Methods for forming deep trench isolation structures and non-transitory computer readable media for recording related instructions thereon

Abstract

A method for forming a deep trench isolation (DTI) structure having only two interfaces. In some embodiments, a method for forming a deep trench isolation structure may include the following steps: etching a trench having a high aspect ratio in a substrate material; repairing the surfaces of the trench from damage caused by the etching of the trench; growing an epitaxial layer on the surfaces of the trench to form a homogeneous passivation region as part of the substrate material; doping the epitaxial layer with a dopant to form a passivation charge region; performing a charge diffusion process to embed the dopant into the substrate material; forming a positive pad layer on the homogeneous passivation region in the trench; and filling the trench with an optical reflective material.

Description

Technical Field

[0001] Examples of this principle generally relate to semiconductor processing of semiconductor substrates. Prior Technology

[0002] Optoelectronic components are formed on substrates very close to each other. Trenches are typically created between the components to retain incident light waves in each component. Color filters restrict the wavelength of each component. The inventors have discovered that if the wavelengths of adjacent pixels are allowed to enter another pixel with a different color filter, unwanted noise is generated in the adjacent pixels, thus reducing the pixel's signal-to-noise ratio (SNR) and performance. As aspect ratios increase, optically separating pixels becomes more challenging, leading to a corresponding decrease in SNR and poor performance.

[0003] Therefore, the inventors have provided an improved process and structure for deep trench isolation of pixels, which significantly improves pixel performance. Summary of the Invention

[0004] This article provides methods and structures for improved deep trench isolation.

[0005] In some embodiments, a method for forming a deep trench isolation (DTI) structure in a substrate may include the following steps: etching a trench having a high aspect ratio in a substrate material; repairing the surface of the trench from damage caused by the etching; growing an epitaxial layer on the surface of the trench to form a homogeneous passivation region as part of the substrate material; doping the epitaxial layer with an additional dopant to engineer a passivation charge region; performing a charge diffusion process to embed the additional dopant into the substrate material; forming a conformal pad layer or a conformal barrier layer on the homogeneous passivation region in the trench; and filling the trench with an optical reflective material.

[0006] In some embodiments, the method may further include the following steps: wherein the charge diffusion process is a millisecond annealing process or an oxidation process, and the surface of the deep trench is repaired by the following steps: forming a dry oxide on the surface of the trench and selectively removing the dry oxide from the surface of the trench, wherein the additional dopant is boron, wherein the positive pad layer or the positive barrier layer is silicon dioxide, and wherein the homogeneous passivation region is formed by single-crystal epitaxial growth or oxidation of amorphous doped materials in a condensation process. In the process, the epitaxial layer or the amorphous doped material is oxidized with an additional dopant to embed the additional dopant and form the positive pad layer or the positive barrier layer. Before filling the trench with the optical reflective material, a refractive layer is deposited on the positive pad layer or the positive barrier layer. Before filling the trench with the optical reflective material, a portion of the refractive layer is selectively removed from the inside of the trench. After filling the trench with the optical reflective material, a portion of the optical reflective material is removed from a field of the substrate using a patterning process, and / or a color filter layer or an optical barrier layer is formed on the field of the substrate.

[0007] In some embodiments, a non-transitory computer-readable medium has instructions stored thereon that, when executed, cause a method for forming a deep trench isolation (DTI) structure in a substrate to be performed. This method may include the following steps: etching a trench in a substrate material having a high aspect ratio of the DTI structure; repairing the surface of the trench from damage caused by the etching; growing an epitaxial layer on the surface of the trench to form a homogeneous passivation region of the DTI structure as part of the substrate material; doping the epitaxial layer with a dopant to form a passivation charge region of the DTI structure; performing a charge diffusion process to embed the dopant into the substrate material; forming a positive pad layer of the DTI structure on the homogeneous passivation region in the trench; and filling the trench with an optically reflective material.

[0008] In some embodiments, the method on a non-transitory computer-readable medium may further include the following steps: depositing a refractive layer on the conformal liner before filling the trench with the optical reflective material; selectively removing a portion of the refractive layer from the interior of the trench before filling the trench with the optical reflective material; removing a portion of the optical reflective material from a field of the substrate using a patterning process after filling the trench with the optical reflective material; forming a color filter layer or an optical barrier layer on the field of the substrate after performing the patterning process; and / or repairing the surfaces of the trench by the following steps: forming a dry oxide on the surfaces of the trench and selectively removing the dry oxide from the surfaces of the trench; using a millisecond annealing process as the charge diffusion process; wherein the dopant is boron, the conformal liner is silicon dioxide, and the epitaxial layer is formed from a single crystal.

[0009] In some embodiments, a deep trench isolation (DTI) structure formed in a substrate may include: a trench of the DTI structure etched in a first dielectric material on the substrate, wherein the trench has a high aspect ratio; a homogeneous passivation region of the DTI structure, the homogeneous passivation region of the DTI structure being formed as a portion of the first dielectric material on the surface of the trench, wherein the homogeneous passivation region is optically transparent; a pad layer of the DTI structure of a second dielectric material, the pad layer being conformally formed on the homogeneous passivation region; and an optical reflective material of the DTI structure, the optical reflective material of the DTI structure filling the trench, wherein the homogeneous passivation region, the pad layer, and the optical reflective material form the DTI structure, and wherein only two interfaces of different materials are formed in the DTI structure between any adjacent pixel and the optical reflective material, a first interface between the optical reflective material and the pad layer, and a second interface between the pad layer and the homogeneous passivation region formed as a portion of the first dielectric material.

[0010] In some embodiments, the deep trench isolation structure may further include: wherein the optical reflective material is aluminum, wherein the second dielectric material is silicon dioxide, wherein the DTI structure has an abrupt charge passivation region adjacent to the homogeneous passivation region, the abrupt charge passivation region being configured to change an operating function of the DTI structure, wherein the abrupt charge passivation region has a charge formation of approximately 3e18 / cm³ to approximately 3e21 / cm³, wherein the high aspect ratio is at least approximately 75:1, a refractive layer formed on a field of the substrate adjacent to the optical reflective material, and at least one color filter layer formed on the refractive layer adjacent to the optical reflective material.

[0011] Other and further embodiments are disclosed below. Simple Explanation of the Diagram

[0012] Embodiments of this principle have been briefly summarized above and are discussed in more detail below, which can be understood by referring to the exemplary embodiments of this principle illustrated in the accompanying drawings. However, the accompanying drawings only illustrate typical embodiments of this principle, and since this principle allows for other equivalent embodiments, the accompanying drawings should not be considered as a limitation of the scope of this disclosure.

[0013] Figure 1 illustrates a cross-sectional view of an optical pixel in a substrate according to some embodiments of this principle.

[0014] Figure 2 illustrates a method for forming a deep trench isolation structure in a substrate according to some embodiments of this principle.

[0015] Figure 3A illustrates a cross-sectional view of a deep trench isolation structure after an etching process, according to some embodiments of this principle.

[0016] Figure 3B illustrates a cross-sectional view of a deep trench isolation structure following a dry oxidation process according to some embodiments of this principle.

[0017] Figure 3C illustrates a cross-sectional view of a deep trench isolation structure following a selective oxide removal process, according to some embodiments of this principle.

[0018] Figure 3D illustrates a cross-sectional view of a deep trench isolation structure after the formation of a passivation region, according to some embodiments of this principle.

[0019] Figure 3E illustrates a cross-sectional view of a deep trench isolation structure following an optional gas doping process in the passivation region, according to some embodiments of this principle.

[0020] Figure 3F illustrates a cross-sectional view of a deep trench isolation structure after an annealing process for further embedding dopants, according to some embodiments of this principle.

[0021] Figure 3G illustrates a cross-sectional view of a deep trench isolation structure after the formation of a positive liner layer, according to some embodiments of this principle.

[0022] Figure 3H illustrates a cross-sectional view of a deep trench isolation structure following an alternative method of forming a positive liner layer, according to some embodiments of this principle.

[0023] Figure 3I illustrates a cross-sectional view of a deep trench isolation structure after the formation of an optical refractive layer, according to some embodiments of this principle.

[0024] Figure 3J illustrates a cross-sectional view of a deep trench isolation structure after selectively removing a portion of the optical refractive layer, according to some embodiments of this principle.

[0025] Figure 3K illustrates a cross-sectional view of a deep trench isolation structure after being filled with optical reflective material, according to some embodiments of this principle.

[0026] Figure 3L illustrates a cross-sectional view of a deep trench isolation structure after patterning of an optical reflective material, according to some embodiments of this principle.

[0027] Figure 3M illustrates a cross-sectional view of a deep trench isolation structure after a portion of the optical reflective material has been removed from the field of the substrate, according to some embodiments of this principle.

[0028] Figure 3N illustrates a cross-sectional view of a deep trench isolation structure after a color filter layer or optical barrier layer has been formed on a substrate in some embodiments according to this principle.

[0029] Figure 4 illustrates an integrated tool based on some embodiments of this principle.

[0030] Figure 5A illustrates the first process of a second method according to some embodiments of this principle.

[0031] Figure 5B illustrates a second process of a second method according to some embodiments of this principle.

[0032] Figure 6 illustrates a structure formed using techniques from some embodiments based on this principle.

[0033] For ease of understanding, the same numerical designations are used to represent the same elements in the figures where possible. For clarity, the figures are not drawn to scale and may be simplified. Elements and features in one embodiment may be advantageously used in other embodiments without further description. Implementation

[0034] These methods and structures provide a high-performance deep trench isolation solution that significantly improves the signal-to-noise ratio (SNR) of associated pixels. Deep trench isolation (DTI) structures form fewer optical interfaces between the pixel and the reflective material of the DTI structure, increasing the number and intensity of light waves reflected back to adjacent pixels from the DTI structure, thereby increasing the pixel's SNR performance. The reduction in interfaces also means fewer layers, allowing for a higher aspect ratio in the DTI structure while allowing for increased pixel density without sacrificing pixel performance (or in some cases, even improved performance through higher density). The refractive material is used only on the field surface of the substrate in the DTI structure, further reducing the optical interfaces and retaining the refractive material only where needed. The performance of the DTI structure is further improved by creating a transient charge passivation region that allows for a larger usable effective pixel area between DTI structures, for example, enabling high dynamic range (HDR) capabilities for pixels.

[0035] The DTI structure based on this principle utilizes novel materials and film properties to simplify interface and structural complexity. High-performance HAR DTI structures are generated using novel engineering methods for damage repair, damage-free layer formation, working function engineering, and refractive and reflective layers in selective regions. Compared to higher photon losses due to more complex structural designs, the advantages of this approach include higher SNR performance through structural simplification. Higher carrier mobility is achieved by using homogeneous layers with higher charges, compared to the lower charges of heterogeneous films. Homogeneous layers also offer the advantage of no optical loss compared to heterogeneous layers with high optical penalties. Further advantages are gained by selectively forming refractive and reflective layers only in the desired regions. Furthermore, DTI structures are highly advantageous for component scaling due to fewer layers in the structure, minimizing the required space and allowing for increased HAR.

[0036] Optoelectronic components involve photon transmission, reflection, refraction, and absorption elements. Conventional structures cannot comprehensively separate different target layers and require capability trade-offs. This method forms a structure with layers and desired functions only in the desired structural regions to achieve a higher signal-to-noise ratio. Figure 1 illustrates a cross-sectional view 100 of an optical pixel 106 in a substrate 102 according to some embodiments. A DTI structure 104 of this principle has been formed between the optical pixel 106 and the non-pixel area 108. A color filter 110 is formed on the optical pixel 106 to allow only specific light wavelengths to enter the optical pixel 106. An optical barrier layer 112 is formed on the non-pixel area 108 to limit unwanted noise from photons entering the substrate outside the pixel area. Figures 3A-3N illustrate the formation of the DTI structure 104 such as example 114 of Figure 1 and are referenced in conjunction with method 200 of Figure 2. The DTI structure 104 serves two purposes—one is to prevent electrical crosstalk between pixels, and the other is to prevent optical crosstalk between pixels. By using a reflective material in the DTI structure 104, the DTI structure 104 has the possibility of reflecting light back to the pixel, thereby increasing the pixel's performance by improving the pixel's quantum efficiency (QE).

[0037] Figure 2 illustrates a method 200 for forming a deep trench isolation structure 104 in a substrate 102 according to some embodiments. In block 202, an etching process forms a deep trench 105 in the substrate 102, as shown in view 300A of Figure 3A. The etching process typically uses a hard mask layer 302 to protect the area from the effects of the etching process. In some embodiments, the aspect ratio of the deep trench 105 is at least about 50:1. In some embodiments, the aspect ratio of the deep trench 105 is at least about 75:1. In some embodiments, the aspect ratio of the deep trench 105 is at least about 100:1. As a side effect of the etching process, damage 304 occurs on the surface 305 of the deep trench 105. Damage 304 may include crystal damage to the substrate material, contaminants or residues from the etching process, and / or dangling bonds or the like in the substrate material. After the etching process is completed, the hard mask layer 302 is removed.

[0038] In box 204, damage 304 to the surface 305 of the deep trench 105 is repaired. As shown in view 300B of FIG3B, the top surface of the field 103 or substrate 102 and the surface 305 of the deep trench 105 undergo a dry oxidation process to form an oxide layer 107, which partially consumes material of the substrate 102 (including the damaged portion). The dry oxidation process can be performed at temperatures below 450 degrees Celsius and produces fewer contaminants and residues compared to wet oxidation processes. Furthermore, the dry oxidation process can be used for structures with significantly higher aspect ratios (e.g., aspect ratios greater than 100:1) than wet oxidation (e.g., aspect ratios less than 50:1). In some embodiments, the dry oxidation process is performed using a plasma oxidation chamber with or without a remote plasma source. Dry oxidation processes help embed oxygen into the surface 305 of the deep trench 105 to repair damage to the surface 305 and reduce stress-induced leakage current (SILC) and interface trap density (Dit).

[0039] The dry oxidation process can also be controlled to provide oxide layers 107 of varying thicknesses 306. Parameters such as exposure time, plasma density, temperature, and similar parameters can help determine the oxidation rate. The thickness is then controlled by the duration of the oxidation process. In conventional methods such as wet oxidation, the oxidation process is self-limiting and the oxide thickness cannot be adjusted. Wet oxidation typically stops at a thickness of 1 nm to 2 nm at a saturation point. Dry oxidation has no saturation point and is not self-limiting, allowing for any degree of thickness to be obtained. In some embodiments, for trenches with an aspect ratio greater than 100:1, the dry oxidation process can achieve greater than 95% conformability in the deep trench 105, thereby enabling scaling of the deep trench isolation structure using this principle. As shown in view 300C of FIG3C, the oxide layer 107 is then selectively removed from the substrate 102 and the deep trench 105. In some embodiments, a plasma-based chamber can be used to selectively remove the oxide layer 107 with a selectivity ratio such as greater than 50:1 (e.g., oxide material to Si / SiGe material). Selective removal of oxides removes all oxides without damaging any underlying material of the substrate or generating contaminants / residues, leaving an undamaged surface of the deep trench 105.

[0040] In frame 206, a passivation region 308 is formed on the surface 305 of the deep trench 105 and the field 103 of the substrate 102, as shown in view 300D of FIG. 3D. In some embodiments, the passivation region 308 is formed of a homogeneous material similar to the material of the substrate 102. The passivation region 308 is formed from a single crystal of a material doped with dopant 312 (shown as a P-type material but not intended to limit) to form positive or negative charges (e.g., boron-doped silicon, gallium, phosphorus, arsenic, etc.) on the substrate 102 and can be manufactured by two methods. The first method is to use a low-temperature epitaxial growth process below about 450 degrees Celsius. The second method involves a two-part process. The first part involves forming an amorphous doped material layer 502 on the field 103 (as shown in view 500A of FIG. 5A). The second part includes material engineering processes (such as oxidation or heat treatment 504) to drive the dopant to diffuse from the amorphous doped material layer 502 into the surface of the substrate 102 (as shown in view 500B of FIG. 5B). The amorphous doped material layer 502 becomes an oxide layer 502A. The passivation region 308 is formed as a single-crystal material beneath the field 103.

[0041] In essence, regardless of the method used, the single-crystal homogeneous layer becomes part of the substrate material and does not form an interface between the passivation region 308 and the substrate 102, thus eliminating the interfaces commonly found in conventional processes. When photons pass through the passivation region 308, there is no optical loss because the photons pass through the material of the substrate 102 without any degradation or change (refraction) in the optical path. The formation of the passivation region also serves to repair dangling bonds on the surface 305 of the deep trench 105 caused during the etching process. In some embodiments, the passivation region 308 may also be formed from a heteromaterial doped with materials such as Ge or carbon (for creating energy bands, photosensitivity, etc.), and formed with a gradient transition from the material of the substrate 102 to the passivation region 308 without any interface forming therebetween.

[0042] Optionally, in some embodiments, the passivation region 308 may be formed without dopant and then introduced via gas 310, as shown in view 300E of FIG3E. In a further alternative embodiment, the passivation region 308 may be formed with dopant and then reinforced with additional dopant by exposure to gas. The substrate 102 is exposed to gas 310, which includes dopant 312B embedded in the passivation region 308 on the surface 305 of the field 103 and deep trench 105 of the substrate 102. For simplicity and not intended to be limiting, the dopant 312B in FIG3E (as shown) has a positive charge. The dopant 312B may also have a negative charge (not shown). Gas 310 may also contain substances such as Ge, carbon, for materials engineering purposes in terms of composition, energy bands, photosensitivity, etc. The density and / or type of dopant 312B can be adjusted to provide a given positive or negative charge level required for the DTI structure 104.

[0043] In block 208, the operating function of the passivation region 308 can be changed, as shown in view 300F of FIG3F. The dopant 312 is further embedded into the material of the substrate 102 via a dopant diffusion process 314. In some embodiments, the dopant diffusion process 314 may be a millisecond annealing process, which uses a high-power and high-temperature laser (e.g., 700°C to 900°C) pulsed in the millisecond range to anneal the substrate 102 without heating it to a high temperature. In some embodiments, the dopant diffusion process 314 may be an oxidation process, in which the dopant or component diffuses from the passivation region 308 into the substrate 102 once the material composition of the passivation region 308 changes to an oxide. This process is the same as and can be combined with the second method mentioned in block 206 for forming the passivation region 308. The dopant diffusion process 314 creates abrupt charge boundaries in the material of the substrate 102, which, in contrast to conventional techniques for forming large gradient charge regions, increases the effective pixel area of ​​adjacent optical pixels. In some embodiments, the abrupt charge boundary or abrupt charge passivation region has a charge formation of approximately 3e18 / cm³ to approximately 3e21 / cm³. The increased effective pixel area can provide enhanced pixel performance enabling HDR, etc.

[0044] In frame 210, a barrier layer or pad layer 316 is formed on the passivation region 308, as shown in view 300G of FIG3G. The pad layer 316 may be an oxide layer or compound having a metal diffusion barrier function deposited on the passivation region 308. In some embodiments, the pad layer 316 is silicon dioxide. The pad layer 316 prevents the reflective material subsequently used to fill the deep trench 105 from migrating into the substrate 102. In some embodiments, the pad layer 316 may be deposited by atomic layer deposition (ALD) and similar processes. The pad layer 316 may also be used as an etch stop layer. In an alternative embodiment, after dopant implantation by a condensation process, the epitaxial growth material of the passivation region 308 may be oxidized to drive the dopant further into the material of the substrate 102 and form an oxide layer 318, as shown in view 300H of FIG3H. In practice, without an annealing process such as the millisecond annealing process described above, the passivation region 308 produces a pad layer 318 and an embedded charge region. Furthermore, the epitaxial growth in alternative embodiments can be polycrystalline rather than monocrystalline.

[0045] In block 212, a refractive layer 320 is deposited on substrate 102, as shown in view 300I of FIG3I. In some embodiments, the deposition process of the refractive layer 320 is anisotropic and produces a thicker layer on field 103 of substrate 102 than on surface 305 of deep trench 105. In block 214, the refractive layer 320 is selectively removed from the interior of deep trench 105, as shown in view 300J of FIG3J. During the selective removal process, the thickness of the material of the refractive layer 320 on field 103 of substrate 102 can be reduced. The refractive layer 320 within deep trench 105 is completely removed, exposing the pad layer 316 inside deep trench 105. In some embodiments, an optional photolithographic mask 322 can be used to mask the refractive layer 320 prior to the selective removal process, thereby maintaining the deposition thickness of the refractive layer 320 on field 103 of substrate 102. In some embodiments, a reflective material filling process may be performed prior to the deposition process of the refractive material, such that the refractive material is deposited on the reflective material, thereby eliminating the selective removal of the refractive material from the interior of the deep trench 105. The deposition of the reflective material is discussed below.

[0046] In block 216, reflective material 324 is deposited in the deep trench 105 and on the substrate 102, filling the deep trench 105 and forming a layer on the field 103 of the substrate 102, as shown in view 300K of FIG3K. In some embodiments, reflective material 324 may be, for example, aluminum or any reflective material and the like. In some embodiments, chemical vapor deposition (CVD) processes and similar processes may be used to deposit reflective material 324. In block 218, a pattern 330 is formed on the reflective material 324 on the substrate 102, as shown in view 300L of FIG3L. The reflective material 324 is then etched to remove the reflective material 324 on the field 103 of the substrate 102, exposing the refractive layer 320, as shown in view 300M of FIG3M. The pattern 330 is then removed after the etching process is completed. In block 220, a color filter layer 326 and / or an optical barrier layer 328 are formed on the refractive layer 320 on the substrate, as shown in view 300N of FIG3N. The color filter layer 326 filters the wavelength of light based on the intended purpose of the optical pixels 106 below. The optical barrier layer 328 prevents light from penetrating into the non-pixel area 108 to reduce / eliminate unwanted photons entering adjacent pixel structures and similar structures.

[0047] View 600 of Figure 6 illustrates a structure 602 formed using techniques according to some embodiments of this principle. This method allows structure 602 to form a reflective material 324 located at the center of a deep trench 105 in a substrate 102 and a padding layer 316 surrounding the reflective material 324 in the deep trench 105. The reflective material 324 is exposed at an upper end 604, which is also side-mounted by a refractive layer 320 below a color filter layer 326. Structure 602 enhances the performance of adjacent pixel structures because only reflective material is used inside the deep trench 105 to reflect light back to the pixel structures from the inside, and refractive material is found only at the top of structure 602 to guide (refract) light into adjacent pixel structures. Conventional DTI structures include reflective and refractive materials inside and / or around the trench, which reduces the performance of the DTI structure and subsequently reduces the performance of pixel structures adjacent to the DTI structure.

[0048] The method described herein can be implemented in individual processing chambers, which can be provided either independently or as part of a cluster tool (such as the integrated tool 400 described below with respect to FIG. 4, i.e., the cluster tool). An advantage of using the integrated tool 400 is the absence of vacuum disruption, thus eliminating the need for substrate degassing and pre-cleaning prior to treatment within the chamber. For example, in some embodiments, the inventive method discussed above can be advantageously implemented in the integrated tool, resulting in limited or no vacuum interruptions between processes, thereby limiting or preventing substrate contamination. The integrated tool 400 includes a vacuum-sealed processing platform 401, a factory interface 404, and a system controller 402. The processing platform 401 includes multiple processing chambers (such as 414A, 414B, 414C, 414D, 414E, and 414F) operatively coupled to vacuum substrate transfer chambers (transfer chambers 403A, 403B). The plant interface 404 is operatively coupled to the transfer chamber 403A via one or more loading gate chambers (two loading gate chambers, 406A and 406B as shown in FIG4).

[0049] In some embodiments, the fab interface 404 includes at least one docking station 407 and at least one fab interface robot 438 to facilitate the transfer of semiconductor substrates. The docking station 407 is configured to receive one or more front-opening wafer transfer cassettes (FOUPs). In the embodiment of FIG. 4, four FOUPs are shown, such as 405A, 405B, 405C, and 405D. The fab interface robot 438 is configured to transfer substrates from the fab interface 404 through loading gate chambers (such as 406A and 406B) to the processing platform 401. Each of the loading gate chambers 406A and 406B has a first port coupled to the fab interface 404 and a second port coupled to the transfer chamber 403A. Loading gate chambers 406A and 406B are coupled to a pressure control system (not shown), which evacuates and vents the loading gate chambers 406A and 406B to facilitate the transfer of substrates between the vacuum environment of transfer chamber 403A and the physical surrounding environment (e.g., atmosphere) of the plant interface 404. Transfer chambers 403A and 403B have vacuum robots 442A and 442B disposed in the respective transfer chambers 403A and 403B. Vacuum robot 442A is capable of transferring substrate 421 between loading gate chambers 406A and 406B, processing chambers 414A and 414F, and cooling station 440 or pre-cleaning station 442. Vacuum robot 442B is capable of transferring substrate 421 between cooling station 440 or pre-cleaning station 442 and processing chambers 414B, 414C, 414D, and 414E.

[0050] In some embodiments, processing chambers 414A, 414B, 414C, 414D, 414E, and 414F are coupled to transfer chambers 403A and 403B. Processing chambers 414A, 414B, 414C, 414D, 414E, and 414F may include, for example, atomic layer deposition (ALD) processing chambers, physical vapor deposition (PVD) processing chambers, chemical vapor deposition (CVD) chambers, annealing chambers, or similar chambers. As described above, these chambers may include any chamber suitable for performing all or part of the methods described herein, such as dry oxide removal chambers or pre-cleaning chambers and epitaxial growth chambers, as well as etching and deposition chambers. In some embodiments, one or more optional service chambers (represented as 416A and 416B) may be coupled to transfer chamber 403A. Service chambers 416A and 416B can be configured to perform other substrate processes, such as degassing, orientation, substrate metering, cooling and similar processes.

[0051] System controller 402 controls the operation of tool 400 by directly controlling processing chambers 414A, 414B, 414C, 414D, 414E, and 414F, or by controlling a computer (or controller) associated with processing chambers 414A, 414B, 414C, 414D, 414E, and 414F and tool 400. During operation, system controller 402 can collect data and feedback from the various chambers and systems to optimize the performance of tool 400. System controller 402 typically includes a central processing unit (CPU) 430, memory 434, and support circuitry 432. CPU 430 can be any type of general-purpose computer processor that can be used in an industrial environment. Support circuitry 432 is typically coupled to CPU 430 and may include cache, clock circuitry, input / output subsystems, power supply, and the like. The software program (as described above) can be stored in memory 434, and when the CPU 430 executes the software program, the software program converts the CPU 430 into a dedicated computer (system controller) 402. The software program can also be stored and / or executed by a second controller (not shown) located remotely at the end of tool 400.

[0052] Embodiments based on this principle can be implemented in hardware, firmware, software, or any combination thereof. Embodiments can also be implemented using instructions stored on one or more computer-readable media, which can be read and executed by one or more processors. The computer-readable media may include any mechanism for storing or transmitting information in a form readable by a machine, such as a computing platform or a "virtual machine" running on one or more computing platforms. For example, the computer-readable media may include any suitable form of volatile or non-volatile memory. In some embodiments, the computer-readable media may include non-transitory computer-readable media.

[0053] Although the foregoing descriptions are embodiments of this principle, other and further embodiments disclosed herein may be designed without departing from the basic scope of this principle.

[0054] 100: Cross-sectional view 102:Substrate 103: Field 104: DTI Structure 105: Deep trench 106: Optical pixels 107: Oxide layer 108: Non-pixel area 110: Color Filter 112: Optical barrier layer 114: Example 200: Method 202: Box 204: Box 206: Box 208: Box 210: Box 212: Box 214: Box 216: Box 218: Box 220: Box 300A-N: View 302: Masking layer 304: Damage 305: Surface 306: Thickness 308: Passivation region 310: Gas 312: Dopant 312B: Dopant 314: Dopant Diffusion Process 316: Lining layer 320: Refractive layer 322: Photolithography mask 324: Reflective materials 326: Color Filter Layer 328: Optical barrier layer 330: Patterning 400: Integrated Tools 401: Processing Platform 402: System Controller 403A-B: Transfer Chamber 404: Factory Interface 405A-D:FOUP 406A-B: Loading gate chamber 414A-F: Processing Chamber 416A-B: Service Chamber 421:Substrate 440: Cooling Station 442: Pre-cleaning station 442A-B: Vacuum Robot 430: CPU 432: Support Circuit 434: Memory 438: Factory Interface Robot 500A-B: View 502: Amorphous doped material layer 502A: Oxide layer 504: Handling 600: View 602: Structure 604: Top

[0055] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A method for forming a deep trench isolation (DTI) structure in a substrate, comprising the following steps: etching a trench having a high aspect ratio in a substrate material; repairing the surface of the trench from damage caused by etching of the trench; growing an epitaxial layer on the surface of the trench to form a homogeneous passivation region as part of the substrate material; doping the epitaxial layer with an additional dopant to engineer a passivation charge region; performing a charge diffusion process to embed the additional dopant into the substrate material to form a sudden charge passivation region in the substrate material; directly forming a conformal pad layer or a conformal barrier layer on the homogeneous passivation region in the trench; and filling the trench with an optical reflective material after performing the charge diffusion process.

2. The method as described in claim 1, wherein the charge diffusion process is a millisecond annealing process.

3. The method as described in claim 1 further includes the following steps: repairing the surface of the trench by the following steps: forming a dry oxide on the surface of the trench at a temperature below 450 degrees Celsius; and selectively removing the dry oxide from the surface of the trench.

4. The method as described in claim 1, wherein the additional dopant is boron.

5. The method as described in claim 1, wherein the conformal liner layer or the conformal barrier layer is silicon dioxide.

6. The method as described in claim 1, wherein the homogeneous passivation region is formed by single-crystal epitaxial growth or by oxidizing an amorphous doped material.

7. The method as described in claim 6 further includes the step of: oxidizing the epitaxial layer or the amorphous doped material containing additional dopant in a condensation process to embed the additional dopant and form the positive pad layer or the positive barrier layer.

8. The method as claimed in claim 1 further includes the steps of: depositing a refractive layer on the conformal pad layer or the conformal barrier layer before filling the trench with the optical reflective material; and selectively removing a portion of the refractive layer from the interior of the trench before filling the trench with the optical reflective material.

9. The method as described in claim 8 further includes the following steps: after filling the trench with the optical reflective material, removing a portion of the optical reflective material from a field of the substrate using a patterning process.

10. The method as described in claim 9 further includes the step of: forming a color filter layer or an optical barrier layer on the field of the substrate.

11. A non-transitory computer-readable medium having instructions stored thereon, which, when executed, cause a method for forming a deep trench isolation (DTI) structure in a substrate to be performed, the method comprising the steps of: etching a trench in a substrate material having a high aspect ratio of the DTI structure; repairing the surface of the trench from damage caused by etching of the trench; growing an epitaxial layer on the surface of the trench to form a homogeneous passivation region of the DTI structure as part of the substrate material; doping the epitaxial layer with a dopant to form a passivation charge region of the DTI structure; performing a charge diffusion process to embed the dopant into the substrate material to form a sudden charge passivation region in the substrate material; directly forming a positive pad layer of the DTI structure on the homogeneous passivation region in the trench; and after performing the charge diffusion process, filling the trench with an optically reflective material.

12. The non-transitory computer-readable medium as claimed in claim 11, wherein the method further comprises the following steps: depositing a refractive layer on the conformal pad layer before filling the trench with the optical reflective material; selectively removing a portion of the refractive layer from the interior of the trench before filling the trench with the optical reflective material; removing a portion of the optical reflective material from a field of the substrate using a patterning process after filling the trench with the optical reflective material; and forming a color filter layer or an optical barrier layer on the field of the substrate after performing the patterning process.

13. The non-transitory computer-readable medium as described in claim 11, wherein the method further comprises the following steps: repairing the surfaces of the trench by the following steps: forming a dry oxide on the surfaces of the trench at a temperature below 450 degrees Celsius; selectively removing the dry oxide from the surfaces of the trench; and using a millisecond annealing process as the charge diffusion process, wherein the dopant is boron, the positive pad layer is silicon dioxide, and the epitaxial layer is formed from a single crystal.

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