Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
  • H10P95/90—Thermal treatments, e.g. annealing or sintering
  • H10P95/906—Thermal treatments, e.g. annealing or sintering for altering the shape of semiconductors, e.g. smoothing the surface
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/20—Exposure; Apparatus therefor
  • G03F7/2022—Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure
  • G03F7/203—Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure comprising an imagewise exposure to electromagnetic radiation or corpuscular radiation
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/0035—Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/038—Macromolecular compounds which are rendered insoluble or differentially wettable
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/095—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having more than one photosensitive layer
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/60—Formation of materials, e.g. in the shape of layers or pillars of insulating materials
  • H10P14/63—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by the formation processes
  • H10P14/6326—Deposition processes
  • H10P14/6342—Liquid deposition, e.g. spin-coating, sol-gel techniques or spray coating
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/60—Formation of materials, e.g. in the shape of layers or pillars of insulating materials
  • H10P14/65—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by treatments performed before or after the formation of the materials
  • H10P14/6516—Formation of materials, e.g. in the shape of layers or pillars of insulating materials characterised by treatments performed before or after the formation of the materials of treatments performed after formation of the materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P14/00—Formation of materials, e.g. in the shape of layers or pillars
  • H10P14/60—Formation of materials, e.g. in the shape of layers or pillars of insulating materials
  • H10P14/68—Organic materials, e.g. photoresists
  • H10P14/683—Organic materials, e.g. photoresists carbon-based polymeric organic materials, e.g. polyimides, poly cyclobutene or PVC
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
  • H10P95/08—Planarisation of organic insulating materials

Definitions

• Photolithography also called microlithography
• Photolithography uses radiation, such as ultraviolet or visible light, to generate fine patterns in a semiconductor device design.
• semiconductor devices such as diodes, transistors, and integrated circuits, can be constructed using semiconductor fabrication techniques including photolithography, etching, film deposition, surface cleaning, metallization, and so forth.
• Exposure systems also called tools are used to implement photolithographic techniques.
• An exposure system typically includes an illumination system, a reticle (also called a photomask) or spatial light modulator (SLM) for creating a circuit pattern, a projection system, and a wafer alignment stage for aligning a photosensitive resist-covered semiconductor wafer.
• the illumination system illuminates a region of the reticle or SLM with a (preferably) rectangular slot illumination field.
• 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 pattern of light on a wafer that is relatively flat or planar, preferably having less than 10 microns of height deviation. Thus, a method for correcting any wafer bow is desired.
• the present disclosure relates to a method of processing a substrate, including forming a bow modification stress film on a backside of a wafer, the wafer including a working surface and the backside opposite the working surface, the bow modification stress film including a stress-modification agent, the bow modification stress film being sensitive to a predetermined wavelength of actinic radiation; exposing the bow modification stress film to a pattern of the actinic radiation at the predetermined wavelength, the bow modification stress film configured to release the stress-modification agent at locations along the bow modification stress film exposed to the pattern of the actinic radiation, a concentration of the released stress-modification agent corresponding to the pattern of the actinic radiation; and executing a curing process, the curing process activating the released stress-modification agent and causing a stress change within the bow modification stress film, the stress change modifying a bow of the wafer.
• the present disclosure additionally relates to a method of processing a substrate, including forming a first bow modification stress film on a backside of a wafer, the wafer including a working surface and the backside opposite the working surface, the first bow modification stress film configured to release a first stress-modification agent in response to actinic radiation having a first predetermined wavelength; forming a second bow modification stress film on the first bow modification stress film, the second bow modification stress film configured to release a second stress-modification agent in response to the actinic radiation having a second predetermined wavelength; exposing the first bow modification stress film and the second bow modification stress film to a first pattern of the actinic radiation at the first predetermined wavelength, the first bow modification stress film configured to release the first stress-modification agent at locations along the first bow modification stress film exposed to the first pattern of the actinic radiation, a concentration of the released first stress-modification agent corresponding to the first pattern of the actinic radiation; exposing the first bow modification stress film and the second bow modification stress film to a second pattern
• FIG.1A is a perspective-view schematic of layers on a wafer having a defect introduced in one of the layers.
• FIG.1B is a schematic of various types and severities of resulting wafer bow.
• FIGs.2A-2C are stress maps for a bow mitigation stress film arranged on a wafer and exposed to actinic radiation, according to an embodiment of the present disclosure.
• FIG.3 is a cross-sectional substrate segment illustrating structures or devices formed on a surface, according to an embodiment of the present disclosure.
• FIG.4 is a cross-sectional substrate segment illustrating a bow modification stress film formed on the backside of the wafer, according to an embodiment of the present disclosure.
• FIG.5 is a cross-sectional substrate segment illustrating exposure of the stress film, according to an embodiment of the present disclosure.
• FIG.6 is a cross-sectional substrate segment illustrating the stress film after exposure, according to an embodiment of the present disclosure.
• FIG.7 is a flow chart for a method of fabricating a semiconductor device, according to an embodiment of the present disclosure. DETAILED DESCRIPTION [0018]
• the following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting.
• first and second features are formed in direct contact
• additional features may be formed between the first and second features, such that the first and second features may not be in direct contact
• present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
• spatially relative terms such as “top,” “bottom,” “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures.
• the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.
• the apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
• the spin-on film can be based on a film that undergoes crosslinking/decrosslinking under external stimulus where direct write is achieved by, but is not limited to, 365 nm exposure and subsequent cure is used to "pattern-in" stress. Moreover, the film need not be limited to a spin-on process, and other deposition methods may be used. A develop step is not required with techniques herein (but can be optional), which provides additional significant benefit. An amount of bow (or internal stress to create or affect a bow signature) can be tuned with exposure dose, bake temperature, bake time and number of bakes.
• the stress-modification films herein can be organic in nature and have the characteristics or components to crosslink upon exposure to light, or crosslink after light exposure followed by a bake or cure step.
• FIG.1A is a perspective-view schematic of layers on a wafer having a defect introduced in one of the layers.
• 128 layers can be used for 3D NAND devices on a 300 mm wafer.
• a defect in an underlaying, earlier layer can be magnified to cause severe bow with later layers.
• FIG.1B shows the systematic increase in the number of layers in the front side 3D NAND stack results in further wafer bow and increases the severity of the problem.
• Some mitigation strategies include depositing silicon nitride films on the backside of the wafer via, for example, chemical vapor deposition (CVD), which can cause a large amount of stress on the wafer and the devices. Then, predetermined portions of the silicon nitride can be imaged, illuminated, or exposed, and subsequently removed, alleviating the stress in certain points on the wafer, hence re-shaping the wafer in a different manner.
• CVD chemical vapor deposition
• the problem introduced via the silicon nitride film method is that the method requires different tooling, which can mean a simple track-based process may be incompatible, and thus it can require loading the wafers into an entirely different tool. Furthermore, the method can also be time-consuming to put the desired amount of silicon nitride on the back of the wafers. Additionally, the method is generally a very complex process to image the silicon nitride films or to tune the patterns in the silicon nitride film to alleviate the bow of the water. [0023] Described herein, an organic-based, cross-linkable bow mitigation film can be deposited on the backside of a wafer. The bow mitigation film can allow flexibility in global as well as local bow mitigation.
• global bow mitigation can be applied to the film.
• local bow mitigation can be applied via a programmable direct write stress pattern on the film on the backside of the wafer, wherein the direct write stress pattern can be based on a bow modification stress map (herein referred to as “stress map) of the front side.
• the bow mitigation film is a polymer-based, organic film that is deposited on the backside of the wafer using tools that can allow continuous processing in a track-based process.
• a predetermined wavelength of actinic radiation can be applied to image, illuminate, or expose the film based on the stress map to embed stress into the film and thereby the wafer that mitigates the undesirable bow on the opposite side or surface.
• the exposure process which can include an exposure step and a heat or bake step, need not require a develop step.
• this method can be deemed a direct-write process to produce the bow mitigation film.
• the bow mitigation film can also be described as a stress film, in that the film can be embedded with stress to mitigate the wafer bow.
• the tool can handle (i.e., move, transport, and manipulate) wafers but can experience handling issues when wafer bow approaches and exceeds 300 ⁇ m.
• methods described herein can allow an increase of secondary bow mitigation up to 150 ⁇ m while maintaining 300-400 ⁇ m primary bow mitigation. Although this is a direct-write, a develop step can still be included.
• the develop step can allow flexibility in higher cure temperatures when unexposed material is present in the areas that have not been exposed to light. If, for example, a photoacid generator decomposition temperature is not high, these areas can also be crosslinked at high temperatures.
• methods described herein can leverage chemistries including epoxy acrylates, epoxy novolaks, benzene cyclobutadiene (BCB) chemistry where Diels Alder reactions can induce crosslinking, and polyimides.
• BCB benzene cyclobutadiene
• Other types of chemistry that can be used include any photo-initiating chemistry that causes crosslinking or bond rearrangement to form some type of stress upon irradiation and subsequent heating, or just exposure.
• an organic formulation can be deposited on the surface of a wafer through a spin coat process or any deposition process.
• the film can be baked to remove excess solvent.
• the film can then be exposed to a pattern of actinic radiation.
• This pattern of actinic radiation can define a stress modification pattern or can be based on a stress modification pattern.
• Various lithography tools can be used.
• a direct-write laser or lithography tool can be used. This can be a digital light processing (DLP) chip, laser galvanometer, etc., that projects a pattern as one image or as a scan.
• DLP digital light processing
• a mask-based lithographic exposure using a scanner or stepper tool can be used.
• direct-write tools have lower resolution than mask-based tools, the resolution needed to fine tune stress can be much lower as compared to patterning transistors.
• a stress map created with a mask can be static, whereas using a direct-write tool can be dynamic so a stress map can be created or projected and changed on a wafer-by-wafer basis if desired.
• the wavelength of light i.e., the actinic radiation
• Wavelength can be dependent on components included in a given organic film.
• Embodiments herein can also include using multiple films that respond to different wavelengths of light.
• the film can be heated during a post exposure bake.
• a develop step is not required and the film can then be cured at a higher temperature, the time and temperature of which can be dependent on the thickness of the film and the amount of stress required.
• a development step can be executed before curing, but this is optional. Curing temperature should be high enough to induce a more complete crosslinking within the film.
• FIGs.2A-2C are stress maps for a bow mitigation stress film arranged on a wafer and exposed to actinic radiation, according to an embodiment of the present disclosure.
• the wafer can include a first surface and a second surface.
• the first surface of the wafer can be a working surface where the target devices are fabricated and the second surface can be a backside of the wafer.
• the backside of the wafer can have the bow modification stress film (herein referred to as “stress film”) formed thereon.
• the stress film can be an organic film, or a polymer-based film.
• FIGs.2A-2C demonstrate how the organic stress film can affect wafer bow.
• the stress film can be deposited on the backside of the wafer via, for example, spin-coating.
• Other deposition processes can be contemplated, such as sputter coating, spray coating, doctor blading, CVD, physical vapor deposition (PVD), and atomic layer deposition (ALD), among others.
• the stress film can be exposed according to a predetermined pattern or shape, such as a strip of the stress film through a middle of the wafer. As shown in FIGs.2A- 2C, a 100 mm strip of the stress film was exposed down a middle of the wafer and exposed to light having a 365 nm wavelength.
• the wafer including the exposed stress film can be heated during a post-exposure bake, then cured at higher temperatures.
• FIGs.2A-2C show process conditions in the table (left) and corresponding stress maps for an epoxy novolak film with resulting saddle pattern images through a center of the wafer.
• a first cure was performed at 175oC for 10 minutes, which resulted in a wafer bow of approximately 88 ⁇ m for the stress film having a thickness of 17 ⁇ m.
• a second cure was performed at 200oC for an additional 10 minutes, which resulted in a wafer bow of approximately 214 ⁇ m.
• a third cure was performed at 200oC for an additional 5 minutes, which resulted in a wafer bow of approximately 260 ⁇ m.
• the chemistries included in such stress films can include, but are not limited to, epoxy acrylates, epoxy novolaks, BCB chemistry where Diels Alder reactions can induce crosslinking, and polyimides.
• the wafer bows shown in FIGs. 2A-2C demonstrate that the stress film can indeed cause wafer bow, and as such, can be used on a wafer already bowed due to the devices fabricated thereon in order to mitigate or correct said wafer bow.
• coater developer systems can be used for spin-on deposition of stress films herein. These tools can include multiple modules for coating wafers, baking wafers, and developing films. Coater-developer tools described herein can also include direct-write exposure modules. The coater developer system can then shuttle wafers between the various spin coating, baking/curing modules, and exposure modules, or to an attached scanner/stepper tool. Moreover, the coater developer tools described herein can also include point-of-dispense mixing. That is, chemicals can be mixed at or proximate to a dispense nozzle, immediately prior to dispensing on the wafer. For example, a solvent can be added to a resist at the nozzle to modulate viscosity or film thickness.
• FIG.3 is a cross-sectional substrate segment illustrating structures or devices 399 formed on a surface, according to an embodiment of the present disclosure.
• a wafer 305 includes a first surface 310 and a second surface 315.
• the first surface 310 of the wafer can be a working surface where the target devices are fabricated and the second surface 315 can be a backside of the wafer.
• the devices 399 formed on the working surface 310 can be active devices or partially formed active devices such as transistors or memory cells.
• the wafer 305 can be received in a coating module of a coater-developer tool or other track-based tool.
• FIG.4 is a cross-sectional substrate segment illustrating a bow modification stress film 325 (herein referred to as “stress film 325”) formed on the backside 315 of the wafer 305, according to an embodiment of the present disclosure.
• the wafer 305 can be flipped and the stress film 325 can be formed on the backside 315, but the wafer 305 need not be flipped.
• the tool can include systems for vertically upward directed coating, spraying, or deposition. That is, the wafer 305 can continue on the track and the tool can form the stress film 315 on the backside 315 of the wafer by spray coating.
• the stress film 325 can be formed on the backside 315, and the stress film 325 can be an organic film configured to release a stress-modification agent in response to actinic radiation. That is, the stress film 325 can include one or more photo acid generators, thermal acid generators, photo initiators, photo destructive bases, or the like.
• the stress film 325 can include various epoxy materials or resins or other organic materials that will result in stresses (tensile or compressive) within the stress film 325 from curing in the presence of acids, bases, or radicals.
• a protective fill or protective film can be deposited, or a carrier wafer can be attached, to facilitate handling of the wafer 305.
• working surface 310 and the backside 315 are used herein to label opposing sides of the wafer 305. In some microfabrication processes, a given wafer can have active devices or power delivery structures formed on both sides. In this case, either the working surface 310 or the backside 315 can receive the stress film 325 depending on fabrication process stage.
• FIG.5 is a cross-sectional substrate segment illustrating exposure of the stress film 325, according to an embodiment of the present disclosure.
• the stress film 325 can be exposed to a pattern of actinic radiation that releases the stress-modification agent within the stress film 325.
• This exposure step can be executed within a direct write module on the coater-developer tool or be transferred to a separate or connected tool for exposure.
• the actinic radiation can be patterned wherein more or less radiation is received at coordinate locations on the backside 315 of the wafer 305 having the stress film 325. Resolution can be dependent on a particular lithography system selected for executing the exposure.
• FIG.6 is a cross-sectional substrate segment illustrating the stress film 325 after exposure, according to an embodiment of the present disclosure.
• one or more curing steps can be executed, such as those described in FIGs.2A-2C.
• the wafer 305 can be transferred to a bake/curing module of the coater developer tool.
• the curing process can activate the stress-modification agent in the stress film 325 and cause a modified stress within the stress film 325 sufficient to modify bow of the wafer 305.
• a photoacid generator (in a non-limiting example) can produce a photoacid which in turn catalyzes an epoxy crosslinking reaction upon bake and cure. It is the crosslinking reaction in the stress film 325 that causes the stress mitigation.
• the imaging or exposure to the pattern of actinic radiation can directly change the stress film 325 and thereby directly change or modify bow of the wafer 305.
• the stress can be alleviated with imaging and removing bonding interactions, such as hydrogen bonding interactions, via the patterned exposure. That is, instead of inducing stress, the patterned exposure can relieve the stress through activating, for example, a photoactive compound (PAC) and removing the inhibition effect of the pre-exposed PAC.
• PAC photoactive compound
• the modified stress can be caused by crosslinking, modified bonds among species, or other entanglement.
• the amount of, for example, cross-linking of the stress film 325 via the stress-modification agent can correspond to the concentration of the stress-modification agent released at the given coordinate location based on the pattern of the actinic radiation.
• the stress can be tensile or compressive internal stress.
• the resulting stress in the stress film 325 can then, for example, counter-act stresses in the wafer from microfabrication process steps.
• FIG.6 illustrates the stress film 325 having more or less stress by coordinate location in the stress film 325 based on the projected pattern of light and curing step or steps.
• a warped wafer can be flattened with the stress film 325 described herein.
• the direct write programmable pattern essentially activates (or pre-activates) stress through cross-linking or chemical transformation that is activated by a particular wavelength of light or electromagnetic energy that can include longer wavelengths in the infrared (IR) or thermal regions.
• the IR wavelengths can be used to pattern the stress film 325 through the wafer 305, that is, exposed through the working surface 310.
• device fabrication on the working 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.
• the backside film may be activated using a wafer chuck with spatial temperature control either in the track device or in the device fabrication equipment. Stress activation can be tailored using different wavelengths of light based on additives instead of a polymer in a given organic film.
• the stress film 325 herein therefore induces a counter stress instead of releasing stress as with etched films, but no etch step is needed.
• the wafer can be flipped over (such as the wafer of FIG.5) so the electromagnetic energy is being patterned onto the side that is being imaged instead of via the backside 315. [0043] As previously described, a developing process or step can be executed before curing.
• a mismatch in the height on the backside of the wafer can result.
• a fill can be deposited or formed over the stress film 325 on the backside.
• the backfill can then be planarized prior to flipping the wafer 305 back over for continued fabrication and processing, otherwise the mismatch of the film height in specific locations could itself induce mis-shape of the wafer 305.
• direct write a planar film can be formed, bow can be induced, and the film remains planar.
• two or more stress films 325 can be deposited.
• Each given film can be activated by a same or different wavelength.
• This multi-layer process can be used to create cumulative or differential stress.
• films herein can be activated simply by targeted or patterned heating without a photo-activated pattern step (i.e., global bow mitigation).
• a zone-based heating or mask-based heating cure or microwave heating can cause location-specific crosslinking.
• either a photo acid generator (PAG) or thermal acid generator (TAG) can be used because most PAGs can act as TAGs at sufficiently high temperatures.
• backside integration of the stress films can lead to tradeoffs that can impact device yield.
• the stress film 325 can be formed on the working surface 310, such as in areas between devices on the wafer 305, along a periphery of the working surface 310, or even on top of the devices.
• Techniques herein can affect wafer bow of hundreds of microns, which is sufficient to counteract wafer bow and warpage observed on wafers during semiconductor manufacturing.
• Resulting bow modification herein can be first order and second order bowing correction, such as a saddle bow. Techniques herein can be used throughout the semiconductor fabrication process.
• FIG.7 is a flow chart for a method 700 of processing a substrate, according to an embodiment of the present disclosure.
• the wafer 305 can be received by the tool, the wafer 305 include the first surface 310 (the working surface 310) and the second surface 315 (the backside 315).
• the stress film 325 can be formed on the backside 315 of the wafer 305.
• the stress film 325 can include a stress-modification agent, the stress film 325 being sensitive to the predetermined wavelength of the actinic radiation.
• the stress film 325 can be exposed to the pattern of the actinic radiation at the predetermined wavelength.
• the stress film 325 can be configured to release the stress- modification agent at locations along the stress film 325 exposed to the pattern of the actinic radiation. A concentration of the released stress-modification agent can correspond to the pattern of the actinic radiation.
• the curing process can be executed.
• the curing process can activate the released stress-modification agent and cause a stress change within the stress film 325 to modify a bow of the wafer 305 and bring the wafer 305 closer to planarity.
• the developing process can optionally be executed before curing.
• substrate or “target substrate” as used herein generically refers to an object being processed in accordance with the invention.
• the substrate may include any material portion or structure of a device, particularly a semiconductor or other electronics device, and may, for example, be a base substrate structure, such as a semiconductor wafer, reticle, or a layer on or overlying a base substrate structure such as a thin film.
• substrate is not limited to any particular base structure, underlying layer or overlying layer, patterned or un-patterned, but rather, is contemplated to include any such layer or base structure, and any combination of layers and/or base structures.
• the description may reference particular types of substrates, but this is for illustrative purposes only.

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