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 method is applied to a semiconductor device, and the method comprises the steps that the semiconductor device is placed on a carrying table, the opening is formed in the semiconductor device, and the surface of the side wall of the opening is plated with a preset film layer; forming a covering layer on the surface of the preset film layer; etching the covering layer by using an ion beam, removing a partial region of the covering layer, and exposing a first part of the preset film layer, the first part being a part, facing one side of the opening port, of the preset position in the preset film layer, the incident angle of the ion beam and the surface where the semiconductor device is located forming a first angle, the value range of the first angle is from-90 degrees to 0 degree and from 0 degree to 90 degrees, and the first angle does not comprise an end point value; removing the first part of the preset film layer; a remaining portion of the capping layer is removed. According to the method, in the process of etching the covering layer, the area influenced by the shielding effect can be controlled by setting the first angle, accurate control over the etching position is achieved, and the accuracy of the etching position is improved.

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, thereby packaging more functions into the integrated circuit without increasing the plane size of the integrated circuit. It should be noted that in integrated circuits, through silicon via interconnection 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.

[0003] At present, when TSVs are used to interconnect different chips, a through hole is usually made in a semiconductor device first, and then metal is plated in the through hole to achieve conduction between different chips. However, based on the functions of the semiconductor device, sometimes the TSV needs to connect some devices while disconnecting other devices, which requires the removal of metal at a specific location on the sidewall of the TSV. However, when removing the metal layer at a specific location on the sidewall of the TSV, the accuracy of the etching position needs to be improved. Summary of the invention

[0004] 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 improve the accuracy of the etching position when applied to the fabrication of a through silicon via.

[0005] Specifically, this application provides the following technical solutions:

[0006] A method for etching a film layer located on a sidewall surface of an opening, applied to a semiconductor device, the method comprising:

[0007] Placing the semiconductor device on a carrier, wherein the semiconductor device has an opening, and a sidewall surface of the opening is plated with a preset film layer;

[0008] forming a covering layer on the surface of the preset film layer;

[0009] Etching the cover layer by using an ion beam to remove a portion of the cover layer to expose a first portion of the preset film layer, wherein the first portion is a portion of the preset film layer located at a preset position facing the side of the opening port, and an incident angle of the ion beam forms a first angle with a surface where the semiconductor device is located, and a value range of the first angle is -90° to 0° and 0° to 90°, excluding endpoint values, that is, excluding -90°, 0° and 90°;

[0010] removing a first portion of the preset film layer;

[0011] The remaining portion of the cover layer is removed.

[0012] Optionally, the opening is a through hole, and the port shape of the opening is circular; etching the covering layer by using an ion beam to remove a portion of the covering layer to expose the first portion of the preset film layer comprises:

[0013] While the cover layer is being etched by the ion beam, the stage is rotated until a partial area of ​​the cover layer is removed to expose the first portion of the preset film layer.

[0014] Optionally, the rotation speed of the carrier ranges from 0 rpm to 80 rpm.

[0015] Optionally, during the process of etching the cover layer, the carrier rotates uniformly.

[0016] Optionally, the opening is a groove, and the port shape of the opening is rectangular; the area to be etched of the cover layer includes a plurality of sub-areas arranged along a first direction, the plurality of sub-areas are equidistant from the carrier, and the first direction is parallel to the sidewall of the opening and the carrier; etching the cover layer using an ion beam to remove a portion of the cover layer, and exposing the first portion of the preset film layer includes:

[0017] A sub-region of the covering layer is etched using an ion beam. After the etching of the sub-region is completed, the etching is stopped. After the carrier is rotated, another sub-region of the covering layer is etched using the ion beam. The process is repeated until portions of multiple sub-regions of the covering layer are all removed, exposing the first portion of the preset film layer.

[0018] Optionally, the method for stopping etching includes:

[0019] The ion beam is shielded by a shielding plate to stop etching the cover layer.

[0020] Optionally, the method for stopping etching includes:

[0021] Stopping the etching of the cover layer by stopping the beam drawing;

[0022] Optionally, the method for stopping etching includes: stopping etching of the covering layer by extinguishing an ion source.

[0023] Optionally, etching the cover layer by using an ion beam to remove a portion of the cover layer includes:

[0024] The cover layer is etched by using at least one etching method selected from the group consisting of standard ion beam etching, reactive ion beam etching and chemically assisted ion beam etching to remove a portion of the cover layer.

[0025] Optionally, the etching gas used in the standard ion beam etching is an inert gas.

[0026] Optionally, the etching gas used in the reactive ion beam etching includes an inert gas or a reactive gas.

[0027] Optionally, the etching gas used in the chemically assisted ion beam etching includes at least one of an inert gas and a reactive gas.

[0028] Optionally, the inert gas includes at least one of He, Ne, Ar, Kr, Xe and N2.

[0029] Optionally, the reactive gas includes at least one of F-based, Cl-based, Br-based gas and O2.

[0030] Optionally, the value range of the first angle θ is α-5° to α+5°: tan α=d / h;

[0031] 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 and parallel to the cross-sectional view of the semiconductor device.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Optionally, during the etching of the cover layer,

[0037] The energy value range of the ion beam when it is extracted is 0 to 2000 eV;

[0038] The ion source power has a value range of 0 to 3000 W;

[0039] 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;

[0040] The temperature range of the carrier is 0°C to 300°C.

[0041] The embodiment of the present application provides an etching method for a film layer located on the side wall of an opening. When etching the covering layer, 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 0° and 0° to 90°, excluding the endpoint value. Therefore, in the process of etching the covering 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 covering layer located above the preset position, and will not etch the portion of the covering layer located below the preset position. Therefore, in the process of etching the covering layer, the area affected by the shielding effect can be controlled by setting the first angle, thereby achieving precise control of the etching position and improving the accuracy of the etching position. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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.

[0043] 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.

[0044] Figure 1 A schematic diagram of a through silicon via in a semiconductor device;

[0045] Figure 2-Figure 5 A schematic diagram of the etching process of the metal film layer in the through silicon via is currently used;

[0046] 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;

[0047] Figure 7 and Figure 8 Two schematic diagrams of structures in which a cover layer covers a preset film layer in an etching method of a film layer located on a sidewall surface of an opening provided in one embodiment of the present application;

[0048] Figure 9-13 A 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;

[0049] Figure 14-Figure 19 A schematic diagram of the asymmetric morphology of the sidewall of a through hole in a semiconductor device;

[0050] Fig. 20 Schematic diagram of a groove in a semiconductor device under ideal conditions;

[0051] Figure 21-Figure 27 A schematic diagram of an etching process of an etching method for a film layer located on a sidewall surface of an opening provided in another embodiment of the present application;

[0052] Figure 28-Figure 33 A schematic diagram of the asymmetric sidewall of a groove in a semiconductor device. DETAILED DESCRIPTION

[0053] 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.

[0054] 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.

[0055] 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.

[0056] As described in the background technology section, when removing the metal layer at a specific position on the sidewall of a through silicon via, the accuracy of the etching position needs to be improved.

[0057] This is because 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.

[0058] 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.

[0059] exist 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, since there is no change in the film layer material, 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.

[0060] In view of this, an embodiment of the present application provides a method for etching a film layer located on a sidewall surface of an opening, which is applied to semiconductor devices, such as Figure 6 As shown, the etching method comprises:

[0061] S1: placing the semiconductor device on a carrier, wherein the semiconductor device has an opening, and the sidewall surface of the opening is plated with a preset film layer, and optionally, the preset film layer may be a metal film layer, and the formation process of the preset film layer may be a deposition process, but the present application does not limit this, and in other embodiments of the present application, the preset film layer may also be a film layer of other materials, and the formation process of the preset film layer may also adopt other processes, depending on the specific situation;

[0062] S2: forming a covering layer on the surface of the preset film layer;

[0063] S3: etching the cover layer by using an ion beam to remove a part of the cover layer and expose a first part of the preset film layer, wherein the first part is a part of the preset film layer located at a preset position and facing the opening port, and an incident angle of the ion beam forms a first angle with a surface where the semiconductor device is located, and a value range of the first angle is -90° to 0° and 0° to 90°, excluding endpoint values, that is, excluding 0°, 90° and -90°;

[0064] S4: removing the first part of the preset film layer;

[0065] S5: removing the remaining portion of the covering layer.

[0066] It should be noted that, in this embodiment, the preset position is a boundary position between the to-be-etched area and the non-etched area of ​​the preset film layer.

[0067] Optionally, based on the above embodiment, in one embodiment of the present application, Figure 7 As shown, in addition to covering the surface of the preset film layer 20, the covering layer 30 can also completely fill the opening 10, but the present application is not limited to this. In other embodiments of the present application, such as Figure 8 As shown, the covering layer 30 may also only cover the surface of the preset film layer 20 and not completely fill the opening 10, depending on the specific situation.

[0068] Based on the above embodiments, in one embodiment of the present application, removing the first portion of the preset film layer includes etching the first portion of the preset film layer using an ion beam to remove the first portion of the preset film layer, but the present application is not limited to this. In other embodiments of the present application, a wet etching process can also be used to remove the first portion of the preset film layer, depending on the specific circumstances.

[0069] The embodiment of the present application provides an etching method for a film layer located on the side wall of an opening. When etching the covering layer, 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 0° and 0° to 90°, excluding the endpoint value. Therefore, in the process of etching the covering 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 covering layer located above the preset position, and will not etch the portion of the covering layer located below the preset position. Therefore, in the process of etching the covering layer, the area affected by the shielding effect can be controlled by setting the first angle, thereby achieving precise control of the etching position and improving the accuracy of the etching position.

[0070] It should be noted that, in the process of etching the cover layer using the ion beam, Figure 7 As shown, if both sides of the upper end of the opening 10 (ie, the upper surface of the semiconductor device) are also covered by the covering layer 30, the portions of the covering layer 30 located on both sides of the upper end of the opening 10 will be removed simultaneously.

[0071] It should also be noted that in this embodiment, during the etching of the covering layer, 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 between the covering layer and the predetermined film layer in the area to be etched.

[0072] Optionally, in the present embodiment, the area to be etched of the covering layer includes a plurality of sub-areas arranged along a first direction, the plurality of sub-areas are at equal distances from the carrier, and the first direction is parallel to the side walls of the opening and the carrier. It should be noted that, in the present embodiment of the 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 is described below in conjunction with specific circumstances.

[0073] Embodiment 1

[0074] 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 the covering layer by using an ion beam to remove a portion of the covering layer to expose the first portion of the preset film layer includes:

[0075] While the covering layer is being etched by an ion beam, the carrier is rotated until a portion of the covering layer is removed to expose the first portion of the preset film layer; that is, while the multiple sub-regions of the covering layer are being etched by an ion beam, the carrier is rotated until portions of the multiple sub-regions of the covering layer are removed to expose the first portion of the preset film layer.

[0076] Optionally, in one embodiment of the present application, the rotation speed of the carrier is in the range of 0rpm to 80rpm, that is, during the etching of the covering layer, the rotation speed of the carrier rotating around the center of the carrier (i.e., rotation) is in the range of 0rpm to 80rpm, but the present application does not limit this and it depends on the specific situation.

[0077] Specifically, in one embodiment of the present application, during the process of etching the cover layer, the carrier rotates uniformly, so that the etching of the cover layer is more uniform, and thus the subsequent etching of the preset film layer is more uniform.

[0078] On the basis of any of the above embodiments, in one embodiment of the present application, etching the cover layer by using an ion beam to remove a portion of the cover layer includes:

[0079] The covering layer is etched using at least one etching method selected from standard ion beam etching, reactive ion beam etching and chemically assisted ion beam etching to remove a portion of the covering layer. That is, when etching the covering layer, 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 may be used. The present application does not impose any limitation on this, and the specific method depends on the circumstances.

[0080] 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 (i.e. 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.

[0081] 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.

[0082] 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.

[0083] 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 depend on it.

[0084] It should be noted that, in actual applications, when the covering 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 covering 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 impose any limitation on this, and it depends on the specific circumstances.

[0085] On the basis of any of the above embodiments, in one embodiment of the present application, in the process of etching the covering layer by using an ion beam, 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, reduce process difficulty, and reduce etching costs; 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 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 of the carrier 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.

[0086] It should be noted that the energy of the ion beam when it is extracted is related to the etching rate and etching effect of the covering layer. The greater the energy of the ion beam when it is extracted, the faster the etching rate, and the greater the energy of the ion beam when it is extracted, the easier it is to etch difficult-to-etch materials; the power of the ion source is different from the power of the conventional ICP, and is a value based on the given process parameters and the self-matching of the hardware; the beam current when the ion beam is extracted is related to the etching rate, and is determined according to the required etching rate; the temperature of the carrier and the pressure in the etching chamber are determined according to the specific etching material and structure experiments.

[0087] It should also be noted that, in actual application, due to the existence of a beam divergence angle of the ion beam, the angle actually adopted by the first angle θ is generally the 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; and Figure 8 As shown, d is the size of the opening along the second direction Y 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, that is, the height of the first part of the preset film layer; wherein the second direction is parallel to the plane where the semiconductor device is located, and parallel to the cross-sectional view of the semiconductor device.

[0088] In addition, in a specific application process, when the material of the side wall of the opening is different, the material of the preset film layer located on the side wall of the opening and the material of the covering layer covering the preset film layer may also be different. When the material of the covering layer and the material of the preset film layer are different, the selection of the etching gas and / or the proportion of different gases in the etching gas may also be different, depending on the specific situation.

[0089] Specifically, in one embodiment of the present application, when the material of the opening is SiO2, the material of the covering layer is C, and the material of the preset film layer is Cr, C can be etched using RIBE with O2 introduced, and Cr can be etched using a base gas; when the material of the opening is SiO2, the material of the covering layer is optical resin (PR), and the material of the preset film layer is Mo, PR can be etched using RIBE with O2 introduced, and Mo can be etched using a Cl-based gas.

[0090] 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 Cr, the material of the cover layer is C, and the aperture value range is 2μm to 3μm, that is, the diameter value range of the through hole is 2μm to 3μm. When it is necessary to process a film layer 5μm and above 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 about 21° to 32°. After adjusting the angle according to the actual experiment, first Fig. 9 and Fig.10 As shown, the RIBE method with O2 as the gas is used to remove the covering layer partly to expose the first part of the preset film layer, and then Fig.11 and Fig.12 As shown, the first part of the preset film layer is removed by using Cl-based gas or wet method, and finally as shown in Fig.13 As shown, the remaining portion of the cover layer is removed using O2.

[0091] In another embodiment of the present application, the material of the side wall of the through hole is Si3N4, the material of the preset film layer is Mo, the material of the covering layer is C, and the aperture value range is 2μm~3μm, that is, the diameter range of the through hole is 2μm~3μm. When it is necessary to process a film layer that is 5μm and 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°~32°. After adjusting the angle according to actual experiments, the RIBE method with O2 as the incoming gas is used to first remove part of the covering layer to expose the first part of the preset film layer, and then use Cl-based gas or wet method to remove the first part of the preset film layer, and finally use O2 to remove the remaining part of the covering layer.

[0092] 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 Mo, the material of the covering layer is photoresist (PR), and the aperture value range is 2μm~3μm, that is, the diameter range of the through hole is 2μm~3μm. When it is necessary to process a film layer that is 5μm and 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°~32°. After adjusting the angle according to actual experiments, the RIBE method with O2 as the gas is used to first remove part of the covering layer to expose the first part of the preset film layer, and then use Cl-based gas or wet method to remove the first part of the preset film layer, and finally use O2 to remove the remaining part of the covering layer.

[0093] In addition, in the specific application process, when using an ion beam to etch the covering layer, different ion beam incident angles can 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 covering layer). The calculation formula refers to tanα=d / h.

[0094] From the foregoing, it can be seen that during the etching of the cover layer, any asymmetry of different regions of the opening sidewall will be amplified by the shielding effect of the opening sidewall on the ion beam, thereby generating a height difference at the etching interface between the cover layer and the predetermined film layer in the to-be-etched region.

[0095] Continue as Figure 8 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 14-Figure 19 As shown, given the diameter d of the through hole, the height of the first portion of the preset film layer 20 to be exposed is h, and the ion beam incident angle is determined according to tanα=d / h, then Fig.14 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.15 As shown, Fig.15 Shows Fig.14 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.16 and Fig.17 In the structure shown, Fig.16 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.17 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 incident direction of the ion beam etching different areas has the same angle with the upper end surface of the opening. Fig.18 and Fig.19 As shown, Fig.18 Shows Fig.16 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.19 Shows Fig.17In 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.

[0096] Embodiment 2:

[0097] In another embodiment of the present application, the opening is a groove, and the port shape of the opening is a rectangle; etching the covering layer by using an ion beam to remove a portion of the covering layer to expose the first portion of the preset film layer includes:

[0098] A sub-region of the covering layer is etched using an ion beam. After the etching of the sub-region is completed, the etching is stopped. After the carrier is rotated, another sub-region of the covering layer is etched using the ion beam. The process is repeated until portions of multiple sub-regions of the covering layer are all removed, exposing the first portion of the preset film layer.

[0099] It should be noted that, in this embodiment, since the different sub-regions of the covering layer are directly etched in the same etching chamber, in this embodiment of the application, the etching of the different sub-regions of the covering layer can be regarded as a one-step process.

[0100] On the basis of the above embodiment, in one embodiment of the present application, etching the cover layer by using an ion beam to remove a portion of the cover layer includes:

[0101] The covering layer is etched using at least one etching method selected from standard ion beam etching, reactive ion beam etching and chemically assisted ion beam etching to remove a portion of the covering layer. That is, when etching the covering layer, 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 may be used. The present application does not impose any limitation on this, and the specific method depends on the circumstances.

[0102] 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.

[0103] 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.

[0104] 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 depend on it.

[0105] It should be noted that, in actual applications, when the covering 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 covering 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 impose any limitation on this, and it depends on the specific circumstances.

[0106] 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 covering layer; in another embodiment of the present application, the method for stopping etching includes: stopping the beam pulling to stop etching the covering layer; in another embodiment of the present application, the method for stopping etching includes: using an ion source extinguishing method to stop etching the covering layer; in other embodiments of the present application, other methods can also be used to stop etching the covering layer, and the present application does not limit this, depending on the specific circumstances.

[0107] Optionally, in a specific embodiment of the present application, etching the cover layer by using an ion beam to remove a portion of the cover layer to expose the first portion of the preset film layer includes:

[0108] The first sub-region of the covering layer is etched by an ion beam, and the etching is stopped after the etching of the sub-region is completed; the carrier is rotated, and the second sub-region of the covering layer is etched by an ion beam again, and the etching of the to-be-etched region of the covering layer is completed, exposing the first part of the preset film layer.

[0109] Optionally, in one embodiment of the present application, an incident angle of θ is used to etch a first sub-region of the covering layer 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 carrier is rotated 180° around the center of the carrier (that is, after the carrier rotates 180°), the incident angle of θ is used again to etch a second sub-region of the covering layer using an ion beam.

[0110] In another embodiment of the present application, an incident angle of θ is used to etch the first sub-region of the covering layer 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 carrier is rotated around the ion source that generates the ion beam (that is, after the carrier revolves), an incident angle of -θ is used to etch the second sub-region of the covering layer 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.

[0111] It should be noted that, in actual application, due to the existence of a beam divergence angle of the ion beam, the 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. 20 As shown, d is the size of the opening along the second direction Y 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, and parallel to the cross-sectional view of the semiconductor device.

[0112] On the basis of any of the above embodiments, in one embodiment of the present application, in the process of etching the covering layer by using an ion beam, the angle selection range of the position of the carrier is 0° to 360°, so that the carrier can rotate 360°; the energy range of the ion beam when it is extracted is 0 to 2000eV, so as to be compatible with the process capabilities of existing etching equipment; the ion source power range is 0 to 3000W, so as to be compatible with the process capabilities of existing etching equipment; the beam current range when the ion beam is extracted is The temperature of the etching chamber is 0-2A, so as to be compatible with the process capability of the existing etching equipment; the gas flow rate of the ion source for generating the ion beam or the etching chamber where the semiconductor device is located is in the range of 0-300sccm, so as to be compatible with the process capability of the existing etching equipment; the temperature range of the carrier is: 0°C-300°C, so as to be compatible with the process capability of the existing etching equipment; the pressure range of the etching chamber is 0.001mT-5mT, so as to be compatible with the process capability of the existing etching equipment; but the present application does not limit this, it depends on the specific situation.

[0113] It should be noted that, in a specific application process, when the material of the side wall of the opening is different, the material of the preset film layer located on the side wall of the opening and the material of the covering layer covering the preset film layer may also be different. When the material of the covering layer and the material of the preset film layer are different, the selection of the etching gas and / or the proportion of different gases in the etching gas may also be different, depending on the specific situation.

[0114] Specifically, in one embodiment of the present application, when the material of the opening is SiO2, the material of the covering layer is C, and the material of the preset film layer is Cr, C can be etched using RIBE with O2 introduced, and Cr can be etched using a base gas; when the material of the opening is SiO2, the material of the covering layer is PR, and the material of the preset film layer is Mo, PR can be etched using RIBE with O2 introduced, and Mo can be etched using a Cl-based gas.

[0115] 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 Cr, the material of the covering 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 5μm and above 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°, and then the angle is adjusted according to the actual experiment, such as Fig.21 and Fig. 22 As shown, the RIBE method with O2 as the gas is used to first remove the portion of the cover layer located on one side of the groove side wall, and then Fig.23 and Fig.24As shown, the cover layer is rotated at another angle to remove the portion on the other side of the groove side wall, and then Fig.25 and Fig.26 As shown, the first part of the preset film layer is removed by using Cl-based gas or wet method, and finally as shown in Fig. 27 As shown, the remaining portion of the cover layer is removed using O2.

[0116] From the foregoing, it can be seen that during the etching of the cover layer, any asymmetry of different regions of the opening sidewall will be amplified by the shielding effect of the opening sidewall on the ion beam, thereby generating a height difference at the etching interface between the cover layer and the predetermined film layer to be etched region.

[0117] Continue as Fig. 20 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 28-Figure 33 As shown, given the groove width d, when the height of the first portion of the preset film layer 20 to be processed is h, the ion beam incident angle is determined according to tanα=d / h, then Fig.28 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.29 As shown, Fig.29 Shows Fig.28 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.30 and Fig.31 In the structure shown, Fig.30 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.31 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 incident direction of the ion beam etching different areas has the same angle with the upper end surface of the opening. Fig.32 and Fig.30 As shown, Fig.32 Shows Fig.30In 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.33 Shows Fig.31 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.

[0118] In summary, 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 covering layer, 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° to 0° and 0° to 90°, excluding the endpoint value. Therefore, in the process of etching the covering 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 covering layer located above the preset position, and will not etch the portion of the covering layer located below the preset position. Therefore, in the process of etching the covering layer, the area affected by the shielding effect can be controlled by setting the first angle, thereby achieving precise control of the etching position and improving the accuracy of the etching position.

[0119] 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.

[0120] 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 sidewall surface of an opening, applied to a semiconductor device, characterized in that: The method includes: Placing the semiconductor device on a carrier, wherein the semiconductor device has an opening, and a sidewall surface of the opening is plated with a preset film layer; forming a covering layer on the surface of the preset film layer; Etching the cover layer by using an ion beam to remove a portion of the cover layer and expose a first portion of the preset film layer, wherein the first portion is a portion of the preset film layer located at a preset position and facing the opening port, and an incident angle of the ion beam forms a first angle with a surface where the semiconductor device is located, and a value range of the first angle is -90° to 0° and 0° to 90°, excluding endpoint values; removing a first portion of the preset film layer; The remaining portion of the cover layer is removed.

2. The etching method according to claim 1, characterized in that: The opening is a through hole, and the port shape of the opening is circular; Etching the cover layer by using an ion beam to remove a portion of the cover layer to expose the first portion of the preset film layer comprises: While the cover layer is being etched by the ion beam, the stage is rotated until a partial area of ​​the cover layer is removed to expose the first portion of the preset film layer.

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

4. The etching method according to claim 2, characterized in that: During the process of etching the cover layer, the carrier 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; the area to be etched of the cover layer includes a plurality of sub-areas arranged along a first direction, the plurality of sub-areas are at equal distances from the carrier, and the first direction is parallel to the side wall of the opening and the carrier; Etching the cover layer by using an ion beam to remove a portion of the cover layer to expose the first portion of the preset film layer comprises: A sub-region of the covering layer is etched using an ion beam. After the etching of the sub-region is completed, the etching is stopped. After the carrier is rotated, another sub-region of the covering layer is etched using the ion beam. The process is repeated until portions of multiple sub-regions of the covering layer are all removed, exposing the first portion of the preset film layer.

6. The etching method according to claim 5, characterized in that: The method for stopping etching comprises: The etching of the cover layer is stopped by shielding the ion beam with a shielding plate.

7. The etching method according to claim 5, characterized in that: The method for stopping etching comprises: The etching of the cover layer is stopped by stopping the beam drawing.

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

9. The etching method according to claim 1, characterized in that: Etching the cover layer by using an ion beam to remove a portion of the cover layer includes: The cover layer is etched by using at least one etching method selected from the group consisting of standard ion beam etching, reactive ion beam etching and chemically assisted ion beam etching to remove a portion of the cover layer.

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 and parallel to the cross-sectional view of the semiconductor device.

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: During the etching of the cover layer, 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 carrier is 0°C to 300°C.

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