Multi-parameter implant for managing wafer deformation

Abstract

A stress management method in a substrate is disclosed. The method may include: disposing a stress compensation layer on a major surface of a substrate; and performing a chained implant procedure to implant a set of ions into the stress compensation layer. The chained implant procedure may include: directing a first implant procedure to the substrate, the first implant procedure generating a first damage profile within the stress compensation layer; a second implant different from the first implant is directed to the substrate, where a composite damage profile is generated within the stress compensation layer after the second implant, the composite damage profile resulting in a higher stress response ratio than the first damage profile.

Description

Multiparameter implantation for managing wafer deformation

[0001] Related applications

[0002] This application claims priority to U.S. nonprovisional patent application serial number 18 / 498,813, filed on October 31, 2023, entitled “Multi-parameter implantation for managing wafer deformation,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to stress control in a substrate, and more specifically, to stress compensation to reduce out-of-plane deformation in the substrate. Background Technology

[0004] Devices such as integrated circuits, memory devices, and logic devices can be fabricated on substrates such as semiconductor wafers through a combination of deposition, etching, ion implantation, annealing, and other processes. Typically, the complete fabrication of a device and its associated circuitry may require hundreds of operations, including dozens of lithography operations. Specifically, lithography operations may require the alignment of a given mask used to fabricate a structure in a given area or layer with a pre-existing structure.

[0005] A problem arising from substrate fabrication is the development of out-of-plane distortion (OPD) caused by stress within the wafer, a deformation also known as warping. This OPD can result from stress generated within the wafer during processing. Therefore, OPD management can be critical for achieving proper overlay between structures fabricated at different levels of the device. For example, a common type of OPD encountered is global wafer curvature, which can occur at many processing instances due to stress buildup within the wafer caused by processing operations.

[0006] One method for managing wafer (substrate) stress is to provide a stress compensation layer on the back of the substrate. This layer can be used to counteract existing stress within the substrate, thereby reducing OPD. In specific embodiments, ion implantation has been used to implant ions into the stress compensation layer in an attempt to alter the stress state within the stress compensation layer, and thus indirectly change the stress and OPD in the substrate. However, ion implantation inherently introduces non-uniformity within the thickness of the implanted layer, such as the stress compensation layer, which is not considered in current methods.

[0007] Embodiments of this disclosure are provided in consideration of these and other factors. Summary of the Invention

[0008] In one embodiment, a method is provided. The method may include: forming a stress compensation layer on a main surface of a substrate; and performing a chain implantation procedure to implant a set of ions into the stress compensation layer. The chain implantation procedure may include: guiding a first implantation procedure to the substrate, the first implantation procedure generating a first damage profile within the stress compensation layer; and guiding a second implantation, different from the first implantation, to the substrate, wherein a composite damage profile is generated within the stress compensation layer after the second implantation, the composite damage profile causing a higher stress response ratio than the first damage profile.

[0009] In another embodiment, an ion implantation device is provided. The ion implantation device may include: an ion source for generating an ion beam; an acceleration component for changing the ion energy of the ion beam; and a controller. The controller may include: a processor; and a memory unit coupled to the processor, including a chain implantation mode that operates on the processor to control the ion implantation device to impart a composite damage profile to a stress compensation layer on a substrate by performing multiple implantations under multiple different ion implantation conditions. In this way, a first implantation may generate a first damage profile within the stress compensation layer, and a second implantation may generate a composite damage profile after the second implantation, the composite damage profile having a higher stress response ratio than the first damage profile.

[0010] In another embodiment, a controller for an ion implanter is provided. The controller may include: a processor; and a memory unit coupled to the processor, including a chain implantation mode that operates on the processor to control the ion implanter to impart a composite damage profile to a stress compensation layer on a substrate. The composite damage profile can be implemented by performing a first implantation under a first set of implantation conditions; and a second implantation under a second set of implantation conditions different from the first set. In this way, the first implantation may generate a first damage profile within the stress compensation layer, and the second implantation may generate a composite damage profile after the second implantation, wherein the composite damage profile causes a higher stress response ratio than the first damage profile. Attached Figure Description

[0011] Figure 1 illustrates an exemplary system according to this disclosure.

[0012] Figure 1A illustrates further details of the controller according to some embodiments of the present disclosure.

[0013] Figure 2A shows an example of stress state in a substrate.

[0014] Figure 2B shows the geometry used to manage stress in the substrate.

[0015] Figure 2C shows an example of a substrate shape that is the result of ion implantation to properly compensate for the initial substrate stress shown in Figure 2B.

[0016] Figure 3 is a graph illustrating how complementary implantation according to an embodiment of the present disclosure improves the damage distribution within a layer.

[0017] Figure 4 is a graph showing the curves for achieving defect saturation using a single implantation method and ion implantation.

[0018] Figure 5 presents a plotted representation of the stress response ratio.

[0019] Figure 5A illustrates the correlation of stress response ratio as a function of total ion dose.

[0020] Figure 6 is a graph illustrating the use of a dual-implantation chain ion implantation method to achieve more efficient intralayer defect saturation according to an embodiment of the present disclosure.

[0021] Figure 7 is a graph illustrating the use of complementary implantation to improve the damage distribution within a layer according to an additional embodiment of this disclosure.

[0022] Figure 8 is a graph illustrating the use of the quadruple implantation chain ion implantation method of Figure 7 according to an embodiment of the present disclosure to achieve more efficient intralayer defect saturation.

[0023] Figure 9 is a graph illustrating the use of complementary implantation to improve intralayer damage distribution according to an additional embodiment of the present disclosure.

[0024] Figure 10 is a graph showing the results of such a method according to some embodiments of the present disclosure.

[0025] Figure 11 illustrates an exemplary manufacturing process.

[0026] Figure 12 shows another exemplary process flow. Detailed Implementation

[0027] Embodiments of this disclosure will now be described more fully below with reference to the accompanying drawings, in which some embodiments are illustrated. The subject matter of this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and that they will fully convey the scope of the subject matter to those skilled in the art. In the drawings, the same reference numerals consistently refer to the same elements.

[0028] The embodiments described herein relate to techniques and apparatus for improving substrate stress management. One embodiment of this disclosure proposes a method that employs a new set of implants into layers disposed on a substrate to improve stress relief in the substrate. Specifically, a beam ion implanter can be used to perform a chain of implants, thereby optimizing the damage distribution in the implanted layers for more effective treatment of substrate stress.

[0029] Referring now to Figure 1, which illustrates an exemplary system according to the present disclosure. An ion implantation system (hereinafter “system”) 10 represents a process chamber housing components such as an ion source 14 for generating an ion beam 18, an ion implanter, and a series of beam assemblies 16. The ion source 14 may include a chamber for receiving a gas flow 24 and generating ions therein. The ion source 14 may also include a power source and an extraction electrode assembly disposed near the chamber. The beam assembly 16 may include, for example, a mass analyzer 34, a first acceleration or deceleration stage 36, a collimator 38, a quality resolution slit 40, and other suitable downstream beam assemblies (e.g., an energy filter 42) to accelerate, decelerate, shape, scan, etc., the ion beam 18.

[0030] In a specific embodiment, the bead assembly 16 can filter, focus, accelerate, decelerate, and otherwise manipulate ions or ion beams 18 to achieve desired species, shape, energy, and other qualities. The ion beam 18 passing through the bead assembly 16 can be guided toward a substrate mounted on a platen or fixture within the process chamber 46. As understood, the substrate can be moved in one or more dimensions (e.g., translation, rotation, and tilting).

[0031] As shown in the figure, there may be one or more feed sources 28 that can operate together with the chamber of ion source 14.

[0032] In various embodiments, different species can be used as ions to treat stress in the film. Non-limiting examples of suitable ions include silicon (Si), boron (B), carbon (C), oxygen (O), germanium (Ge), phosphorus (P), arsenic (As), etc., to control substrate stress.

[0033] Although not limiting, ion source 14 may include a power generator, a plasma exciter, a plasma chamber, and the plasma itself. The plasma source may be an inductively coupled plasma (ICP) source, a toroidal coupled plasma source (TCP), a capacitively coupled plasma (CCP) source, a helical source, an electron cyclotron resonance (ECR) source, an indirectly heated cathode (IHC) source, a glow discharge source, an electron beam ionization source, or other plasma sources known to those skilled in the art.

[0034] Ion source 14 generates an ion beam 18 for processing the substrate. In various embodiments, the ion beam (in cross-section) may have a target shape known in the art, such as a dot beam or a strip beam. In the Cartesian coordinate system shown, the propagation direction of the ion beam 18 may be represented as parallel to the Z-axis, while the actual trajectory of the ions within the ion beam 18 may vary. To process the substrate, the ion beam 18 can be accelerated to obtain the target energy by establishing a voltage (potential) difference between the ion source 14 and the wafer (substrate).

[0035] As further shown in Figure 1, system 10 may include controller 50 to control the operation of various components of system 10, such as components for scanning the pressure plate, tilting the pressure plate, scanning the ion beam 18, or adjusting the energy of the ion beam 18. Figure 1A provides details of an embodiment of controller 50, which will be further discussed below.

[0036] Turning to Figure 2A, an example of a stress state in a substrate is shown. In this example, the stress state can be represented by the pattern of OPD. In the example of Figure 2A, the OPD has a symmetrical arrangement in which negative OPD is seen in the vertical soccer ball-shaped regions on the left and right peripheries of the substrate 100, and positive OPD is observed in the horizontal soccer ball-shaped regions on the upper and lower peripheries of the substrate 100. The exemplary stress pattern of Figure 2A is provided for illustrative purposes, and in general, the substrate 100 can be characterized by a simpler stress pattern or by a more complex stress pattern (in which stress and OPD are varied in more complex patterns).

[0037] In the various embodiments detailed herein, a series of implantations are performed using a beam ion implanter to adjust the stress state in the substrate; these implantations can be considered as chain implantations. Turning to Figure 2B, a geometry for managing stress in substrate 100 is shown. In this example, an ion beam 18 is directed to substrate 100, and specifically to layer 102 disposed on the main surface of substrate 100. According to some non-limiting embodiments, layer 102 may be an oxide layer or a nitride layer, such as silicon nitride (hereinafter also referred to as "SiN"). Layer 102 may be deposited on the substrate under stress to change the overall stress state of substrate 100. Layer 102 can then act as a medium for receiving ion implantation doses to change the stress state in layer 102, and thus further change the stress state in substrate 100. In this way, layer 102 can be considered to constitute a stress compensation layer (SCL). As shown in Figure 2B, the substrate may exhibit curvature in the XZ plane of the Cartesian coordinate system shown, thereby resulting in OPD. In a specific embodiment, layer 102 may be intentionally formed under a relatively high stress state, which imparts a relatively large curvature to substrate 100. Through this operation, the stress state of layer 102 is altered, and therefore, for a given set of ion implantation conditions, the curvature change of substrate 100 can be enhanced, as discussed below.

[0038] The curvature shown in Figure 2B can be global or local, and can extend into a two-dimensional pattern as shown in Figure 2A. As an example, substrate 100 may include device structures to be fabricated or in the process of being fabricated on substrate 100, wherein these devices are located on the main surface of substrate 100 relative to layer 102. Therefore, an objective may be to reduce the curvature of substrate 100, thereby reducing OPD and facilitating device handling. Figure 2C shows an example of a properly disposed state of substrate 100, where substrate 100 is shown as flat; this shape may be a result of ion implantation into layer 102 to properly compensate for the initial substrate stress shown in Figure 2B.

[0039] According to embodiments of this disclosure, the ion beam 18 can be guided to layer 102 in a series of chain implantations (which reduces stress within substrate 100). Chain implantations can be implemented by distributing damage more uniformly within layer 102, and thus controlling stress efficiently.

[0040] Figure 3 is a graph illustrating the improvement of damage distribution within a layer using complementary implantation according to embodiments of the present disclosure. Specifically, the graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. The parameter “normalized vacancies” used herein can be understood as the ratio of the actual vacancy level in the layer to the critical vacancy level of the layer, beyond which no further stress changes occur in the layer. For a given material, the critical vacancy level can be determined empirically.

[0041] The total dose of the chain implantation was 2E14 / cm³. The chain implantation was formed as a sum of two implantations, one performed at 60 kEV to implant Si ions at a dose of 4E13 / cm² into the silicon nitride layer, and the other performed at 180 kEV to implant Si ions at a dose of 1.6E14 / cm² into the silicon nitride layer. The lower-energy implantation, indicated by the lowest energy curve, produced a vacancy distribution in the direction perpendicular to the layer surface, which can be referred to as the damage profile. The damage profile reached a concentration peak of 0.2 at a depth of approximately 500 Å from the upper surface of the SiN layer. The higher-energy implantation produced a damage profile with a concentration peak of 0.56 at a depth of approximately 1600 Å. Overall, the chain implantation, representing the sum of the two profiles, produced a relatively flat damage profile, exhibiting a plateau of 0.53 + / - 0.03 at depths greater than 450 Å. For comparison, Figure 3 also shows a curve representing the damage profile induced after a single implantation of 2E14 / cm² Si ions at an energy of 180 keV. Similarly, the damage profile peaks at a depth of approximately 1600 Å, with a peak value of 0.71.

[0042] Note that in the example of Figure 3, for the same total Si ion dose (2E14 / cm²), using two different implants with the aforementioned different energies results in a more uniform damage profile (albeit with lower peak values). The method shown in Figure 3 can be extended to improve and optimize the stress state in layers (e.g., stress-compensating layers). The inventors have realized that ion beam bombardment of stress-compensating layers generates collisional cascades within the stress-compensating layer, which allow layer atoms to reposition from initial higher energy positions to more energy-stable locations, thus reducing wafer stress. Furthermore, in some embodiments, it may be necessary to produce a uniform damage distribution within the stress-reducing layer, meaning that the damage distribution is the same in terms of dose and depth at all points across the wafer.

[0043] In the single-implantation example of 2E14 / cm² shown in Figure 3, the maximum damage profile is located near the membrane / substrate interface. However, significant damage variation exists with depth, with much lower normalized damage at depths below 1400 angstroms. Although the overall damage under the single-implantation condition in Figure 3 may be slightly higher than that under the chain implantation case, and a greater stress reduction can be expected, a more uniform distribution of vacancies as a function of depth may be useful in the chain implantation example.

[0044] Note that, in addition to producing a more uniform damage profile when needed, it may be useful to generate a layer with maximum damage or defects to facilitate maximum stress relief. Referring again to Figure 3, the maximum or saturated defect state can be expressed by a saturation curve, where the normalized vacancy value is 1 over a 2000 angstrom thick SiN layer. To achieve a damage state approximating or close to the saturation curve, more than one implantation procedure may be required.

[0045] Figure 4 is a graph illustrating defect saturation achieved using a single implantation method with ion implantation. Specifically, similar to Figure 3, this graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. The ion energy for a single implantation is 180 keV, and a series of curves are shown representing the dose profile present after a given total dose of Si ions has been implanted into the SiN layer. The lowest curve represents a total dose of 1 E14 / cm², while the highest curve represents a total dose of 1 E15 / cm³. Thus, this series of curves represents the evolution of the damage profile as a function of the total dose. Note that at relatively low total doses, damage saturates within the SiN at relatively large depths. For example, using a normalized vacancy value of 0.9 as the threshold for a highly saturated defect level, this value is exceeded at depths greater than 700 Å for a dose of 5 E14 / cm². However, higher dose levels only slowly increase the normalized vacancy value at depths greater than 700 angstroms, while gradually increasing it at shallower depths. In summary, the single implantation results shown in Figure 4 illustrate the saturation behavior resulting from net defects, which first manifests in the stress-compensated layer region subjected to the most severe ion bombardment.

[0046] Therefore, this single-implantation method may be inefficient at causing damage across the entire depth of the layer, especially at relatively shallow or large depths (where the damage profile tends to be low). The behavior of Figure 4 can be expressed as a response phenomenon in which the implanted layer can be characterized by the stress response ratio (SRR). The stress response ratio provides an indication of the relative change in the stress state of the layer induced by a given ion exposure. A relatively high stress response ratio will indicate a relatively large change in the stress conditions of the implanted layer in response to the implanted ions. Specifically, the term "stress response ratio" can refer to the change in the stress state of the membrane after a certain amount of ion exposure. According to some embodiments of this disclosure, the stress response ratio can be expressed as a change in the ion dose for a given ion energy.

[0047] In one approach, the stress response (S) to a given implant can be determined. I Compared to the maximum theoretical stress response (S) of the stress compensation layer M The stress response ratio is quantified. The maximum theoretical stress response can be determined by determining the overall damage level that causes the maximum stress response. In a specific embodiment, as detailed below, the SRR value can be determined by determining the relationship between the overall damage in the SCL caused by a given implant and the maximum overall damage threshold, beyond which further damage will not change the stress state in the SCL.

[0048] Figure 5 presents a graphical representation of how the stress response ratio is determined. Curve 504 represents the overall damage threshold (normalized to a value of 1), beyond which any further implanted damage (e.g., additional vacancies) will not produce further stress changes in the SCL. Therefore, the area below curve 504 can be considered to represent the stress response ratio of the 2000 angstrom thick SiN layer used as the SCL. M Figure 5 S I The value corresponds to the stress response induced by a single implantation of Si+ ions with an ion energy of 180 keV into a 2000 Å thick SiN layer at a dose of 2E14 / cm². Therefore, the SRR of the single implantation example in Figure 5 is equal to the area under curve 502 (S). I The area under curve 504 (S) M The ratio of SRR to SRR. Therefore, in the example of Figure 5, the value of SRR can be approximately 0.55.

[0049] Figure 5A illustrates the correlation of the stress response ratio as a function of the total ion dose. As presented, the stress response ratio saturates above approximately 7E14 / cm². Therefore, after the stress control layer has received a dose of 7E14 / cm², exposing the stress control layer to additional ion implantation will not further reduce the stress within the stress control layer.

[0050] Referring also to Figure 4, the stress response ratio (SRR) for a given ion dose is calculated using the area under each curve. In Figure 4, damage is represented as a normalized vacancy as described above, where the value of the normalized vacancy is by definition no more than 1. Note that for a given ion implantation procedure, the SRR will vary with the ion dose depending on the ion energy of the implanted ions. The SRR will also depend on whether the ion implantation procedure involves a single implantation under only one implantation condition (i.e., the same ion energy, the same ion species, etc.) or whether the ion implantation procedure involves multiple implantations to produce a given ion dose, where multiple implantations use different ion energies or otherwise change the implantation conditions.

[0051] In this regard, the inventors have discovered that a customized set of multiple implantation procedures can generate a more efficient path to create defects, and thus produce stress relaxation within a given layer. Figure 6 is a graph illustrating the use of a dual-implantation chain ion implantation method according to an embodiment of this disclosure to achieve more efficient defect saturation within a layer. Specifically, as with Figure 4, the graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. The chain implantation is formed as a sum of two implantations, one performed at 60 kEV to implant Si ions into the silicon nitride layer at a relatively shallow depth, and the other performed at 180 kEV to implant Si ions into the silicon nitride layer at a relatively deep depth. Each curve in Figure 6 represents the damage profile (formed by the sum of the two different implantations) after implantation of a given total dose of ions, where SRR is calculated based on the area under each curve. Note that, depending on the exact combination of ion energies used in a chain implantation procedure, the uniformity of damage distribution can be improved for a given total ion dose compared to a single-energy implantation procedure. Furthermore, in a multi-energy chain implantation procedure, the SRR (Surface Reduction Rate) may exceed that obtained using a single implantation for a given ion dose. Specifically, chain implantation methods may be more efficient than single-energy implantation methods in terms of saturation damage at shallower depths.

[0052] In operation, a chain implantation procedure can be determined to achieve a target SRR value. To further illustrate the operation associated with the chain implantation procedure and the use of SRR information for processing the stress compensation layer (SCL), Figure 1A shows further details of the controller 50. In this embodiment, the controller 50 may include a processor 52, such as a microprocessor of known type, a dedicated processor chip, a general-purpose processor chip, or a similar device. The controller 50 may further include a memory or memory cell 54 coupled to the processor 52, wherein the memory cell 54 contains a chain implantation protocol 56. The chain implantation protocol 56 can run on the processor 52 to manage the implantation process using the ion beam 18 and the substrate 100 to apply a certain amount of damage (e.g., damage specified by SRR) to the stress compensation layer, as discussed above. The memory cell 54 may include an article of manufacture. In one embodiment, the memory cell 54 may include any non-transitory computer-readable or machine-readable medium, such as optical, magnetic, or semiconductor memory. The storage medium may store various types of computer-executable instructions to implement one or more logical flows described herein. Examples of computer-readable or machine-readable storage media may include any tangible media capable of storing electronic data (including volatile or non-volatile memory), removable or non-removable memory, erasable or non-erasable memory, writable or rewritable memory, and so on. Examples of computer-executable instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, object-oriented code, visual code, and similar code. The embodiments are not limited to this context.

[0053] In some embodiments, as discussed above, for a given wafer or wafer set, memory unit 54 may receive and / or store stress information related to the substrate / stress compensation layer. In some embodiments, the memory unit may store information related to SRR values ​​for a given combination of ion type / ion energy / ion dose / stress compensation layer / substrate, etc. SRR values ​​may be stored in any suitable format (including databases, tables, etc.) and may include pre-stored SRR values ​​determined for a matrix of suitable ion energy, ion dose, layer thickness, etc., including those values ​​that may be applicable during a given dynamic implantation period. The measured or calculated stress on the wafer can then be used to determine the chain implantation formulation to be implemented on the wafer to compensate for stress patterns. In some embodiments, chain implantation formulation 56 may calculate the optimal chain implantation formulation to be implemented, including the optimal combination of ion energy and ion dose for each implantation in multiple implantations. Suitable criteria for selecting the chain implantation formulation may include using the ion dose most efficiently to generate the target SRR, target uniformity in the damage profile as a function of depth, etc.

[0054] Figure 7 is a graph illustrating the use of complementary implantation to improve the intralayer damage distribution according to an additional embodiment of the present disclosure. Similar to Figure 3, the graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. The total dose of the chain implantation is 2E14 / cm². In this case, the chain implantation is formed as a sum of four implantations, one performed at 30 kEV to implant a Si ion dose of 1.8E13 / cm² into the silicon nitride layer; another performed at 60 kEV to implant Si ions at a dose of 2.5 E13 / cm²; yet another performed at 100 kEV to implant Si ions at a dose of 4.7E13 / cm² into the silicon nitride layer; and an additional implantation performed at 180 kEV to implant Si ions at a dose of 1.1E14 / cm² into the silicon nitride layer. As shown by the lower curves, lower energy implantation produces a damage profile that peaks at a relatively shallow depth (less than 1000 Å from the top surface of the SiN layer). The highest energy implantation produces a damage profile that peaks at a depth of approximately 1600 Å. Chain implantations, representing the sum of these four profiles, together produce a composite damage profile, which is a relatively flat damage profile between depths of approximately 300 Å and 1400 Å, decreasing sharply below 200 Å and relatively gradually decreasing above 1400 Å. For comparison, Figure 7 also shows curves representing the damage profile induced after a single implantation of 2E14 / cm² Si ions at 180 kEV.

[0055] Figure 8 is a graph illustrating the more efficient intralayer defect saturation achieved using the quadruple implantation chain ion implantation method of Figure 7 according to an embodiment of the present disclosure. Specifically, as with Figures 4 and 6, the graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. Each curve in Figure 8 represents the damage profile (formed by the sum of the four different implantations described in Figure 7) after implantation of a given total dose of ions. Note that in this method, after implantation of a total dose of 6E14 / cm², the normalized vacancy level is above 0.9 up to a depth of approximately 1750 Å, except for the top 100 Å of the SiN layer. Therefore, this quadruple implantation chain implantation method reduces the total ion dose required to achieve a uniform vacancy distribution at a high level, thereby achieving more optimized stress relief in layers with less total ion current. In this example, the results of the two-stage implantation method in Figure 6 achieve a normalized vacancy value greater than 0.9 at a relatively shallow depth, at the cost of a smaller normalized vacancy value at depths above approximately 1750 angstroms.

[0056] Furthermore, this multi-implantation chain implantation method can be used to generate more efficient pathways to achieve a maximum normalized vacancy state. In various embodiments, prior to the implantation procedure, for a given ion / stress compensation layer combination, known methods can be used to conveniently calculate the SRR value, and the SRR value can be pre-stored for a matrix of suitable ion energy, ion dose, layer thickness, etc. (which can be applied during implantation). Additionally, in some embodiments, based on the chain implantation combination, these SRR values ​​can be calculated for a series of ion doses, as discussed above with reference to Figure 6. Note that this method provides a way to achieve the target stress change more efficiently through customized implantation procedures (e.g., using chain implantation formulations involving two or four implantation energies). In other words, by partitioning the dose into implantations performed at multiple different energies rather than a single energy, the target stress change can be achieved for a lower total ion dose implanted into the membrane.

[0057] Note that one issue arising from the implementation of the aforementioned chain implantation procedures is that these procedures require altering the ion energies between different components that may constitute a given chain implantation process. In wire ion implantation machines, changing the ion energy of the implanted ions may require retuning the ion source and / or other wire assemblies. Therefore, the overall yield of this method may be affected. This retuning is not required in methods using a single ion energy to implant into a stress-compensating layer.

[0058] Figure 9 is a graph illustrating the use of complementary implantation to improve the intralayer damage distribution according to an additional embodiment of the present disclosure. Similar to Figures 3 and 7, the graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. The total dose of the chain implantation is 2E14 / cm³. In this case, the chain implantation is formed as a sum of two implantations, one performed at 180 kEV to implant a dose of 1.6E14 / cm² of Si ions into the silicon nitride layer with perpendicular incidence onto the main plane of the substrate, and the other performed at 180 kEV to implant a dose of 4E13 / cm² of Si ions at a 60° tilt angle relative to the normal of the main plane of the substrate. The lower curve reflects the damage profile reflecting the normalized vacancy distribution as a function of depth in the SiN film, where the peak of the damage profile skews towards the top of the layer at approximately 500 Å. The damage profile curve of the perpendicular incidence implantation procedure shows a peak towards a depth of 1600 Å. The chain implantation curve represents the sum of the two implantations and exhibits a relatively flat damage profile between depths of 500 Å and 1700 Å. Note that for this specific ion dose and ion energy, the area under the corresponding curve representing SRR is slightly smaller for a single implantation with vertical incidence compared to chain implantations using two different angles of incidence. Furthermore, in the case of chain implantations, the vacancy distribution as a function of depth is substantially more uniform.

[0059] The multi-tilted chain implantation method of Figure 9 can be used to achieve more efficient defect saturation within a stress-compensated layer. Figure 10 is a graph showing the results of this method according to yet another embodiment of the present disclosure. Specifically, as with Figures 4, 6, and 8, the graph depicts a simulation of normalized vacancies generated by Si ion implantation as a function of depth within a 2000 Å thick SiN layer. Each curve in Figure 10 represents the damage profile (formed by the sum of the two different implantations) after implantation of a given total dose of ions, as described with respect to Figure 9. Note that in this method, after implantation of a total dose of 5E14 / cm², the normalized vacancy level is higher than 0.9 at a depth greater than 200 Å. Therefore, compared to the single implantation method of Figure 4, a high vacancy saturation (where "high" can mean higher than 0.9) is achieved at a relatively low total ion dose, except for the top 10% of the layer. Furthermore, this method has the added advantage that the two implants are performed with the same energy, eliminating the need for retuning of the ion source or beam assembly between implants, thereby increasing productivity. While the above example illustrates two implants, in additional embodiments, three or more implants (each with a different tilt angle) can be used to further customize the damage profile, damage generation efficiency as a function of total ion dose, and so on.

[0060] Turning now to Figure 11, a process flow 1100 according to some embodiments of the present disclosure is shown. At block 1102, a stress compensation layer is provided on the main surface of a substrate, such as a silicon wafer. The stress compensation layer may be provided on a main surface opposite to a second main surface on which device processing will be performed or is being performed on the substrate. In some non-limiting embodiments, the stress compensation layer may be a silicon nitride film.

[0061] At block 1104, a first implantation procedure is guided to the substrate. The first implantation procedure can create a first damage profile within the stress compensation layer. In some embodiments, the first implantation procedure may involve implanting a dose of ions at a given ion energy and a given incident angle defined by the tilt angle of the substrate. In some embodiments, the incident angle of the ions may be along a direction perpendicular to the main surface of the substrate. The first implantation can create a first damage profile within the stress compensation layer, as reflected in a normalized vacancy distribution that is a function of the thickness within the stress compensation layer.

[0062] At block 1106, a second implant, different from the first implant, is guided to the substrate. According to some non-limiting embodiments, the second implant may generally differ from the first implant in terms of ion energy or incident angle. In this way, after the second implant, a composite damage profile is generated within the stress compensation layer, wherein the composite damage profile is a result of both the first and second implants. The composite damage profile may be more uniform than the damage profile of the first implant.

[0063] Turning now to Figure 12, a process flow 1200 according to some other embodiments of the present disclosure is shown. At block 1202, a target stress response ratio (SRR) of a stress compensation layer disposed on the main surface of a substrate, such as a silicon wafer, is received. The stress response ratio can be defined as the overall damage (D) generated by the ion beam as a function of the depth through which the stress compensation layer is penetrated. I Compared to the maximum overall damage D of the stress compensation layer M The ratio, where SRR = D I / D M .

[0064] At block 1204, a chain implantation formulation for implementing the target SRR within the stress compensation layer is determined. The chain implantation formulation may include at least two different implantations to be performed under different implantation conditions. The chain implantation formulation may be a set of customized multiple implantation procedures that create a more efficient path to generate defects and thus induce stress relaxation within a given layer.

[0065] At block 1206, multiple implants of the chain implant formulation are guided to the substrate, where the ion energy or tilt angle varies between different implants.

[0066] While the foregoing embodiments can be used to implant stress compensation layers disposed on the back side of a substrate, in additional embodiments, a chain implantation variation detailed herein can be used to modify the stress in a stress compensation layer disposed on the front side of a substrate, wherein the front side of the substrate includes devices, circuitry, active layers, or other components. In specific embodiments, the stress compensation layer may be disposed on the front side of the substrate as a sacrificial layer (e.g., a rigid mask for patterning). The advantage of performing a chain implantation procedure on the front-side SCL (e.g., an existing sacrificial layer such as a rigid mask) is that the sacrificial layer can be used for both patterning and stress compensation.

[0067] The advantages provided by the embodiments of this disclosure are multifaceted. A first advantage is that, compared to known methods, a relatively low total implantation dose can be used to achieve the desired stress response profile, thus providing improved wafer yield. Another advantage is that, by varying the incident angle between successive implantations in a chain implantation, an improved stress response profile can be achieved using an ion implantation formulation that does not require a return ion source and various bead assembly components.

[0068] The scope of this disclosure is not limited to the specific embodiments set forth herein. In fact, various other embodiments and modifications of this disclosure will be apparent to those skilled in the art from the foregoing description and drawings, in addition to what is set forth herein. Therefore, such other embodiments and modifications are intended to fall within the scope of this disclosure. Furthermore, this disclosure has been set forth herein in the context of specific implementations in specific environments for specific purposes; however, those skilled in the art will recognize that its usefulness is not limited thereto, and that this disclosure can be advantageously practiced in any number of environments for any number of purposes. Therefore, the claims set forth below are to be interpreted in accordance with the full scope and spirit of this disclosure set forth herein.

Claims

1. A stress management method in a substrate, comprising: A stress compensation layer is provided on the main surface of the substrate; And to perform a chain implantation procedure to implant a set of ions into the stress compensation layer, the chain implantation procedure including: guiding a first implantation procedure to the substrate, the first implantation procedure generating a first damage profile within the stress compensation layer; And guiding a second implant, different from the first implant, to the substrate, wherein a composite damage profile is generated within the stress compensation layer after the second implant, the composite damage profile causing a higher stress response ratio than the first damage profile.

2. The method of claim 1, wherein the stress response ratio is determined as the stress response (S) to a given implant. I Compared to the maximum theoretical stress response (S) of the stress compensation layer M The ratio of ).

3. The method of claim 1, wherein the first implantation is performed with a first ion energy, and the second implantation is performed with a second ion energy different from the first ion energy.

4. The method of claim 1, wherein guiding the first implant and the second implant includes guiding a silicon ion beam to the substrate, and wherein the stress compensation layer comprises a silicon nitride material.

5. The method of claim 1, wherein the stress compensation layer is disposed on the front side of the substrate, the front side of the substrate comprising one or more of the following: a device, a circuit, and a structure to be formed into the device or circuit.

6. The method of claim 5, wherein the stress compensation layer comprises an existing sacrificial patterning layer disposed on the front side.

7. The method of claim 1, wherein the first implantation is performed at a first incident angle, and the second implantation is performed at a second incident angle different from the first incident angle.

8. The method of claim 7, wherein the implantation procedure is performed after the second implantation and no further implantation is performed.

9. An ion implantation device, comprising: An ion source, used to generate an ion beam; An acceleration component for changing the ion energy of the ion beam; and a controller, the controller including: a processor; And a memory unit coupled to the processor, including a chain implantation mode that operates on the processor to control the ion implanter to impart a composite damage profile to a stress compensation layer on a substrate by performing multiple implantations under multiple different ion implantation conditions, wherein a first implantation will generate a first damage profile within the stress compensation layer, and wherein a second implantation will generate a composite damage profile after the second implantation, the composite damage profile having a higher stress response ratio than the first damage profile.

10. The ion implanter of claim 9, wherein the chain implantation mode operates on the processor to control the ion implanter to receive a target value of the stress response ratio (SRR) of the stress compensation layer; and to calculate the composite damage profile based on the target value of the stress response ratio, the stress response ratio being determined as the stress response (SRR) for a given implantation. I Compared to the maximum theoretical stress response (S) of the stress compensation layer M The ratio of ).

11. The ion implanter of claim 10, wherein the chain implantation mode operates on the processor to control the ion implanter to determine the combination of ion energy and ion dose for the first implantation and the second implantation based on a set of criteria.

12. The ion implantation device of claim 11, wherein the set of criteria includes one or more of the following: efficient use of ion dosage to generate the target value of the stress response ratio; and target uniformity in the composite damage profile as a function of depth.

13. The ion implantation device according to claim 9, wherein the first implantation is performed with a first ion energy, and the second implantation is performed with a second ion energy different from the first ion energy.

14. The ion implantation device of claim 9, wherein guiding the first implantation and the second implantation includes guiding a silicon ion beam to the substrate.

15. The ion implantation device of claim 9, wherein the stress compensation layer comprises silicon nitride material, and the ion beam comprises silicon ions.

16. The ion implantation device according to claim 9, wherein the first implantation is performed at a first incident angle, and the second implantation is performed at a second incident angle different from the first incident angle.

17. The ion implantation device of claim 9, wherein the stress compensation layer is disposed on the front side of the substrate, the front side of the substrate comprising one or more of the following: a device, a circuit, and a structure to be formed into the device or circuit.

18. The ion implantation device of claim 17, wherein the stress compensation layer comprises an existing sacrificial pattern layer disposed on the front side.

19. A controller for an ion implantation machine, comprising: processor; And a memory unit coupled to the processor, including a chain implantation mode that operates on the processor to control an ion implanter to impart a composite damage profile to a stress compensation layer on a substrate by performing a first implantation under a first set of implantation conditions; And a second implantation is performed under a second set of implantation conditions different from the first set of implantation conditions, wherein the first implantation will produce a first damage profile within the stress compensation layer, and wherein the second implantation will produce a composite damage profile after the second implantation, the composite damage profile causing a higher stress response ratio than the first damage profile.

20. The controller of claim 19, wherein the chain implantation routine operates on the processor to control the ion implanter to receive a target value of the stress response ratio (SRR) of the stress compensation layer; and calculates the composite damage profile based on the target value of the stress response ratio, the stress response ratio being determined as the stress response (SRR) to a given implantation. I Compared to the maximum theoretical stress response (S) of the stress compensation layer M The ratio of ).

Images