Preparation method of magnetic memory and magnetic memory

Abstract

The invention discloses a preparation method of a magnetic memory and the magnetic memory, which are applied to the technical field of memorizers, and comprises the following steps: preparing a bottom metal interconnection structure; an etching stop layer is arranged on the surface of the bottom metal interconnection structure; sequentially preparing a through hole metal layer, a bottom electrode layer, an MTJ and a top electrode layer from bottom to top based on the etching stop layer; at least one of the elements in the material of the protective layer of the MTJ and the elements in the material of the etching stop layer is different; and etching the top electrode layer, detecting elements in the etching groove in the etching process, and when it is detected that different types of elements of the etching stop layer and the protection layer exist in the etching groove, performing certain excessive etching to ensure that the surface of the wafer is etched, and finally completing the preparation of the magnetic memory. The etching stop layer with different elements from the protection layer of the MTJ is arranged, so that the etching stop layer can play a role in limiting the etching stop position, and the copper exposure defect is eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of memory, and in particular to a method for preparing a magnetic memory and a magnetic memory. Background Art

[0002] With the development of semiconductor devices, the size of chips has gradually decreased, and the requirements for the process have also become higher. Multi-layer interconnection technology has become an important part of the manufacturing process of large-scale integrated circuits and ultra-large-scale integrated circuits.

[0003] The MTJ (Magnetic Tunneling Junction) protection layer needs to be opened during the top electrode etching. Currently, the metal diffusion barrier layer on the bottom metal surface of the magnetic storage device and the MTJ protection layer are very thin and made of the same material. As a result, the etching barrier layer on the bottom metal surface and the MTJ protection layer are easily judged as the same layer during the etching process, causing the etching barrier layer on the bottom metal surface to be over-etched, resulting in copper exposure defects, which seriously affects the yield.

[0004] Therefore, how to prevent the etch barrier layer from being over-etched and causing copper exposure defects when etching the top electrode is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] An object of the present invention is to provide a method for preparing a magnetic memory, which can prevent an etch barrier layer from being overetched; another object of the present invention is to provide a magnetic memory, whose etch barrier layer will not be overetched.

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a magnetic memory, comprising:

[0007] preparing a bottom metal interconnect structure;

[0008] Disposing an etch stop layer on the surface of the bottom metal interconnect structure;

[0009] Based on the etching stop layer, a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer are sequentially prepared from bottom to top; the elements in the protective layer material of the MTJ are different from the elements in the etching stop layer material in at least one element;

[0010] The top electrode layer is etched, and the elements in the etching groove are detected during the etching process. When it is detected that different types of elements of the etching stop layer and the protective layer exist in the etching groove, over-etching is performed to finally form the magnetic memory.

[0011] Optionally, the size of the through-hole metal layer is smaller than the size of the bottom metal interconnection structure, and the etch stop layer covers the surface of the bottom metal interconnection structure that is not in contact with the through-hole metal layer and faces the through-hole metal layer.

[0012] Optionally, the elements of the material of the etch stop layer include at least one element that is different from the elements of the materials of each film layer in the core structure layer.

[0013] Optionally, providing an etching stop layer on the surface of the bottom metal interconnect structure includes:

[0014] Disposing a diffusion barrier sublayer on the surface of the bottom metal interconnect structure;

[0015] An etch stop sublayer is disposed on the surface of the diffusion barrier sublayer; the elements in the material of the etch stop sublayer are different from the elements in the material of the protection layer in at least one element.

[0016] Optionally, the thickness of the etch stop sublayer ranges from 10 nm to 30 nm, including endpoint values.

[0017] Optionally, the thickness of the etch stop layer ranges from 20 nm to 100 nm, including endpoint values.

[0018] Optionally, the amount of over-etching is 0% to 50%.

[0019] Optionally, the etching stop layer is a SiN film layer, and the protective layer is an AlO film layer.

[0020] Optionally, the etching stop layer is an AlO film layer, and the protective layer is a SiN film layer.

[0021] The present invention further provides a magnetic memory, which is a magnetic memory prepared by any one of the above-mentioned methods for preparing a magnetic memory.

[0022] The present invention provides a method for preparing a magnetic memory, comprising: preparing a bottom metal interconnection structure; setting an etching stop layer on the surface of the bottom metal interconnection structure; preparing a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer in order from bottom to top based on the etching stop layer; the elements in the protective layer material of the MTJ are different from the elements in the etching stop layer material in at least one element; etching the top electrode layer, and detecting the elements in the etching groove during the etching process, and when it is detected that the etching stop layer and the protective layer have different types of elements in the etching groove, over-etching is performed to finally form a magnetic memory.

[0023] By setting a film layer with different elements from the MTJ protective layer as an etching stop layer, the type of elements in the etching groove is detected during etching. When an element unique to the etching stop layer is detected, a certain amount of over-etching is performed to ensure that the wafer surface is completely etched, so that the above-mentioned etching stop layer can limit the etching stop position, avoid over-etching of the etching barrier layer, eliminate copper exposure defects, and improve product yield.

[0024] The present invention also provides a magnetic storage device, which also has the above-mentioned beneficial effects and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A flowchart of a method for preparing a magnetic memory provided by an embodiment of the present invention;

[0027] Figures 2 to 9 A process flow chart of a specific method for preparing a magnetic memory provided by an embodiment of the present invention;

[0028] Figures 10 to 14 A process flow chart of another specific method for preparing a magnetic memory provided by an embodiment of the present invention;

[0029] Figures 15 to 19 The present invention provides a process flow chart of another specific method for preparing a magnetic memory according to an embodiment of the present invention.

[0030] In the figure: 1. bottom metal interconnect structure, 2. etch stop layer, 21. diffusion barrier sublayer, 22. etch stop sublayer, 3. first dielectric layer, 4. through-hole metal layer, 41. bottom electrode metal layer, 5. MTJ, 6. protective layer, 7. second dielectric layer, 8. top electrode layer. DETAILED DESCRIPTION

[0031] The core of the present invention is to provide a method for preparing a magnetic memory. In the prior art, the protective layer of the MTJ needs to be opened during the etching of the top electrode. At present, the metal diffusion barrier layer on the bottom metal surface of the magnetic memory device and the protective layer of the MTJ are very thin and made of the same material, which makes it easy to judge the etching barrier layer on the bottom metal surface and the MTJ protective layer as the same layer during the etching process, so that the etching barrier layer on the bottom metal surface is over-etched, causing copper exposure defects, which seriously affects the yield.

[0032] The present invention provides a method for preparing a magnetic memory, comprising: preparing a bottom metal interconnect structure; setting an etching stop layer on the surface of the bottom metal interconnect structure; preparing a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer in order from bottom to top based on the etching stop layer; the elements in the protective layer material of the MTJ are different from the elements in the etching stop layer material in at least one element; etching the top electrode layer, and detecting the elements in the etching groove during the etching process, and when it is detected that the etching stop layer and the protective layer have different types of elements in the etching groove, a certain amount of over-etching is performed to ensure that the wafer surface is completely etched, and finally the etching is terminated to complete the preparation of the magnetic memory.

[0033] By setting a film layer with different elements from the protective layer of the MTJ as an etching stop layer, the type of elements in the etching groove is detected during etching. When an element unique to the etching stop layer is detected, the etching is stopped, so that the above-mentioned etching stop layer can limit the etching stop position, avoid over-etching of the etching barrier layer, eliminate copper exposure defects, and improve product yield.

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Please refer to Figure 1 , Figure 1 The present invention provides a flowchart of a method for preparing a magnetic memory according to an embodiment of the present invention.

[0036] See also Figure 1 In an embodiment of the present invention, a method for preparing a magnetic memory includes:

[0037] S101: Prepare a bottom metal interconnection structure.

[0038] In this embodiment, it is necessary to first prepare each film layer from bottom to top, and then etch downward from the top electrode layer 8 to form an independent MTJ structure to make the final magnetic memory. In this step, the bottom metal interconnection structure 1 can be formed by photolithography, development, etching, deposition and other processes in sequence. The specific structure of the bottom metal interconnection structure can refer to the prior art and will not be described in detail here.

[0039] The bottom metal interconnect structure 1 may be specifically disposed in a substrate, and the substrate may specifically be composed of a composite structure such as a bottom dielectric layer and a bottom barrier layer. In this embodiment, the specific structure of the substrate is not specifically limited.

[0040] S102: Disposing an etching stop layer on the surface of the bottom metal interconnect structure.

[0041] In this step, an etch stop layer 2 is usually provided on the surface of the bottom metal interconnect structure 1 by, for example, a deposition process. The present application has specific requirements for the element types of the etch stop layer 2, which requires that the element unique to the etch stop layer 2 can be detected from the etching groove in the subsequent etching process. Generally, in this embodiment, there is no specific limitation on the parameters such as the strength of the etch stop layer 2. The specific contents of the etch stop layer 2 will be described in detail in the following invention embodiments and will not be repeated here.

[0042] S103: Based on the etching stop layer, a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer are sequentially prepared from bottom to top.

[0043] In this embodiment, the elements in the material of the protective layer 6 of the MTJ5 are different from the elements in the material of the etching stop layer 2 in at least one element. The structure prepared in this step is a structure in which the magnetic memory is mainly used to realize the storage function. The structure includes a through-hole metal layer 4, a bottom electrode metal layer 41, an MTJ5 and a top electrode layer 8 from bottom to top, wherein the MTJ5 is mainly used to realize the storage function. The outer layer of the MTJ5 is usually provided with a protective layer 6. The specific structure of the MTJ5 can refer to the prior art and will not be repeated here; the above-mentioned bottom electrode metal layer 41 is the bottom electrode of the MTJ5, the through-hole metal layer 4 and the bottom electrode metal layer 41 are mainly used to realize the connection between the MTJ5 and the bottom metal interconnection structure 1, and the top electrode layer 8 needs to be connected to the MTJ5, and a separate electrode is formed to be electrically connected to other external components after the subsequent etching is completed. Between the above-mentioned structures, a dielectric layer is usually filled. When preparing the above-mentioned through-hole metal layer 4, the bottom electrode metal layer 41 and the MTJ5, it is usually necessary to pattern the formed film layer to form a specific structure.

[0044] Specifically, when preparing the through-hole metal layer 4, it is usually necessary to first form a metal hole through the steps of photolithography, etching, chemical mechanical polishing, etc.; then fill the metal in the metal hole to form the through-hole metal layer 4; and form the bottom electrode metal layer 41 through the steps of photolithography, etching, chemical mechanical polishing, etc. The thickness of the through-hole metal layer 4 is usually 10nm-50nm. Of course, in this embodiment, there is no specific limitation on the thickness of the through-hole metal layer 4, and its specific value depends on the specific situation. It should be noted that in this embodiment, the size of the through-hole metal layer 4 is usually smaller than the size of the bottom metal interconnection structure 1 it contacts, so the etching stop layer 2 needs to cover the surface of the bottom metal interconnection structure 1 facing the through-hole metal layer 4 that is not in contact with the through-hole metal layer 4. That is, except for the surface in contact with the through-hole metal layer 4, the surface of the bottom metal interconnection structure 1 needs to be covered by the etching stop layer 2 to ensure that the etching stop layer 2 can be detected in time when the preset depth is subsequently etched. Of course, if the accuracy of the subsequent etching process is high enough, the etching stop layer 2 can be only disposed at the position corresponding to the etching groove on the surface of the bottom metal interconnect structure 1 to reduce the amount of the etching stop layer 2 used.

[0045] After forming the bottom electrode metal layer 41, MTJ5 can be formed by steps such as photolithography, etching, chemical mechanical polishing, etc. The specific preparation process can refer to the prior art. The thickness of the protective layer 6 of the MTJ5 is usually 10nm-50nm. Of course, in this embodiment, there is no specific limitation on the thickness of the protective layer 6, and its specific value depends on the specific situation. The above-mentioned etching stop layer 2 and the protective layer 6 are usually filled with a dielectric to form a first dielectric layer 3; the upper layer of the protective layer 6 is also usually filled with a dielectric to form a second dielectric layer 7.

[0046] Afterwards, a top electrode layer 8 may be disposed on the top of the MTJ 5 based on a deposition process or other processes to form a top electrode after subsequent cutting. The thickness of the top electrode layer 8 is generally between 10 nm and 50 nm. Of course, in this embodiment, the thickness of the top electrode layer 8 is not specifically limited, and its specific value depends on the specific situation.

[0047] In this embodiment, in order to ensure that the etching stop layer 2 can be detected in time during etching, in this step, the elements of the material of the etching stop layer 2 can include at least one element that is different from the elements of the materials of each film layer in the core structure layer. That is, the etching stop layer 2 has at least one element that is not only not present in the protective layer 6, but also not present in the entire core structure layer, so as to ensure that the detection will not be interfered by the elements of other etched film layers, thereby ensuring the accuracy of the detection result.

[0048] S104: etching the top electrode layer and detecting the elements in the etching groove during the etching process. When it is detected that different types of elements of the etching stop layer and the protective layer exist in the etching groove, over-etching is performed to finally form a magnetic memory.

[0049] This embodiment is specifically directed to the etching process of the top electrode. In this step, when etching the top electrode layer 8, the elements in the etching groove are detected, at least for detecting the type of elements in the etching groove. Since at least one of the elements forming the etching stop layer 2 in this embodiment is not present in the protective layer 6. Therefore, when etching the top electrode layer 8, when it is detected that there are elements in the etching stop layer 2 but not in the protective layer 6, that is, the etching stop layer 2 and the protective layer 6 are different in type, it is determined that the etching stop layer 2 has been etched. In this embodiment, a certain amount of over-etching is specifically required to ensure that the wafer surface is completely etched to form the structure of the magnetic memory.

[0050] After determining that the etching stop layer 2 has been etched, since the etching stop layer 2 has a certain thickness in this embodiment, in order to ensure that the etching is completed on the wafer surface, a certain amount of over-etching can be added. The amount of over-etching is usually 0% to 50%, that is, usually 0% to 50% over-etching is added to ensure that the etching is completed on the wafer surface.

[0051] A method for preparing a magnetic memory provided by an embodiment of the present invention, by setting a film layer with elements different from the protective layer 6 of MTJ5 as an etching stop layer 2, by detecting the type of elements in the etching groove during etching, when an element unique to the etching stop layer 2 is detected, the etching is stopped, so that the above-mentioned etching stop layer 2 can play a role in limiting the etching stop position, avoiding over-etching of the etching barrier layer, eliminating copper exposure defects, and improving product yield.

[0052] The specific contents of the method for preparing a magnetic memory provided by the present invention will be described in detail in the following embodiments of the invention.

[0053] Please refer to Figures 2 to 9 , Figures 2 to 9 A process flow chart of a specific method for preparing a magnetic memory provided by an embodiment of the present invention.

[0054] See also Figure 2 In an embodiment of the present invention, a method for preparing a magnetic memory includes:

[0055] S201: Prepare a bottom metal interconnection structure.

[0056] See also Figure 3This step is basically the same as S101 in the above-mentioned invention embodiment. For details, please refer to the above-mentioned invention embodiment, and no further details will be given here.

[0057] S202: Disposing a diffusion barrier sublayer on the surface of the bottom metal interconnect structure.

[0058] See also Figure 4 In this step, a double-layer structure is provided as an etching stop layer 2. Specifically, in this step, a diffusion barrier sublayer 21 is first provided on the surface of the bottom metal interconnect structure 1 by deposition or other processes. The diffusion barrier sublayer 21 mainly plays a role of diffusion barrier, limiting the atoms in the bottom metal interconnect structure 1 from penetrating into other structures. The material of the diffusion barrier sublayer 21 can refer to the material of the diffusion barrier layer in the prior art, and is not specifically limited here.

[0059] S203: Disposing an etching stop sublayer on the surface of the diffusion barrier sublayer.

[0060] See also Figure 5 In this embodiment, the elements in the material of the etching stop sublayer 22 are different from the elements in the material of the protective layer 6 in at least one element. In this step, the etching stop sublayer 22 can be set on the surface of the diffusion barrier sublayer 21 by deposition and other processes. The role of the above-mentioned etching stop sublayer 22 is mainly used to realize the role of positioning the etching stop position. The elements in the material of the etching stop sublayer 22 are different from the elements in the material of the above-mentioned protective layer 6 in at least one element, so that based on the element detection process in the above-mentioned etching process, the etching stop process is realized at the position where the etching stop sublayer 22 is located, so as to realize the role of the etching stop sublayer 22 in positioning the etching stop position. In the present application, the diffusion barrier sublayer 21 is used to realize the role of blocking diffusion, and the etching stop sublayer 22 is used to realize the role of positioning the etching stop position. In this embodiment, the diffusion blocking function and the etching stop position positioning function are realized by two separately set sublayers. A diffusion blocking sublayer 21 is first set on the surface of the bottom metal interconnection structure 1, and then an etching stop sublayer 22 is set on the surface of the diffusion blocking sublayer 21. The stacked structure of the diffusion blocking sublayer 21 and the etching stop sublayer 22 forms an etching stop layer 2 with the above functions. In this embodiment, the thickness of the above diffusion blocking sublayer 21 is generally in the range of 20nm to 70nm, including the end value. The thickness of the above etching stop sublayer 22 is generally in the range of 10nm to 30nm, including the end value.

[0061] Specifically, in order to ensure the accuracy of subsequent measurements in this embodiment, the elements of the material of the etching stop sublayer 22 include at least one element that is different from the elements of the materials of each film layer in the core structure layer. Usually, the material of the diffusion barrier sublayer 21 can be SiN, AlO and other materials, and SiN can be specifically selected in this embodiment; the material of the etching stop sublayer 22 can be SiN, AlO and other materials, and AlO can be specifically selected in this embodiment. In this step, it is usually necessary to set a first dielectric layer 3 on the surface of the etching stop sublayer 22 to facilitate the subsequent preparation of the core structure layer.

[0062] S204: Based on the etching stop layer, a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer are sequentially prepared from bottom to top.

[0063] See also Figures 6 to 8 In this step, the above-mentioned through-hole metal layer 4, bottom electrode metal layer 41, MTJ5 and top electrode layer 8 are prepared based on the etching stop layer 2 of the stacked structure of the above-mentioned diffusion barrier sublayer 21 and the etching stop sublayer 22. The specific contents of the above-mentioned structure can be referred to the above-mentioned invention embodiment, and will not be repeated here. The side wall of the above-mentioned MTJ5 is covered with a protective layer 6, and the second dielectric layer 7 is filled between the top of the protective layer 6 and the top metal layer. The bottom electrode metal layer 41 and the through-hole metal layer 4 are connected to the bottom metal interconnection structure 1. The material of the protective layer 6 in the above-mentioned core structure layer can be SiN, AlO and other materials. In this embodiment, SiN can be specifically selected.

[0064] S205: etching the top electrode layer and detecting the elements in the etching groove during the etching process. When it is detected that different types of elements of the etching stop layer and the protective layer exist in the etching groove, over-etching is performed to finally form a magnetic memory.

[0065] See also Fig. 9 The specific content of this step is basically the same as S104 in the above-mentioned embodiment of the invention. In this step, when it is detected that there are different types of elements in the etching stopper sublayer 22 and the protective layer 6 in the etching groove, the etching stop process is completed. When excessive etching is performed, the etching process will usually end at the diffusion barrier sublayer 21.

[0066] A method for preparing a magnetic memory provided by an embodiment of the present invention, by setting a film layer with elements different from the protective layer 6 of MTJ5 as an etching stop layer 2, by detecting the type of elements in the etching groove during etching, when an element unique to the etching stop layer 2 is detected, the etching is stopped, so that the above-mentioned etching stop layer 2 can play a role in limiting the etching stop position, avoiding over-etching of the etching barrier layer, eliminating copper exposure defects, and improving product yield.

[0067] The specific contents of the method for preparing a magnetic memory provided by the present invention will be described in detail in the following embodiments of the invention.

[0068] Please refer to Figures 10 to 14 , Figures 10 to 14 A process flow chart of another specific method for preparing a magnetic memory provided by an embodiment of the present invention.

[0069] In an embodiment of the present invention, a method for preparing a magnetic memory includes:

[0070] S301: Prepare a bottom metal interconnection structure.

[0071] This step is basically the same as S101 in the above-mentioned embodiment of the invention. Please refer to the above-mentioned embodiment of the invention for details, and will not be described again here.

[0072] S302: Disposing an etching stop layer on the surface of the bottom metal interconnect structure.

[0073] See also Fig.10 This step is basically the same as S102 in the above-mentioned invention embodiment. Please refer to the above-mentioned invention embodiment for details. In this step, AlO material can be selected to manufacture the etching stop layer 2 by deposition and other processes, and a first dielectric layer 3 is provided on the surface of the etching stop layer 2. In subsequent steps, SiN material can be selected to manufacture the protective layer 6 in the core structure layer, that is, in this embodiment, the etching stop layer 2 is an AlO film layer, and the protective layer 6 is a SiN film layer.

[0074] In this step, the thickness of the etching stop layer 2 is relatively thick, which can simultaneously achieve the function of blocking diffusion and locating the etching stop position. That is, in addition to locating the etching stop position, the etching stop layer 2 can limit the atoms in the bottom metal interconnect structure 1 from penetrating into other structures. In this step, the thickness of the etching stop layer 2 is generally in the range of 20nm to 100nm, including the end value.

[0075] S303: Based on the etching stop layer, a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer are sequentially prepared from bottom to top.

[0076] See also Figures 11 to 13 This step is basically the same as S103 in the above invention embodiment. Please refer to the above invention embodiment for details, and no further description will be given here. In this step, SiN material can be used to make the protective layer 6 in the core structure layer.

[0077] S304: etching the top electrode layer and detecting the elements in the etching groove during the etching process. When it is detected that different types of elements of the etching stop layer and the protective layer exist in the etching groove, over-etching is performed to finally form a magnetic memory.

[0078] See also Fig.14 This step is basically the same as S104 in the above-mentioned invention embodiment. Please refer to the above-mentioned invention embodiment for details, which will not be repeated here. In this step, when the element Al or the element O is detected, it means that the etching has reached the etching stop layer 2 and the etching stop process needs to be completed. In the case of excessive etching, the etching process will usually end at the etching stop layer 2.

[0079] A method for preparing a magnetic memory provided by an embodiment of the present invention, by setting a film layer with elements different from the protective layer 6 of MTJ5 as an etching stop layer 2, by detecting the type of elements in the etching groove during etching, when an element unique to the etching stop layer 2 is detected, the etching is stopped, so that the above-mentioned etching stop layer 2 can play a role in limiting the etching stop position, avoiding over-etching of the etching barrier layer, eliminating copper exposure defects, and improving product yield.

[0080] The specific contents of the method for preparing a magnetic memory provided by the present invention will be described in detail in the following embodiments of the invention.

[0081] Please refer to Figures 15 to 19 , Figures 15 to 19 The present invention provides a process flow chart of another specific method for preparing a magnetic memory according to an embodiment of the present invention.

[0082] In an embodiment of the present invention, a method for preparing a magnetic memory includes:

[0083] S401: Prepare a bottom metal interconnection structure.

[0084] This step is basically the same as S101 in the above-mentioned embodiment of the invention. Please refer to the above-mentioned embodiment of the invention for details, and will not be described again here.

[0085] S402: Disposing an etching stop layer on the surface of the bottom metal interconnect structure.

[0086] See also Fig.15 This step is basically the same as S102 in the above-mentioned invention embodiment. Please refer to the above-mentioned invention embodiment for details. In this step, SiN material can be selected to make the etching stop layer 2 by deposition and other processes. In the subsequent steps, AlO material can be selected to make the protective layer 6 in the core structure layer, that is, in this embodiment, the etching stop layer 2 is a SiN film layer, and the protective layer 6 is an AlO film layer.

[0087] In this step, the thickness of the etching stop layer 2 is relatively thick, which can simultaneously achieve the function of blocking diffusion and locating the etching stop position. That is, in addition to locating the etching stop position, the etching stop layer 2 can limit the atoms in the bottom metal interconnect structure 1 from penetrating into other structures. In this step, the thickness of the etching stop layer 2 is generally in the range of 20nm to 100nm, including the end value.

[0088] S403: Based on the etching stop layer, a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer are sequentially prepared from bottom to top.

[0089] See also Figures 16 to 18 This step is basically the same as S103 in the above invention embodiment. Please refer to the above invention embodiment for details, and no further description will be given here. In this step, AlO material can be used to make the protective layer 6 in the core structure layer.

[0090] S404: etching the top electrode layer and detecting the elements in the etching groove during the etching process. When it is detected that different types of elements of the etching stop layer and the protective layer exist in the etching groove, over-etching is performed to finally form a magnetic memory.

[0091] See also Fig.19 This step is basically the same as S104 in the above-mentioned invention embodiment. Please refer to the above-mentioned invention embodiment for details, which will not be repeated here. In this step, when the element N or the element Si is detected, it means that the etching has reached the etching stop layer 2 and the etching stop process needs to be completed. In the case of excessive etching, the etching process will usually end at the etching stop layer 2.

[0092] A method for preparing a magnetic memory provided by an embodiment of the present invention, by setting a film layer with elements different from the protective layer 6 of MTJ5 as an etching stop layer 2, by detecting the type of elements in the etching groove during etching, when an element unique to the etching stop layer 2 is detected, the etching is stopped, so that the above-mentioned etching stop layer 2 can play a role in limiting the etching stop position, avoiding over-etching of the etching barrier layer, eliminating copper exposure defects, and improving product yield.

[0093] The embodiment of the present invention further provides a magnetic memory, which is a magnetic memory prepared by a method for preparing a magnetic memory provided by any of the above invention embodiments. The specific structure of the magnetic memory such as MTJ5 can refer to the prior art and will not be described in detail here.

[0094] A magnetic memory provided in an embodiment of the present invention is prepared by the method for preparing a magnetic memory in the above-mentioned embodiment of the present invention. Therefore, the magnetic memory does not have the risk of copper exposure and has a higher yield rate.

[0095] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0096] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0097] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0098] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0099] The above is a detailed introduction to a method for preparing a magnetic memory and a magnetic memory provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a magnetic memory, characterized in that: include: preparing a bottom metal interconnect structure; Disposing an etch stop layer on the surface of the bottom metal interconnect structure; Based on the etching stop layer, a through-hole metal layer, a bottom electrode metal layer, an MTJ and a top electrode layer are sequentially prepared from bottom to top; the elements in the protective layer material of the MTJ are different from the elements in the etching stop layer material in at least one element; The top electrode layer is etched, and the elements in the etching groove are detected during the etching process. When it is detected that different types of elements of the etching stop layer and the protective layer exist in the etching groove, over-etching is performed to finally form the magnetic memory.

2. The preparation method according to claim 1, characterized in that: The size of the through-hole metal layer is smaller than the size of the bottom metal interconnection structure, and the etch stop layer covers the surface of the bottom metal interconnection structure that faces the through-hole metal layer and is not in contact with the through-hole metal layer.

3. The preparation method according to claim 2, characterized in that: The elements of the material of the etching stop layer include at least one element that is different from the elements of the materials of each film layer in the core structure layer.

4. The preparation method according to claim 1, characterized in that: The step of providing an etching stop layer on the surface of the bottom metal interconnect structure comprises: Disposing a diffusion barrier sublayer on the surface of the bottom metal interconnect structure; An etch stop sublayer is disposed on the surface of the diffusion barrier sublayer; the elements in the material of the etch stop sublayer are different from the elements in the material of the protection layer in at least one element.

5. The preparation method according to claim 4, characterized in that: The thickness of the etch stop sublayer ranges from 10 nm to 30 nm, including the end points.

6. The preparation method according to claim 1, characterized in that: The thickness of the etch stop layer ranges from 20 nm to 100 nm, including the end points.

7. The preparation method according to claim 1, characterized in that: The amount of over-etching is 0% to 50%.

8. The preparation method according to claim 1, characterized in that: The etching stop layer is a SiN film layer, and the protection layer is an AlO film layer.

9. The preparation method according to claim 1, characterized in that: The etching stop layer is an AlO film layer, and the protection layer is a SiN film layer.

10. A magnetic memory, characterized in that: A magnetic memory prepared by the method for preparing a magnetic memory as claimed in any one of claims 1 to 9.

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