Backside film deposition for correction of overlay error

Abstract

One disclosed example provides a method of mitigating substrate warpage. The method includes depositing a backside film having a controlled variable thickness profile on a warped substrate. The method further includes clamping the warped substrate on a chuck. Clamping the warped substrate is to flatten the backside film against the chuck, thereby bending the warped substrate to mitigate substrate warpage.

Description

Background Technology

[0001] Semiconductor device manufacturing involves a series of processes for depositing and patterning structures on a substrate. As the complexity and / or inhomogeneity of structures and / or materials on or across wafers increase, the stress exerted on the substrate by the material film formed and patterned on the substrate can cause substrate deformation (e.g., bending, twisting, etc.). This deformation can affect multiple aspects of device manufacturing. Summary of the Invention

[0002] This invention is provided to introduce the chosen concepts in a simplified form, which will be further described in the following detailed implementations. This invention is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that address any or all of the shortcomings mentioned in any part of this disclosure.

[0003] One disclosed example provides a method for mitigating substrate warpage. The method includes depositing a back-side film having a controlled, variable thickness profile on a warped substrate. The method further includes clamping the warped substrate in a chuck, wherein clamping the warped substrate causes the back-side film to flatten against the chuck, thereby bending the warped substrate to mitigate substrate warpage.

[0004] In some such examples, the method also includes performing substrate-to-substrate bonding while holding the warped substrate.

[0005] Alternatively or additionally, in some such examples, the method also includes performing photolithography on the warped substrate while holding the warped substrate.

[0006] Alternatively or additionally, in some such examples, the stress of the dorsal membrane is between -2 GPa and 2 GPa.

[0007] Alternatively or additionally, in some such examples, the back-side membrane is deposited using a nozzle base.

[0008] Alternatively or additionally, in some such examples, the warped substrate has asymmetrical warping, and the method includes performing a first back-side deposition stage with a first concentration gradient of the reactant gas relative to the diluent gas as a function of the X-axis position of the warped substrate; rotating the warped substrate; and then performing a second back-side deposition stage with a second concentration gradient of the reactant gas relative to the diluent gas as a function of the Y-axis position of the warped substrate.

[0009] Alternatively or additionally, in some such examples, the dorsal membrane comprises a parabolic membrane profile.

[0010] Alternatively or additionally, in some such examples, the dorsal membrane comprises a hyperbolic paraboloid membrane profile.

[0011] Alternatively or additionally, in some such examples, the back-side membrane comprises either a dielectric film or a metal film.

[0012] Alternatively or additionally, in some such examples, the back-side film comprises one or more of silicon oxide, silicon nitride, silicon oxynitride, aluminum, or tungsten.

[0013] Another example provides a nozzle base for depositing a film with a controlled, variable thickness profile. The nozzle base includes: a plurality of first process gas channels fluidly connected to a first process gas inlet, each first process gas channel including a plurality of first process gas outlet orifices. The nozzle base also includes: a plurality of second process gas channels fluidly connected to a second process gas inlet, each second process gas channel including a plurality of second process gas outlet orifices. The arrangement of the first and second process gas outlet orifices is configured to provide a concentration gradient of the first process gas relative to the second process gas along one or more of the X-axis or Y-axis directions of the nozzle base.

[0014] In some such examples, one or more of the plurality of first processing gas channels are arranged alternately with one or more of the plurality of second processing gas channels.

[0015] Alternatively or additionally, in some such examples, the first processing gas outlet orifice includes a vertical orifice at the center of the nozzle base and inclined outlet orifices in other areas of the nozzle base.

[0016] Alternatively or additionally, in some such examples, the second processing gas outlet orifice includes a vertical orifice at the edge of the nozzle base and an inclined outlet orifice in other areas of the nozzle base.

[0017] Another example provides a processing tool for depositing a back-side film to mitigate substrate warpage. The processing tool includes a processing chamber. The processing tool includes a substrate support configured to support a substrate. The processing tool includes a nozzle base configured to allow a precursor gas and a dilution gas to flow to the back side of a substrate placed on the substrate support, the nozzle base further configured to provide a concentration gradient of the precursor gas relative to the dilution gas along at least one of an X-axis or Y-axis direction of the nozzle base. The processing tool includes a controller configured to control the processing tool to perform back-side film deposition on the substrate placed on the substrate support. The controller is configured to cause the processing tool to allow the processing gas and dilution gas to flow to the nozzle base, the back-side film having a controlled variable thickness profile, under conditions configured to form a back-side film on the back side of the substrate.

[0018] In some such examples, the nozzle base includes: a plurality of first processing gas channels fluidly connected to a first processing gas inlet, each first processing gas channel including a plurality of first processing gas outlet holes; and a plurality of second processing gas channels fluidly connected to a second processing gas inlet, each second processing gas channel including a plurality of second processing gas outlet holes, wherein the arrangement of the first processing gas outlet holes and the second processing gas outlet holes is configured to provide the concentration gradient of the precursor gas relative to the diluent gas along at least one of the X-axis or Y-axis directions of the nozzle base.

[0019] Alternatively or additionally, in some such examples, the controller is also configured to cause the processing tool to provide a selected concentration gradient of the precursor gas relative to the diluent gas along the X-axis direction of the nozzle base to deposit the back-side film, the back-side film comprising a parabolic film profile.

[0020] Alternatively or additionally, in some such examples, the processing tool is configured to rotate the substrate by 90 degrees, and the controller is further configured to cause the processing tool to deposit the back-side film on the back side of the substrate by: performing a first back-side deposition stage with a first concentration gradient of the precursor gas relative to the diluent gas as a function of the X-axis direction on the substrate; rotating the substrate by 90 degrees; and then performing a second back-side deposition stage with a second concentration gradient of the precursor gas relative to the diluent gas as a function of the Y-axis direction position on the substrate.

[0021] Alternatively or additionally, in some such examples, the controller is configured to cause the processing tool to deposit one or more of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum film, or a tungsten film.

[0022] Alternatively or additionally, in some such examples, the processing tool also includes a chuck, and the controller is configured to clamp the substrate onto the chuck after the back-side film is deposited, so that the back-side film is flat against the chuck, thereby bending the substrate to reduce substrate warping. Attached Figure Description

[0023] Figure 1 A schematically shows an exemplary substrate with a back-side film having been deposited with a variable thickness profile.

[0024] Figure 1 B schematically shows Figure 1 The dorsal membrane of A is flattened by pressing against the chuck.

[0025] Figure 2 An exemplary substrate profile is shown, in which a saddle-shaped warp is displayed.

[0026] Figure 3 The display shows a graphical description illustrating the magnitude and direction of overlay error as having... Figure 2 The substrate profile is a function of the position on the substrate.

[0027] Figure 4 The diagram illustrates the magnitude and direction of overlay error as follows after depositing a back-side film with a variable thickness profile and clamping the substrate. Figure 3 A function of position on the substrate.

[0028] Figure 5 Display a graphical description, the description of which is applied to Figure 2 The thickness profile of the back-side film of the substrate, to achieve relative to Figure 3 exist Figure 4 The overprinting error correction is explained in the text.

[0029] Figure 6A A cross-sectional view is shown of an exemplary nozzle base suitable for forming a back-side membrane with a variable thickness profile.

[0030] Figures 6B-6D schematically shown Figure 6A Additional view of the nozzle base.

[0031] Figure 7 Showing a top cross-sectional view of another exemplary nozzle base suitable for forming a back-side membrane with a variable thickness profile.

[0032] Figure 8 An exemplary processing tool comprising a nozzle base for backside film deposition is schematically shown.

[0033] Figure 9 A flowchart showing an exemplary method for mitigating substrate warping. Detailed Implementation

[0034] Some integrated circuit manufacturing processes involve performing substrate-to-substrate bonding. Substrate-to-substrate bonding involves joining a first substrate and a second substrate face-to-face to connect the electrical features of an integrated circuit formed on the first substrate to the electrical features of an integrated circuit formed on the second substrate. However, circuit performance problems can occur when the electrical features on the first and second substrates are not properly aligned during bonding. This misalignment of the electrical features on the first and second substrates is called overlay error. Overlay error can cause a variety of problems. For example, the resistance of the interface between the integrated circuit on the first substrate and the integrated circuit on the second substrate increases with increasing overlay error. This leads to greater heat dissipation and power consumption at the interface, thus impairing device performance.

[0035] Overlay errors can be caused by a variety of reasons. One source of overlay error is misalignment of the first substrate relative to the second substrate. This misalignment can be translational and / or rotational. The misalignment of the first and second substrates can be relatively easily resolved by moving one or both substrates using a device that holds the substrates in place during the substrate-to-substrate bonding process prior to bonding.

[0036] Another source of overlay error is substrate deformation. Substrate warpage is an example of deformation that can lead to overlay errors. As mentioned above, the stress exerted on the substrate by the material film formed and patterned on it can cause substrate warpage. Warpage can cause features on the substrate surface to be closer or farther apart during clamping. This change in the position of substrate surface features can introduce overlay errors when bonded to another substrate. For example, a symmetrically curved substrate can cause isotropic scaling of the wafer dimensions. The magnitude of overlay error in such a substrate can increase isotropically from the center to the edge of the substrate.

[0037] Overlay errors caused by symmetrical bending can be corrected by bending the substrate to an appropriate degree during substrate-to-substrate bonding processes. For example, this bending can be achieved by using an actuated chuck to clamp the substrate during substrate-to-substrate bonding. The actuated chuck can mechanically deform the substrate to the desired degree by applying mechanical force to reduce or avoid overlay errors with another substrate.

[0038] However, asymmetrically bent wafers (also known as saddle-shaped wafers) cause substrate surface features to be closer together in one direction (e.g., X) and further apart in another direction (e.g., Y). This overlay error is difficult to correct because it is difficult to asymmetrically bend the substrate using an actuation chuck.

[0039] Therefore, this paper discloses examples of depositing back-side films with controlled shape profiles to automatically bend the substrate to a desired shape when clamped onto a flat chuck surface. For example, to correct a warped substrate, the back-side film may have a thickness profile that varies radially (e.g., circularly) symmetrically from the center of the substrate to the edge. As another example, to correct a saddle-shaped substrate, the back-side film can be deposited with a hyperbolic paraboloid film profile. By mitigating substrate warpage through bending, the disclosed examples can help reduce overlay errors in various integrated circuit manufacturing processes, such as substrate-to-substrate bonding and photolithography.

[0040] Figure 1 A schematic diagram shows an exemplary substrate 100 with a back-side film 102 having a variable profile. This back-side film 102 is deposited to bend the substrate in a certain way, thereby mitigating overlay errors. Overlay errors may be caused by stress on a film (not shown) deposited on the front side 104 of the substrate. The substrate 100 and back-side film 102 are not shown to scale, but rather with exaggerated features for clarity.

[0041] As shown in the figure, the back-side film 102 has a variable thickness profile, thicker at the center of the substrate 100 and thinner at the edges of the substrate 100. For substrates with symmetrical warpage, this film profile can be radially symmetrical. This radially symmetrical back-side film 102 can help correct cupping warpage of the substrate. Other film profiles can be used to correct other types of substrate warpage, as described below.

[0042] Figure 1 B schematically illustrates the situation after the substrate is placed on chuck 106, for example, for bonding to another substrate. Chuck 106 may comprise an electrostatic chuck for electrostatically adsorbing the substrate 100, or a vacuum chuck for securing the substrate using a pressure differential. The attraction force that adsorbs the substrate 100 to chuck 106 causes the back-side film 102 to adhere tightly to chuck 106. This causes the substrate 100 to bend due to the variable thickness profile of the back-side film 102. As indicated by the arrow above the front side 104, the front side 104 is stretched, thereby further separating the features on the front side 104. This helps correct overlay errors between the substrate 100 and another substrate (not shown) in substrate-to-substrate bonding processes. This can also be used to correct substrate alignment in photolithography processes, and / or any other suitable processes where the substrate is clamped and overlay errors may cause problems.

[0043] Backside films with controlled thickness profiles can also be used to mitigate substrate overlay errors with symmetrical or asymmetrical warp (e.g., saddle warp and / or other complex asymmetrical warp). Figure 2A graphical description showing the modeling results, outlining the contours of an exemplary substrate with saddle-shaped warping. The substrate has a first pair of opposing sides 200A, 200B that are raised relative to the substrate center, and a second pair of opposing sides 202A, 202B that are rotated and offset ninety degrees from the first pair of opposing sides and lowered relative to the substrate center. As shown... Figure 2 As shown by the dashed outline, the displacement of region 204A is between -30.0 μm and -22.5 μm. The displacement of region 204B is between -22.5 μm and -12.5 μm. The displacement of region 204C is between -12.5 μm and -5.0 μm. The displacement of region 204D is between -5.0 μm and 5.0 μm. The displacement of region 204E is between 5.0 μm and 12.5 μm. The displacement of region 204F is between 12.5 μm and 22.5 μm. The displacement of region 204G is between 22.5 μm and 30.0 μm.

[0044] Figure 3 Includes arrows, whose descriptions serve as... Figure 2 The direction and magnitude of the overlay error as a function of the location on the substrate. The length of each arrow represents the approximate magnitude of the overlay error, ranging from 0 nm to 50 nm. Arrows along line 300, extending horizontally from the center to the left and right edges, point inwards towards the center, and their magnitude increases from the center to the substrate edge. This indicates that features at those locations on the substrate are compressed together relative to their ideal location. Conversely, arrows along line 302 (reference) extending horizontally from the center to the top and bottom edges... Figure 3 The arrows (in the direction of the lines) point outwards towards the substrate edge. This indicates that the features at these locations on the substrate are stretched relative to their ideal positions. Arrows at other locations on the substrate show a direction transverse to these two lines, and their magnitude is a function of the radial distance from the substrate center. The overlay error (mean + 3 standard deviations) in the x-direction is 72.27 nm, and the overlay error in the y-direction is also 72.27 nm.

[0045] Figure 4 Displayed graphically Figure 2 The substrate has been deposited with Figure 5 The back-side membrane, showing its thickness profile, is clamped afterward. Figure 2 Substrate modeling results. Reference Figure 5 The film thickness is indicated by the dashed outline. The thickness of region 504A is between 0 and 3 μm. The thickness of region 504B is between 3 and 6 μm. The thickness of region 504C is between 6 and 9 μm. The thickness of region 504D is between 9 and 12 μm. The thickness of region 504E is between 12 and 15 μm. The thickness of region 504F is between 15 and 18 μm. The thickness of region 504G is between 18 and 20 μm.

[0046] Refer again Figure 4 Through deposition with Figure 5 The thickness profile of the film corrects for substrate overlay errors. The overlay error (mean + 3 standard deviations) in the x-direction is 3.06 nm, and the overlay error in the y-direction is 3.54 nm. Therefore, depositing films with controlled, variable profiles can be used to correct substrate warpage and the resulting overlay errors during substrate-to-substrate bonding.

[0047] The backside membrane can be deposited using any suitable membrane profile, such as a parabolic membrane profile or a hyperbolic parabolic membrane profile. In some examples, the hyperbolic parabolic membrane profile can contain different curvatures in the x-axis and y-axis directions.

[0048] Any suitable type of film can be deposited as a back-side film to correct overlay errors. Some illustrative examples include silicon oxide, silicon nitride, silicon oxynitride, other dielectric films, aluminum, tungsten, and other metal films. In some examples, the film stress in the back-side film can range from -2 gigapascals (GPa) to 2 GPa. Bringing the film stress close to zero helps reduce the effect of film stress on the substrate shape, thus avoiding complicating overlay errors. In other examples, a back-side film with the desired tensile or compressive stress can be used to aid in bending the substrate. In some examples, the back-side film stress may vary with location.

[0049] According to various examples, the thickness profile of the deposited film is adjusted by controlling the concentrations of precursor and diluent gases adjacent to the substrate during material deposition. The concentrations of these precursor and diluent gases can be controlled by varying the amount of precursor and diluent gases flowing from a gas distributor (e.g., a nozzle or nozzle base) along at least one of the x-axis and y-axis directions of the nozzle or nozzle base. Structural components of the gas distributor can be configured to alter the distribution of precursor and / or diluent gases from the gas distributor. The precursor and diluent gas profile adjacent to the substrate can conform to (or substantially match) the desired thickness profile of the material deposited on the substrate. In some embodiments, the output of the precursor and diluent gases can be divided into multiple regions to produce a specific thickness profile. In many examples, the precursor and diluent gas outputs can be interleaved, alternating, or otherwise integrated within one or more other regions for further control (e.g., smoothing the desired profile within and / or between one or more regions), thereby further producing a specific thickness profile. In some examples, to deposit a film comprising a hyperbolic parabolic profile, a film can be deposited with a parabolic film profile of a first thickness. The substrate is then rotated 90 degrees, and a parabolic film profile of a second thickness is deposited. The first and second thicknesses can be adjusted according to the desired overlay error compensation in the x-axis and y-axis directions.

[0050] Figure 6AA cross-sectional view of an exemplary nozzle base 600 is shown, which is suitable for depositing a back-side film with controlled variable thickness to help mitigate overlay errors. Figure 6A The view is cropped along the xz and yz planes, see reference. Figure 6A The coordinate axes are shown in the figure. As shown, the nozzle base 600 includes a first region (region 1) and a second region (region 2). Region 1 and region 2 contain staggered, alternating process gas channels, examples of which are shown as 602A in region 1 and 602B in region 2.

[0051] Each processing gas channel 602A in region 1 is connected to the processing gas inlet 604A of region 1 via a corresponding spoke 606A. Similarly, each processing gas channel 602B in region 2 is connected to the processing gas inlet 604B of region 2 via a corresponding spoke 606B (e.g., ...). Figure 6D (As shown). The spokes of region 1 are configured to form different process gas flow rates for different process gas channels flowing into region 1. Similarly, the spokes of region 2 are configured to form different process gas flow rates for different process gas channels flowing into region 2. As a more specific example, the process gas flow rates from the different process gas channels in region 1 can decrease from the center to the edge of the nozzle base. Conversely, the process gas flow rates from the different process gas channels in region 2 can increase from the center to the edge of the nozzle base. Each process gas channel in regions 1 and 2 is fluidly connected to a series of gas outlet holes 608, examples of which are shown as process gas outlet hole 608A and process gas outlet hole 608B, respectively, to output process gas to the back side of the substrate located on the nozzle base 600.

[0052] Figure 6B and 6C Exemplary configurations of processing gas channels 602A and 602B are shown. Figure 6B The processing gas passage, including the inclined gas outlet orifice 612, is shown. Figure 6C The processing gas passage, including the vertical gas outlet orifice 614, is shown. Return Figure 6A The nozzle base 600 includes a gas outlet hole 614A in a vertical region 1 located at the center and a gas outlet hole 614B in a vertical region 2 facing the edge of the nozzle base 600. Furthermore, the nozzle base includes inclined gas outlet holes in the region between the center and the edge. Additionally, the row of gas outlet holes between adjacent processing gas channels 602A, 602B may include alternating inclined gas outlet holes 612A in region 1 and inclined gas outlet holes 612B in region 2. In other examples, the nozzle base may include different configurations for the processing gas channels and processing gas outlet holes.

[0053] Figure 6DA top view schematic of the spoke configuration in the nozzle 600 is shown. As shown, multiple region 1 spokes 606A extend radially to supply gas to one end of the corresponding region 1 process gas channel 602A. Furthermore, multiple region 2 spokes 606B extend radially to supply gas to one end of the corresponding region 2 process gas channel 602B. In some examples, the spokes, process gas channels, and gas outlet orifices are configured to provide a concentration gradient of the process gas as a function of at least one of the x-axis or y-axis directions of the substrate. Figure 6D For clarity, the gas processing channels 602A and 602B are shown as dashed lines.

[0054] With this configuration, if one or more reactive gases for forming the back-side film are introduced into region 1, and one or more diluent gases are introduced into region 2, the relative concentration of the reactive gas and the inert diluent gas output from the nozzle base will be higher at the center of the nozzle base than at the edges closer to the nozzle base. Conversely, if one or more reactive gases for forming the back-side film are introduced into region 2, and one or more inert diluent gases are introduced into region 2, the relative concentration of the reactive gas and the diluent gas will be higher at the edges of the nozzle base than at the center.

[0055] Using the nozzle base 600, the following can be obtained by performing a first deposition stage and a second deposition stage. Figure 4 The film profile is defined as follows: In the first deposition stage, one or more reactive gases are introduced into region 1, while one or more diluent gases are introduced into region 2; In the second deposition stage, compared to the first deposition stage, the substrate is rotated 90 degrees, and one or more reactive gases are introduced into region 2, while one or more diluent gases are introduced into region 1. The thickness of the back-side film deposited in the first and second deposition stages can be adjusted according to the amount of overlay error compensation required for each corresponding direction.

[0056] exist Figure 6A In the example, the process gas outlet orifice 608A of region 1 is vertically oriented in the central region of the nozzle base 600 (as shown in 614A) and inclined between the central and edge regions of the nozzle base 600 (as shown in 612A). Similarly, the process gas outlet orifice 608B of region 2 is vertically oriented in the edge region of the nozzle base 600 (as shown in 614B) and inclined between the edge and central regions of the nozzle base (as shown in 612B). This helps to achieve the desired concentration gradient between the process gas and the inert diluent gas. In other examples, the gas outlet orifices of regions 1 and 2 may have any other suitable configuration different from the configuration shown.

[0057] Figure 7A schematic top view of another exemplary nozzle base 700 is shown, which includes multiple regions to allow controllable variation of the film thickness profile deposited on the back side of the substrate, thereby mitigating overlay errors when the substrate is clamped. The nozzle base 700 includes multiple regions 1 spokes 706A that extend radially to supply gas to one end of a corresponding region 1 processing gas channel 702A. Furthermore, multiple regions 2 spokes 706B extend radially to supply gas to one end of a corresponding region 2 processing gas channel 702B. Therefore, the nozzle base 700 includes a region 1 facing the center of the nozzle base and a region 2 located at the edge of the nozzle base. However, compared with… Figures 6A-6D Compared to nozzle base 600, nozzle base 700 does not have alternating processing gas channels in area 1 / area 2.

[0058] The examples disclosed herein are not limited to wafer bonding, but also applicable to any other suitable use case for clamping substrates. Another example involves photolithography.

[0059] Further examples of appropriate gas distribution hardware for depositing back-side films with controlled, variable profiles to compensate for substrate warping during substrate-to-substrate bonding are described in U.S. Provisional Application No. 63 / 578,289, the disclosure of which is incorporated herein by reference.

[0060] Figure 8 A schematic diagram of an exemplary processing tool 800, which can achieve back-side film deposition with controlled variable thickness according to the disclosed example, is shown. The processing tool 800 is described in the context of chemical vapor deposition (CVD) tools, including plasma-enhanced CVD (PECVD) tools. However, the back-side film deposition according to the disclosed example can be performed in other types of processing tools, such as atomic layer deposition (ALD) tools.

[0061] Processing tool 800 is configured to perform a deposition process on substrate 802. An exemplary substrate includes a semiconductor substrate, such as a silicon wafer. Processing tool 800 includes a processing station 804 in which substrate 802 can be processed. Processing station 804 is located within processing chamber 806. In some examples, two or more processing stations 804 may be located in the same processing chamber 806. This is in... Figure 8 The following explanation uses additional processing stations 807 as examples. Each additional processing station 807 is located within processing chamber 806.

[0062] The processing tool 800 is configured to allow selective processing on either the front or back side of the substrate. Therefore, the processing tool 800 includes a nozzle base 808 configured to dispense processing chemicals (e.g., reactive precursors and / or diluting gases) onto the back side of the substrate. Nozzle bases 600 and 700 are examples of nozzle base 808.

[0063] The processing tool 800 also includes a nozzle 810 positioned facing a nozzle base 808. The nozzle 810 is configured to dispense processing chemicals (e.g., reactive precursors and / or inert gases) onto the front side of a substrate, depending on the process being performed. In some examples, the nozzle 810 is electrically coupled to an RF power supply 812 via an RF matching network 815. The RF power supply 812 may be controlled by a controller 820. In other examples, RF power may be supplied to the nozzle base 808 instead of the nozzle 810. In this example, the RF power supply 812, the RF matching network 815, the nozzle 810, and the nozzle base 808 include a plasma generator configured to form capacitively coupled plasma between the nozzle base 808 and the nozzle 810. In other examples, the plasma generator may be configured to form inductively coupled plasma. In a further example, the plasma generator may be configured to form plasma at a location remote from processing station 804 and additional processing station 807. In such an example, flow control hardware can be used to deliver reactive materials generated in a remote plasma to the processing chamber 806. In a further example, both the nozzle 810 and the nozzle base 808 can be connected to an RF power supply. In some such examples, more than one RF power supply / matching network can be used.

[0064] Substrate 802 is located on substrate support 824. Substrate support 824 is in the form of a carrier ring, which can be mechanically rotated and / or moved to other processing stations. Figure 8 In this configuration, substrate 802 is positioned for backside processing. Therefore, substrate support 824 is positioned on bracket 826, which is configured to hold substrate 802 at a selected distance above nozzle base 808. In this configuration, precursor and / or dilution gas can be dispensed to the backside of substrate 802 using nozzle base 808, while inert gas can be dispensed to the frontside of substrate 802 using nozzle 810 (e.g., to prevent precursors intended for the backside from reaching the frontside).

[0065] When processing the front side of substrate 802, substrate 802 is located on nozzle base 808, and substrate support 824 is located on the bearing ring support area 827 of nozzle base 808. An end effector (not shown) can be used to place substrate 802 and substrate support 824 on nozzle base 808 for front-side processing, or on support 826 for back-side processing.

[0066] In some examples, at least a portion of the processing station 804 may be movable relative to the processing chamber 806. For example, the processing tool 800 may include a motor-driven telescopic bladder (not shown) to vertically move the nozzle base 808 (together with the substrate 802). Movement of the nozzle base 808 may be facilitated by one or more flexible gas lines (not shown) coupled to airflow path components leading to the nozzle base 808.

[0067] The processing tool 800 also includes a processing gas source 832. The processing gas source 832 contains reactive precursor gases and / or inert gases. A controller 820 controls the delivery of the processing gas from the processing gas source 832 through a flow path 833 to the nozzle 810. As a specific example, when the deposition target is the back side of substrate 802, the inert gas flow is directed through the nozzle 810 to the front side of substrate 802. The inert gas flow prevents precursors from entering the space between the nozzle 810 and the front side of the substrate and / or pushes precursors away from the front side of the substrate, thereby protecting the front side from unnecessary processing during back side processing.

[0068] In various examples, the process chemicals may be premixed or introduced separately into the process chamber 806 before being introduced. The process gas exits the process chamber 806 via one or more outlets. For example, an exhaust system 817 is used to extract the process gas and maintain appropriate pressure within the reactor.

[0069] Figure 8 Various sources of processed chemicals are also shown. A dilution gas source 834 is configured to supply one or more dilution gases to the nozzle base 808 via a flow path 835. Exemplary dilution gases include helium, neon, argon, krypton, and nitrogen.

[0070] Precursor source 836 is configured to provide one or more reactive precursor gases to nozzle base 808 via flow path 837. Exemplary precursors include precursors for forming silicon oxides, silicon nitrides, silicon oxynitrides, and other dielectric films. Further examples include precursors for forming aluminum, tungsten, and other metal films.

[0071] As described above, in some implementations, the outputs of the precursor and diluent gases can be divided into multiple zones within the nozzle base to produce a back-side film with a specific thickness profile. Therefore, in some examples, the reactive precursor gas and diluent gas can flow into two or more process gas inlets of the nozzle base 808 to deliver to two or more zones. Reference Figures 6A-6DIn the example using nozzle base 600, the reactive precursor gas can flow into process gas inlet 604A to output the reactive precursor gas to region 1. Similarly, dilution gas can flow into process gas inlet 604B to output the dilution gas to region 2. In some examples, nozzle base 700 can be used to divide the process gas into multiple regions. In some examples, a gas mixture containing a precursor gas of a first concentration flows to region 1, and a gas mixture containing a precursor gas of a second concentration different from the first concentration flows to region 2.

[0072] Flow paths 833, 835, and 839 may each contain any suitable flow control hardware to allow selective delivery of the processed chemicals to the processing chamber 806 and additional processing station 807. Examples include valves and mass flow controllers.

[0073] Additional processing station 807 may also receive power from RF power supply 812 via RF matching network 815. Additional processing station 807 may also be controlled by controller 820. In some examples, different RF power / matching networks and / or different processing chemical sources may be applied to different stations, allowing the processing at each individual processing station to be controlled independently.

[0074] In some examples, the processing tool 800 includes a chuck that clamps the substrate 802 so that the deposited back-side film rests flat against the chuck. As described above, forming a back-side film with a controlled variable thickness on the substrate 802 and then clamping the substrate against the chuck to allow the back-side film to rest flat against the chuck can help mitigate substrate warpage. After clamping, additional processing can be performed on the substrate 802, for example, in an additional processing station 807. Exemplary processing includes substrate-to-substrate bonding and photolithography. In some examples, such processes can be performed at a processing tool separate from the processing tool 800.

[0075] Figure 9 A flowchart of an exemplary method 900 for mitigating substrate warping in a warped substrate is shown. At 902, method 900 includes depositing a back-side film having a controlled, variable thickness on the warped substrate. In some examples, at 904, method 900 includes depositing the back-side film using a nozzle base (e.g., nozzle base 600 or 700). In some examples, at 906, the back-side film has a parabolic profile. In some examples, at 908, the back-side film has a hyperbolic parabolic profile. In some examples, at 910, the stress of the back-side film is between -2 GPa and 2 GPa.

[0076] In some examples, at step 912, a first back-side deposition stage is performed when the deposition of the back-side film includes a first concentration gradient of the reactant gas relative to the diluent gas as a function of the X-axis direction of the warped substrate. Step 912 also includes rotating the substrate (e.g., 90 degrees) and performing a second back-side deposition stage when a second concentration gradient of the reactant gas relative to the diluent gas is performed as a function of the Y-axis direction of the warped substrate.

[0077] Any suitable film can be deposited on the back side of the warped substrate. In some examples, at 914, method 900 comprises depositing a dielectric film or a metal film. In some more specific examples, at 916, the method comprises depositing one of silicon oxide, silicon nitride, silicon oxynitride, aluminum, or tungsten.

[0078] Continuing, at 918, method 900 further includes clamping the warped substrate onto a chuck so that the back-side film rests flat against the chuck. This causes the warped substrate to bend, thereby mitigating substrate warping. In some examples, at 920, method 900 further includes performing substrate-to-substrate bonding while clamping the warped substrate. In some examples, at 922, method 900 includes performing photolithography on the warped substrate while clamping it. By using a back-side film with a controlled, variable thickness to mitigate substrate warping, the disclosed examples can help reduce overlay errors in various substrate processes, such as substrate-to-substrate bonding and photolithography.

[0079] The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of various processes, systems and configurations, as well as other features, functions, behaviors and / or characteristics disclosed herein, and any and all equivalent schemes thereof.

Claims

1. A method for mitigating substrate warpage, comprising: Depositing a back-side film with a controlled variable thickness profile on a warped substrate; and The warped substrate is clamped in a chuck, wherein clamping the warped substrate is such that the back-side film is flat against the chuck, thereby bending the warped substrate to reduce the warping of the substrate.

2. The method of claim 1, further comprising performing substrate-to-substrate bonding while clamping the warped substrate.

3. The method of claim 1, further comprising performing photolithography on the warped substrate while holding the warped substrate.

4. The method according to claim 1, wherein the stress of the back membrane is between -2 GPa and 2 GPa.

5. The method of claim 1, wherein the back-side film is deposited using a nozzle base.

6. The method of claim 1, wherein the warped substrate has asymmetric warping, and wherein the method comprises performing a first back-side deposition stage as a function of the X-axis position of the warped substrate with respect to a first concentration gradient of the reactant gas relative to the diluent gas; rotating the warped substrate; and then performing a second back-side deposition stage as a function of the Y-axis position of the warped substrate with respect to a second concentration gradient of the reactant gas relative to the diluent gas.

7. The method of claim 1, wherein the back-side membrane comprises a parabolic membrane profile.

8. The method of claim 1, wherein the dorsal membrane comprises a hyperbolic paraboloid membrane profile.

9. The method of claim 1, wherein the back-side film comprises either a dielectric film or a metal film.

10. The method of claim 9, wherein the back-side film comprises one of silicon oxide, silicon nitride, silicon oxynitride, aluminum, or tungsten.

11. A nozzle base for depositing a film having a controlled variable thickness profile, the nozzle base comprising: Multiple first processing gas channels, fluidly connected to a first processing gas inlet, each first processing gas channel including multiple first processing gas outlet holes; and Multiple second processing gas channels are fluidly connected to a second processing gas inlet, and each second processing gas channel includes multiple second processing gas outlet holes. The arrangement of the first and second processed gas outlet holes is configured to provide a concentration gradient of the first processed gas relative to the second processed gas along one or more of the X-axis or Y-axis directions of the nozzle base.

12. The nozzle base according to claim 11, wherein one or more of the plurality of first processing gas channels are arranged alternately with one or more of the plurality of second processing gas channels.

13. The nozzle base according to claim 11, wherein the first processing gas outlet hole comprises a vertical hole at the center of the nozzle base and inclined outlet holes in other areas of the nozzle base.

14. The nozzle base according to claim 13, wherein the second processing gas outlet hole comprises a vertical hole at the edge of the nozzle base and an inclined outlet hole in other areas of the nozzle base.

15. A processing tool for depositing a back-side film to mitigate substrate warpage, the processing tool comprising: Processing room; A substrate support configured to support a substrate; A nozzle base is configured to allow precursor gas and dilution gas to flow to the back side of a substrate placed on the substrate support, and the nozzle base is further configured to provide a concentration gradient of the precursor gas relative to the dilution gas along at least one of the X-axis or Y-axis directions of the nozzle base. as well as A controller configured to control the processing tool to perform back-side film deposition on the substrate placed on the substrate support, the controller being configured to: The processing tool is configured to form a back-side film on the back side of the substrate, causing processing gas and dilution gas to flow to the nozzle base, the back-side film having a controlled variable thickness profile.

16. The processing tool according to claim 15, wherein the nozzle base comprises: Multiple first processing gas channels, fluidly connected to a first processing gas inlet, each first processing gas channel including multiple first processing gas outlet holes; and Multiple second processing gas channels are fluidly connected to a second processing gas inlet, and each second processing gas channel includes multiple second processing gas outlet holes. The arrangement of the first and second processed gas outlet holes is configured to provide the concentration gradient of the precursor gas relative to the diluent gas along at least one of the X-axis or Y-axis directions of the nozzle base.

17. The processing tool of claim 15, wherein the controller is further configured to provide a selected concentration gradient of the precursor gas relative to the diluent gas along the X-axis direction of the nozzle base to deposit the back-side film, the back-side film comprising a parabolic film profile.

18. The processing tool of claim 15, wherein the processing tool is configured to rotate the substrate by 90 degrees, and wherein the controller is further configured to cause the processing tool to deposit the back-side film on the back side of the substrate by: performing a first back-side deposition stage with a first concentration gradient of the precursor gas relative to the diluent gas as a function of the X-axis direction on the substrate; rotating the substrate by 90 degrees; and then performing a second back-side deposition stage with a second concentration gradient of the precursor gas relative to the diluent gas as a function of the Y-axis direction position on the substrate.

19. The processing tool of claim 15, wherein the controller is configured to cause the processing tool to deposit one or more of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, an aluminum film, or a tungsten film.

20. The processing tool of claim 15, further comprising a chuck, wherein the controller is configured to clamp the substrate onto the chuck after the back-side film is deposited, such that the back-side film is flat against the chuck, thereby bending the substrate to mitigate substrate warping.

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