Method for correcting wafer warpage using a directly drawn stress film

Abstract

Techniques herein include methods for forming direct-write tunable stress films and using said stress films to correct wafer bow. The method may be performed in a coater / developer tool or a track-based tool. The stressed film may be based on, but is not limited to, a film that undergoes cross-linking / de-cross-linking under an external stimulus where direct writing is achieved by 365 nm exposure and subsequent curing is used to "build in" the stress. A development step may be eliminated, providing the additional significant advantage that the film remains flat. The amount of warping (or internal stresses that create or affect the warping properties) may be tuned by exposure dose, bake temperature, bake time, and bake times.

Description

Technical Field

[0004]

[0001] The present disclosure relates to a semiconductor manufacturing method. More particularly, it relates to wafer bow relaxation.

[0002] Cross - reference to Related Applications The present disclosure claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 175,123, filed on April 15, 2021, and U.S. Patent Application No. 17 / 703,072, filed on March 24, 2022, which are hereby incorporated by reference in their entirety.

Background Art

[0003] The background description provided herein is for the purpose of generally presenting the background of the present disclosure. The research of the inventors within the scope described in this background section and aspects of the description that would not originally be recognized as prior art at the time of filing are not admitted as prior art to the present disclosure, either explicitly or implicitly.

[0004] Semiconductor manufacturing includes a plurality of various steps and processes. One typical manufacturing process is known as photolithography (also called microlithography). In photolithography, radiation such as ultraviolet light or visible light is used to generate fine patterns in semiconductor device design. Using semiconductor manufacturing techniques including photolithography, etching, film deposition, surface cleaning, metallization, etc., various semiconductor devices such as diodes, transistors, and integrated circuits can be constructed.

[0005] The implementation of photolithography techniques utilizes an exposure system (also called an exposure tool). An exposure system typically includes an illumination system, a reticle (also called a photomask) or spatial light modulator (SLM) for creating the circuit pattern, a projection system, and a wafer alignment stage for aligning a semiconductor wafer covered with a photoresist. The illumination system illuminates a region of the reticle or SLM with an illumination field (preferably) in a rectangular slot. The projection system projects an image of the illuminated region of the reticle pattern onto the wafer. For accurate projection, it is important to expose a relatively flat or planar wafer, preferably with a height deviation of less than 10 microns, to the pattern of light. Therefore, a method for correcting any wafer warping is required. [Overview of the project] [Means for solving the problem]

[0006] This disclosure relates to a method for processing a substrate, comprising the steps of: forming a warp-modifying stress film on the back side of a wafer, wherein the wafer includes a processed surface and a back side opposite to the processed surface, the warp-modifying stress film includes a stress-modification agent, and the warp-modifying stress film is sensitive to a predetermined wavelength of actinic radiation; exposing the warp-modifying stress film to a pattern of actinic radiation at the predetermined wavelength, wherein the warp-modifying stress film is configured to release the stress-modifying agent at a position along the exposed warp-modifying stress film, the concentration of the released stress-modifying agent corresponding to the pattern of actinic radiation; and performing a curing process, wherein the curing process activates the released stress-modifying agent, causing a stress change within the warp-modifying stress film, and the stress change modifies the warp of the wafer.

[0007] The disclosure further includes the steps of: forming a first warpage-modulating stress film on the back side of a wafer, wherein the wafer includes a processed side and a back side opposite to the processed side, and the first warpage-modulating stress film is configured to release a first stress modifier in response to a chemical beam having a first predetermined wavelength; forming a second warpage-modulating stress film on the first warpage-modulating stress film, wherein the second warpage-modulating stress film is configured to release a second stress modifier in response to a chemical beam having a second predetermined wavelength; and exposing the first warpage-modulating stress film and the second warpage-modulating stress film to a first pattern of chemical beams at a first predetermined wavelength, wherein the first warpage-modulating stress film is configured to release a first stress modifier at a position along the first warpage-modulating stress film exposed to the first pattern of chemical beams, and the released first stress modifier A method for processing a substrate, comprising the steps of: a step in which the concentration of a chemical beam corresponds to a first pattern of chemical beams; a step in which a first warpage-adjusting stress film and a second warpage-adjusting stress film are exposed to a second pattern of chemical beams at a second predetermined wavelength, wherein the second warpage-adjusting stress film is configured to release a second stress modifier at a position along the second warpage-adjusting stress film exposed to the second pattern of chemical beams, the concentration of the released second stress modifier corresponds to a second pattern of chemical beams; and a step in which a curing step is performed, the curing step activating the released first stress modifier and the released second stress modifier, the curing step causing a first stress change in the first warpage-adjusting stress film and a second stress change in the second warpage-adjusting stress film, the first stress change and the second stress change together adjusting the warpage of the wafer.

[0008] It should be noted that this summary section does not specify all embodiments and / or progressively novel aspects of the invention as described in this disclosure or claims. Instead, the summary of the invention provides only a preliminary consideration of different embodiments and corresponding novelty aspects. For further details and / or anticipated aspects of the invention and embodiments, readers should refer to the “Modes for Carrying Out the Invention” section and corresponding drawings of this disclosure, which are discussed further below.

[0009] Various embodiments of this disclosure, proposed as examples, will be described in detail with reference to the following figures. In the drawings, similar numbers refer to similar elements. [Brief explanation of the drawing]

[0010] [Figure 1A] This is a schematic perspective view of a layer on a wafer in which a defect has been introduced into one of the layers. [Figure 1B] This is a schematic diagram illustrating the various types and degrees of wafer warping that result from this process. [Figure 2A] This is a stress map for a warpage-relaxing stress film placed on a wafer and exposed to chemical radiation, according to an embodiment of the present disclosure. [Figure 2B] This is a stress map for a warpage-relaxing stress film placed on a wafer and exposed to chemical radiation, according to an embodiment of the present disclosure. [Figure 2C] This is a stress map for a warpage-relaxing stress film placed on a wafer and exposed to chemical radiation, according to an embodiment of the present disclosure. [Figure 3] This is a cross-sectional substrate segment showing a structure or device formed on a surface according to an embodiment of the present disclosure. [Figure 4] This is a cross-sectional substrate segment showing a warpage adjustment stress film formed on the back side of a wafer according to an embodiment of the present disclosure. [Figure 5] This is a cross-sectional substrate segment showing the exposure of a stress film according to an embodiment of the present disclosure. [Figure 6]This is a cross-sectional substrate segment showing the stress film after exposure, according to an embodiment of the present disclosure. [Figure 7] This is a flowchart of a method for manufacturing a semiconductor device according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0011] The following disclosure provides various embodiments or examples for implementing various features of the subject matter presented. For the sake of brevity, specific examples of components and configurations are described below. Naturally, these are merely examples and are not intended to be limiting. For example, the formation of a first feature above or on a second feature in the following description may include embodiments in which the first and second features are formed in direct contact, or may include embodiments in which an additional feature is formed between the first and second features in such a way that they cannot directly contact each other. In addition, the disclosure may repeat reference numbers and / or letters in various examples. This repetition is for the sake of brevity and clarity and does not, in itself, refer to the relationships between the various embodiments and / or configurations discussed. Furthermore, for the sake of simplicity, this specification may use spatially relative terms such as “above,” “below,” “down,” “below,” “lower,” “above,” and “up” to describe the relationship of one element or feature to another, as shown in the figures. Spatial relation terms shall include not only the orientation shown in the illustration, but also other orientations of the device in use or operation. The device may be in other orientations (rotated by 90 degrees, or in other orientations), and the spatial relation descriptors used herein shall be interpreted accordingly.

[0012] The order in which the different steps described herein are presented is for the purpose of clarity. In general, these steps can be performed in any suitable order. Furthermore, different features, techniques, structures, etc., described herein may be referred to in different places within this disclosure, but each concept can be performed independently or in combination with others. Therefore, the present invention can be embodied and explored in many different ways.

[0013] This specification describes a technique for providing a tunable stress film for spin-on direct lithography and a method for correcting wafer warpage. The process described herein can be performed using a coater-developer tool (also known as a track tool). Such a technique achieves corrected wafer warpage in fewer and less expensive steps. The spin-on film can be based on a film that undergoes crosslinking / decrosslinking under external stimuli, where direct lithography is achieved by 365 nm exposure, followed by curing, which is used to "pattern-in" the stress. Furthermore, the film does not have to be limited to the spin-on process, and other deposition methods may be used. A develop step is not essential (but may be optional) in the techniques described herein, but provides further significant benefits. The amount of warpage (or internal stress that forms or affects the warpage characteristics) can be controlled by exposure dose, bake temperature, bake time, and number of bakes. However, the stress-modulating films described herein may be organic in nature and may have properties or components that crosslink when exposed to light, or after exposure to light followed by a bake or curing step. The properties of the films also enable back-side wafer coating.

[0014] In the manufacturing of 3D NAND memory devices, the device structure can extend perpendicularly from the processed surface of the wafer. As the amount of memory stored in these devices increases, the devices become heavier. Figure 1A is a schematic perspective view of a layer on a wafer in which a defect has been introduced in one of the layers. For example, a 3D NAND device on a 300 mm wafer may use 128 layers. As shown, a defect in a preceding underlying layer can expand, causing severe warping in subsequent layers. Figure 1B shows that systematically increasing the number of layers in the front-side 3D NAND stack further increases wafer warping and exacerbates the problem. This can lead to problems including non-uniformity, non-planarity, overlay mismatch in the lithography or other processes, and deterioration of wafer handling.

[0015] Some mitigation methods include, for example, depositing a silicon nitride film on the back of the wafer by chemical vapor deposition (CVD), which can generate significant stress on the wafer and device. Then, predetermined portions of the silicon nitride are imaged, illuminated, or exposed and subsequently removed to relieve stress at specific points on the wafer, thereby allowing the wafer to be reshaped in different ways. A problem with the silicon nitride film method is that it requires the provision of different tools, which can make simple track-based processes incompatible. Therefore, it may be necessary to load the wafer onto entirely different tools. Furthermore, this method can also be time-consuming to deposit the desired amount of silicon nitride on the back of the wafer. In addition, this method is generally a very complex process, involving imaged silicon nitride films or pattern adjustments within the silicon nitride film to mitigate wafer warping.

[0016] As described herein, an organic-based, crosslinkable warp-relieving film may be deposited on the back side of a wafer. The warp-relieving film may be flexible in providing both overall and local warp relief. In one embodiment, overall warp relief may be applied to the film. In one embodiment, local warp relief may be applied via a programmable direct-draw stress pattern on the film on the back side of the wafer. The direct-draw stress pattern may be based on a front-side warp-adjusting stress map (referred to herein as the “stress map”). Notably, the warp-relieving film is a polymer-based organic film deposited on the back side of a wafer using a tool that allows for continuous processing in a track-based process. Given a predetermined wavelength of chemical light, the film may be imaged, illuminated, or exposed based on the stress map to incorporate stresses into the film and, consequently, the wafer, that relieve undesirable warp on the opposite side or face. Furthermore, the exposure step, which may include a heating or baking step, does not necessarily require a develop step. Thus, this method can be considered a direct-draw process for manufacturing a warp-relieving film. A warp-relieving film can also be described as a stress film, in that the film may incorporate stress to alleviate the warp of the wafer.

[0017] Regarding the impact of warping on manufacturing tools, while tools can handle wafers (i.e., move, transport, and manipulate them), handling problems may be experienced when wafer warping approaches and exceeds 300 μm. Notably, the method described herein can allow for an increase in secondary warping relaxation of up to 150 μm while maintaining primary warping relaxation of 300–400 μm. This is direct drawing, but a development step may still be included. The development step can provide flexibility at higher curing temperatures if unexposed material exists in areas not exposed to light. For example, if the decomposition temperature of the photoacid generator is not high, these areas can also be crosslinked at high temperatures.

[0018] In connection with chemical substances, the methods described herein can utilize epoxy acrylates, epoxy novolacs, benzene cyclobutadiene (BCB) substances where a Diels - Alder reaction can induce cross - linking, and chemical substances including polyimides. Other types of chemical substances that can be used include photo - initiating chemical substances where cross - linking or bond rearrangement occurs upon irradiation and subsequent heating, or upon exposure alone, to form some type of stress. If wafer bow can be mitigated using a back - side coat on the track, the complex silicon nitride film deposition process can be eliminated.

[0019] In one embodiment, an organic formulation can be deposited on the surface of a wafer through a spin - coating process or any deposition process. The film can be baked to remove excess solvent. Then, the film can be exposed to a pattern of actinic radiation. This pattern of actinic radiation can define a stress - adjustment pattern or be based on a stress - adjustment pattern. Various lithography tools can be used. Preferably, a direct - write laser or a lithography tool can be used. This can be a digital light processing (DLP) chip, a laser galvanometer, etc., which projects the pattern as one image or as a scan. In one embodiment, mask - based lithographic exposure using a scanner or a stepper tool can be used. The direct - write tool has a lower resolution than the mask - based tool, but the resolution required to finely adjust stress can be much lower compared to patterning transistors. Also, the stress map created with a mask is static, whereas using a direct - write tool can be dynamic, so the stress map can be created or projected and changed wafer - by - wafer as needed.

[0020] As described herein, the wavelength of the light (i.e., actinic radiation) can be 365 nm, but other wavelengths can be used as well. The wavelength can depend on the components included in a given organic film. Embodiments herein can also include using multiple films that respond to different wavelengths of light. After exposure, the film can be heated in a post-exposure bake. However, the development step is not essential, and then the film can be cured at a higher temperature. The time and temperature can depend on the film thickness and the amount of stress required. The development step may be performed prior to curing, but note that this is optional. The curing temperature should be high enough to induce more complete cross-linking bonds within the film. By the initial flood exposure and curing of the organic stress film, wafer warpage of tens or hundreds of microns can be achieved.

[0021] Next, referring to the drawings, FIGS. 2A-2C are stress maps of a warp relaxation stress film disposed on a wafer and exposed to actinic radiation, according to embodiments of the present disclosure. In one embodiment, the wafer can include a first surface and a second surface. For example, the first surface of the wafer can be the processing surface on which the target device is fabricated. The second surface can be the backside of the wafer. The backside of the wafer can have a warp adjustment stress film (referred to herein as a "stress film") formed thereon. The stress film can be an organic film or a polymer-based film.

[0022] In one embodiment, Figures 2A-2C illustrate how an organic stress film may affect wafer warpage. The stress film can be deposited on the back of the wafer, for example, by spin coating. Other deposition processes may be considered, in particular, such as sputter coating, spray coating, doctor blade, CVD, physical vapor deposition (PVD), and atomic layer deposition (ALD). The stress film may be exposed according to a predetermined pattern or shape, such as a strip of stress film running through the center of the wafer. As shown in Figures 2A-2C, a 100 mm strip of stress film was exposed below the center of the wafer and exposed to light with a wavelength of 365 nm. The wafer containing the exposed stress film may be heated in a post-exposure bake and then cured at a higher temperature. Additional curing steps increase wafer warpage, enabling a tunable stress film. Each stress map is accompanied by the same table containing additional process information for reference.

[0023] Figures 2A to 2C show the processing conditions in the table (left) and the corresponding stress maps of the epoxy novolac film, along with the resulting saddle pattern image passing through the center of the wafer.

[0024] In Figure 2A, the first curing was performed at 175°C for 10 minutes, resulting in a wafer warp of approximately 88 μm in a stress film with a thickness of 17 μm.

[0025] In Figure 2B, a second curing process was performed at 200°C for an additional 10 minutes, resulting in a wafer warp of approximately 214 μm.

[0026] In Figure 2C, a third curing process was performed at 200°C for an additional 5 minutes, resulting in a wafer warp of approximately 260 μm.

[0027] As mentioned above, the chemical substances included in such stress films include, but are not limited to, epoxy acrylates, epoxy novolacs, BCB chemicals that can induce crosslinking through the Diels-Alder reaction, and polyimides. Again, the wafer warping shown in Figures 2A to 2C demonstrates that stress films can indeed cause wafer warping, and therefore can be used on wafers that are already warped due to devices manufactured on them in order to alleviate or correct the aforementioned wafer warping.

[0028] As described above, coater / developer systems may be used in this specification for spin-on deposition of stress films. These tools may include multiple modules for wafer coating, wafer baking, and film development. The coater / developer tools described herein may also include a direct drawing / exposure module. The coater / developer system may then move the wafer back and forth between various spin-coating, baking / curing modules, and exposure modules, or to an attached scanner / stepper tool. Furthermore, the coater / developer tools described herein may also include point-of-dispense mixing. That is, chemicals may be mixed at or near the supply nozzle immediately before being supplied to the wafer. For example, a solvent may be added to the resist at the nozzle to adjust viscosity or film thickness.

[0029] The techniques described herein may be used to mitigate or counteract warping caused by microfabrication processes. The stress films described herein may be deposited multiple times through a given microfabrication process. For example, as described above, a 3D NAND memory device may have 128 or more layers of laminated film to create the memory device. This laminate of layers imparts significant stress to the wafer, which can result in warping where overlay errors become a problem. Similarly, 3D logic has many layers and is expected to have a similar need to correct wafer warping.

[0030] For this purpose, Figure 3 is a cross-sectional substrate segment showing a structure or device 399 formed on the surface according to an embodiment of the present disclosure. In one embodiment, the wafer 305 includes a first surface 310 and a second surface 315. For example, the first surface 310 of the wafer may be the processed surface on which the target device is manufactured. The second surface 315 may be the back side of the wafer. The device 399 formed on the processed surface 310 may be an active device such as a transistor or memory cell, or a partially formed active device. The wafer 305 may be received by a coating module of a coater / developer tool or other track-based tool.

[0031] Figure 4 is a cross-sectional substrate segment showing a warpage-modulating stress film 325 (hereinafter referred to as “stress film 325”) formed on the back side 315 of a wafer 305 according to an embodiment of the present disclosure. In one embodiment, the wafer 305 may be inverted and the stress film 325 may be formed on the back side 315, but the wafer 305 may not be inverted. For example, the tool may include a system for vertically upward coating, spraying, or deposition. That is, the wafer 305 may remain on a track and the tool may form the stress film 315 on the back side 315 of the wafer by spray coating. In any case, the stress film 325 may be formed on the back side 315. The stress film 325 may be an organic film configured to release a stress modifier in response to chemical radiation. That is, the stress film 325 may include one or more photoacid generators, thermoacid generators, photoinitiators, photodestruction bases, etc. As described above, the stress film 325 may include various epoxy materials or resins, or other organic materials, that impart stress (tensile or compressive) within the stress film 325 through curing in the presence of acids, bases, or radicals. For the device 399 placed on the processed surface 310, a protective filler or protective film may be deposited, or a carrier wafer may be attached, to facilitate the handling of the wafer 305.

[0032] It should be noted that in this specification, the processed surface 310 and the back surface 315 are used to indicate both sides of the wafer 305. In some microfabrication processes, a given wafer may have active devices or power supply structures formed on both sides. In this case, either the processed surface 310 or the back surface 315 may receive a stress film 325, depending on the stage of the manufacturing process.

[0033] Figure 5 is a cross-sectional substrate segment showing the exposure of a stress film 325 according to an embodiment of the present disclosure. In one embodiment, the stress film 325 may be exposed to a pattern of chemical rays that emit stress modifiers within the stress film 325. This exposure step may be performed within the direct drawing module of a coater / developer tool or transferred to a separate or connected tool for exposure. The chemical rays may be patterned so that more or less radiation is received at coordinate locations on the back side 315 of the wafer 305 having the stress film 325. The resolution may depend on the specific lithography system selected to perform the exposure. The concentration of stress modifiers emitted at a given coordinate location may be based on the pattern of chemical rays illuminating the stress film 325. This is represented by the more densely shaded portion of the stress film 325 in Figure 6.

[0034] Figure 6 is a cross-sectional substrate segment showing the stress film 325 after exposure according to an embodiment of the present disclosure. In one embodiment, one or more curing steps may be performed, as described in Figures 2A to 2C. The wafer 305 may be transferred to the bake / curing module of the coater / developer tool. The curing process activates stress modifiers in the stress film 325, generating stress in the stress film 325 that is well-tuned to adjust the warpage of the wafer 305. For example, upon exposure to light, (in a non-limiting example) a photoacid generator (PAG) generates photoacid, which may catalyze an epoxy crosslinking reaction during baking and curing. The crosslinking reaction in the stress film 325 results in stress relaxation. In some embodiments, imaging of or exposure to a chemical beam pattern can directly alter the stress film 325, thereby directly altering or adjusting the warpage of the wafer 305. For example, stress can be relaxed by imaging and eliminating bonding interactions, such as hydrogen bonding interactions, through patterned exposure. In other words, rather than inducing stress, patterned exposure can relieve stress, for example, by activating photoactive compounds (PACs) and removing the inhibitory effect of previously exposed PACs. The regulated stress can be brought about by crosslinking, regulated interspecies bonding, or other entanglements. For example, the amount of crosslinking in the stress film 325 via the stress modifier may correspond to the concentration of the stress modifier released at a given coordinate position, based on the pattern of chemical rays. Depending on the properties of the agent and the film, the stress can be tensile or compressive internal stress. The resulting stress in the stress film 325 can then counteract, for example, the stress generated in the wafer from a microfabrication step. Figure 6 shows stress films 325 with more or less stress at different coordinate positions, based on the light projection pattern and one or more curing steps.

[0035] Therefore, a warped wafer can be planarized with a stress film 325 as described herein. A programmable direct drawing pattern activates (or pre-activates) stress through crosslinking or chemical changes, which are activated by specific wavelengths of light or electromagnetic energy that may include longer wavelengths, located in the infrared (IR) or thermal region. IR wavelengths may be used to pattern the stress film 325 through the wafer 305, i.e., through the wafer 305 exposed through the processed surface 310. However, device manufacturing on the processed surface of the wafer may impair the ability to pattern the stress film 325 through the wafer, particularly in later stages of the device manufacturing process. In some embodiments, the back-side film may be activated using a wafer chuck with spatial temperature control, either within a track device or within device manufacturing equipment. Stress activation may be tuned using different wavelengths of light, based on additives rather than polymers in a given organic film. Therefore, the stress film 325 in this specification does not release stress, but rather induces counteracting stress, as in an etched film, but without the etching step. In some embodiments, the wafer may be flipped over (such as the wafer in Figure 5) so that electromagnetic energy is patterned on the image-forming side rather than through the back side 315.

[0036] As described above, a developing process or step may be performed before hardening. If a developing process is performed, a height mismatch may occur on the back side of the wafer. Therefore, a filler may be deposited or formed on the stress film 325 on the back side. The back-side filler may then be flattened before the wafer 305 is turned over for further manufacturing and processing. Otherwise, the height mismatch of the film at a particular location itself could cause a shape defect in the wafer 305. However, this should further highlight the advantage of direct drawing control, which does not require a developing process and does not result in any kind of film height mismatch. Direct drawing forms a flat film, which can be induced by warping, but the film remains flat.

[0037] In one embodiment, two or more stress films 325 may be deposited. Each given film may be activated by the same or different wavelengths. This multilayer process may be used to introduce cumulative or differential stress. For lower-resolution wafer warpage correction, the films described herein may be activated simply by targeted or patterned heating without a photoactivation pattern step (i.e., overall warpage relaxation). Zone-based heating, or mask-based heat curing, or microwave heating may produce position-specific crosslinking. In this case, either a photoacid generator (PAG) or a thermoacid generator (TAG) may be used, since most PAGs can function as TAGs at sufficiently high temperatures.

[0038] In one embodiment, incorporating the stress film on the back side may introduce a trade-off that could affect the device yield. The advantages of this technology can be realized without trade-offs through the coordinated optimization of design techniques in which the multi-directional stress film is planned to be incorporated on the front side. In such an implementation, the stress film 325 may be formed on a processed surface 310, such as a region between devices on the wafer 305, along the periphery of the processed surface 310, or even on the device.

[0039] The techniques described herein can affect wafer warpage of several hundred microns, which is sufficient to counteract wafer warpage and warp observed in wafers during semiconductor manufacturing. The resulting warpage corrections described herein may be primary and secondary bowing corrections, such as saddle warpage. The techniques described herein can be used throughout the semiconductor manufacturing process. For example, after the initial warpage has been corrected with the film described herein, further processing can be performed. This further processing may result in further warp. At this point, a second warpage correction film may be added, patterned, and then cured. Alternatively, after the first warpage correction film is removed, the wafer warp may be measured a second time, and then subsequent warpage corrections may be deposited and patterned according to the second wafer warpage measurement.

[0040] Figure 7 is a flowchart of a method 700 for processing a substrate according to an embodiment of the present disclosure.

[0041] In step 705, wafer 305 may be received by the tool. Wafer 305 includes a first surface 310 (processing surface 310) and a second surface 315 (back side 315).

[0042] In step 710, a stress film 325 may be formed on the back side 315 of the wafer 305. The stress film 325 may contain a stress modifier and be sensitive to a predetermined wavelength of chemical rays.

[0043] In step 715, the stress film 325 may be exposed to a pattern of chemical rays at a predetermined wavelength. The stress film 325 may be configured to release a stress modifier at a location along the stress film 325 exposed to the pattern of chemical rays. The concentration of the released stress modifier may correspond to the pattern of chemical rays.

[0044] In step 720, a curing process may be performed. The curing process activates the released stress modifier, causing stress changes within the stress film 325, thereby adjusting the warp of the wafer 305 and making the wafer 305 closer to flat.

[0045] In step 725, optionally, a developing process may be performed before curing.

[0046] In the preceding description, specific details have been provided, including the particular geometric shape of the processing system and descriptions of the various components and processes used. However, it should be understood that the techniques described herein may be implemented in other embodiments different from these specific details, and that such details are for illustrative purposes only and not to limit the scope. Multiple embodiments disclosed herein have been described with reference to the accompanying drawings. Similarly, specific numbers, materials, and configurations have been described for illustrative purposes to ensure a complete understanding. Nevertheless, multiple embodiments can be implemented without such specific details. Components having substantially the same functional structure are denoted by similar reference numerals, and therefore any redundant descriptions may be omitted.

[0047] To facilitate understanding of various embodiments, various techniques have been described as multiple separate actions. The order of description should not be interpreted as suggesting that these actions are necessarily order-dependent. In fact, these actions do not need to be performed in the order presented. The described actions may be performed in a different order than in the embodiments described. In additional embodiments, various additional actions may be performed, and / or the described actions may be omitted.

[0048] As used herein, “substrate” or “target substrate” refers collectively to an object processed in accordance with the present invention. A substrate may include any material portion or structure of a device, in particular a semiconductor device or other electronic device, such as a base substrate structure, reticle, or layer on or superimposed on a base substrate structure, such as a thin film. Therefore, a substrate is not limited to any particular base structure, underlay, or coating layer, whether patterned or not, but rather is intended to include any such layer or base structure, and any combination of layers and / or base structures. The description may refer to specific types of substrates, but these are for illustrative purposes only.

[0049] Those skilled in the art will also understand that even with numerous modifications to the operation of the techniques described above, the same objectives of the present invention can still be achieved. Such modifications are intended to be included within the scope of this disclosure. Therefore, the above description of embodiments of the present invention is not intended to be limiting. Rather, any limitations on embodiments of the present invention are presented in the following claims.

Claims

1. A method for processing a substrate, wherein the method is This is a step in which a warpage adjustment stress film is formed on the back side of the wafer. The wafer includes a processed surface and the back side opposite to the processed surface, The aforementioned warpage adjustment stress film contains a stress adjustment agent, The aforementioned warpage adjustment stress film is sensitive to a predetermined wavelength of chemical rays. Steps and The step involves exposing the warpage adjustment stress film to the pattern of chemical rays at the predetermined wavelength, The warpage adjustment stress film is configured to release the stress adjustment agent at a position along the warpage adjustment stress film that is exposed to the pattern of the chemical rays, The concentration of the released stress modifier corresponds to the pattern of the chemical rays. Steps and This is the step in which the curing process is performed. The curing step activates the released stress modifier and causes a stress change within the warpage adjustment stress film. The aforementioned stress change adjusts the warping of the wafer, The material of the warpage adjustment stress film is at least one selected from the group consisting of epoxy acrylates and epoxy novolacs. Steps and Methods that include...

2. The curing process activates the released stress modifier. Based on the pattern of the chemical rays, to create cross-linking bonds within the warpage adjustment stress film, The method according to claim 1, further comprising:

3. The warpage adjustment stress film is a photoacid generator that generates acid according to the predetermined wavelength of the chemical beam, The method according to claim 1, including the method described in claim 1.

4. The warpage adjustment stress film comprises a photoinitiator that generates radicals according to the predetermined wavelength of the chemical beam, The method according to claim 1, including the method described in claim 1.

5. The steps of forming the warpage adjustment stress film, exposing the warpage adjustment stress film to the pattern of the chemical rays, and performing the curing process are performed without introducing a developer to the wafer. The method according to claim 1.

6. The step of performing the aforementioned curing process is, Applying heat to the wafer until a predetermined degree of crosslinking is achieved within the warpage adjustment stress film, The method according to claim 1, further comprising:

7. The step of exposing the warpage adjustment stress film to the pattern of the chemical rays is, Irradiating with a chemical beam of a certain intensity based on the selected value of curvature adjustment to be achieved, The method according to claim 1, further comprising:

8. In the step of performing the curing process, the stress change adjusts the warping of the wafer. To reduce the warpage value of the wafer on the processed surface, and as a result, to reduce the curvature of the wafer compared to before the deposition of the warpage adjustment stress film, The method according to claim 1, further comprising:

9. The above method further, The step involves depositing a second warpage adjustment stress film on the back side of the wafer. The second warpage adjustment stress film comprises a second stress adjustment agent, The second warpage adjustment stress film is sensitive to a second predetermined wavelength of the chemical beam. Steps and The steps include exposing the second warpage adjustment stress film to the second pattern of the chemical beam, Includes, The curing step activates the released second stress modifier and causes the stress change within the warpage adjustment stress film. The aforementioned stress change adjusts the warpage of the wafer. The method according to claim 1.

10. The above method further, The step involves depositing a second warpage adjustment stress film on the back side of the wafer. The second warpage adjustment stress film comprises a second stress adjustment agent, The second warpage adjustment stress film is sensitive to a second predetermined wavelength of the chemical beam. Steps and The steps include exposing the second warpage adjustment stress film to the second pattern of the chemical beam, This is the step of performing the second curing process. The second curing step activates the released second stress modifier, causing a stress change within the warpage adjustment stress film. The aforementioned stress change adjusts the warping of the wafer. Steps and The method according to claim 1, including the method described in claim 1.

11. The first predetermined wavelength and the second predetermined wavelength are different. The method according to claim 10.

12. The pattern of the chemical lines is based on a warpage adjustment stress map for the wafer. The method according to claim 1.

13. The warpage adjustment stress map indicates stress values ​​to be relieved across coordinate positions along the back side of the wafer. The method according to claim 1.

14. The aforementioned warpage-adjusting stress film is deposited by spin-on deposition. The method according to claim 1.

15. The pattern of the chemical lines is provided by a direct drawing lithography system. The method according to claim 1.

16. The pattern of the chemical lines is provided by a mask-based lithography system. The method according to claim 1.

17. A method for processing a substrate, wherein the method is This is a step of forming a first warpage adjustment stress film on the back side of the wafer. The wafer includes a processed surface and the back surface opposite to the processed surface, The first warpage-adjusting stress film is configured to release a first stress-adjusting agent in response to a chemical beam having a first predetermined wavelength. Steps and The step is to form a second warpage adjustment stress film on the first warpage adjustment stress film, The second warpage-adjusting stress film is configured to release a second stress-adjusting agent in response to the chemical beam having a second predetermined wavelength. Steps and The step is to expose the first warpage adjustment stress film and the second warpage adjustment stress film to a first pattern of chemical rays at the first predetermined wavelength, The first warpage-adjusting stress film is configured to release the first stress modifier at a position along the first warpage-adjusting stress film that is exposed to the first pattern of the chemical rays, The concentration of the released first stress modifier corresponds to the first pattern of the chemical rays. Steps and The step is to expose the first warpage adjustment stress film and the second warpage adjustment stress film to a second pattern of the chemical beam at the second predetermined wavelength, The second warpage-adjusting stress film is configured to release the second stress modifier at a position along the second warpage-adjusting stress film that is exposed to the second pattern of the chemical rays, The concentration of the released second stress modifier corresponds to the second pattern of the chemical rays. Steps and This is the step in which the curing process is performed. The curing step activates the released first stress modifier and the released second stress modifier. The hardening process causes a first stress change to occur within the first warpage adjustment stress film. A second stress change is generated within the second warpage adjustment stress film. The first stress change and the second stress change together adjust the warpage of the wafer. Steps and Includes, The material of the warpage adjustment stress film is at least one selected from the group consisting of epoxy acrylates and epoxy novolacs. method.

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