Etching method of film layer located on surface of side wall of opening

Abstract

The invention provides an etching method of a film layer located on the surface of the side wall of an opening, the etching method is applied to a semiconductor device, the semiconductor device is provided with the opening, the surface of the side wall of the opening is plated with a preset film layer, the method comprises the steps that the semiconductor device is placed on a base station, and a to-be-etched area of the preset film layer comprises a plurality of sub-areas arranged in the first direction; and etching a plurality of sub-regions of a preset film layer on the side wall of the opening in the semiconductor device by using an ion beam until all regions to be etched of the preset film layer are removed, the incident angle of the ion beam and the surface where the semiconductor device is located form a first angle, and the value range of the first angle is-90 degrees to 90 degrees and does not include-90 degrees, 0 degree and 90 degrees. According to the method, only one process is needed, the process steps are greatly reduced, the opening does not need to be filled with a filling material, and therefore the problem that for some holes with small diameters, the filling process is large in difficulty is solved.

Description

Technical Field

[0001] 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

[0002] With the development of semiconductor technology, the integration of semiconductor devices is getting higher and higher. Specifically, in application, semiconductor devices use silicon through vias to stack multiple chips vertically to reduce the interconnection length, so that more functions can be packaged into the integrated circuit without increasing the plane 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 a lower power. However, the current manufacturing process of silicon through vias has many steps, and for some holes with smaller diameters, the filling process of silicon through vias is more difficult. Summary of the invention

[0003] In view of this, the present application provides an etching method for a film layer located on the surface of an opening sidewall, so as to reduce the process steps and lower the process difficulty when applied to the production of through silicon vias.

[0004] Specifically, this application provides the following technical solutions

[0005] A method for etching a film layer located on a 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, the method comprising:

[0006] 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;

[0007] 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°.

[0008] 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 side wall 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:

[0009] 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.

[0010] Optionally, the rotation speed of the base platform ranges from 0 rpm to 80 rpm.

[0011] 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 table is rotated uniformly.

[0012] Optionally, the opening is a groove, and the port shape of the opening is a rectangle; etching multiple sub-regions of a preset film layer located on the side wall 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:

[0013] 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.

[0014] Optionally, the method for stopping etching includes:

[0015] The ion beam is shielded by a shielding plate to stop etching the preset film layer.

[0016] Optionally, the method for stopping etching includes: stopping the etching of the preset film layer by stopping the beam drawing.

[0017] Optionally, the method for stopping etching includes: stopping etching of the preset film layer by extinguishing an ion source.

[0018] Optionally, 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 includes:

[0019] At least one etching method selected from among 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 preset film layer located on the sidewall of the opening in the semiconductor device.

[0020] Optionally, the etching gas used in the standard ion beam etching is an inert gas.

[0021] Optionally, the etching gas used in the reactive ion beam etching includes an inert gas or a reactive gas.

[0022] Optionally, the etching gas used in the chemically assisted ion beam etching includes at least one of an inert gas and a reactive gas.

[0023] Optionally, the inert gas includes at least one of He, Ne, Ar, Kr, Xe and N2.

[0024] Optionally, the reactive gas includes at least one of F-based, Cl-based, Br-based gas and O2.

[0025] Optionally, the value range of the first angle θ is α-5° to α+5°: tan α=d / h;

[0026] 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.

[0027] Optionally, 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.

[0028] 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 height of the portion to be etched in the preset film layer.

[0029] 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 greater than the height of the portion to be etched in the preset film layer.

[0030] 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.

[0031] Optionally, in the process of etching a plurality of sub-regions of the preset film layer located on the sidewall of the opening in the semiconductor device,

[0032] The energy value range of the ion beam when it is extracted is 0 to 2000 eV;

[0033] The ion source power has a value range of 0 to 3000 W;

[0034] 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;

[0035] The temperature range of the base is: 0°C to 300°C. The etching method of the film layer located on the side wall of the opening provided in the embodiment of the present application directly uses 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 the silicon through hole, compared with the current process of processing the side wall film layer at a specific position in the silicon through hole, only one process is required to complete it, which greatly reduces the process steps.

[0036] Moreover, when etching the preset film layer, 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 greater difficulty in the filling process for some holes with smaller diameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, 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 embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0038] The structures, proportions, sizes, etc. illustrated 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 used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0039] Figure 1 A schematic diagram of a through silicon via in a semiconductor device;

[0040] Figure 2-Figure 5 A schematic diagram of the etching process of the metal film layer in the through silicon via is currently used;

[0041] Figure 6 A flow chart of a method for etching a film layer located on a sidewall surface of an opening provided in one embodiment of the present application;

[0042] Figure 7 Schematic diagram of a through hole in a semiconductor device under ideal conditions;

[0043] Figure 8-Figure 13 A schematic diagram of the asymmetric morphology of the sidewall of a through hole in a semiconductor device;

[0044] Figure 14-15A schematic diagram of an etching process of an etching method for a film layer located on a sidewall surface of an opening provided in one embodiment of the present application;

[0045] Fig.16 Schematic diagram of a groove in a semiconductor device under ideal conditions;

[0046] Figure 17-Figure 22 A schematic diagram of the asymmetric sidewall of a groove in a semiconductor device. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0048] It is obvious to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit or scope of the present application. Therefore, the present application is intended to cover modifications and changes of the present application that fall within the scope of the corresponding claims (technical solutions for protection) and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.

[0049] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0050] 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.

[0051] It should be noted that in semiconductor devices, when through silicon vias are used 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 through silicon via needs to connect some devices while disconnecting other devices, which requires removing the metal at a specific position on the side wall of the through silicon via to achieve this.

[0052] Currently, when processing the sidewall film layer at a specific position in a through silicon via (i.e., removing the metal layer at a specific position on the sidewall of the through silicon via), it is necessary to first fill the through silicon via with a filling material, and then use inductively coupled plasma (ICP) to etch the filling material in the through silicon via, etch the filling material back to a specific position, and then use ICP to remove the exposed target sidewall film layer, and finally etch the remaining filling material.

[0053] like Figure 1 As shown, Figure 1 FIG. 1 shows a through silicon via 01 in a semiconductor device, wherein region A is a portion of a film layer to be disconnected; Figure 2 As shown, firstly, a filling material 02 is filled in the through silicon via 01, and the filling material 02 completely fills the through silicon via 01; Figure 3 As shown, the filling material 02 in the through silicon via 01 is etched using inductively coupled plasma (ICP), and the filling material 02 is etched back to a specific position to expose a portion A of the film layer to be disconnected in the through silicon via 01; Figure 4 As shown, the portion A of the film layer to be disconnected in the exposed silicon through hole 01 is removed by ICP; Figure 5 As shown, the remaining portion of the filling material 02 is removed.

[0054] according to Figure 1-Figure 5 It can be seen that currently, when using silicon vias to connect some devices and disconnect other devices, four process steps are required, which is a large number of process steps; moreover, for silicon vias with smaller diameters, the filling process is more difficult when filling the filling material in the silicon vias.

[0055] In addition, Figure 3 As shown, the filling material in the silicon via is etched using ICP. When 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. 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.

[0056] 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.

[0057] like Figure 6 As shown, the etching method of the film layer located on the surface of the side wall of the opening provided in the embodiment of the present application includes:

[0058] S1: 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 surface of the base;

[0059] S2: 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 to-be-etched regions of the preset film layer are removed, the incident angle of the ion beam being at a first angle to the surface of the semiconductor device, and optionally, the first angle being in the range of -90° to 0° and 0° to 90°, excluding endpoint values.

[0060] The etching method for a film layer located on the side wall of an opening provided in an embodiment of the present application directly utilizes an ion beam to etch multiple sub-regions of a preset film layer located on the side wall of an 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 location in a through silicon via, compared with the current process for processing the side wall film layer at a specific location in a through silicon via, only one step is required to complete the process, thereby greatly reducing the process steps.

[0061] Moreover, when etching the preset film layer, 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 greater difficulty in the filling process for some holes with smaller diameters.

[0062] 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 used, so that the ion beam can only etch the part of the preset film layer located above the specific position, and will not etch the part 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. Among them, the specific position is the boundary between the area to be etched and the non-etched area in the preset film layer.

[0063] 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 an opening in the semiconductor device, if both sides of the upper port of the opening (i.e., the upper surface of the semiconductor device) are 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.

[0064] It should also be noted that, in the present embodiment, during the etching of the preset film layer located on the side wall of the opening, any asymmetry of different regions 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.

[0065] 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 is given below in conjunction with specific circumstances.

[0066] Embodiment 1

[0067] 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 side wall 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:

[0068] 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.

[0069] 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 circumstances.

[0070] Specifically, in one embodiment of the present application, during the process of etching multiple sub-regions of a preset film layer located on the side wall of an opening in the semiconductor device, the base rotates uniformly so that the etching of the multiple sub-regions of the preset film layer located on the side wall of an opening in the semiconductor device is more uniform.

[0071] Based on any of the above embodiments, in one embodiment of the present application, etching multiple sub-regions of a preset film layer located on the sidewall of an opening in the semiconductor device by using an ion beam includes:

[0072] At least one etching method selected from among 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 side wall of the opening in the semiconductor device. That is, when etching the preset film layer located on the side wall of the opening, a standard ion beam etching process may be used, a reactive ion beam etching process may be used, a chemically assisted ion beam etching process may be used, or any combination of a standard ion beam etching process, a reactive ion beam etching process and a chemically assisted ion beam etching process may be used. This application does not impose any limitation on this, and it depends on the specific circumstances.

[0073] It should be noted that standard ion beam etching (IBE, Ion Beam Etching), also known as ion milling (IBM, Ion Beam Milling), and some people call it ion sputtering etching, is to use the principle of glow discharge to decompose argon gas into argon ions. The argon ions are accelerated by the anode electric field to physically bombard the sample surface to achieve the effect of etching. The etching process is to fill the Ar gas into the ion source discharge chamber and ionize it to form a plasma, and then the grid will lead out and accelerate the ions in a beam form. The ion beam with a certain energy enters the studio and shoots at the solid surface to bombard the atoms on the solid surface, causing the material atoms to sputter and achieve the purpose of etching. It is pure physical etching. There is a mask for preparing grooves on the surface of the workpiece. In the end, the exposed part will be etched away, while the mask part will be retained to form the required etching pattern. Reactive ion beam etching (RIBE) is based on ion beam etching (IBE) with the addition of corrosive gas. Therefore, it not only retains the physical etching ability of ion beam, but also increases the chemical reaction ability of corrosive gas to the sample after ionization. It also supports the chemically assisted etching ability of non-ionized corrosive gas (ie chemically-assisted ion beam etching: CAIBE, Chemically-Assisted Ion Beam Etching), which can greatly increase the etching rate and improve the etching quality for materials suitable for chemical assistance.

[0074] 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.

[0075] 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, it depends on the specific circumstances.

[0076] 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.

[0077] 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 directly introduced into the etching chamber where the semiconductor device is located. The present application does not limit this, and it depends on the specific circumstances.

[0078] On the basis of any of the above embodiments, in one embodiment of the present application, in a process of using an ion beam to etch multiple sub-regions of a preset film layer located on the side wall of an opening in the semiconductor device until all the to-be-etched regions of the preset film layer are removed, the energy value range of the ion beam when it is extracted is 0 to 2000 eV, 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 extracted, the greater the etching rate; the ion source power range is 0 to 3000 W, so as to be compatible with the process capabilities of existing etching equipment; the ion beam The beam current when being extracted ranges from 0 to 2A to be compatible with the process capabilities of existing etching equipment. The larger the beam current when the ion beam is extracted, the greater the etching rate; the gas flow rate introduced into the ion source that generates the ion beam or the etching chamber where the semiconductor device is located ranges from 0 to 300 sccm to be compatible with the process capabilities of existing etching equipment; the temperature range of the base is: 0°C to 300°C to be compatible with the process capabilities of existing etching equipment; the pressure in the etching chamber ranges from 0.001mT to 5mT to be compatible with the process capabilities of existing etching equipment; but this application does not limit this and it depends on the specific circumstances.

[0079] 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° to α+5°: tanα=d / h; wherein α is the theoretical value of the first angle; Figure 7 As shown, 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.

[0080] It should also be noted that, in a specific application process, when the side wall 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.

[0081] 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 circumstances.

[0082] 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).

[0083] 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.

[0084] 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 is in the range of 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 range is 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.

[0085] 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 introduced is used to partially remove the area to be etched of the preset film layer.

[0086] From the above, it can be seen that during the etching process 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 generating a height difference at the etching interface of the area to be etched of the preset film layer.

[0087] Continue as Figure 7 As shown, 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, such as Figure 8-Figure 13 As shown, 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, then Figure 8 In the structure shown, 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 h. At this time, the height difference generated by the etching interface of the to-be-etched area of ​​the preset film layer 20 is like Fig. 9 As shown, Fig. 9 Shows Figure 8 In the structure shown, after the etching of the to-be-etched area of ​​the preset film layer is completed, a height difference y1 is generated on the etching interface; Fig.10 and Fig.11 In the structure shown, Fig.10 In the structure shown, 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. Fig.11 In the structure shown, 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 generated by the etching interface of the to-be-etched area of ​​the preset film layer 20 is Wherein, x is the distance that the asymmetric sidewall of the opening deviates from the ideal position, β is the angle between the asymmetric sidewall of the opening and the ideal position, the direction of the dashed single arrow represents the incident direction of the ion beam, and the angle between the ion beam etching different areas and the upper end surface of the opening is the same. Fig.12 and Fig.13 As shown, Fig.12 Shows Fig.10 In the structure shown, after the etching of the to-be-etched area of ​​the preset film layer is completed, the height difference y2 generated at the etching interface is Fig.13 Shows Fig.12 In the structure shown, the height difference y2 generated by the etching interface after the etching of the to-be-etched area of ​​the preset film layer is completed. It should be noted that in practical applications, if a height difference that meets the above formula appears in the asymmetric opening, it can be determined that the structure is completed by this process.

[0088] Embodiment 2:

[0089] 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 preset film layer located on the side wall 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:

[0090] 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.

[0091] 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 different sub-regions of the preset film layer can be regarded as a one-step process.

[0092] Based on the above embodiments, in one embodiment of the present application, etching multiple sub-regions of a preset film layer located on the sidewall of an opening in the semiconductor device by using an ion beam includes:

[0093] At least one etching method selected from among 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 side wall of the opening in the semiconductor device. That is, when etching the preset film layer located on the side wall of the opening, a standard ion beam etching process may be used, a reactive ion beam etching process may be used, a chemically assisted ion beam etching process may be used, or any combination of a standard ion beam etching process, a reactive ion beam etching process and a chemically assisted ion beam etching process may be used. This application does not impose any limitation on this, and it depends on the specific circumstances.

[0094] 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.

[0095] 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, it depends on the specific circumstances.

[0096] 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 depend on it.

[0097] 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 directly introduced into the etching chamber where the semiconductor device is located. The present application does not limit this, and it depends on the specific circumstances.

[0098] 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: stopping the beam pulling to stop etching the preset film layer; in another embodiment of the present application, the method for stopping etching includes: using an ion source extinguishing method 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, depending on the specific circumstances.

[0099] Optionally, in a specific embodiment of the present application, 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:

[0100] like Fig.14 As shown, the first sub-region of the preset film layer located on the side wall of the opening in the semiconductor device is etched by using an ion beam, and the etching is stopped after the etching of the sub-region is completed; the base is rotated, as shown in FIG. Fig.15As shown, an ion beam is then used to etch a second sub-region of the preset film layer located on the side wall of the opening in the semiconductor device to complete the etching of the to-be-etched region of the preset film layer.

[0101] 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.

[0102] 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.

[0103] 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° to α+5°: tanα=d / h; wherein α is the theoretical value of the first angle; Fig.16 As shown, 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.

[0104] 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 by using an ion beam 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 ion source power 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 when the ion beam is extracted is in the range of 0 to 2A, so as to be compatible with the process capabilities of existing etching equipment; the gas flow rate introduced into 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; but the present application does not limit this, and it depends on the specific circumstances.

[0105] It should 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. It should also be noted that, in the process of etching the sub-region of the preset film layer located on the sidewall of the opening, different ion beam incident angles can also be selected or matched based on different modification depths.

[0106] 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 circumstances.

[0107] 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, the groove diameter ranges from 2μm to 3μm, that is, the width of the groove ranges from 2μm to 3μm, and 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 actual experiments, 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 to another angle to remove the portion of the preset film layer on the other side of the groove side wall.

[0108] From the above, it can be seen that during the etching process 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 generating a height difference at the etching interface of the area to be etched of the preset film layer.

[0109] Continue as Fig.16 As shown, 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, such as Figure 17-Figure 22 As shown, given the groove width d, the height of the portion of the preset film layer 20 to be processed is h, and the ion beam incident angle is determined according to tanα=d / h, then Fig.17 In the structure shown, the side wall of the opening is not perpendicular to the top surface of the opening, and when the height of the inclined portion of the side wall of the opening is h, the height difference generated by the etching interface of the to-be-etched area of ​​the predetermined film layer 20 is like Fig.18 As shown, Fig.18 Shows Fig.17 In the structure shown, after the etching of the to-be-etched area of ​​the preset film layer 20 is completed, a height difference y1 is generated at the etching interface; Fig.19 and Fig. 20 In the structure shown, Fig.19 In the structure shown, 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. Fig. 20 In the structure shown, 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 generated by the etching interface of the to-be-etched area of ​​the preset film layer 20 is Wherein, x is the distance that the asymmetric sidewall of the opening deviates from the ideal position, β is the angle between the asymmetric sidewall of the opening and the ideal position, the direction of the dashed single arrow represents the incident direction of the ion beam, and the angle between the ion beam etching different areas and the upper end surface of the opening is the same. Fig.21 and Fig. 22 As shown, Fig.21 Shows Fig.19 In the structure shown, after the etching of the to-be-etched area of ​​the preset film layer is completed, the height difference y2 generated at the etching interface is Fig. 22 Shows Fig. 20 In the structure shown, the height difference y2 generated by the etching interface after the etching of the to-be-etched area of ​​the preset film layer is completed. It should be noted that in practical applications, if a height difference that meets the above formula appears in the asymmetric opening, it can be determined that this structure is completed by this process.

[0110] 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 processing of the side wall film layer at a specific position in a through silicon via, compared with the current process for processing the side wall film layer at a specific position in a through silicon via, not only only one step is required to complete, which greatly reduces the process steps, but also solves the problem of greater difficulty in the filling process for some holes with smaller diameters, and can also accurately control the etching depth.

[0111] In this specification, each embodiment is described in a progressive, parallel, or progressive and parallel manner. Each embodiment focuses on the differences from other embodiments, and 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.

[0112] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those 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 will not be limited to the embodiments shown herein, but will 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 etching method selected from among 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 preset film layer located on the sidewall of the opening in the semiconductor device.

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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