer 150 may have an equivalent etching rate to a specific etching chemistry, so that the third layer 140 and the fourth layer 150 may be etched until the first material A and the third material C of the corresponding first layer 120 and the third layer 140 are exposed, leaving a flat surface. Alternatively, a chemical mechanical polishing step may be used to planarize the surface to reveal the first layer 120. The formed structure 110 includes a planarized top surface 1101 of the first layer 120 and the third layer 140, with an inclined interface between the first layer and the third layer.

[0083] The first material A and the third material C of the respective first layer 120 and third layer 140 may have the same molecular composition, but have different stresses due to their respective molecular structures or due to the deposition manner of the materials. Fig.11 The formed stress-correcting layer of the construction 110 can be composed of compressive silicon nitride regions in the third material C of the third layer 140 and tensile silicon nitride regions in the first material A of the first layer 120. Other embodiments can have regions of low tensile stress material and regions of high tensile stress material. The sloped interface between the compressive material and the tensile material provides a smoother transition between the thrust region and the tension region.

[0084] Fig. 12A 1 shows a cross-sectional configuration according to one aspect of the present disclosure. Fig. 12A As shown, the structure 1200 may include a substrate 1201 on which a first layer 1202 of compressive material and a second layer 1203 of tensile material are deposited. The structure 1200 may include an interface 1210 between the first layer 1202 and the second layer 1203. The first layer 1202 and the second layer 1203 may correspond to Fig.11 The third layer 140 and the first layer 120 are shown and can be formed by a similar stress adjustment process to produce the structure 110, except that the interface 1210 is different from the adjustable slope 710. The interface 1210 can be formed by changing the solubility of a particular layer to produce a slope of the interface that defines a transition region between the materials. The interface 1210 includes a steep vertical slope and constitutes an abrupt stress transition between the adjacent materials of the first 1202 and second layers 1203 without a transition gradient.

[0085] Fig. 12B According to one aspect of the present disclosure Fig. 12A . The film stress graph 1220 includes a y-axis representing the film stress ranging from compression to tension, and an x-axis representing the position from the first layer 1202 to the second layer 1203 in the horizontal direction along the surface of the substrate 1201. As shown in the film stress graph 1220, only binary control is provided as the stress jump from compression in the first layer 1202 to tension in the second layer 1203.

[0086] Fig.13A 1 shows a cross-sectional configuration according to one aspect of the present disclosure. Fig.13A As shown, the structure 1300 may include a substrate 1301 on which a first layer 1302 of compressive material and a second layer 1303 of tensile material are deposited. The structure 1300 may include an interface 1310 between the first layer 1302 and the second layer 1303. The first layer 1302 and the second layer 1303 may correspond to Fig.11The third layer 140 and the first layer 120 are shown and can be formed by a similar stress adjustment process to produce the structure 110, except that the interface 1310 is slightly different from the adjustable slope 710. The interface 1310 can be formed by changing the solubility of a particular layer to produce a slope of the interface that defines a transition region between the materials. The interface 1310 includes a moderate slope and promotes a gradual stress transition between the adjacent materials of the first layer 1302 and the second layer 1303.

[0087] Fig. 13B Shows Fig.13A . The film stress graph 1320 includes a y-axis representing film stress ranging from compression to tension, and an x-axis representing the position from the first layer 1302 to the second layer 1303 in the horizontal direction along the surface of the substrate 1301. As shown in the film stress graph 1320, a gradual control is provided as a stress transition from compression in the first layer 1302 to tension in the second layer 1303. The moderate slope of the interface 1310 provides an inclined material transition between stress control materials, thereby producing better stress control for wafer bow removal / correction.

[0088] Fig.14A 1 shows a cross-sectional configuration according to one aspect of the present disclosure. Fig.14A As shown, the structure 1400 may include a substrate 1401 on which a first layer 1402 of compressive material and a second layer 1403 of tensile material are deposited. The structure 1400 may include an interface 1410 between the first layer 1402 and the second layer 1403. The first layer 1402 and the second layer 1403 may correspond to Fig.11 The third layer 140 and the first layer 120 are shown and can be formed by a similar stress adjustment process to produce the structure 110, except that the interface 1410 is different from the adjustable slope 710. The interface 1410 can be formed by changing the solubility of a particular layer to produce a slope of the interface that defines a transition region between the materials. The interface 1410 includes a gentle slope and constitutes a clear gradual stress transition between the adjacent materials of the first layer 1402 and the second layer 1403.

[0089] Fig. 14B Shows Fig.14A. The film stress graph 1420 includes a y-axis representing the film stress ranging from compression to tension, and an x-axis representing the position in the horizontal direction along the surface of the substrate 1401 from the first layer 1402 to the second layer 1403. As shown in the film stress graph 1420, a gradual control is provided as a stress transition from compression in the first layer 1402 to tension in the second layer 1403. The gentle slope of the interface 1410 provides an inclined material transition between the stress control materials, thereby producing better stress control for wafer bow removal / correction.

[0090] Fig.15A 1 shows a cross-sectional configuration according to one aspect of the present disclosure. Fig.15A As shown, the structure 1500 may include a substrate 1501 on which a first layer 1502 of compressive material and a second layer 1503 of tensile material are deposited. The first layer 1502 may be disposed on both sides of the second layer 1503. The structure 1500 may include interfaces 1510 and 1511 between the first layer 1502 and the second layer 1503 and on both sides of the second layer 1503. The first layer 1502 and the second layer 1503 may correspond to Fig.11 The third layer 140 and the first layer 120 are shown and can be formed by a similar stress adjustment process to produce the structure 110, except that the interfaces 1510 and 1511 are different from the adjustable slope 710. The interfaces 1510 and 1511 can be formed by changing the solubility of the specific layers to produce the slope of the interface that defines the transition area between the materials. Both interfaces 1511 and 1510 include a gentle slope and constitute a first stress transition and a second stress transition between adjacent materials of the first layer 1502 and the second layer 1503, which stress transitions have a clear gradual transition from compression to tension and from tension to compression.

[0091] Fig. 15B Shows Fig.15A . The film stress graph 1520 includes a y-axis representing the film stress ranging from compression to tension, and an x-axis representing the position in the horizontal direction along the surface of the substrate 1501 from the first layer 1502 through the interface 1510 to the second layer 1503 and from the second layer 1503 through the interface 1511 to the first layer 1502. As shown in the film stress graph 1520, a gradual control is provided as a stress transition from compression in the first layer 1502 through the interface 1510 to tension in the second layer 1503 (first stress transition), and then back to compression in the first layer 1502 (second stress transition) through the interface 1511. The gentle slope of the interfaces 1510 and 1511 provides an inclined material transition between the stress control materials, thereby producing better stress control for wafer bow removal / correction.

[0092] In view of the foregoing, the stress adjustment process and the above-described techniques provide a graded stress transition by location on the substrate to improve stress control to obtain a flatter substrate or a substrate with less overlay error.

[0093] Fig.16 1 is a flow chart of a method for stress adjustment of a substrate according to an exemplary aspect of the present disclosure. In step S101, a first layer is deposited on a substrate. For example, Figure 2 As shown, a first material A may be coated or deposited on the substrate 110 to form a first layer 120 .

[0094] In step S102, a second layer is deposited on the first layer. Figure 3 As shown, a second layer 130 of a second material B may be deposited on the first layer 120 .

[0095] In step S103, the solubility of the second layer at one or more coordinate positions is changed to create a transition region. For example, the solubility of the second layer 130 can be changed from the top surface of the second layer 130 down to a predetermined depth in the second layer 130 at each coordinate position.

[0096] In step S104, the soluble part of the second layer is removed so that the slope is retained in the transition region. Figure 4 As shown, a specific developer may be used to remove the soluble portion of the second layer 130. The remaining portion of the second layer 130 may have a slope 410 in the transition region from a first z-height 411 of the second layer 130 to a second z-height 412 of the second layer 130. The angle of the slope 410 is predetermined and may vary based on the desired final stress transition (e.g., Figure 5A , Figure 5B and Figure 5C exemplified in ).

[0097] In step S105, an etching process is performed to transfer the slope from the second layer to the first layer in the transition region. Figure 6 As shown, an etching process may be performed that simultaneously etches the first material of the first layer 120 and the second material of the second layer 130. The etching process transfers the slope 410 formed in the structure 104 of the second layer 130 to the first layer 120, thereby forming a slope 610 in the second layer 130 and a slope 620 in the first layer 120. In addition, as shown in FIG. Figure 7 As shown, the second layer 130 may be completely removed and its slope may be completely transferred into the first layer 120 , thereby forming a slope 710 in the first layer 120 .

[0098] In step S106, a third layer is deposited on the first layer. Figure 8As shown, a third layer 140 of a third material C may be deposited on the first layer 120 and on the exposed portion of the substrate 110 , thereby forming a second stress-controlling film and providing a desired stress.

[0099] In step S107, a fourth layer is deposited on the third layer. Fig. 9 As shown, a fourth layer 150 of a fourth material D may be deposited on the third layer 140 .

[0100] In step S108, the solubility of the fourth layer is changed in the region of greater z-height. For example, the top portion of the fourth layer 150 may be made soluble in the region of greater z-height.

[0101] In step S109, some portions of the fourth layer are removed to planarize the top surface of the structure. Fig.10 As shown, the soluble portion of the fourth layer 150 may be developed to remove it, such that removing the soluble portion of the fourth layer 150 results in a planarized top surface 1001 .

[0102] In step S110, the top surface of the structure is planarized until the surface of the first layer is exposed. Fig.11 As shown, the third layer 140 and the fourth layer 150 may be planarized to leave only the first layer 120 and the third layer 140. The resulting construction 110 includes a planarized top surface 1101 of the first layer 120 and the third layer 140 with a sloped interface therebetween.

[0103] In this way, the disclosed stress tuning methods can be used to effectively create a graded pressure transition by location on a substrate to improve stress control, resulting in a flatter substrate or a substrate with less overlay error.

[0104] In the foregoing description, specific details have been set forth, such as the specific geometry of the processing system and the description of the various components and processes used therein. However, it should be understood that the technology herein can be implemented in other aspects that are separated from these specific details, and such details are for the purpose of explanation rather than limitation. Various aspects disclosed herein have been described with reference to the accompanying drawings. Similarly, for the purpose of explanation, specific numbers, materials, and configurations have been set forth in order to provide a thorough understanding. However, various aspects can be practiced without these specific details. Components having substantially the same functional configuration are represented by similar reference numerals, and therefore any redundant description can be omitted.

[0105] Various techniques have been described as multiple discrete operations to help understand various aspects. The order of description should not be interpreted as meaning that these operations must be order-dependent. In fact, these operations do not need to be performed in the order presented. The described operations can be performed in an order different from the described aspects. In additional aspects, various additional operations can be performed and / or the described operations can be omitted.

[0106] As used herein, "substrate" generally refers to an object processed according to the present disclosure. A substrate may include any material portion or structure of a device (particularly a semiconductor or other electronic device), and may be, for example, a base substrate structure (such as a semiconductor wafer, a mask), or a layer (such as a thin film) on or overlying a base substrate structure. Thus, a substrate is not limited to any particular infrastructure, underlying layer, or overlying layer, patterned or unpatterned, but is contemplated to include any such layer or infrastructure, and any combination of layers and / or infrastructure. The description may refer to a specific type of substrate, but this is for illustrative purposes only.

[0107] Those skilled in the art will also appreciate that many changes may be made to the operation of the above-mentioned techniques while still achieving the same purpose of the present disclosure. The scope of the present disclosure is intended to include these changes. Therefore, the foregoing description of the various aspects of the present disclosure is not intended to be restrictive. On the contrary, any limitation to the various aspects of the present disclosure is presented in the appended claims.

Claims

1. A method for regulating stress on a substrate, the method comprising: depositing a first layer of a first material on the substrate; depositing a second layer of a second material on the first layer; changing the solubility of the second layer at one or more coordinate locations on the substrate, wherein the solubility of the second layer is changed at each of the one or more coordinate locations from a top surface of the second layer down to a predetermined depth in the second layer, and wherein changing the solubility of the second layer includes creating a transition region defining a predetermined slope of solubility change across the transition region; and The developer is used to remove the soluble portion of the second layer so that the remaining portion of the second layer includes the predetermined slope from the first z height of the second layer to the second z height of the second layer in the transition region, wherein the first z height of the second layer is less than the second z height of the second layer.

2. The method of claim 1, further comprising: An etching process is performed, the etching process simultaneously etches the first material and the second material to transfer the predetermined slope to the first layer.

3. The method of claim 2, further comprising: A third material is deposited on the substrate to create a planar surface of the substrate, the third material filling an area of ​​the substrate to a maximum z-height of the first layer.

4. The method of claim 1, wherein: Changing the solubility of the second layer includes creating a second transition region defining a second predetermined slope of solubility change across the second transition region.

5. The method of claim 1, further comprising: A third material is deposited on the substrate to create a planar surface of the substrate, the third material filling an area of ​​the substrate to a maximum z-height of the second layer.

6. The method of claim 1, further comprising: depositing a third material on the substrate; as well as The substrate is planarized to remove excess portions of the third material, the third material having the predetermined slope in the transition region.

7. The method of claim 1, wherein: The transition region defining the predetermined slope of the solubility change is created based on the desired stress transition in the transition region.

8. The method of claim 1, further comprising: depositing a third material on the substrate, the third material filling a region of the substrate having a smaller z-height; depositing a fourth material on the substrate, the fourth material filling a region of the substrate having a smaller z-height; as well as The fourth material is planarized by changing the solubility of the fourth material at relatively large z-height locations and removing soluble portions of the fourth material using a developer.

9. The method of claim 1, wherein: The first material has a different internal stress than the second material.

10. The method of claim 3, wherein: The first material has a different internal stress than the third material.

11. The method of claim 1, wherein: The predetermined slope is selected based on a design stress transition.

12. The method of claim 1, wherein: The first layer and the second layer are deposited on a backside surface of the substrate, the backside surface being opposite to a frontside surface of the substrate, the frontside surface of the substrate including a semiconductor device.

13. A method for regulating stress on a substrate, the method comprising: depositing a first layer of a first material on the substrate; changing the solubility of the first layer at one or more coordinate locations on the substrate, wherein the solubility of the first layer is changed at each of the one or more coordinate locations from a top surface of the first layer down to a predetermined depth in the first layer, and wherein changing the solubility of the first layer comprises creating a transition region defining a predetermined slope of solubility change across the transition region, the predetermined slope being greater than zero degrees and less than 90 degrees; and A specific developer is used to remove the soluble portion of the first layer so that the remaining portion of the first layer includes the predetermined slope from the first z height of the first layer to the second z height of the first layer in the transition region, wherein the first z height of the first layer is less than the second z height of the first layer. 14 . The method of claim 13 , further comprising depositing a second layer of a second material on the substrate, the second material and the first material forming an interface having the predetermined slope, the second material and the first material having different internal stresses.

15. A method for regulating stress on a substrate, the method comprising: forming a stress adjustment layer on the substrate, wherein the stress adjustment layer includes a first region formed of a first material and a second region formed of a second material, wherein the first material includes a first internal stress and the second material includes a second internal stress, and wherein the first internal stress is different than the second internal stress; and Transition regions are formed between the first regions and the second regions, wherein the transition regions include an interface between the first material and the second material, the interface having a predetermined slope greater than zero degrees and less than 90 degrees.

16. The method of claim 15, wherein: The predetermined slope is greater than 15 degrees and less than 75 degrees.

17. The method of claim 15, further comprising forming transition regions having different interface slopes based on coordinate positions on the substrate.

18. The method of claim 15, wherein: The first internal stress is a compressive stress, and the second internal stress is a compressive stress, or Wherein, the first internal stress is tensile stress, and the second internal stress is tensile stress.

19. The method of claim 15, wherein: The first internal stress is a compressive stress, and the second internal stress is a tensile stress.

20. The method of claim 15, wherein: The first material and the second material have the same molecular composition and different internal stresses.

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