Method for etching film layer located on surface of side wall of opening

Abstract

Provided in the present application is a method for etching a film layer located on the surface of a side wall of an opening. The method is applied to a semiconductor device, wherein the semiconductor device has an opening, and the surface of a side wall of the opening is plated with a preset film layer. The method comprises: placing a semiconductor device on a stage, wherein a region to be etched of a preset film layer comprises a plurality of sub-regions arranged in a first direction; and using an ion beam to etch the plurality of sub-regions of the preset film layer which is located on a side wall of an opening in the semiconductor device until said region of the preset film layer has been completely removed, wherein an incident angle of the ion beam forms a first angle with the surface on which the semiconductor device is located, and the value range of the first angle is -90° to 90°, excluding -90°, 0°and 90°. The method can be completed only using a one-step process, so that process steps are greatly reduced, without the need for filling openings with filling materials, thereby solving the problem of filling processes for some holes having relatively small diameters being more difficult.

Description

A method for etching a film layer located on a sidewall surface of an opening

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 14, 2023, with application number 202311188612.3 and invention name “A method for etching a film layer located on the sidewall surface of an opening”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of semiconductor process technology, and in particular to a method for etching a film layer located on the surface of an opening sidewall. Background Art

[0003] With the development of semiconductor technology, the integration of semiconductor devices is getting higher and higher. Specifically, in applications, semiconductor devices use silicon vias to stack multiple chips vertically to reduce the interconnection length, thereby packaging more functions into the integrated circuit without increasing the planar size of the integrated circuit. It should be noted that in integrated circuits, interconnection through silicon vias can not only achieve less delay, smaller capacitance, and lower inductance, but also allow higher-speed communication between different chips, a higher number of interconnections, and connect each circuit at lower power. However, the current silicon via manufacturing process has many steps, and for some holes with smaller diameters, the filling process of the silicon via is more difficult.

[0004] Summary of the Invention

[0005] In view of this, the present application provides a method for etching a film layer located on the surface of an opening sidewall, so as to reduce process steps and lower process difficulty when applied to the fabrication of through silicon vias.

[0006] Specifically, this application provides the following technical solutions

[0007] A method for etching a film layer located on a sidewall surface of an opening is applied to a semiconductor device, wherein the semiconductor device has an opening and the sidewall surface of the opening is plated with a predetermined film layer. The method comprises:

[0008] Placing the semiconductor device on a base, wherein the area to be etched of the predetermined film layer includes a plurality of sub-areas arranged along a first direction, the plurality of sub-areas are equidistant from the base, and the first direction is parallel to the sidewall of the opening and the base;

[0009] An ion beam is used to etch multiple sub-regions of a preset film layer located on the side wall of the opening in the semiconductor device until all the to-be-etched regions of the preset film layer are removed. The incident angle of the ion beam forms a first angle with the surface where the semiconductor device is located. The value range of the first angle is -90° to 90°, excluding -90°, 0° and 90°.

[0010] Optionally, the opening is a through hole, and the shape of the port of the opening is circular; etching multiple sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device by using an ion beam until all the to-be-etched regions of the preset film layer are removed includes:

[0011] While etching a plurality of sub-regions of a predetermined film layer on a sidewall of an opening in the semiconductor device, the base table is rotated until all the to-be-etched regions of the predetermined film layer are removed.

[0012] Optionally, the rotation speed of the base platform ranges from 0 rpm to 80 rpm.

[0013] Optionally, while etching a plurality of sub-regions of a preset film layer located on the sidewalls of the opening in the semiconductor device, the base is rotated uniformly.

[0014] Optionally, the opening is a groove, and the port shape of the opening is rectangular; etching multiple sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device by using an ion beam until all the to-be-etched regions of the preset film layer are removed includes:

[0015] An ion beam is used to etch a sub-region of a preset film layer located on the side wall of an opening in the semiconductor device. After the etching of the sub-region is completed, the etching is stopped. After rotating the base, the ion beam is used to etch another sub-region of the preset film layer located on the side wall of the opening in the semiconductor device. The process is repeated until all the areas to be etched of the preset film layer are removed.

[0016] Optionally, the method for stopping etching includes:

[0017] The ion beam is shielded by a shielding plate to stop etching the preset film layer.

[0018] Optionally, the method for stopping etching includes: stopping the etching of the preset film layer by stopping the beam drawing.

[0019] Optionally, the method for stopping etching includes: stopping etching of the preset film layer by extinguishing an ion source.

[0020] Optionally, etching the plurality of sub-regions of the predetermined film layer located on the sidewalls of the opening in the semiconductor device by using an ion beam includes:

[0021] At least one etching method selected from standard ion beam etching, reactive ion beam etching, and chemically assisted ion beam etching is used to etch a plurality of sub-regions of the predetermined film layer on the sidewalls of the opening in the semiconductor device.

[0022] Optionally, the etching gas used in the standard ion beam etching is an inert gas.

[0023] Optionally, the etching gas used in the reactive ion beam etching includes an inert gas or a reactive gas.

[0024] Optionally, the etching gas used in the chemically assisted ion beam etching includes at least one of an inert gas and a reactive gas.

[0025] Optionally, the inert gas includes at least one of He, Ne, Ar, Kr, Xe and N2.

[0026] Optionally, the reactive gas includes at least one of F-based, Cl-based, Br-based gas and O2.

[0027] Optionally, the value range of the first angle θ is α-5° to α+5°: tanα=d / h;

[0028] Among them, α is the theoretical value of the first angle, d is the size of the opening along the second direction on the cross-sectional view of the semiconductor device, h is the height from the preset film layer to be etched area to the port position of the opening, and the second direction is parallel to the plane where the semiconductor device is located.

[0029] Optionally, the sidewall of the opening is perpendicular to the top surface of the opening, or the sidewall of the opening is not perpendicular to the top surface of the opening.

[0030] Optionally, the sidewall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the sidewall of the opening is the height of the portion to be etched in the preset film layer.

[0031] Optionally, the sidewall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the sidewall of the opening is greater than the height of the portion to be etched in the preset film layer.

[0032] Optionally, the side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is the same as the height of the side wall.

[0033] Optionally, in the process of etching a plurality of sub-regions of the predetermined film layer located on the sidewall of the opening in the semiconductor device,

[0034] The energy of the ion beam when it is extracted ranges from 0 to 2000 eV;

[0035] The ion source power ranges from 0 to 3000W;

[0036] The beam current range of the ion beam when it is extracted is 0-2A, and the gas flow range of the ion source generating the ion beam or the etching chamber where the semiconductor device is located is 0-300 sccm;

[0037] The temperature range of the base is 0°C to 300°C. The etching method for a film layer located on the sidewall of an opening provided in an embodiment of the present application directly utilizes an ion beam to etch multiple sub-regions of the predetermined film layer located on the sidewall of the opening in the semiconductor device when etching the predetermined film layer. When applied to the processing of the sidewall film layer at a specific location in a through-silicon via, compared to the current process for processing the sidewall film layer at a specific location in a through-silicon via, only one process is required, greatly reducing the number of process steps.

[0038] Moreover, the etching method of the film layer located on the side wall of the opening provided in the embodiment of the present application does not need to fill the opening with filling material when etching the preset film layer, thereby solving the problem of the difficulty of the filling process for some holes with smaller diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0040] The structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not intended to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size, without affecting the efficacy and objectives that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0041] FIG1 is a schematic diagram of a through silicon via in a semiconductor device;

[0042] Figures 2 to 5 are schematic diagrams of the etching process of the metal film layer in the current through-silicon via;

[0043] FIG6 is a flow chart of a method for etching a film layer located on a sidewall surface of an opening provided by one embodiment of the present application;

[0044] FIG7 is a schematic diagram of a through hole in a semiconductor device under ideal conditions;

[0045] 8 to 13 are schematic diagrams showing asymmetric sidewalls of through holes in semiconductor devices;

[0046] 14-15 are schematic diagrams of an etching process of a method for etching a film layer located on a sidewall surface of an opening provided in one embodiment of the present application;

[0047] FIG16 is a schematic diagram of a groove in a semiconductor device under ideal conditions;

[0048] 17 to 22 are schematic diagrams showing the asymmetric sidewalls of a groove in a semiconductor device. DETAILED DESCRIPTION

[0049] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] It will be apparent to those skilled in the art that various modifications and variations can be made in this application without departing from the spirit or scope of this application. Therefore, this application is intended to cover modifications and variations of this application that fall within the scope of the corresponding claims (technical solutions claimed for protection) and their equivalents. It should be noted that the embodiments provided in the examples of this application can be combined with each other without contradiction.

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0052] As described in the background technology section, the current manufacturing process of TSVs involves many steps, and for some holes with smaller diameters, the filling process of TSVs is more difficult.

[0053] It should be noted that in semiconductor devices, when using silicon vias to achieve interconnection between different chips, a through hole is usually first made in the semiconductor device, and then metal is plated in the through hole to achieve conduction between different chips. However, based on the functions implemented by the semiconductor device, sometimes the silicon via needs to connect some devices while disconnecting other devices. This requires removing the metal at a specific position on the side wall of the silicon via to achieve this.

[0054] Currently, when processing the sidewall film layer at a specific location in a TSV (i.e., removing the metal layer at a specific location on the TSV sidewall), it is necessary to first fill the TSV with a filling material, then use inductively coupled plasma (ICP) to etch the filling material in the TSV back to the specific location, then use ICP to remove the exposed target sidewall film layer, and finally etch the remaining filling material.

[0055] As shown in FIG1 , FIG1 shows a through silicon via 01 in a semiconductor device, wherein region A is a portion of a film layer to be disconnected; as shown in FIG2 , a filling material 02 is first filled into the through silicon via 01, and the filling material 02 completely fills the through silicon via 01; as shown in FIG3 , an inductively coupled plasma (ICP) is used to etch the filling material 02 in the through silicon via 01, and the filling material 02 is etched back to a specific position, exposing a portion A of the film layer to be disconnected in the through silicon via 01; as shown in FIG4 , the exposed portion A of the film layer to be disconnected in the through silicon via 01 is removed using ICP; and as shown in FIG5 , the remaining portion of the filling material 02 is removed.

[0056] As can be seen from Figures 1 to 5, currently, using silicon vias to connect some devices and disconnect other devices requires four process steps, which is a large number of process steps. Moreover, for silicon vias with smaller diameters, the filling process is more difficult when filling the silicon vias with filling materials.

[0057] In addition, when the filling material in the silicon via is etched using ICP as shown in Figure 3 and the filling material is etched back to a specific position, the etching endpoint can only be achieved by controlling the etching depth through the process time, and the etching amount of the filling material cannot be effectively guaranteed, thereby affecting the accuracy of the removal position of the plating on the side wall of the silicon via.

[0058] In view of this, an embodiment of the present application provides an etching method for a film layer located on the side wall surface of an opening, which is applied to a semiconductor device, wherein the semiconductor device has an opening, and the side wall surface of the opening is coated with a preset film layer. Optionally, the preset film layer can be a metal film layer, and the formation process of the preset film layer is a deposition process, but the present application is not limited to this. In other embodiments of the present application, the preset film layer can also be a film layer of other materials, and the formation process of the preset film layer can also adopt other processes, depending on the specific circumstances.

[0059] As shown in FIG6 , the etching method of the film layer located on the sidewall surface of the opening provided in the embodiment of the present application includes:

[0060] S1: placing the semiconductor device on a base, wherein the area to be etched of the predetermined film layer includes a plurality of sub-areas arranged along a first direction, the plurality of sub-areas are equidistant from the base, and the first direction is parallel to the sidewall of the opening and the surface of the base;

[0061] S2: Use an ion beam to etch multiple sub-regions of a preset film layer located on the side wall of the opening in the semiconductor device until all the to-be-etched regions of the preset film layer are removed, and the incident angle of the ion beam forms a first angle with the surface where the semiconductor device is located. Optionally, the value range of the first angle is -90° to 0° and 0° to 90°, excluding endpoint values.

[0062] The etching method for the film layer located on the side wall of the opening provided in the embodiment of the present application directly utilizes an ion beam to etch multiple sub-regions of the preset film layer located on the side wall of the opening in the semiconductor device when etching the preset film layer. When applied to the processing of the side wall film layer at a specific position in a silicon through-hole, compared with the current process for processing the side wall film layer at a specific position in a silicon through-hole, only one step is required to complete the process, which greatly reduces the process steps.

[0063] Moreover, the etching method of the film layer located on the side wall of the opening provided in the embodiment of the present application does not need to fill the opening with filling material when etching the preset film layer, thereby solving the problem of the difficulty of the filling process for some holes with smaller diameters.

[0064] In addition, in the etching method of the film layer located on the side wall of the opening provided in the embodiment of the present application, when etching the preset film layer, the incident angle of the ion beam and the surface where the semiconductor device is located are at a first angle, and the value range of the first angle is -90° to 0° and 0° to 90°, excluding the endpoint value. Therefore, in the process of etching the preset film layer, the shielding effect of the side wall of the opening on the ion beam can be utilized, so that the ion beam can only etch the portion of the preset film layer located above a specific position, and will not etch the portion of the preset film layer located below the specific position. Therefore, in the process of etching the preset film layer, the area affected by the shielding effect can be controlled by setting the first angle, thereby achieving precise control of the etching position. Wherein, the specific position is the boundary between the area to be etched and the non-etched area in the preset film layer.

[0065] It should be noted that in the process of using an ion beam to etch multiple sub-regions of a preset film layer located on the side walls of the opening in the semiconductor device, if the upper port of the opening (i.e., the upper surface of the semiconductor device) is also covered by a preset film layer, then the portions of the preset film layer located on both sides of the upper port of the opening will be removed at the same time.

[0066] It should also be noted that in this embodiment, during the etching of the preset film layer located on the side wall of the opening, any asymmetry of different areas of the side wall of the opening will be amplified by the shielding effect of the side wall of the opening on the ion beam, thereby producing a height difference at the etching interface of the area to be etched of the preset film layer.

[0067] Optionally, in an embodiment of the present application, the opening may be a through hole or a groove, and the port shape of the opening may be circular or rectangular. The present application does not limit this, and a description will be given below in conjunction with specific circumstances.

[0068] Example 1

[0069] Specifically, in one embodiment of the present application, when the opening is a through hole and the port shape of the opening is circular, etching multiple sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device using an ion beam until all the to-be-etched regions of the preset film layer are removed includes:

[0070] While etching a plurality of sub-regions of a predetermined film layer on a sidewall of an opening in the semiconductor device, the base table is rotated until all the to-be-etched regions of the predetermined film layer are removed.

[0071] Optionally, in one embodiment of the present application, the rotation speed of the base is in the range of 0rpm to 80rpm, that is, in the process of etching multiple sub-regions of a preset film layer located on the side wall of the opening in the semiconductor device, the rotation speed of the base rotating around its own center (i.e., rotating) is in the range of 0rpm to 80rpm, but the present application does not limit this, and it depends on the specific situation.

[0072] Specifically, in one embodiment of the present application, during the process of etching multiple sub-regions of the preset film layer located on the side wall of the opening in the semiconductor device, the base rotates evenly so that the etching of the multiple sub-regions of the preset film layer located on the side wall of the opening in the semiconductor device is more uniform.

[0073] Based on any of the above embodiments, in one embodiment of the present application, etching the plurality of sub-regions of the predetermined film layer located on the sidewall of the opening in the semiconductor device using an ion beam includes:

[0074] At least one etching method selected from standard ion beam etching, reactive ion beam etching, and chemically assisted ion beam etching is used to etch multiple sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device. That is, when etching the preset film layer located on the sidewall of the opening, a standard ion beam etching process, a reactive ion beam etching process, a chemically assisted ion beam etching process, or any combination of a standard ion beam etching process, a reactive ion beam etching process, and a chemically assisted ion beam etching process can be used. This application does not impose any restrictions on this, and the specific process depends on the circumstances.

[0075] It should be noted that standard ion beam etching (IBE), also known as ion milling (IBM) or ion sputtering, utilizes the principle of glow discharge to decompose argon gas into argon ions. These argon ions are accelerated by the anode electric field and physically bombard the sample surface to achieve the etching effect. The etching process involves filling the ion source discharge chamber with Ar gas and ionizing it to form a plasma. The ions are then drawn out and accelerated by the grid in a beam-like form. The ion beam, with a certain energy, enters the chamber and strikes the solid surface, bombarding the atoms on the solid surface and causing sputtering to achieve the etching purpose. This is a purely physical etching process. A mask is placed on the workpiece surface to prepare the grooves. Ultimately, the exposed portion is etched away, while the masked portion is retained, forming the desired etched pattern. Reactive Ion Beam Etching (RIBE) is based on ion beam etching (IBE) by adding corrosive gas. Therefore, it not only retains the physical etching ability of the ion beam, but also increases the chemical reaction ability of the corrosive gas to the sample after ionization. It also supports the chemically assisted etching capability of the non-ionized corrosive gas (i.e., chemically-assisted ion beam etching: CAIBE, Chemically-Assisted Ion Beam Etching), which can significantly increase the etching rate and improve the etching quality for materials suitable for chemical assistance.

[0076] Specifically, in one embodiment of the present application, the etching gas used in the standard ion beam etching is an inert gas; the etching gas used in the reactive ion beam etching includes an inert gas or a reactive gas; and the etching gas used in the chemically assisted ion beam etching includes at least one of an inert gas and a reactive gas.

[0077] Optionally, in one embodiment of the present application, the inert gas includes at least one of He, Ne, Ar, Kr, Xe and N2, that is, the inert gas may include one or a combination of He, Ne, Ar, Kr, Xe and N2; the reactive gas includes at least one of F-based, Cl-based, Br-based gas and O2, that is, the reactive gas includes one or a combination of F-based, Cl-based, Br-based gas and O2; the present application does not limit this, and the specific situation depends on the circumstances.

[0078] Specifically, in one embodiment of the present application, the F-based gas may be CF4, CF8, CHF3, or BF3, the Cl-based gas may be HCl, CCl4, BCl3, or Cl2, and the Br-based gas may be HBr; the present application does not limit this, and the specific situation may vary.

[0079] It should be noted that, in actual applications, when the preset film layer is etched by standard ion beam etching or reactive ion beam etching, the inert gas or the reactive gas is directly introduced into the ion source that generates the ion beam; when the preset film layer is etched by chemically assisted ion beam etching, the inert gas and the reactive gas can be directly introduced into the ion source that generates the ion beam, or can be directly introduced into the etching chamber where the semiconductor device is located. This application does not limit this, and it depends on the specific situation.

[0080] On the basis of any of the above embodiments, in one embodiment of the present application, in the process of etching multiple sub-regions of a preset film layer located on the side wall of the opening in the semiconductor device using an ion beam until all the areas to be etched of the preset film layer are removed, the energy value range of the ion beam when it is drawn out is 0 to 2000eV, so as to be compatible with the process capabilities of existing etching equipment and reduce process difficulty and etching costs. It should be noted that the greater the energy of the ion beam when it is drawn out, the greater the etching rate; the value range of the ion source power is 0 to 3000W, so as to be compatible with the process capabilities of existing etching equipment; the ion beam The beam current when being extracted is in the range of 0 to 2A, so as to be compatible with the process capabilities of existing etching equipment. The greater the beam current when the ion beam is extracted, the greater the etching rate; the gas flow rate of the ion source that generates the ion beam or the etching chamber where the semiconductor device is located is in the range of 0 to 300 sccm, so as to be compatible with the process capabilities of existing etching equipment; the temperature range of the base is: 0°C to 300°C, so as to be compatible with the process capabilities of existing etching equipment; the pressure range in the etching chamber is 0.001mT to 5mT, so as to be compatible with the process capabilities of existing etching equipment; but this application does not limit this, and it depends on the specific situation.

[0081] It should be noted that, in actual application, due to the existence of a beam divergence angle of the ion beam, the actual first angle θ is generally a theoretical angle α±5°. Therefore, based on any of the above embodiments, in an embodiment of the present application, the value range of the first angle θ is α-5°~α+5°: tanα=d / h; wherein, α is the theoretical value of the first angle; as shown in Figure 7, d is the size of the opening along the second direction on the cross-sectional view of the semiconductor device, that is, the diameter of the through hole; h is the height from the preset film layer to be etched area to the port position of the opening; wherein, the second direction is parallel to the plane where the semiconductor device is located.

[0082] It should also be noted that, in a specific application process, when the sidewall material of the opening and the material of the preset film layer are different, the selection of the etching gas may be the same or different, depending on the specific situation.

[0083] Specifically, in one embodiment of the present application, when the material of the opening is SiO2 and the material of the preset film layer located on the side wall of the opening is TiN, the etching gas can be selected to be Cl-based; in another embodiment of the present application, when the material of the opening is SiO2 and the material of the preset film layer located on the side wall of the opening is Cr, the etching gas can be selected to be Cl-based, but the present application does not limit this. In other embodiments of the present application, when the material of the preset film layer is different, the choice of the etching gas may also be different, depending on the specific situation.

[0084] In addition, in the specific application process, when using an ion beam to etch multiple sub-regions of a preset film layer located on the side wall of the opening in the semiconductor device, different ion beam incident angles can also be selected or matched based on the different apertures of the through holes and different modification depths (i.e., the depth of the area to be etched of the preset film layer).

[0085] Optionally, in one embodiment of the present application, the material of the side wall of the through hole is SiO2, the material of the preset film layer is TiN, the diameter of the through hole ranges from 2μm to 3μm, and when it is necessary to process a film layer that is 5μm or more away from the through hole port, the incident angle of the ion beam is calculated according to the formula tanα=d / h to obtain an incident angle of approximately 21° to 32°. After adjusting the angle according to actual experiments, the RIBE method with Cl2 as the gas is used to partially remove the area to be etched of the preset film layer.

[0086] In another embodiment of the present application, the material of the through hole is Si3N4, the material of the preset film layer is Cr, the diameter of the through hole ranges from 2μm to 3μm, and when it is necessary to process a film layer that is 5μm or more away from the through hole port, the incident angle of the ion beam is calculated according to the formula tanα=d / h, and the incident angle ranges from about 21° to 32°. After adjusting the angle according to actual experiments, the RIBE method with Cl-based gas is used to remove part of the area to be etched of the preset film layer.

[0087] In another embodiment of the present application, the material of the side wall of the through hole is SiO2, the material of the preset film layer is C, the diameter of the through hole ranges from 2μm to 3μm, and when it is necessary to process a film layer that is 5μm or more away from the through hole port, the incident angle of the ion beam is calculated according to the formula tanα=d / h to obtain an incident angle of approximately 21° to 32°. After adjusting the angle according to actual experiments, the RIBE method with O2 as the gas is used to remove part of the area to be etched of the preset film layer.

[0088] From the above, it can be seen that in the process of etching the preset film layer located on the side wall of the opening, any asymmetry of different areas of the opening side wall will be amplified by the shielding effect of the opening side wall on the ion beam, thereby producing a height difference at the etching interface of the area to be etched of the preset film layer.

[0089] Continuing with FIG7 , ideally, the sidewalls of the opening 10 are symmetrical everywhere and the sidewalls of the opening 10 are perpendicular to the top surface of the opening 10; in practical applications, when the sidewalls of the opening are not perpendicular to the top surface of the opening, the asymmetric forms of the sidewalls of the opening 10 are roughly divided into three types, as shown in FIG8 to FIG13 . Given the diameter d of the through hole and the height of the portion of the preset film layer 20 to be processed being h, the ion beam incident angle is determined according to tanα=d / h. In the structure shown in FIG8 , the sidewalls of the opening are not perpendicular to the top surface of the opening, and the height of the inclined portion of the sidewalls of the opening is h. At this time, the height difference generated by the etching interface of the to-be-etched area of ​​the preset film layer 20 As shown in FIG9 , FIG9 shows the height difference y1 generated at the etching interface after the etching of the to-be-etched area of ​​the preset film layer in the structure shown in FIG8 is completed; in the structures shown in FIG10 and FIG11 , wherein, in the structure shown in FIG10 , the side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is greater than h; in the structure shown in FIG11 , the side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is the height of the side wall. In these two structures, the height difference y1 generated at the etching interface of the to-be-etched area of ​​the preset film layer 20 is Wherein, x is the distance that the asymmetric side wall of the opening deviates from the ideal position, β is the angle of the asymmetric side wall of the opening relative to the ideal position, the direction of the dotted single arrow represents the incident direction of the ion beam, and the angle between the ion beam etching different areas and the upper end face of the opening is the same. As shown in Figures 12 and 13, Figure 12 shows the height difference y2 generated at the etching interface after the etching of the area to be etched of the preset film layer in the structure shown in Figure 10 is completed, and Figure 13 shows the height difference y2 generated at the etching interface after the etching of the area to be etched of the preset film layer in the structure shown in Figure 12 is completed. It should be noted that in actual applications, if a height difference calculated in accordance with the above formula appears in the asymmetric opening, it can be determined that this structure is completed by this process.

[0090] Example 2:

[0091] In another embodiment of the present application, the opening is a groove, and the port of the opening is rectangular; etching multiple sub-regions of a predetermined film layer located on the sidewall of the opening in the semiconductor device using an ion beam until all the to-be-etched regions of the predetermined film layer are removed includes:

[0092] An ion beam is used to etch a sub-region of a preset film layer located on the side wall of an opening in the semiconductor device. After the etching of the sub-region is completed, the etching is stopped. After rotating the base, the ion beam is used to etch another sub-region of the preset film layer located on the side wall of the opening in the semiconductor device. The process is repeated until all the areas to be etched of the preset film layer are removed.

[0093] It should be noted that, in this embodiment, since the different sub-regions of the preset film layer are directly etched in the same etching chamber, in this embodiment of the application, the etching of the different sub-regions of the preset film layer can be regarded as a one-step process.

[0094] Based on the above embodiment, in one embodiment of the present application, etching a plurality of sub-regions of a predetermined film layer located on a sidewall of an opening in the semiconductor device using an ion beam includes:

[0095] At least one etching method selected from standard ion beam etching, reactive ion beam etching, and chemically assisted ion beam etching is used to etch multiple sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device. That is, when etching the preset film layer located on the sidewall of the opening, a standard ion beam etching process, a reactive ion beam etching process, a chemically assisted ion beam etching process, or any combination of a standard ion beam etching process, a reactive ion beam etching process, and a chemically assisted ion beam etching process can be used. This application does not impose any restrictions on this, and the specific process depends on the circumstances.

[0096] Specifically, in one embodiment of the present application, the etching gas used in the standard ion beam etching is an inert gas; the etching gas used in the reactive ion beam etching includes an inert gas or a reactive gas; and the etching gas used in the chemically assisted ion beam etching includes at least one of an inert gas and a reactive gas.

[0097] Optionally, in one embodiment of the present application, the inert gas includes at least one of He, Ne, Ar, Kr, Xe and N2, that is, the inert gas may include one or a combination of He, Ne, Ar, Kr, Xe and N2; the reactive gas includes at least one of F-based, Cl-based, Br-based gas and O2, that is, the reactive gas includes one or a combination of F-based, Cl-based, Br-based gas and O2; the present application does not limit this, and the specific situation depends on the circumstances.

[0098] Specifically, in one embodiment of the present application, the F-based gas may be CF4, CF8, CHF3, BF3, the Cl-based gas may be HCl, CCl4, BCl3, Cl2, and the Br-based gas may be HBr; the present application does not limit this, and the specific situation may vary.

[0099] It should be noted that, in actual applications, when the preset film layer is etched by standard ion beam etching or reactive ion beam etching, the inert gas or the reactive gas is directly introduced into the ion source that generates the ion beam; when the preset film layer is etched by chemically assisted ion beam etching, the inert gas and the reactive gas can be directly introduced into the ion source that generates the ion beam, or can be directly introduced into the etching chamber where the semiconductor device is located. This application does not limit this, and it depends on the specific situation.

[0100] On the basis of any of the above embodiments, in one embodiment of the present application, the method for stopping etching includes: using a shielding plate to block the ion beam to stop etching the preset film layer; in another embodiment of the present application, the method for stopping etching includes: using a method of stopping beam pulling to stop etching the preset film layer; in another embodiment of the present application, the method for stopping etching includes: using a method of extinguishing the ion source to stop etching the preset film layer; in other embodiments of the present application, other methods can also be used to stop etching the preset film layer, and the present application does not limit this, and it depends on the specific circumstances.

[0101] Optionally, in a specific embodiment of the present application, etching a plurality of sub-regions of a predetermined film layer located on the sidewalls of the opening in the semiconductor device using an ion beam until all the to-be-etched regions of the predetermined film layer are removed includes:

[0102] As shown in Figure 14, an ion beam is used to etch a first sub-region of a preset film layer located on the side wall of an opening in the semiconductor device. After the etching of the sub-region is completed, the etching is stopped. The base is rotated, as shown in Figure 15, and an ion beam is used to etch a second sub-region of the preset film layer located on the side wall of an opening in the semiconductor device to complete the etching of the area to be etched of the preset film layer.

[0103] Optionally, in one embodiment of the present application, an incident angle of θ is used to etch a first sub-region of a preset film layer located on the side wall of the opening in the semiconductor device using an ion beam, that is, the angle between the transmission direction of the ion beam and the surface where the semiconductor device is located is θ; after the etching of the sub-region is completed, the etching is stopped; after the base is rotated 180° around the center of the base (that is, after the base rotates 180°), the incident angle of θ is used again to etch a second sub-region of the preset film layer located on the side wall of the opening in the semiconductor device using an ion beam.

[0104] In another embodiment of the present application, an incident angle of θ is used to etch a first sub-region of a preset film layer located on the side wall of the opening in the semiconductor device using an ion beam, that is, the angle between the transmission direction of the ion beam and the surface where the semiconductor device is located is θ; after the etching of the sub-region is completed, the etching is stopped; after the base is rotated around the ion source that generates the ion beam (that is, after the base revolves), an incident angle of -θ is used to etch a second sub-region of the preset film layer located on the side wall of the opening in the semiconductor device using an ion beam, and the angle between the transmission direction of the ion beam and the surface where the semiconductor device is located is -θ.

[0105] It should be noted that, in actual application, due to the existence of a beam divergence angle of the ion beam, the actual first angle θ is generally a theoretical angle α±5°. Therefore, based on any of the above embodiments, in an embodiment of the present application, the value range of the first angle θ is α-5°~α+5°: tanα=d / h; wherein, α is the theoretical value of the first angle; as shown in Figure 16, d is the size of the opening along the second direction on the cross-sectional view of the semiconductor device, that is, the width of the groove; h is the height from the preset film layer to be etched area to the port position of the opening; wherein, the second direction is parallel to the plane where the semiconductor device is located.

[0106] Based on any of the above embodiments, in one embodiment of the present application, in the process of using an ion beam to etch multiple sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device until all the to-be-etched regions of the preset film layer are removed, the energy of the ion beam when it is extracted is in the range of 0 to 2000 eV, so as to be compatible with the process capabilities of existing etching equipment and reduce process difficulty and etching cost; the power of the ion source is in the range of 0 to 3000 W, so as to be compatible with the process capabilities of existing etching equipment; the beam current of the ion beam when it is extracted is in the range of 0 to 2 A, so as to be compatible with the process capabilities of existing etching equipment; the gas flow rate entering the ion source or etching chamber is in the range of 0 to 300 sccm, so as to be compatible with the process capabilities of existing etching equipment; the temperature of the base is in the range of 0°C to 300°C, so as to be compatible with the process capabilities of existing etching equipment; the pressure in the etching chamber is in the range of 0.001 mT to 5 mT, so as to be compatible with the process capabilities of existing etching equipment; however, this application does not impose any limitation on this, and the specific situation depends on the circumstances.

[0107] It should be noted that, in specific applications, when the materials of the sidewalls of the opening and the materials of the predetermined film layer are different, the etching gas selected may be the same or different, depending on the specific situation. It should also be noted that, when etching the sub-region of the predetermined film layer located on the sidewalls of the opening, different ion beam incident angles may be selected or combined based on different modification depths.

[0108] Specifically, in one embodiment of the present application, when the material of the opening is SiO2 and the material of the preset film layer located on the side wall of the opening is TiN, the etching gas can be selected to be Cl-based; in another embodiment of the present application, when the material of the opening is SiO2 and the material of the preset film layer located on the side wall of the opening is Cr, the etching gas can be selected to be Cl-based, but the present application does not limit this. In other embodiments of the present application, when the material of the preset film layer is different, the choice of the etching gas may also be different, depending on the specific situation.

[0109] Optionally, in one embodiment of the present application, the material of the side wall of the groove is SiO2, the material of the preset film layer is C, and the groove diameter ranges from 2μm to 3μm, that is, the width of the groove ranges from 2μm to 3μm. When it is necessary to process a film layer that is 5μm or more away from the groove port, the incident angle of the ion beam is calculated according to the formula tanα=d / h to obtain an incident angle of approximately 21° to 32°. After adjusting the angle according to the actual experiment, the RIBE method with O2 as the gas is used to first remove the portion of the preset film layer on one side of the groove side wall, and then rotate it to another angle to remove the portion of the preset film layer on the other side of the groove side wall.

[0110] From the above, it can be seen that in the process of etching the preset film layer located on the side wall of the opening, any asymmetry of different areas of the opening side wall will be amplified by the shielding effect of the opening side wall on the ion beam, thereby producing a height difference at the etching interface of the area to be etched of the preset film layer.

[0111] Continuing with FIG16 , ideally, the sidewalls of the opening 10 are symmetrical everywhere and the sidewalls of the opening 10 are perpendicular to the top surface of the opening 10; in practical applications, when the sidewalls of the opening are not perpendicular to the top surface of the opening, the asymmetric forms of the sidewalls of the opening 10 are roughly divided into three types, as shown in FIG17 to FIG22 . Given a groove width d, and a height of a portion of the preset film layer 20 to be processed being h, the ion beam incident angle is determined according to tanα=d / h. In the structure shown in FIG17 , when the sidewalls of the opening are not perpendicular to the top surface of the opening, and the height of the inclined portion of the sidewalls of the opening is h, the height difference generated by the etching interface of the to-be-etched region of the preset film layer 20 is As shown in FIG18, FIG18 shows the height difference y1 generated at the etching interface after the etching of the to-be-etched area of ​​the preset film layer 20 in the structure shown in FIG17 is completed; in the structures shown in FIG19 and FIG20, wherein, in the structure shown in FIG19, the side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is greater than h, and in the structure shown in FIG20, the side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is the height of the side wall. In these two structures, the height difference y1 generated at the etching interface of the to-be-etched area of ​​the preset film layer 20 is Wherein, x is the distance that the asymmetric side wall of the opening deviates from the ideal position, β is the angle of the asymmetric side wall of the opening relative to the ideal position, the direction of the dotted single arrow represents the incident direction of the ion beam, and the angle between the ion beam etching different areas and the upper end face of the opening is the same. As shown in Figures 21 and 22, Figure 21 shows the height difference y2 generated at the etching interface after the etching of the area to be etched of the preset film layer in the structure shown in Figure 19 is completed, and Figure 22 shows the height difference y2 generated at the etching interface after the etching of the area to be etched of the preset film layer in the structure shown in Figure 20 is completed. It should be noted that in actual applications, if a height difference calculated in accordance with the above formula appears in the asymmetric opening, it can be determined that this structure is completed by this process.

[0112] In summary, the etching method of the film layer located on the side wall of the opening provided in the embodiment of the present application directly utilizes an ion beam to etch multiple sub-regions of the preset film layer located on the side wall of the opening in the semiconductor device when etching the preset film layer. When applied to the treatment of the side wall film layer at a specific position in a silicon through hole, compared with the current process for treating the side wall film layer at a specific position in a silicon through hole, not only only one step is required to complete the process, which greatly reduces the process steps, but also solves the problem of greater difficulty in filling the process for some holes with smaller diameters, and can also accurately control the etching depth.

[0113] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For relevant parts, refer to the description of the methods.

[0114] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for etching a film layer located on the side wall surface of an opening, applied to a semiconductor device, wherein the semiconductor device has an opening, and the side wall surface of the opening is plated with a preset film layer, characterized in that: The method includes: Placing the semiconductor device on a base, the region to be etched of the preset film layer includes a plurality of sub-regions arranged along a first direction, the plurality of sub-regions are equidistant from the base, and the first direction is parallel to the sidewall of the opening and the base; An ion beam is used to etch multiple sub-regions of a preset film layer located on the side wall of the opening in the semiconductor device until all the to-be-etched regions of the preset film layer are removed, and the incident angle of the ion beam forms a first angle with the surface where the semiconductor device is located, and the value range of the first angle is -90° to 90°, excluding -90°, 0° and 90°.

2. The etching method according to claim 1, characterized in that: The opening is a through hole, and the shape of the port of the opening is circular; Etching a plurality of sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device by using an ion beam until all the to-be-etched regions of the preset film layer are removed includes: While etching a plurality of sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device, the base table is rotated until all the to-be-etched regions of the preset film layer are removed.

3. The etching method according to claim 2, characterized in that: The rotation speed of the base platform ranges from 0 rpm to 80 rpm.

4. The etching method according to claim 2, characterized in that: While etching a plurality of sub-regions of a preset film layer on the sidewall of an opening in the semiconductor device, the base table rotates uniformly.

5. The etching method according to claim 1, characterized in that: The opening is a groove, and the port shape of the opening is a rectangle; Etching a plurality of sub-regions of a preset film layer located on the sidewall of the opening in the semiconductor device by using an ion beam until all the to-be-etched regions of the preset film layer are removed includes: An ion beam is used to etch a sub-region of a preset film layer located on the side wall of an opening in the semiconductor device. After the etching of the sub-region is completed, the etching is stopped. After the base is rotated, the ion beam is used to etch another sub-region of the preset film layer located on the side wall of the opening in the semiconductor device. The process is repeated until all the areas to be etched of the preset film layer are removed.

6. The etching method according to claim 5, characterized in that: The method for stopping etching comprises: The ion beam is shielded by a shielding plate to stop etching the preset film layer.

7. The etching method according to claim 5, characterized in that: The method for stopping etching includes: stopping the etching of the preset film layer by stopping the beam drawing.

8. The etching method according to claim 5, characterized in that: The method for stopping etching includes: stopping etching of the preset film layer by extinguishing an ion source.

9. The etching method according to claim 1, characterized in that: Etching a plurality of sub-regions of a preset film layer located on the sidewall of an opening in the semiconductor device by using an ion beam comprises: At least one of standard ion beam etching, reactive ion beam etching and chemically assisted ion beam etching is used to etch a plurality of sub-regions of a predetermined film layer on the sidewall of the opening in the semiconductor device. Line etching.

10. The etching method according to claim 9, characterized in that: The etching gas used in the standard ion beam etching is an inert gas.

11. The etching method according to claim 9, characterized in that: The etching gas used in the reactive ion beam etching includes an inert gas or a reactive gas.

12. The etching method according to claim 9, characterized in that: The etching gas used in the chemically assisted ion beam etching includes at least one of an inert gas and a reactive gas.

13. The etching method according to any one of claims 10 to 12, characterized in that: The inert gas includes at least one of He, Ne, Ar, Kr, Xe and N2.

14. The etching method according to any one of claims 10 to 12, characterized in that: The reactive gas includes at least one of F-based, Cl-based, Br-based gases and O2.

15. The etching method according to claim 1, characterized in that: The value range of the first angle θ is α-5° to α+5°: tanα=d / h; Among them, α is the theoretical value of the first angle, d is the size of the opening along the second direction on the cross-sectional view of the semiconductor device, h is the height from the preset film layer to be etched area to the port position of the opening, and the second direction is parallel to the plane where the semiconductor device is located.

16. The etching method according to claim 1, characterized in that: The side wall of the opening is perpendicular to the top surface of the opening, or the side wall of the opening is not perpendicular to the top surface of the opening.

17. The etching method according to claim 16, characterized in that: The side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is the height of the portion to be etched in the preset film layer.

18. The etching method according to claim 16, characterized in that: The side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is greater than the height of the portion to be etched in the preset film layer.

19. The etching method according to claim 16, characterized in that: The side wall of the opening is not perpendicular to the top surface of the opening, and the height of the inclined portion of the side wall of the opening is the same as the height of the side wall.

20. The etching method according to claim 1, characterized in that: In the process of etching a plurality of sub-regions of a predetermined film layer located on the sidewall of an opening in the semiconductor device, The energy value range of the ion beam when it is extracted is 0 to 2000 eV; The ion source power has a value range of 0 to 3000 W; The beam current range of the ion beam when it is extracted is 0-2A, and the gas flow range of the ion source generating the ion beam or the etching chamber where the semiconductor device is located is 0-300 sccm; The temperature range of the base is 0°C to 300°C.

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