Method to correct wafer warping using a Direct Light stress film

Abstract

The techniques of this specification include direct light, a method for forming an adjustable stress film, and a method for correcting wafer warping using said stress film. The method may be executed on a coater-developer tool or a track-based tool. The stress film may be based on a film that undergoes crosslinking / decrosslinking under an external stimulus where subsequent curing is used for "pattern-in" stress, with direct light achieved by but not limited to 365 nm exposure. A developing step may not be required, which provides additional significant gains when preserving film flatness. The amount of warping (or internal stress that creates or influences warping features) may be adjusted according to the exposure amount, baking temperature, baking time, and number of baking cycles.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] The present disclosure claims the benefit of U.S. Provisional Application No. 63 / 175,123 (April 15, 2021) and U.S. Regular Application No. 17 / 703,072 (March 24, 2022), the entirety of which is incorporated herein by reference.

[0003] Field of the present invention

[0004] The present disclosure relates to a semiconductor manufacturing method, and in particular to wafer warping relief. Background Technology

[0005] The background art provided in this specification is intended to provide a general context for the present disclosure. The work of the inventors currently named, as well as aspects of the description that may not have been recognized as prior art at the time of filing, to the extent described in the background art section, are not explicitly or implicitly recognized as prior art for the present disclosure.

[0006] Semiconductor manufacturing involves a number of diverse steps and processes. One typical manufacturing process is known as photolithography (also called 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, and the like.

[0007] An exposure system (also referred to as a tool) is used to implement photolithography techniques. The exposure system generally includes an illumination system, a reticle (also referred to as a photomask) or spatial light modulator (SLM) for creating a circuit pattern, a projection system, and a wafer alignment stage for aligning a semiconductor wafer covered with a photosensitive resist. The illumination system illuminates a section of the reticle or SLM through a rectangular slot illumination field (preferably). The projection system projects an image of the illuminated section of the reticle pattern onto the wafer. For accurate projection, it is important to expose a pattern of light onto a relatively flat or flat wafer, preferably having a height deviation of less than 10 micrometers. Therefore, a method for correcting any wafer warping is desired.

[0008] The present disclosure relates to a method for processing a substrate, the method comprising: forming a bending strain stress film on the back surface of a wafer, wherein the wafer comprises a processing surface and a back surface opposite to the processing surface, the bending strain stress film comprises a stress strainer, and the bending strain stress film is sensitive to chemical radiation of a predetermined wavelength; exposing the bending strain stress film to a pattern of chemical radiation of a predetermined wavelength, wherein the bending strain stress film is configured to release a stress strainer at a location along the bending strain stress film exposed to the pattern of chemical radiation, and the concentration of the released stress strainer corresponds to the pattern of chemical radiation; and performing a curing process, wherein the curing process activates the released stress strainer and induces a stress change within the bending strain stress film, and the stress change deforms the bending of the wafer.

[0009] The present disclosure additionally relates to a method for processing a substrate, the method comprising: forming a first bending strain stress film on a back surface of a wafer, wherein the wafer comprises a processing surface and a back surface opposite to the processing surface, and the first bending strain stress film is configured to emit a first stress strainer in response to chemical radiation having a first predetermined wavelength; forming a second bending strain stress film on the first bending strain stress film, wherein the second bending strain stress film is configured to emit a second stress strainer in response to chemical radiation having a second predetermined wavelength; and exposing the first bending strain stress film and the second bending strain stress film to a first pattern of chemical radiation of a first predetermined wavelength, wherein the first bending strain stress film is configured to emit a first stress strainer at a location along the first bending strain stress film exposed to the first pattern of chemical radiation, and the concentration of the emitted first stress strainer corresponds to the first pattern of chemical radiation. The method comprises: a step of exposing a first bending strain stress film and a second bending strain stress film to a second pattern of chemical radiation of a second predetermined wavelength, wherein the second bending strain stress film is configured to emit a second stress strainer at a location along the second bending strain stress film exposed to the second pattern of chemical radiation, and the concentration of the emitted second stress strainer corresponds to the second pattern of chemical radiation; and a step of performing a curing process, wherein the curing process activates the emitted first stress strainer and the emitted second stress strainer, and the curing process induces a first stress change within the first bending strain stress film and a second stress change within the second bending strain stress film, and the first stress change and the second stress change together deform the bending of the wafer.

[0010] It should be noted that the content of this invention does not specify all embodiments and / or progressively novel aspects of the present disclosure or the claimed invention. Instead, the content of this invention provides only a preliminary discussion of different embodiments and corresponding points of novelty. For additional details and / or possible aspects of the invention and embodiments, the reader is directed to the detailed description of this disclosure and the corresponding drawings, as further discussed below. Brief explanation of the drawing

[0011] Various embodiments of the present disclosure presented as examples will be described in detail with reference to the following drawings, in which similar reference numerals indicate similar elements: FIG. 1a is a schematic perspective view of layers on a wafer in which a defect is introduced into one of the layers. Figure 1b is a schematic diagram of the various types and severity of the resulting wafer warping. FIGS. 2a to 2c are stress maps for a bending relief stress film disposed on a wafer and exposed to chemical radiation according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional substrate portion illustrating a structure or device formed on a surface according to an embodiment of the present disclosure. FIG. 4 is a cross-sectional substrate portion illustrating a bending strain stress film formed on the back surface of a wafer according to an embodiment of the present disclosure. FIG. 5 is a cross-sectional substrate portion illustrating the exposure of a stress film according to an embodiment of the present disclosure. FIG. 6 is a cross-sectional substrate portion illustrating a stress film after exposure according to an embodiment of the present disclosure. FIG. 7 is a flowchart of a method for manufacturing a semiconductor device according to an embodiment of the present disclosure. Specific details for implementing the invention

[0012] The following disclosure provides many different embodiments or examples for implementing different features of the subject matter provided. To simplify the disclosure, specific examples of components and devices are described below. These are, of course, merely examples and are not intended to be limiting. For example, in the following description, the formation of a first feature through or on a second feature may include embodiments in which the first and second features are formed to be in direct contact, and may also include embodiments in which additional features may be formed between the first and second features so that the first and second features are not in direct contact. Furthermore, the disclosure may repeat reference numerals and / or letters in various examples. Such repetition is for simplicity and clarity and does not itself describe the relationship between the various embodiments and / or configurations being discussed. Furthermore, spatially related terms such as "top," "bottom," "beneath," "below," "lower," "above," and "upper" may be used herein for ease of explanation to describe the relationship of one element or feature to another element(s) or feature(s) as illustrated in the drawings. Spatially related terms are intended to include different orientations of the device in use or operation in addition to the orientations illustrated in the drawings. The device may be oriented differently (rotated 90 degrees or in a different orientation), and spatially related technical terms used herein may likewise be interpreted accordingly.

[0013] The order of discussion of different steps as described herein is presented for clarity. In general, these steps may be performed in any suitable order. Additionally, while each of the different features, techniques, configurations, etc. of this specification may be discussed in different places within this disclosure, it is intended that each of the concepts may be practiced independently of one another or in combination with one another. Accordingly, the present invention may be embodied and shown in many different ways.

[0014] Techniques for providing spin-on, direct write, and adjustable stress films, and methods for correcting wafer warping, are described herein. The processes of this specification may be executed on a coater-developer tool (also known as a track tool). These techniques achieve wafer warping correction in fewer and less expensive steps. The spin-on film may be based on a film that undergoes crosslinking / decrosslinking under an external stimulus where subsequent curing is used for "pattern-in" stress, with direct write achieved by a 365 nm exposure, but not limited thereto. Furthermore, the film does not need to be limited to a spin-on process, and other deposition methods may be used. In the techniques of this specification, a developing step is not required (but may be optional), which provides additional significant advantages. The amount of warping (or internal stress that creates or influences warping features) can be adjusted according to the exposure amount, baking temperature, baking time, and number of baking cycles. However, the stress strain film of this specification may be essentially organic and may have characteristics or components that crosslink upon exposure to light, or crosslink after exposure to light and then undergo a baking or curing step. The characteristics of the film may also allow for back-wafer coating.

[0015] In the manufacturing of 3D NAND memory devices, the device structure can extend vertically far from the processing plane of the wafer. As more memory is stored in this device, the device becomes heavier. Fig. 1a is a schematic perspective view of layers on a wafer with a defect introduced in one of the layers. For example, 128 layers may be used in a 3D NAND device on a 300 mm wafer. As shown, a defect in the lower, initial layer can magnify and cause severe warping in later layers. Fig. 1b indicates that a systematic increase in the number of layers in a frontal 3D NAND stack causes additional wafer warping and increases the severity of the problem. This can lead to problems including non-uniformity, non-planarity, overlay mismatch for lithography or other processes, and wafer processing degradation.

[0016] Some mitigation strategies involve, for example, depositing a silicon nitride film on the back of a wafer via chemical vapor deposition (CVD), which can induce significant stress on the wafer and device. Subsequently, a predetermined portion of the silicon nitride is imaged, illuminated, or exposed, and subsequently removed to relieve stress at specific points on the wafer, thereby allowing the wafer to be reshaped in a different way. The problem introduced by the silicon nitride film method is that it requires different tooling, which may mean that simple track-based processes are incompatible and thus require loading the wafer into different tools. Furthermore, this method can also be time-consuming in terms of placing the desired amount of silicon nitride on the back of the wafer. Additionally, this method is generally a very complex process that mitigates wafer warping by imaging the silicon nitride film or adjusting the pattern of the silicon nitride film.

[0017] As described herein, an organic crosslinkable warp relief film may be deposited on the back side of a wafer. The warp relief film may allow for flexibility in both global and local warp relief. In one embodiment, global warp relief may be applied to the film. In one embodiment, local warp relief may be applied via a programmable direct light stress pattern on the film on the back side of the wafer, and the direct light stress pattern may be based on a warp strain stress map on the front side (referred to herein as the "stress map"). In particular, the warp relief film is a polymer-based organic film deposited on the back side of the wafer using a tool that allows for continuous processing in a track-based process. Chemical radiation of a predetermined wavelength may be applied to image, illuminate, or expose the film based on the stress map to insert stress into the film and thereby relieve undesirable warping on the opposite side or surface of the wafer. Furthermore, the exposure process, which may include an exposure step and a heating or baking step, does not require a development step. Therefore, this method can be considered a direct light process for creating a warp-relieving film. The warp-relieving film can also be described as a stress film in that stress can be embedded in the film to relieve wafer warping.

[0018] Regarding the effect of warping on manufacturing tools, the tool can process wafers (i.e., move, transport, and manipulate), but may experience processing problems when wafer warping approaches and exceeds 300 µm. In particular, the method described herein can increase secondary warping relief up to 150 µm while maintaining primary warping relief of 300 to 400 µm. Although this is direct light, a developing step may still be included. The developing step may allow flexibility at higher curing temperatures when unexposed material is present in areas not exposed to light. For example, if the photocatalytic decomposition temperature is not high, these areas may also be crosslinked at high temperatures.

[0019] In terms of chemical properties, the method described herein may affect epoxy acrylates, epoxy novolaks, benzene cyclobutadiene (BCB) chemicals in which Diels-Alder reactions can induce crosslinking, and chemicals including polyimides. Other types of chemicals that may be used include any photoinitiating chemicals that induce crosslinking or bond rearrangement to form some type of stress upon irradiation and subsequent heating or merely exposure. If wafer warping can be mitigated using a back coating on the track, complex silicon nitride film deposition processes may be avoided.

[0020] In one embodiment, an organic formulation may be deposited on the surface of a wafer via a spin coating process or any deposition process. The film may be baked to remove excess solvent. Subsequently, the film may be exposed to a pattern of chemical radiation. This chemical radiation pattern may define a stress modification pattern or may be based on a stress modification pattern. Various lithography tools may be used. Preferably, a direct light laser or lithography tool may be used. This may be a digital light processing (DLP) chip, a laser galvanometer, etc., that projects the pattern as a single image or scan. In one embodiment, mask-based lithography exposure using a scanner or stepper tool may be used. Direct-input tools have lower resolution than mask-based tools, but the resolution required to fine-tune stress may be much lower than that required for patterning transistors. Additionally, while the stress map generated using a mask may be static, the one using a direct-input tool may be dynamic, allowing the stress map to be generated, projected, or modified on a wafer basis if desired.

[0021] As described herein, the wavelength of the light (i.e., chemical radiation) may be 365 nm, but other wavelengths may also be used. The wavelength may vary depending on the components included in the given organic film. Embodiments of this specification may also include using multiple films that respond to light of different wavelengths. After exposure, the film may be heated during post-exposure baking. However, a development step is not required, and the film may subsequently be cured at a higher temperature, the time and temperature of which may vary depending on the thickness of the film and the amount of stress required. Note that a development step may be performed before curing, but this is optional. The curing temperature must be sufficiently high to induce more complete crosslinking within the film. Upon initial flood exposure and curing of the organic stress film, wafer warping of tens or hundreds of micrometers may be achieved.

[0022] Now, referring to the drawings, FIGS. 2a through 2c are stress maps for a bending relief stress film disposed on a wafer and exposed to chemical radiation according to an embodiment of the present disclosure. In one embodiment, the wafer may include a first surface and a second surface. For example, the first surface of the wafer may be a processing surface on which a target device is manufactured, and the second surface may be a back surface of the wafer. The back surface of the wafer may have a bow bending strain stress film (hereinafter referred to as "stress film") formed thereon. The stress film may be an organic film or a polymer-based film.

[0023] In one embodiment, FIGS. 2a through 2c illustrate how an organic stress film can affect wafer warping. The stress film can be deposited on the back surface of the wafer, for example, via spin-coating. In particular, other deposition processes such as sputter coating, spray coating, doctor blading, CVD, physical vapor deposition (PVD), and atomic layer deposition (ALD) may be considered. The stress film can be exposed according to a predetermined pattern or shape, such as a strip of the stress film, through the center of the wafer. As illustrated in FIGS. 2a through 2c, a 100 mm strip of the stress film was exposed below the center of the wafer and exposed to light having a wavelength of 3365 nm. The wafer containing the exposed stress film can be heated during baking after exposure and then cured at a higher temperature. An additional curing step can increase wafer warping, thereby allowing for an adjustable stress film. Each stress map is accompanied by the same table containing additional process information for reference.

[0024] Figures 2a to 2c show the process conditions of the table (left) and the corresponding stress maps for the epoxy novolak film, and consequently have a saddle pattern image passing through the center of the wafer.

[0025] In Fig. 2a, the first curing was performed at 175°C for 10 minutes, which caused a wafer warping of approximately 88 µm for a stress film with a thickness of 17 µm.

[0026] In Fig. 2b, a second curing was performed at 200°C for an additional 10 minutes, which caused a wafer warping of approximately 214 μm.

[0027] In Fig. 2c, a third curing was performed at 200°C for an additional 5 minutes, which caused a wafer warping of approximately 260 μm.

[0028] As previously mentioned, the chemicals included in these stress films may include, but are not limited to, epoxy acrylates, epoxy novolaks, BCB chemicals capable of inducing cross-linking via Diels-Alder reactions, and polyimides. Again, the wafer warping illustrated in FIGS. 2a through 2c indicates that the stress film can actually cause wafer warping, and thus can be used on a wafer that is already warped due to a device manufactured thereon to alleviate or correct said wafer warping.

[0029] As described above, a coater developer system may be used for the spin-on deposition of stress films as described herein. Such a tool may include a number of modules for wafer coating, wafer baking, and film development. The coater developer tool described herein may also include a direct-introduction exposure module. Subsequently, the coater developer system may move the wafer between various spin coating, baking / curing, and exposure modules, or with an attached scanner / stepper tool. Furthermore, the coater developer tool described herein may also include mixing at the dispensing point. That is, chemicals may be mixed at or near the dispensing nozzle immediately before dispensing onto the wafer. For example, a solvent may be added to the resist at the nozzle to control viscosity or film thickness.

[0030] The techniques of this specification may be used to mitigate or address warping from microfabrication processes. The stress films of this specification may be deposited multiple times through a given microfabrication process. For example, as previously mentioned, 3D NAND memory devices may have film stacks of 128 or more layers to create the memory device. This layer stack exerts significant stress on the wafer, resulting in warping, which can cause overlay errors to become a problem. Similarly, 3D logic is expected to have similar requirements for correcting many layers and wafer warping.

[0031] To this end, FIG. 3 is a cross-sectional substrate portion illustrating a structure or device (399) formed on a surface according to an embodiment of the present disclosure. In one embodiment, a wafer (305) comprises a first surface (310) and a second surface (315). For example, the first surface (310) of the wafer may be a processing surface on which a target device is manufactured, and the second surface (315) may be a back surface of the wafer. The device (399) formed on the processing surface (310) may be an active device or a partially formed active device, such as a transistor or a memory cell. The wafer (305) may be accommodated in a coating module of a coater-developer tool or other track-based tool.

[0032] FIG. 4 is a cross-sectional substrate portion illustrating a bending strain stress film (325) (referred to herein as "stress film (325)") formed on the back surface (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 surface (315), but the wafer (305) does not need to be inverted. For example, the tool may include a system for vertical upward coating, spraying, or deposition. That is, the wafer (305) may continue on a track, and the tool may form the stress film (315) on the back surface (315) of the wafer by spray coating. In any case, the stress film (325) may be formed on the back surface (315), and the stress film (325) may be an organic film configured to release a stress strain agent in response to chemical radiation. That is, the stress film (325) may include one or more photoinitiators, thermal acid initiators, photoinitiators, photodestructive bases, etc. As shown above, the stress film (325) may include various epoxy materials, resins, or other organic materials that generate stress (tension or compression) within the stress film (325) from curing in the presence of acids, bases, or radicals. For the device (399) placed on the processing surface (310), a protective filler or protective film may be deposited, or a carrier wafer may be attached to facilitate handling of the wafer (305).

[0033] Note that the processed surface (310) and the back surface (315) are used in this specification to label the opposite sides of the wafer (305). In some microfabrication processes, a given wafer may have active devices or power transfer structures formed on both sides. In this case, the processed surface (310) or the back surface (315) may accommodate a stress film (325) depending on the manufacturing process step.

[0034] FIG. 5 is a cross-sectional substrate portion illustrating 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 radiation emitting a stress strainer within the stress film (325). This exposure step may be performed within the direct light module of a coater-developer tool or transferred to a separate or connected tool for exposure. Chemical radiation may be patterned, and more or less radiation is received at coordinate locations on the back surface (315) of the wafer (305) having the stress film (325). The resolution may vary depending on the specific lithography system selected to perform the exposure. The concentration of the stress strainer emitted at a given coordinate location may be based on the pattern of chemical radiation illuminating the stress film (325). This is indicated in FIG. 6 by a more densely shaded portion of the stress film (325).

[0035] FIG. 6 is a cross-sectional substrate portion illustrating a stress film (325) after exposure according to an embodiment of the present disclosure. In one embodiment, one or more curing steps as described in FIG. 2a through 2c may be performed. The wafer (305) may be transferred to a baking / curing module of a coater developer tool. The curing process may activate a stress strainer in the stress film (325) and induce a strained stress within the stress film (325) sufficient to deform the warping of the wafer (305). For example, upon exposure to light, (in non-limiting examples) a photoacid generator (PAG) may generate a photo that ultimately catalyzes an epoxy crosslinking reaction during baking and curing. It is the crosslinking reaction in the stress film (325) that causes stress relief. In some embodiments, imaging or exposure to a pattern of chemical radiation may directly alter the stress film (325) and thereby directly alter or modify the warping of the wafer (305). For example, stress can be relieved by imaging and eliminating bonding interactions, such as hydrogen bonding interactions, through patterned exposure. That is, instead of inducing stress, patterned exposure can relieve stress by, for example, activating a photoactive compound (PAC) and eliminating the inhibitory effect of the pre-exposed PAC. Deformed stress can be induced by crosslinking, deformed bonding between species, or other entanglements. For example, the amount of crosslinking of the stress film (325) through a stress strainer can correspond to the concentration of the stress strainer emitted at a given coordinate location based on the pattern of chemical radiation. Depending on the agent and film characteristics, the stress can be tensile or compressive internal stress. Thus, the resulting stress of the stress film (325) can offset the stress of the wafer, for example, during the microfabrication process step.FIG. 6 illustrates a stress film (325) having more or less stress based on coordinate positions within the stress film (325) based on the light projection pattern and curing steps or steps.

[0036] Accordingly, the warped wafer can be flattened by the stress film (325) described herein. Direct light programmable patterns activate (or pre-activate) the stress through crosslinking or chemical conversion that is activated by light or electromagnetic energy of a specific wavelength, which may include longer wavelengths in the infrared (IR) or thermal zones. The IR wavelength can be used to pattern the stress film (325) through the wafer (305), that is, it can be exposed through the processing surface (310). However, device fabrication on the processing surface of the wafer may impair the ability to pattern the stress film (325) through the wafer, particularly at later stages of the device fabrication process. In some embodiments, the back film can be activated using a wafer chuck capable of space temperature control in a track device or device fabrication equipment. Stress activation can be adjusted using light of different wavelengths based on additives instead of the polymer of a given organic film. Therefore, the stress film (325) of this specification induces reverse stress instead of releasing stress as in an etched film, but the etching step is not required. In some embodiments, the wafer may be flipped (as in the wafer of FIG. 5) and patterned on the side where electromagnetic energy is imaged instead of passing through the back side (315).

[0037] As previously described, the development process or step may be performed before curing. When the development process is performed, a height discrepancy may occur on the back of the wafer. Therefore, a filler may be deposited or formed on the stress film (325) on the back. Subsequently, the backfill may be flattened before the wafer (305) is flipped over again for continued manufacturing and processing, otherwise the film height discrepancy itself at a specific location may cause an incorrect shape of the wafer (305). However, this should further highlight the benefits of direct light control, which does not require a development process and does not cause any film height discrepancy. In direct light, a flat film may be formed, warping may be induced, and the film remains flat.

[0038] 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 can be used to generate cumulative or differential stress. For lower resolution wafer warping correction, the films of this specification may be activated simply by targeted or patterned heating without a photoactivation pattern step (i.e., overall warping relief). Zone-based heating, mask-based heat curing, or microwave heating may induce location-specific crosslinking. In this case, a photocatalytic agent (PAG) or a thermal catalyst (TAG) may be used, as most PAGs can act as TAGs at sufficiently high temperatures.

[0039] In one embodiment, rear integration of the stress film may result in trade-offs that may affect device yield. Through joint optimization of design technology planning a multi-directional operating stress film for front integration, the benefits of the technology can be realized without trade-offs. In this embodiment, the stress film (325) may be formed on the processing surface (310), for example, in the area between devices on the wafer (305), along the periphery of the processing surface (310), or even on the top of the device.

[0040] The technique of this specification can affect wafer warping of several hundred micrometers, which is sufficient to offset wafer warping and twisting observed in wafers during semiconductor fabrication. The resulting warping deformation of this specification may be primary and secondary warping corrections, such as saddle warping. The technique of this specification may be used throughout the semiconductor manufacturing process. For example, after correcting initial warping using the film of this specification, additional processing may be performed. Such additional processing may eventually cause additional twisting. At this point, a second warping deformation film may be added, patterned, and then cured. Alternatively, after the first warping deformation film is peeled off, wafer twisting is measured a second time, and then subsequent warping deformation is deposited and patterned according to the second wafer warping measurement.

[0041] FIG. 7 is a flowchart of a method (700) for processing a substrate according to an embodiment of the present disclosure.

[0042] In step (705), the wafer (305) can be received by a tool, and the wafer (305) includes a first surface (310) (processed surface (310)) and a second surface (315) (back surface (315)).

[0043] In step (710), a stress film (325) may be formed on the back surface (315) of the wafer (305). The stress film (325) may contain a stress strainer, and the stress film (325) is sensitive to a predetermined wavelength of chemical radiation.

[0044] In step (715), the stress film (325) may be exposed to a pattern of chemical radiation of a predetermined wavelength. The stress film (325) may be configured to emit a stress strainer at a location along the stress film (325) exposed to the pattern of chemical radiation. The concentration of the emitted stress strainer may correspond to the pattern of chemical radiation.

[0045] In step (720), a curing process may be performed. The curing process activates the released stress strainer and induces a change in stress within the stress film (325) to deform the warping of the wafer (305) and make the wafer (305) closer to flatness.

[0046] In step (725), the development process can be optionally performed before curing.

[0047] In the preceding description, specific details such as the specific geometric structure of the processing system, descriptions of various components, and the processes used in this specification have been presented. However, it should be understood that the techniques of this specification may be practiced in other embodiments that deviate from these specific details, and that these details are for illustrative purposes only and are not limiting. The embodiments disclosed in this specification have been described with reference to the accompanying drawings. Likewise, for illustrative purposes, specific numbers, materials, and configurations have been presented to provide a complete understanding. Nevertheless, embodiments may be practiced without these specific details. Components having substantially the same functional configuration are denoted by similar reference letters, so any unnecessary description may be omitted.

[0048] To aid in understanding various embodiments, various techniques have been described as multiple distinct operations. The order of description should not be interpreted as implying that these operations are necessarily dependent on the order. In practice, these operations do not need to be performed in the order presented. The described operations may be performed in a different order than that described in the embodiments. Various additional operations may be performed and / or described operations may be omitted in additional embodiments.

[0049] As used herein, “substrate” or “target substrate” collectively refers to the object being processed according to the present invention. A substrate may comprise a structure or any portion of material of a device, particularly a semiconductor or other electronic device, and may, for example, be a base substrate structure, such as a semiconductor wafer or reticle, or a layer on or covering a base substrate structure, such as a thin film. Accordingly, a substrate is not limited to any specific base structure, inherent layer, or covering layer that is patterned or unpatterned, but is rather considered to include any such layer or base structure, and any combination of layers and / or base structures. The description may refer to a specific type of substrate, but this is for illustrative purposes only.

[0050] Those skilled in the art will also understand that many modifications may be made to the operation of the technique described above while still achieving the same objective of the present invention. Such modifications are intended to be included within the scope of this disclosure. As such, the above description of the embodiments of the present invention is not intended to be limiting. Rather, any limitations on the embodiments of the present invention are set forth in the following claims.

Claims

Claim 1 A method for processing a substrate, comprising the step of forming a bending strain stress film on the back surface of a wafer, wherein the wafer comprises a processing surface and the back surface opposite to the processing surface, the bending strain stress film comprises a stress strainer, and the bending strain stress film is sensitive to chemical radiation of a predetermined wavelength; and the step of exposing the bending strain stress film to a pattern of chemical radiation of the predetermined wavelength, wherein the bending strain stress film is maintained flat during and after exposure without forming a relief structure or undergoing a development step, and the bending strain stress film is configured to release the stress strainer at a location along the bending strain stress film exposed to the pattern of chemical radiation, and the concentration of the released stress strainer corresponds to the pattern of chemical radiation. A method for treating a substrate, comprising the step of performing a curing process, wherein the curing process activates the released stress strainer and induces a stress change within the bending strain stress film, and the stress change deforms the bending of the wafer, wherein the material of the bending strain stress film is at least one selected from the group consisting of epoxy acrylate and epoxy novolak. Claim 2 A method according to claim 1, wherein the curing process that activates the released stress strainer further comprises inducing crosslinking within the bending strain stress film based on the pattern of the chemical radiation. Claim 3 A method according to claim 1, wherein the bending deformation stress film comprises a photocatalytic agent that generates acid in response to the chemical radiation of the predetermined wavelength. Claim 4 A method according to claim 1, wherein the bending strain stress film comprises a photoinitiator that generates radicals in response to the chemical radiation of the predetermined wavelength. Claim 5 A method according to claim 1, wherein the steps of forming the bending strain stress film, exposing the bending strain stress film to the pattern of the chemical radiation, and performing the curing process are performed without introducing a developer onto the wafer. Claim 6 A method according to claim 1, wherein the step of carrying out the curing process further comprises applying heat to the wafer until a predetermined degree of crosslinking in the bending deformation stress film is reached. Claim 7 The method of claim 1, wherein the step of exposing the bending deformation stress film to the pattern of the chemical radiation further comprises illuminating chemical radiation of a specific intensity based on a selected value of bending deformation to be achieved. Claim 8 A method according to claim 1, further comprising a stress change that deforms the bending of the wafer, which reduces the wafer bending value across the processing surface to produce a wafer having reduced curvature compared to before the bending deformation stress film is deposited. Claim 9 A method according to claim 1, wherein the bending deformation stress film comprises a photobase generator. Claim 10 A method according to claim 1, comprising the step of depositing a second bending strain stress film on the back surface of the wafer, wherein the second bending strain stress film comprises a second stress strainer and the second bending strain stress film is sensitive to a second predetermined wavelength of the chemical radiation; and further comprising the step of exposing the second bending strain stress film to a second pattern of the chemical radiation, wherein the curing process activates the released second stress strainer and induces the stress change within the bending strain stress film, and the stress change deforms the bending of the wafer. Claim 11 A method according to claim 1, further comprising the step of depositing a second bending strain stress film on the back surface of the wafer, wherein the second bending strain stress film comprises a second stress strainer and the second bending strain stress film is sensitive to a second predetermined wavelength of the chemical radiation; the step of exposing the second bending strain stress film to a second pattern of the chemical radiation; and the step of performing a second curing process, wherein the second curing process activates the released second stress strainer and induces the stress change within the bending strain stress film, and the stress change deforms the bending of the wafer. Claim 12 In paragraph 11, the above-mentioned predetermined wavelength and the above-mentioned second-determined wavelength are different, in a method. Claim 13 A method according to claim 1, wherein the pattern of the chemical radiation is based on a bending strain stress map for the wafer. Claim 14 In claim 13, the bending deformation stress map represents a stress value that is relieved across coordinate positions along the back surface of the wafer. Claim 15 A method according to claim 1, wherein the bending strain stress film is deposited by spin-on deposition. Claim 16 A method according to claim 1, wherein the pattern of the chemical radiation is provided by a direct write lithography system. Claim 17 In claim 1, the pattern of the chemical radiation is provided by a mask-based lithography system. Claim 18 A method for processing a substrate, comprising: a step of forming a first bending strain stress film on the back surface of a wafer, wherein the wafer comprises a processing surface and the back surface opposite to the processing surface, and the first bending strain stress film is configured to emit a first stress strain agent in response to chemical radiation having a first predetermined wavelength; a step of forming a second bending strain stress film on the first bending strain stress film, wherein the second bending strain stress film is configured to emit a second stress strain agent in response to chemical radiation having a second predetermined wavelength; and a step of exposing the first bending strain stress film and the second bending strain stress film to a first pattern of chemical radiation of the first predetermined wavelength, wherein no development step is performed and the exposed first and second bending strain stress films are maintained in a flat and undeveloped state, and the first bending strain stress film is configured to emit the first stress strain agent at a location along the first bending strain stress film exposed to the first pattern of chemical radiation, and the emitted first A step in which the concentration of the stress strainer corresponds to the first pattern of the chemical radiation; a step of exposing the first bending strain stress film and the second bending strain stress film to a second pattern of the chemical radiation of the second predetermined wavelength, wherein the second bending strain stress film is configured to emit the second stress strainer at a location along the second bending strain stress film exposed to the second pattern of the chemical radiation, and the concentration of the emitted second stress strainer corresponds to the second pattern of the chemical radiation;A method for treating a substrate, comprising the step of performing a curing process, wherein the curing process activates the released first stress strainer and the released second stress strainer, and the curing process induces a first stress change in the first bending strain stress film and a second stress change in the second bending strain stress film, and the first stress change and the second stress change together deform the bending of the wafer, wherein the material of the bending strain stress film is at least one selected from the group consisting of epoxy acrylate and epoxy novolak. Claim 19 delete Claim 20 delete

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