WO2022160627A1 - 半导体结构的形成方法 - Google Patents

半导体结构的形成方法 Download PDF

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Publication number
WO2022160627A1
WO2022160627A1 PCT/CN2021/108401 CN2021108401W WO2022160627A1 WO 2022160627 A1 WO2022160627 A1 WO 2022160627A1 CN 2021108401 W CN2021108401 W CN 2021108401W WO 2022160627 A1 WO2022160627 A1 WO 2022160627A1
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Prior art keywords
region
mask layer
layer
protective layer
forming
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PCT/CN2021/108401
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English (en)
French (fr)
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夏军
占康澍
李森
徐朋辉
宛强
刘涛
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长鑫存储技术有限公司
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Priority to US17/504,636 priority Critical patent/US20220246437A1/en
Publication of WO2022160627A1 publication Critical patent/WO2022160627A1/zh

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    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10BELECTRONIC MEMORY DEVICES
    • H10B12/00Dynamic random access memory [DRAM] devices
    • H10B12/01Manufacture or treatment
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10BELECTRONIC MEMORY DEVICES
    • H10B12/00Dynamic random access memory [DRAM] devices

Definitions

  • the embodiments of the present application relate to the field of semiconductors, and in particular, to a method for forming a semiconductor structure.
  • DRAM Dynamic Random Access Memory
  • DRAM is a semiconductor memory device commonly used in computers, consisting of many repeated memory cells. With the continuous evolution of the DRAM process technology, the integration level continues to increase, and the component size continues to shrink.
  • DRAM adopts a stacked capacitor structure, and its capacitor (Capacitor) is a vertical cylindrical shape with a high aspect ratio.
  • the increased surface area includes a lower electrode layer connected to the substrate, a capacitive dielectric layer deposited on the lower electrode layer, and an upper electrode layer deposited on the capacitive dielectric layer.
  • the insulating layer is directly etched in the first area by using a patterned mask layer to form trenches for depositing the lower electrode layer, the dielectric layer and the upper electrode layer, and then the upper surface of the insulating layer in the second area is removed.
  • the mask layer and the mask layer on the upper surface of the remaining insulating layer in the first region because when the trench is formed in the first region, the mask layer with a partial thickness of the first region will be etched, so that after the trench is formed, the first region
  • the thickness of the mask layer is smaller than that of the second area.
  • Embodiments of the present application provide a method for forming a semiconductor structure, which solves the problems of damage to the insulating layer in the first region and residues of the mask layer in the second region during the formation of the semiconductor structure.
  • An embodiment of the present application provides a method for forming a semiconductor structure.
  • the semiconductor structure includes a first region and a second region, including: providing a substrate, an insulating layer, and a mask layer that are stacked in sequence, and the first region has a through-hole at least one trench of the mask layer and the insulating layer, the upper surface of the mask layer in the second region is higher than the upper surface of the mask layer in the first region; forming a first protection layer, the first protective layer covers the upper surface and sidewalls of the mask layer in the first region; after the first protective layer is formed, the mask layer in the second region is removed; After removing the mask layer in the second area, removing the first protective layer; removing the mask layer in the first area.
  • a first protective layer covering the sidewall and upper surface of the mask layer in the first region is formed, the mask layer in the first region and the mask layer in the second region are removed separately, The mask layer in the second area is removed. Since the upper surface and sidewalls of the mask layer in the first area have a first protective layer, the mask layer in the first area will not be removed during the process of removing the mask layer in the second area. Then remove the first protective layer, and then remove the mask layer in the first area; because the mask layers in the first area and the second area are removed separately, it is eliminated when removing the mask layers in different areas at the same time. The influence of the uneven thickness of the mask layer in the region on the process of removing the mask layer.
  • the upper surface and sidewalls of the mask layer in the first region have a first protective layer
  • the first protective layer will not be affected.
  • the mask layer in the region has an influence, the mask layer can be completely removed, no mask layer residue is left, and the insulating layer in the first region is not etched, and the formed semiconductor structure has high flatness.
  • FIG. 1 and FIG. 2 are schematic structural diagrams of each step of a method for forming a semiconductor structure
  • 3 to 12 are schematic structural diagrams of each step of a method for forming a semiconductor structure according to the first embodiment of the present application;
  • 13 to 15 are schematic structural diagrams of each step of a method for forming a semiconductor structure according to the second embodiment of the present application.
  • FIG. 1 and FIG. 2 are schematic structural diagrams of various steps of a method for forming a semiconductor structure.
  • the semiconductor structure has a first region A and a second region B, including: a substrate 100 , an insulating layer 101 and a mask layer 103 which are stacked in sequence. Since at least one trench 102 penetrating the mask layer 103 and the insulating layer 101 is formed in the first region A, the mask layer 103 with a partial thickness of the first region A will be etched, so after the trench 102 is formed, the second region B The upper surface of the mask layer 103 is higher than the upper surface of the mask layer 103 of the first region A; with reference to FIG.
  • the mask layers 103 of the first region A and the second region B are simultaneously removed, and the Under the same removal process conditions, the thickness of the mask layer 103 in the first region A and the second region B removed is the same; because before the removal process, the thickness of the mask layer 103 in the second region B is larger than that in the first region A. 103 thickness, so when the mask layer 103 in the first area A is removed, there will still be some residues 104 left in the second area B. Continuing to remove the remaining residues 104 will cause part of the insulating layer 101 in the first area A to be removed. etching.
  • an embodiment of the present application provides a method for forming a semiconductor structure. Before removing the mask layer, a first protective layer covering the sidewall and upper surface of the mask layer in the first region is formed. layer and the mask layer in the second area are removed separately, first remove the mask layer in the second area. The layering process does not affect the mask layer in the first region, thereby improving the flatness of the semiconductor structure.
  • FIG. 3 to 12 are schematic structural diagrams of each step of a method for forming a semiconductor structure according to the first embodiment of the present application, wherein FIG. 3 is a detailed structural schematic diagram of a semiconductor structure substrate.
  • the semiconductor structure includes a first region A and a second region B, including: providing a substrate 200 , an insulating layer 201 and a mask layer 203 stacked in sequence, and the first region A has a through-hole In the mask layer 203 and at least one trench 202 of the insulating layer 201 , the upper surface of the mask layer 203 in the second region B is higher than the upper surface of the mask layer 203 in the first region A.
  • the semiconductor structure includes an array area and a peripheral area around the array area.
  • the array area includes a unit area and a non-unit circuit area.
  • the first area A is the unit area
  • the second area B is the non-unit circuit area.
  • the substrate 200 includes a conductive layer 210 and an isolation layer 220 .
  • the isolation layer 220 is located at the bottom of the insulating layer 201 in the first area A and is in contact with the insulating layer 201 in the first area A.
  • the material of the conductive layer 210 includes conductive materials such as tungsten metal, silver metal or gold metal, and the conductive layer 210 can be used as a storage node contact structure.
  • the material of the isolation layer 220 includes insulating materials such as silicon nitride or silicon oxide.
  • the material of the insulating layer 201 includes insulating materials such as silicon nitride or silicon oxide, and is used as a support layer.
  • the support layer is used to support the lower electrode layer of the capacitor, and the formed lower electrode layer is located on the sidewall of the support layer.
  • the mask layer 203 and part of the insulating layer 201 in the first region A are etched, and at least one trench 202 is formed in the first region A through the mask layer 203 and the insulating layer 201 .
  • the upper surface of the mask layer 203 in the first region A is flush with the upper surface of the mask layer 203 in the second region B; in order to form the trench 202 in the first region A for subsequent formation
  • the electrode layer, the dielectric layer and the upper electrode layer need to form the trench 202 in the first area A; since the width of the mask layer 203 in the first area A is smaller than the width of the mask layer 203 in the second area B, the width of the mask layer 203 in the first area A is The pattern density is greater than that of the second area B, so when the trench 202 is formed in the first area A, due to the etching load effect, the thickness of the mask layer 203 in the first area A etched by the etching gas is greater than that in the second area A.
  • the thickness of the mask layer 203 in the area B is smaller than that in the second area B, so the thickness of the mask layer 203 in the second area B is The surface is higher than the upper surface of the mask layer 203 of the first region A.
  • the material of the mask layer 203 includes polysilicon, and the mask layer 203 is used to protect the insulating layer when the trench 202 is formed.
  • a first protective layer 204 is formed, and the first protective layer 204 covers the upper surface and sidewalls of the mask layer 203 in the first region A. As shown in FIG.
  • a first protective layer 204 is formed on the upper surface and sidewalls of the mask layer 203 in the first region A, and then the mask layers 203 in the first region A and the second region B are removed step by step. Due to the presence of the first protective layer 204, When the mask layer 203 in the second region B is removed, the mask layer 203 in the first region A is protected from being affected, and then the mask layer 203 in the first region A is removed, ensuring that after the mask layer 203 is removed , there will be no mask layer residue left in the second region B, and no influence on the topography of the insulating layer 201 in the first region A, which improves the smoothness of the topography of the semiconductor structure.
  • the first protective layer 204 not only covers the upper surface and sidewalls of the mask layer 203 in the first region A, but also the first protective layer 204 formed fills the trench 202 , and the first protective layer 204 covers the first The upper surface of the mask layer 203 in the region A.
  • the steps of forming the first protective layer 204 in this embodiment are as follows: firstly, an initial protective layer 205 is formed, the formed initial protective layer 205 fills the trench 202 , and the initial protective layer 205 covers the upper surface of the mask layer 203 in the second region B; After the initial protective layer 205 is formed, the initial protective layer 205 on the upper surface of the mask layer 203 in the second region B is removed to expose the mask layer 203 in the second region B, and the remaining initial protective layer 205 forms the first protective layer 204 .
  • the chemical vapor deposition process can be used to form the initial protective layer 205 .
  • the chemical vapor deposition process has a fast deposition rate, saves production time, and is beneficial to improve the production efficiency of the semiconductor structure.
  • the formed first protective layer 204 fills the trench 202, and the mask layer 203 of the first region A is subsequently removed.
  • the first protective layer 204 filling the trenches 202 can protect the substrate 200 at the bottom of the trenches 202 from contact with residues generated by removing the mask layer 203, thereby improving the performance of the semiconductor structure.
  • the material of the first protective layer 204 includes photoresist, and the photoresist as a protective layer has good fluidity and filling properties. 204 , the upper surface and sidewalls of the mask layer 203 in the first region A can be covered relatively uniformly and without gaps.
  • the thickness of the first protective layer 204 formed on the upper surface of the mask layer 203 of the first region A is 100 nanometers to 200 nanometers, specifically 130 nanometers, 160 nanometers or 190 nanometers.
  • the thickness of the first protective layer 204 on the upper surface of the mask layer 203 in the first region A is too thin.
  • the mask layer 203 in the second region B is removed by etching, it is easy to make the first protective layer 204 in the first region A also is removed, and then affects the mask layer 203 in the first region A, which in turn affects the subsequent removal of the mask layer 203 in the first region A, which affects the performance of the semiconductor structure; the upper surface of the mask layer 203 in the first region A is The thickness of the first protective layer 204 is too thick. After removing the mask layer 203 in the second area B, there is still a thick first protective layer 204 in the first area A. The subsequent removal will take a long time. It is beneficial to improve the efficiency of semiconductor process.
  • the first protective layer 204 may only cover the upper surface and sidewalls of the mask layer 203 of the first region A. Referring to FIG. Using the atomic layer deposition process to form the first protective layer 204 can form a dense and thinner first protective layer 204, while protecting the mask layer 203 in the first region A, saving materials and reducing the removal of the mask layer 203 cost.
  • the material of the first protective layer 204 formed by the atomic layer deposition process includes: silicon oxide.
  • the first protective layer in addition to covering the upper surface and sidewalls of the mask layer in the first region, also covers the bottom and sidewalls of the trenches.
  • An atomic layer deposition process is used to form a first protective layer covering the bottom and sidewalls of the trench.
  • the first protective layer located at the bottom and sidewalls of the trench can protect the substrate at the bottom of the trench. , it will not come into contact with the residue generated by removing the mask layer, and the performance of the semiconductor structure is improved.
  • the first protective layer 204 not only covers the sidewalls and upper surfaces of the mask layer 203 and the bottom and sidewalls of the trenches 202 in the first region A, but also covers the second The upper surface and sidewalls of the mask layer 203 in the region B.
  • the first protective layer 204 covers not only the first region A but also the second region B, when forming the first protective layer 204, there is no need to distinguish regions, which is beneficial to the overall formation.
  • first protective layer 204 covering the upper surface and sidewalls of the mask layer 203 in the second region B needs to be removed before the mask layer 203 in the second region B is removed. 203 the first protective layer 204 on the upper surface.
  • the mask layer 203 in the second region B is removed.
  • the mask layer 203 in the first region A will not be affected when the mask layer 203 in the second region B is removed, and the mask layer 203 can be completely removed without leaving the mask layer residues, and the insulating layer 201 of the first region A will not be etched, and the formed semiconductor structure has high flatness.
  • the first protective layer 204 is removed; the mask layer 203 in the first region A is removed.
  • the process steps of removing the first protective layer 204 and the mask layer 203 in the first region A include: referring to FIG. 10 , removing part of the first protective layer 204 to expose the mask layer 203 in the first region A; refer to FIG. FIG. 11 , after the mask layer 203 of the first area A is exposed, the mask layer 203 of the first area A is removed; referring to FIG. 12 , after the mask layer 203 of the first area A is removed, the remaining first protective layer is removed 204.
  • the first protective layer 204 is removed step by step.
  • the trench 202 is filled with the first protective layer 204, and the mask produced by the mask layer 203 in the first region A is removed.
  • the layer residues do not fall into the trenches 202 and do not contact the substrate 200 at the bottom of the trenches 202, improving the performance of the semiconductor structure.
  • the process steps of removing the first protective layer and the mask layer in the first region include: removing all the first protective layer to expose the mask layer in the first region; after exposing the mask layer in the first region A , to remove the mask layer in the first region. Before removing the mask layer in the first area, completely remove the first protective layer, which is easier to achieve in terms of process. A dry etching process can be used to completely remove the mask layer without affecting the first area. first protective layer.
  • the first protective layer 204 is removed by using oxygen-containing plasma. Because the material of the first protective layer 204 is photoresist, the oxygen-containing plasma can rapidly react with the photoresist. Therefore, the method for removing the first protective layer 204 includes: providing the first protective layer 204 with oxygen-containing plasma , the oxygen-containing plasma reacts with the first protective layer 204 to generate carbon dioxide, carbon monoxide and water. The reaction between the oxygen-containing plasma and the first protective layer 204 is rapid, the first protective layer 204 can be quickly removed, and the efficiency of removing the photoresist is improved.
  • oxygen is used to form oxygen-containing plasma
  • the gas flow rate of the oxygen used is 1000 standard milliliters per minute to 15000 standard milliliters per minute, specifically 5000 standard milliliters per minute, 10000 standard milliliters per minute or 12000 standard milliliters per minute ml per minute.
  • a carrier gas also needs to be introduced into the reaction chamber, and the carrier gas includes argon gas or nitrogen gas.
  • the mask layer 203 is removed by using a hydrogen-containing plasma. Because the material of the mask layer 203 is polysilicon, which is easy to react with the plasma containing hydrogen, the mask layer 203 can be quickly removed.
  • the process of removing the mask layer 203 and the process of removing the first protective layer 204 are performed in the same reaction chamber. In this way, the entire process of removing the first protective layer 204 and the mask layer 203 is performed in the same reaction chamber, which avoids the risk of the photoresist being polluted by the external environment when changing chambers in different steps, and at the same time simplifies the process environment, so that the entire process is The removal process is easier to implement.
  • removing the first protective layer and removing the masking layer may be performed in different reaction chambers.
  • a first protective layer 204 covering the sidewall and upper surface of the mask layer 203 in the first region A, the mask layer 203 in the first region A and the mask layer 203 in the second region B are formed.
  • the mask layer 203 is removed separately, and the mask layer 203 in the second region B is removed first. Since the upper surface and sidewalls of the mask layer 203 in the first region A have the first protective layer 204, the mask layer 203 in the second region B is removed before removing the mask layer 203.
  • the process of film layer 203 will not affect the mask layer 203 of the first area A, then remove the first protective layer 204, and then remove the mask layer 203 of the first area A; because the first area A and the first area A are removed separately.
  • the mask layers 203 in the two regions B therefore, when removing the mask layers 203 in different regions at the same time, the influence on the process of removing the mask layers 203 due to the inconsistent thickness of the mask layers 203 in different regions is eliminated.
  • the second embodiment of the present application provides a method for forming a semiconductor structure, which is substantially the same as the first embodiment of the present application, with the main difference being that before removing the mask layer in the first region, a first Two protective layers, the following will describe the formation method of the semiconductor structure provided by the second embodiment of the present application in detail with reference to the accompanying drawings. For the same or corresponding parts as the previous embodiment, reference may be made to the description of the previous embodiment, which will not be repeated below. .
  • 13 to 15 are schematic structural diagrams of each step of a method for forming a semiconductor structure according to the second embodiment of the present application.
  • the semiconductor structure includes a first region A and a second region B, and further includes a substrate 300 , an insulating layer 301 and a mask layer 303 stacked in sequence, and the mask layer in the first region A is exposed.
  • the method further includes: forming a second protective layer 306 covering the upper surface of the insulating layer 301 of the second area B; referring to FIG. 14, removing the mask layer of the first area A 303 ; Referring to FIG. 15 , after removing the mask layer 303 of the first region A, the second protective layer 306 is removed.
  • the material of the first protective layer 304 and the material of the second protective layer 306 are the same, and may specifically be polysilicon.
  • a second protective layer 306 is formed on the upper surface of the insulating layer 301 in the second region B, which ensures that when the mask layer 303 in the first region A is removed , the insulating layer 301 of the second region B will not be affected, and the performance of the semiconductor structure is improved.

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Abstract

本申请实施例提供一种半导体结构的形成方法,所述半导体结构包括第一区域以及第二区域,包括:提供依次堆叠设置的基底、绝缘层以及掩膜层,所述第一区域具有贯穿所述掩膜层以及所述绝缘层的至少一个沟槽,所述第二区域的所述掩膜层的上表面高于所述第一区域的所述掩膜层的上表面;形成第一保护层,所述第一保护层覆盖所述第一区域的所述掩膜层的上表面和侧壁;在形成所述第一保护层后,去除所述第二区域的所述掩膜层;在去除所述第二区域的所述掩膜层之后,去除所述第一保护层;去除所述第一区域的所述掩膜层。本申请实施例提供的半导体结构的形成方法,有利于提高半导体结构的平整度。

Description

半导体结构的形成方法
交叉引用
本申请基于申请号为202110128741.8、申请日为2021年01月29日的中国专利申请提出,并要求该中国专利申请的优先权,该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本申请实施例涉及半导体领域,特别涉及一种半导体结构的形成方法。
背景技术
动态随机存储器(Dynamic Random Access Memory,DRAM)是计算机中常用的半导体存储器件,由许多重复的存储单元组成。随着DRAM制程工艺的持续演进,集成度不断提高,元件尺寸不断地微缩,在DRAM制程中,DRAM均采用堆栈式的电容构造,其电容器(Capacitor)是垂直的高深宽比的圆柱体形状以增加表面积,包括与衬底连接的下电极层、沉积于下电极层上的电容介质层以及沉积于电容介质层上的上电极层。
现有技术中,利用图形化的掩膜层直接在第一区域刻蚀绝缘层,形成用于沉积下电极层、电介质层和上电极层的沟槽,然后去除第二区域的绝缘层上表面的掩膜层和第一区域剩余绝缘层上表面的掩膜层,由于在第一区域形成沟槽时,会刻蚀第一区域部分厚度的掩膜层, 导致形成沟槽后,第一区域的掩膜层厚度小于第二区域的掩膜层,在去除掩膜层的过程中,由于不同区域的掩膜层厚度不同,去除掩膜层的工艺结束后,第二区域有部分掩膜层残渣,而第一区域的部分绝缘层被刻蚀,导致半导体结构不平整,降低了半导体结构的性能。
如何提高半导体结构的平整度,成为本领域技术人员亟须解决的问题。
发明内容
本申请实施例提供一种半导体结构的形成方法,解决在形成半导体结构时,第一区域绝缘层损伤和第二区域有掩膜层残留物的问题。
本申请实施例提供一种半导体结构的形成方法,所述半导体结构包括第一区域以及第二区域,包括:提供依次堆叠设置的基底、绝缘层以及掩膜层,所述第一区域具有贯穿所述掩膜层以及所述绝缘层的至少一个沟槽,所述第二区域的所述掩膜层的上表面高于所述第一区域的所述掩膜层的上表面;形成第一保护层,所述第一保护层覆盖所述第一区域的所述掩膜层的上表面和侧壁;在形成所述第一保护层后,去除所述第二区域的所述掩膜层;在去除所述第二区域的所述掩膜层之后,去除所述第一保护层;去除所述第一区域的所述掩膜层。
本申请实施例至少具有以下优点:
上述技术方案中,在去除掩膜层之前,形成覆盖第一区域掩膜层侧壁和上表面的第一保护层,第一区域的掩膜层和第二区域的掩膜层分开去除,先去除第二区域的掩膜层,由于第一区域的掩膜层的上表 面和侧壁具有第一保护层,在去除第二区域的掩膜层的过程中不会对第一区域的掩膜层造成影响,然后去除第一保护层,再去除第一区域的掩膜层;因为分开去除第一区域和第二区域的掩膜层,所以消除了同时去除不同区域掩膜层时,由于不同区域掩膜层厚度不一致对去除掩膜层工艺的影响,同时由于第一区域的掩膜层上表面和侧壁有第一保护层,在去除第二区域的掩膜层时不会对第一区域的掩膜层产生影响,可以彻底的去除掩膜层,不会留有掩膜层残渣,且不会刻蚀第一区域的绝缘层,形成的半导体结构具有较高的平整度。
附图说明
一个或多个实施例通过与之对应的附图中的图片进行示例性说明,这些示例性说明并不构成对实施例的限定,附图中具有相同参考数字标号的元件表示为类似的元件,除非有特别申明,附图中的图不构成比例限制。
图1、图2为一种半导体结构的形成方法各步骤的结构示意图;
图3~图12为本申请第一实施例提供的一种半导体结构的形成方法各步骤的结构示意图;
图13~图15为本申请第二实施例提供的一种半导体结构的形成方法各步骤的结构示意图。
具体实施方式
由背景技术可知,现有技术的半导体结构的平整度较低。
图1、图2为一种半导体结构的形成方法各步骤的结构示意图。
参考图1,半导体结构具有第一区域A和第二区域B,包括:依次堆叠设置的基底100、绝缘层101和掩膜层103。由于在第一区域A形成贯穿掩膜层103以及绝缘层101的至少一个沟槽102时,会刻蚀第一区域A部分厚度的掩膜层103,所以形成沟槽102后,第二区域B的掩膜层103的上表面高于第一区域A的掩膜层103的上表面;参考图2,形成沟槽102后同时去除第一区域A和第二区域B的掩膜层103,在相同去除工艺条件下,第一区域A与第二区域B的掩膜层103去除的厚度相同;由于去除工艺前,第二区域B的掩膜层103的厚度大于第一区域A的掩膜层103的厚度,所以第一区域A的掩膜层103被去除完时,第二区域B还剩余部分残留物104,继续去除剩余的残留物104,会导致第一区域A的部分绝缘层101被刻蚀。结合图1和图2,在去除掩膜层103的工艺结束后,第二区域B会有部分残留物104和/或第一区域A的绝缘层101受损伤,这样导致形成的半导体结构不平整,降低了半导体结构的性能。
为解决上述问题,本申请实施例提供一种半导体结构的形成方法,在去除掩膜层之前,形成覆盖第一区域掩膜层侧壁和上表面的第一保护层,第一区域的掩膜层和第二区域的掩膜层分开去除,先去除第二区域的掩膜层,由于第一区域的掩膜层的上表面和侧壁具有第一保护层,在去除第二区域的掩膜层的过程中不会对第一区域的掩膜层造成影响,提高了半导体结构的平整度。
为使本申请实施例的目的、技术方案和优点更加清楚,下面将结 合附图对本申请的各实施例进行详细的阐述。然而,本领域的普通技术人员可以理解,在本申请各实施例中,为了使读者更好地理解本申请而提出了许多技术细节。但是,即使没有这些技术细节和基于以下各实施例的种种变化和修改,也可以实现本申请所要求保护的技术方案。
图3~图12为本申请第一实施例提供的一种半导体结构的形成方法各步骤的结构示意图,其中图3为半导体结构基底的详细结构示意图。
参考图3和图4,本实施例中,半导体结构包括第一区域A以及第二区域B,包括:提供依次堆叠设置的基底200、绝缘层201以及掩膜层203,第一区域A具有贯穿掩膜层203以及绝缘层201的至少一个沟槽202,第二区域B的掩膜层203的上表面高于第一区域A的掩膜层203的上表面。
其中,半导体结构包括阵列区和位于阵列区周围的外围区,阵列区包括单元区和非单元电路区,本实施例的第一区域A为单元区,第二区域B为非单元电路区,在去除掩膜层203之后,后续在第一区域A的沟槽202内形成下电极层、介质层和上电极层;同时第一区域A的掩膜层203的图形密度大于第二区域B的掩膜层203的图形密度。
本实施例中,基底200包括导电层210和隔离层220,隔离层220位于第一区域A的绝缘层201的底部,并与第一区域A的绝缘层201接触。
导电层210的材料包括钨金属、银金属或金金属等导电材料,导 电层210可以作为存储节点接触结构。
隔离层220的材料包括氮化硅或氧化硅等绝缘材料。
绝缘层201的材料包括氮化硅或氧化硅等绝缘材料,用于作为支撑层,支撑层用于后续形成电容的下电极层时起支撑作用,形成的下电极层位于支撑层的侧壁。
为了在第一区域A形成位置和尺寸合适的贯穿绝缘层201的至少一个沟槽202,,需要在形成沟槽202之前在第一区域A和第二区域B的绝缘层201的上表面形成掩膜层203,刻蚀第一区域A的掩膜层203和部分绝缘层201,在第一区域A形成贯穿掩膜层203以及绝缘层201的至少一个沟槽202。
在形成沟槽202之前,第一区域A的掩膜层203的上表面和第二区域B的掩膜层203的上表面齐平;为了在第一区域A形成沟槽202用于后续形成下电极层、介质层和上电极层,所以需要在第一区域A形成沟槽202;由于第一区域A的掩膜层203宽度小于第二区域B的掩膜层203宽度,第一区域A的图形密度大于第二区域B的图形密度,所以在第一区域A形成沟槽202时,由于刻蚀负载效应,刻蚀气体刻蚀掉的第一区域A的掩膜层203的厚度大于第二区域B的掩膜层203的厚度;导致形成沟槽202后,第一区域A的掩膜层203厚度小于第二区域B的掩膜层203,所以第二区域B的掩膜层203的上表面高于第一区域A的掩膜层203的上表面。
其中,掩膜层203的材料包括多晶硅,掩膜层203用于在形成沟槽202时对绝缘层起到保护作用。
参考图5和图6,本实施例中,形成第一保护层204,第一保护层204覆盖第一区域A的掩膜层203的上表面和侧壁。
在第一区域A的掩膜层203的上表面和侧壁形成第一保护层204,然后分步去除第一区域A和第二区域B的掩膜层203,由于有第一保护层204,在去除第二区域B的掩膜层203时,保护了第一区域A的掩膜层203不受影响,然后再去除第一区域A的掩膜层203,保证了在去除掩膜层203后,不会在第二区域B留有掩膜层残渣,不会对第一区域A的绝缘层201形貌产生影响,提高了半导体结构形貌的平整性。
本实施例中,第一保护层204不仅覆盖第一区域A的掩膜层203的上表面和侧壁,而且形成的第一保护层204填充满沟槽202,第一保护层204覆盖第一区域A的掩膜层203的上表面。
形成本实施例第一保护层204的步骤为,首先形成初始保护层205,形成的初始保护层205填充满沟槽202,初始保护层205覆盖第二区域B的掩膜层203的上表面;在形成初始保护层205之后,去除第二区域B的掩膜层203上表面的初始保护层205,露出第二区域B的掩膜层203,剩余的初始保护层205形成第一保护层204。本实施例中,可以采用化学气相沉积工艺形成初始保护层205,化学气相沉积工艺沉积速率快,节省了生产时长,有利于提高半导体结构的生产效率。
本实施例中,在沉积形成初始保护层205时,不用区分区域,可以同时沉积,同时形成后的第一保护层204填充满了沟槽202,在后 续去除第一区域A的掩膜层203时,填充满沟槽202的第一保护层204可以保护沟槽202底部的基底200,不会与去除掩膜层203产生的残渣接触,提高了半导体结构的性能。
第一保护层204的材料包括光刻胶,光刻胶作为保护层具有较好的流动性和填充性,在形成覆盖第一区域A的掩膜层203上表面和侧壁的第一保护层204的时候,可以比较均匀且没有间隙的覆盖第一区域A的掩膜层203的上表面和侧壁。
其中,形成的第一区域A的掩膜层203上表面的第一保护层204的厚度为100纳米~200纳米,具体可以为130纳米、160纳米或190纳米。
第一区域A的掩膜层203上表面的第一保护层204的厚度太薄,在刻蚀去除第二区域B的掩膜层203时,容易使得第一区域A的第一保护层204也被去除,然后对第一区域A的掩膜层203产生影响,进而影响后续去除第一区域A的掩膜层203,对半导体结构的性能产生影响;第一区域A的掩膜层203上表面的第一保护层204的厚度太厚,在去除完第二区域B的掩膜层203之后,第一区域A还有很厚一层第一保护层204,后续去除需要比较长的时间,不利于提高半导体制程的效率。
在其他实施例中,参考图7,第一保护层204可以仅覆盖第一区域A的掩膜层203的上表面和侧壁。采用原子层沉积工艺形成第一保护层204,可以形成致密且更薄的第一保护层204,在保护了第一区域A的掩膜层203的同时,节省了材料,降低了去除掩膜层203的成 本。
其中,采用原子层沉积工艺形成的第一保护层204的材料包括:氧化硅。
在其他实施例中,第一保护层除了覆盖第一区域的掩膜层的上表面和侧壁,还覆盖沟槽底部以及侧壁。
采用原子层沉积工艺形成覆盖沟槽底部以及侧壁的第一保护层,在后续去除第一区域的掩膜层时,位于沟槽底部以及侧壁的第一保护层可以保护沟槽底部的基底,不会与去除掩膜层产生的残渣接触,提高了半导体结构的性能。
在其他实施例中,参考图8,第一保护层204不仅覆盖第一区域A的掩膜层203侧壁和上表面、沟槽202的底部和侧壁,第一保护层204还覆盖第二区域B的掩膜层203上表面和侧壁。
由于第一保护层204不仅覆盖第一区域A也覆盖第二区域B,所以在形成第一保护层204时,不用区分区域,有利于整体形成。
可以理解的是,覆盖第二区域B的掩膜层203上表面和侧壁的第一保护层204,在去除第二区域B的掩膜层203之前,需要去除第二区域B的掩膜层203上表面的第一保护层204。
参考图9,本实施例中,在形成第一保护层204后,去除第二区域B的掩膜层203。
先去除第二区域B的掩膜层203,由于第一区域A的掩膜层203的上表面和侧壁具有第一保护层204,在去除第二区域B的掩膜层203的过程中不会对第一区域A的掩膜层203造成影响,然后去除第一保 护层204,再去除第一区域A的掩膜层203;因为分开去除第一区域A和第二区域B的掩膜层203,所以消除了同时去除不同区域掩膜层203时,由于不同区域掩膜层203厚度不一致对去除掩膜层203工艺的影响,同时由于第一区域A的掩膜层203上表面和侧壁有第一保护层204,在去除第二区域B的掩膜层203时不会对第一区域A的掩膜层203产生影响,可以彻底的去除掩膜层203,不会留有掩膜层残渣,且不会刻蚀第一区域A的绝缘层201,形成的半导体结构具有较高的平整度。
在去除第二区域B的掩膜层203之后,去除第一保护层204;去除第一区域A的掩膜层203。
本实施例中,去除第一保护层204以及第一区域A的掩膜层203的工艺步骤包括:参考图10,去除部分第一保护层204,露出第一区域A的掩膜层203;参考图11,露出第一区域A的掩膜层203之后,去除第一区域A的掩膜层203;参考图12,在去除第一区域A的掩膜层203之后,去除剩余的第一保护层204。
分步去除第一保护层204,在去除第一区域A的掩膜层203之时,沟槽202内填满了第一保护层204,去除第一区域A的掩膜层203产生的掩膜层残渣不会掉落到沟槽202中,不会与沟槽202底部的基底200接触,提高了半导体结构的性能。
在其他实施例中,去除第一保护层以及第一区域的掩膜层的工艺步骤包括:去除全部第一保护层,露出第一区域的掩膜层;露出第一区域A的掩膜层之后,去除第一区域的掩膜层。在去除第一区域的掩 膜层之前,全部去除第一保护层,在工艺上更容易实现,可以采用干法刻蚀工艺,在不影响第一区域的掩膜层的基础上,完全去除了第一保护层。
本实施例上述的工艺步骤中,采用含氧的等离子体去除第一保护层204。因为第一保护层204的材料为光刻胶,含氧的等离子体可以与光刻胶快速反应,所以,去除第一保护层204的方法包括:向第一保护层204提供含氧的等离子体,含氧的等离子体与第一保护层204发生反应,生成二氧化碳、一氧化碳和水。采用含氧的等离子体与第一保护层204的反应迅速,可以很快的去除第一保护层204,提高了去除光刻胶的效率。
本实施例中,用氧气形成含氧的等离子体,所用的氧气的气体流量为1000标准毫升每分钟~15000标准毫升每分钟,具体可以为5000标准毫升每分钟、10000标准毫升每分钟或12000标准毫升每分钟。
在去除第一保护层204的过程中,还需要向反应腔室通入载体气体,载体气体包括氩气或氮气。
在上述的工艺步骤中,采用含氢的等离子体去除掩膜层203。因为掩膜层203的材料为多晶硅,易与含氢的等离子体发生反应,可以很快的去除掩膜层203。
本实施例中,去除掩膜层203的工艺和去除第一保护层204的工艺在同一反应腔室中进行。如此,整个去除第一保护层204和掩膜层203工艺都在同一反应腔室中进行,避免了进行不同步骤换腔室时光刻胶被外界环境污染的风险,同时简化了工艺环境,使得整个去除工 艺更容易实现。在其他实施例中,去除第一保护层和去除掩膜层可以在不同的反应腔室中进行。
本实施例中,在去除掩膜层203之前,形成覆盖第一区域A掩膜层203侧壁和上表面的第一保护层204,第一区域A的掩膜层203和第二区域B的掩膜层203分开去除,先去除第二区域B的掩膜层203,由于第一区域A的掩膜层203的上表面和侧壁具有第一保护层204,在去除第二区域B的掩膜层203的过程中不会对第一区域A的掩膜层203造成影响,然后去除第一保护层204,再去除第一区域A的掩膜层203;因为分开去除第一区域A和第二区域B的掩膜层203,所以消除了同时去除不同区域掩膜层203时,由于不同区域掩膜层203厚度不一致对去除掩膜层203工艺的影响,同时由于第一区域A的掩膜层203上表面和侧壁有第一保护层204,在去除第二区域B的掩膜层203时不会对第一区域A的掩膜层203产生影响,可以彻底的去除掩膜层203,不会留有掩膜层残渣,且不会刻蚀第一区域A的绝缘层201,形成的半导体结构具有较高的平整度。
本申请第二实施例提供一种半导体结构的形成方法,与本申请第一实施例大致相同,主要区别在于在去除第一区域的掩膜层之前,在第二区域的绝缘层上表面形成第二保护层,以下将结合附图对本申请第二实施例提供的半导体结构的形成方法进行详细说明,与前一实施例相同或者相应的部分,可参考前述实施例的说明,以下将不做赘述。
图13~图15为本申请第二实施例提供的一种半导体结构的形成方法各步骤的结构示意图。
本实施例中,参考图13,半导体结构包括第一区域A以及第二区域B,还包括依次堆叠设置的基底300、绝缘层301以及掩膜层303,在露出第一区域A的掩膜层303之后,去除第一区域A的掩膜层303之前,还包括:形成覆盖第二区域B的绝缘层301上表面的第二保护层306;参考图14,去除第一区域A的掩膜层303;参考图15,在去除第一区域A的掩膜层303之后,去除第二保护层306。
本实施例中,第一保护层304材料和第二保护层306材料相同,具体可以为多晶硅。
本实施例中,在去除第一区域A的掩膜层203之前,在第二区域B的绝缘层301上表面形成第二保护层306,保证了在去除第一区域A的掩膜层303时,不会对第二区域B的绝缘层301产生影响,提高了半导体结构的性能。
本领域的普通技术人员可以理解,上述各实施方式是实现本申请的具体实施例,而在实际应用中,可以在形式上和细节上对其作各种改变,而不偏离本申请的精神和范围。任何本领域技术人员,在不脱离本申请的精神和范围内,均可作各自更动与修改,因此本申请的保护范围应当以权利要求限定的范围为准。

Claims (15)

  1. 一种半导体结构的形成方法,所述半导体结构包括第一区域以及第二区域,包括:
    提供依次堆叠设置的基底、绝缘层以及掩膜层,所述第一区域具有贯穿所述掩膜层以及所述绝缘层的至少一个沟槽,所述第二区域的所述掩膜层的上表面高于所述第一区域的所述掩膜层的上表面;
    形成第一保护层,所述第一保护层覆盖所述第一区域的所述掩膜层的上表面和侧壁;
    在形成所述第一保护层后,去除所述第二区域的所述掩膜层;
    在去除所述第二区域的所述掩膜层之后,去除所述第一保护层;
    去除所述第一区域的所述掩膜层。
  2. 根据权利要求1所述的半导体结构的形成方法,其中,形成所述第一保护层的方法包括:在所述沟槽底部以及侧壁形成所述第一保护层。
  3. 根据权利要求2所述的半导体结构的形成方法,其中,去除所述第一保护层以及所述第一区域的所述掩膜层的工艺步骤包括:
    去除部分所述第一保护层,露出所述第一区域的所述掩膜层;
    露出所述第一区域的所述掩膜层之后,去除所述第一区域的所述掩膜层;
    在去除所述第一区域的所述掩膜层之后,去除剩余的所述第一保护层。
  4. 根据权利要求2所述的半导体结构的形成方法,其中,去除所 述第一保护层以及所述第一区域的所述掩膜层的工艺步骤包括:
    去除全部所述第一保护层,露出所述第一区域的所述掩膜层;
    露出所述第一区域的所述掩膜层之后,去除所述第一区域的所述掩膜层。
  5. 根据权利要求3或4所述的半导体结构的形成方法,其中,在露出所述第一区域的所述掩膜层之后,去除所述第一区域的所述掩膜层之前,还包括:
    形成覆盖所述第二区域的所述绝缘层上表面的第二保护层;
    在去除所述第一区域的所述掩膜层之后,去除所述第二保护层。
  6. 根据权利要求1所述的半导体结构的形成方法,其中,形成所述第一保护层的工艺步骤包括:形成覆盖所述第二区域的所述掩膜层上表面和侧壁的第一保护层。
  7. 根据权利要求6所述的半导体结构的形成方法,其中,在去除所述第二区域的所述掩膜层之前,还包括:去除所述第二区域的所述掩膜层上表面的所述第一保护层。
  8. 根据权利要求1所述的半导体结构的形成方法,其中,形成的所述第一保护层填充满所述沟槽,所述第一保护层覆盖所述第一区域的所述掩膜层的上表面。
  9. 根据权利要求1所述的半导体结构的形成方法,其中,形成所述第一保护层之前,还包括:形成初始保护层,形成的所述初始保护层填充满所述沟槽,所述初始保护层覆盖所述第二区域的所述掩膜层的上表面。
  10. 根据权利要求9所述的半导体结构的形成方法,其中,形成所述第一保护层的工艺步骤包括:在去除所述第二区域的所述掩膜层之前,去除所述第二区域的所述掩膜层上表面的所述初始保护层,露出所述第二区域的所述掩膜层,剩余的所述初始保护层形成所述第一保护层。
  11. 根据权利要求1所述的半导体结构的形成方法,其中,形成的所述第一区域的所述掩膜层上表面的所述第一保护层的厚度为100纳米~200纳米。
  12. 根据权利要求1所述的半导体结构的形成方法,其中,所述第一保护层的材料包括光刻胶,所述掩膜层的材料包括多晶硅。
  13. 根据权利要求12所述的半导体结构的形成方法,其中,采用含氧的等离子体去除所述第一保护层。
  14. 根据权利要求12所述的半导体结构的形成方法,其中,采用含氢的等离子体去除所述掩膜层。
  15. 根据权利要求1所述的半导体结构的形成方法,其中,去除所述掩膜层的工艺和去除所述第一保护层的工艺在同一反应腔室中进行。
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