Semiconductor device and method of removing deposited layers from a wafer surface

Abstract

The application discloses a semiconductor device and a wafer surface deposition layer removing method, wherein a wafer to be processed, which is etched with a groove on the front surface and has an oxide layer film deposited on the front surface, is placed on a polishing table, the front surface of the wafer to be processed outside the groove is taken as a target plane, primary polishing is performed on the oxide layer film of the target plane on the polishing table until the oxide layer film reaches a target thickness, so that a large amount of oxides on the target plane is preliminarily removed, and secondary polishing is performed on the target plane until the oxide layer film on the target plane is completely removed; the polishing amount of the secondary polishing is small, and the removal amount of the oxide layer film above the target plane can be accurately controlled in the secondary polishing process, so that the oxide layer film is accurately and completely removed, and the removing quality of the wafer surface deposition layer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor device preparation processes, and in particular to a semiconductor device and a wafer surface deposition layer removal method. BACKGROUND

[0002] In the preparation process of MEMS (Micro-Electro-Mechanical System), since the pattern size of MEMS is large, which is different from the logic device below 0.5 um, the pattern of MEMS needs to be made into a mechanical structure, and the size is generally 10-500 um, and the typical size is 100-200 um. A one-step polishing process of large size will cause a large dishing defect (also known as Dishing), and subsequent structures need to be prepared based on the wafer surface with the dishing defect. The subsequent preparation structure will be released with the surface morphology and the oxide layer, causing the upper surface of the cavity to present a convex structure, which affects the use performance of the semiconductor device.

[0003] Therefore, how to improve the removal quality of the wafer surface deposition layer is a technical problem to be solved at present. SUMMARY

[0004] The semiconductor device and the wafer surface deposition layer removal method can improve the removal quality of the wafer surface deposition layer.

[0005] The embodiments of the present application provide the following solutions.

[0006] In a first aspect, the embodiments of the present application provide a wafer surface deposition layer removal method, which comprises the following steps.

[0007] Placing a wafer to be processed on a polishing table, wherein the wafer to be processed is a wafer with a groove etched on the front surface, and an oxide layer film deposited on the front surface;

[0008] Performing primary polishing on the oxide layer film of the target plane on the polishing table until the oxide layer film reaches a target thickness, wherein the target plane is the front surface of the wafer to be processed outside the groove;

[0009] Performing secondary polishing on the oxide layer film of the target plane until the oxide layer film above the target plane is completely removed.

[0010] In an optional embodiment, the primary polishing on the oxide layer film of the target plane on the polishing table until the oxide layer film reaches a target thickness comprises the following steps.

[0011] The oxide layer film of the target plane is subjected to primary chemical mechanical polishing by using a composite polishing pad, so that the oxide removal rate of the oxide layer film is not less than 6000 angstroms per minute.

[0012] When the polishing time of the primary polishing reaches a preset time or the detection spectrum of the primary polishing surface is a target spectrum, it is determined that the oxide layer film reaches 0.5-1.5 um, and the primary polishing of the oxide layer film is stopped.

[0013] In an alternative embodiment, the primary chemical mechanical polishing of the oxide layer film of the target plane by using a composite polishing pad comprises:

[0014] Smoke particles are placed between the composite polishing pad and the target plane.

[0015] The polishing table and the polishing head are controlled to rotate in the same direction, and the rotation speed of each is not less than 80 RPM.

[0016] The contact surface of the polishing table and the polishing head is subjected to regional pressure control, so that the contact pressure is uniform and not less than 5 PSI, thereby performing primary chemical mechanical polishing on the oxide layer film of the target plane.

[0017] In an alternative embodiment, the secondary polishing of the oxide layer film of the target plane comprises:

[0018] The wafer after the primary polishing is moved to a secondary polishing table.

[0019] The oxide layer film is subjected to secondary chemical mechanical polishing by using a water-soluble polishing liquid and a composite polishing pad.

[0020] When the removal ratio of the oxide of the oxide layer film and the silicon dioxide on the front surface of the wafer is 1:0.9-1.1, the secondary polishing of the oxide layer film is controlled to be stopped.

[0021] In an alternative embodiment, the secondary chemical mechanical polishing of the oxide layer film by using a water-soluble polishing liquid and a composite polishing pad comprises:

[0022] Colloidal silicon dioxide with a particle diameter of 50-130 nm is placed between the front surface of the wafer and the composite polishing pad.

[0023] The polishing table and the polishing head are controlled to rotate in the same direction, and the rotation speed of each is not less than 90 RPM.

[0024] The contact surface of the polishing table and the polishing head is subjected to regional pressure control, so that the contact pressure is uniform and not greater than 4 PSI.

[0025] In an alternative embodiment, after detecting that the removal ratio of the oxide of the oxide layer film and the silicon dioxide of the front surface of the wafer is 1:0.9-1.1, the method further comprises:

[0026] stopping the secondary polishing after continuing polishing the oxide layer film of the target plane for 5-15s.

[0027] In an alternative embodiment, after the secondary polishing of the oxide layer film of the target plane, the method further comprises:

[0028] moving the wafer after the secondary polishing to a tertiary polishing station;

[0029] tertiary chemical mechanical polishing of the target plane on the tertiary polishing station until the roughness of the target plane is less than 1nm.

[0030] In an alternative embodiment, the tertiary chemical mechanical polishing of the target plane on the tertiary polishing station comprises:

[0031] attaching a soft polishing pad to the target plane, moving a polishing head to the soft polishing pad, and spraying fine polishing liquid or pure water to the soft polishing pad;

[0032] controlling the polishing station and the polishing head to rotate in the same direction at a speed not less than 100RPM;

[0033] controlling the area pressure of the polishing station and the polishing head to be uniform and not more than 3PSI for tertiary chemical mechanical polishing.

[0034] In an alternative embodiment, the oxide layer film is phosphorus-silicon glass or boron-phosphorus-silicon glass with a thickness not less than 3μm.

[0035] In a second aspect, the embodiments of the present application further provide a semiconductor device, and the deposited layer during the preparation of the semiconductor device is removed by the method of any of the first aspect.

[0036] The semiconductor device and the method for removing the deposited layer of the wafer surface of the present application have the following advantages compared with the prior art:

[0037] The removal method of the present application, by placing the wafer to be processed with a groove etched on the front surface and an oxide layer film deposited on the front surface on the polishing table, taking the front surface of the wafer to be processed outside the groove as the target plane, performing primary polishing on the oxide layer film of the target plane on the polishing table until the oxide layer film reaches the target thickness, to preliminarily remove a large amount of oxide on the target plane, and then performing secondary polishing on the target plane until the oxide layer film on the target plane is completely removed, the polishing amount of the secondary polishing is smaller, and the removal amount of the oxide layer film above the target plane can be accurately controlled during the secondary polishing process, so that the oxide layer film above the target plane is accurately and completely removed, thereby improving the removal quality of the deposition layer on the wafer surface. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0039] Figure 1 A flowchart of a wafer surface deposition layer removal method provided by an embodiment of the present application is shown in the figure.

[0040] Figure 2-1 A structure schematic diagram of a wafer after etching a groove is provided by an embodiment of the present application.

[0041] Figure 2-2 A structure schematic diagram of a wafer with an oxide layer film deposited is provided by an embodiment of the present application.

[0042] Figure 2-3 A structure schematic diagram of a wafer to be processed after primary polishing is provided by an embodiment of the present application.

[0043] Figure 2-4 A structure schematic diagram of a wafer to be processed after secondary polishing is provided by an embodiment of the present application.

[0044] Figure 2-5 A structure schematic diagram of a wafer after depositing a piezoelectric layer is provided by an embodiment of the present application.

[0045] Figure 2-6 A structure schematic diagram of a wafer after releasing a sacrificial layer is provided by an embodiment of the present application.

[0046] Figure 3-1 A structure schematic diagram of a polishing table and a polishing head is provided by an embodiment of the present application.

[0047] Figure 3-2 A structure schematic diagram of a polishing table and a polishing head is provided by an embodiment of the present application.

[0048] Explanation of reference numerals: 1 - wafer, 2 - groove, 3 - oxide film, 4 - piezoelectric layer, 5 - polishing table, 6 - polishing head, 7 - polishing liquid supply pipe. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the embodiments of the present application.

[0050] The embodiments of the present application will be described below with the example of implementation in a MEMS preparation process, and specifically describe how to apply the wafer surface deposition layer removal method proposed in the present application. Compared with the deposition layer in the preparation process of a general IC (Integrated Circuit Chip) chip, the thickness of the deposition layer deposited in the MEMS preparation process is thicker, and the deposition layer can be an oxide film. The existing planarization process mostly uses dry or wet etch back to remove the oxide film on the wafer front surface higher than the groove, which not only needs to increase the steps of photolithography, glue coating, development, dry etching, glue removal and cleaning, but also is difficult to control the uniformity and thickness of etching, thereby causing more unstable factors for the control of subsequent chemical mechanical polishing (CMP), and affecting the performance of the prepared semiconductor device. How to solve the above problems will be described below.

[0051] Please refer to Figure 1 , Figure 1 A flowchart of a wafer surface deposition layer removal method provided by the embodiments of the present application is shown in the figure, and the method comprises the following steps.

[0052] S11, place the wafer to be processed on the polishing table, wherein the wafer to be processed is a wafer with a groove etched on the front surface, and the front surface is deposited with an oxide film.

[0053] Specifically, please refer to Figure 2-1 The distribution structure of the groove 2 on the wafer 1 can be determined based on the device to be prepared, and the groove 2 can be obtained by dry or wet etching on the wafer. Before etching, the wafer is treated by a standard RCA (or industrial standard wet) cleaning process and dried for standby; the groove is etched on the front surface of the wafer by dry or wet etching, and the groove depth is 2.3-30 μm. Please refer to Figure 2-2In the MEMS preparation process, the typical value of the groove depth is 2.6-3.7 μm, and the oxide film 3 is deposited on the front surface of the wafer by using PECVD (Plasma Enhanced Chemical Vapor Deposition), and the thickness of the oxide film 3 is 1.2-2 times the groove depth. The oxide film 3 in the groove can be used as a sacrificial layer for preparing a hollow structure. The oxide film 3 can be phosphorus-silicon glass (PSG, phosphorus-silicon glass) or boron-phosphorus-silicon glass (BPSG, Boro-phospho-silicate Glass) with a thickness not less than 3 μm. After the wafer to be processed is placed on the polishing table, the wafer to be processed can be further cleaned to make the surface clean. The wafer to be processed is placed on the polishing table and enters step S12.

[0054] S12, the oxide film on the target plane is primarily polished on the polishing table until the oxide film reaches a target thickness, wherein the target plane is the front surface of the wafer to be processed outside the groove.

[0055] Specifically, please refer to Figure 2-3 By primarily polishing the oxide film on the target plane, a large amount of oxide film on the target plane can be quickly removed, and the remaining thickness of the oxide film reaches the preset target thickness. The target thickness can be determined according to actual needs, for example, 1-2 μm. The primary polishing can be chemical mechanical polishing, please refer to Figure 3-1 and 3-2 The polishing amount of the chemical mechanical polishing is controlled by the polishing table 5 and the polishing head 6. During the polishing process, the polishing liquid is sprayed through the polishing liquid supply pipe 7. A coarse polishing liquid can be selected for primary polishing, and the polishing table and the polishing head are controlled to have a large contact pressure and a high rotation speed to implement coarse polishing. When the oxide film reaches the target thickness, the primary polishing is stopped.

[0056] In actual application, due to many control factors of the chemical mechanical polishing, the existing control mode cannot accurately control the oxide film to reach the target thickness. Based on this, in one specific embodiment, the oxide film on the target plane is primarily polished on the polishing table until the oxide film reaches the target thickness, including:

[0057] The oxide film on the target plane is primarily polished by using a composite polishing pad to make the oxide removal rate of the oxide film not less than 6000 angstroms per minute. When the polishing time of the primary polishing reaches a preset time or the detection spectrum of the primary polishing surface is a target spectrum, it is determined that the oxide film reaches 0.5-1.5 um, and the primary polishing of the oxide film is stopped.

[0058] Specifically, the composite polishing pad (or stacked pad) can be selected from commercially available products, such as IC100 or IC1010 polishing pads from Dow Chemical Company. The composite polishing pad is placed on the target plane, and the polishing head is placed on the composite polishing pad. The polishing table and the polishing head are controlled to rotate, and the coarse polishing liquid is added, so that the oxide removal rate is not less than 6000 angstroms per minute. For phosphorus-silicon glass and boron-phosphorus-silicon glass, the removal rate is not less than 6000 angstroms per minute, and for silicon oxide film (or PETEOS), the removal rate is not less than 3500 angstroms per minute. After polishing, endpoint detection is performed. The polished primary polishing surface can be irradiated with a light beam to obtain a detection spectrum. The detection spectrum can represent the surface material of the oxide layer film on the target plane after polishing. The detection spectrum is compared with the target spectrum. When the comparison is the same, it is determined that the oxide layer film reaches the target thickness. The target thickness can be set to 0.5-1.5 μm, preferably 1 μm. Of course, the target thickness can also be determined based on the polishing time of the primary polishing. After reaching the preset time, it is determined that the target thickness is reached. Compared with the spectrum detection, the target thickness determined by the polishing time is simpler and faster. Therefore, the preset time can be determined according to the spectrum detection. When the next wafer to be processed is subjected to primary polishing, the target thickness of the oxide layer film can be determined based on the preset time. This control method is more conducive to large-scale industrial applications.

[0059] In a specific embodiment, the primary chemical mechanical polishing of the oxide layer film on the target plane using the composite polishing pad includes:

[0060] The smoke particles are placed between the composite polishing pad and the target plane. The polishing table and the polishing head are controlled to rotate in the same direction, and the rotation speed is not less than 80 RPM. The contact surface of the polishing table and the polishing head is subjected to regional pressure control, so that the contact pressure is uniform and not less than 5 PSI. The oxide layer film on the target plane is subjected to primary chemical mechanical polishing.

[0061] Specifically, the fumigation particles are polishing silica sol, which is a polishing material prepared by high-temperature sintering of silicon dioxide at 1800-2500°C, has many edges, and can quickly remove the oxide layer film during polishing. The same direction rotation of the polishing table and the polishing head can more accurately control the polishing amount of the primary polishing, the first rotation speed w1 of the polishing table and the second rotation speed w2 of the polishing head are both not less than 80 RPM, and the fitting pressure is not less than 5 PSI or 310 HPA, so as to perform primary chemical mechanical polishing on the oxide layer film of the target plane. It can be understood that, in order to ensure uniform removal of the oxide layer film, regional pressure control is performed on the fitting surface, which is centered on the center of the polishing head and has multiple pressure control points arranged along the radial direction thereof. Taking the polishing head with a diameter of 100 mm as an example, a first pressure control zone is arranged in a region 30 mm away from the center, a second pressure control zone is arranged in a region 30-65 mm away from the center, and a third pressure control zone is arranged in a region 65-95 mm away from the center, so that the fitting pressure is uniform and not less than 5 PSI, thereby improving the polishing quality and efficiency of the primary polishing. After the primary polishing of the oxide layer film of the target plane reaches the target thickness, step S13 is performed.

[0062] S13, performing secondary polishing on the oxide layer film of the target plane until the oxide layer film above the target plane is completely removed.

[0063] Specifically, please refer to Figure 2-3 and 2-4 The secondary polishing is performed to completely remove the oxide layer film outside the groove. After polishing, end point detection is performed on the target plane to determine whether the oxide layer film of the target plane is completely removed, and the polishing is stopped if the oxide layer film of the target plane is completely removed.

[0064] In actual application, since the chemical mechanical polishing is performed in the dynamic rotation process of the polishing table, mechanical errors exist in the dynamic balance of the polishing table due to the mechanical errors in the preparation of the polishing table, which adversely affects the removal quality of the oxide layer film on the target plane. In addition, the chemical mechanical polishing is performed with chemical reaction, and the polishing reaction environments of the primary polishing and the secondary polishing are different. If the primary polishing and the secondary polishing are performed on the same polishing table, the removal quality will be further adversely affected. Based on this, in one specific embodiment, the secondary polishing of the oxide layer film of the target plane comprises:

[0065] moving the wafer after the primary polishing to a secondary polishing table; performing secondary chemical mechanical polishing on the oxide layer film by using a water-soluble polishing liquid and a composite polishing pad; and stopping the secondary polishing of the oxide layer film when the removal ratio of the oxide of the oxide layer film to the silicon dioxide on the front surface of the wafer is 1:0.9-1.1.

[0066] Specifically, the structure of the secondary polishing table is the same as that of the primary polishing table, and can be arranged in two independent closed spaces. An openable and closable movable door structure is arranged on the closed spaces. The wafer is moved to the secondary polishing table by the mechanical hand. Since the primary polishing and the secondary polishing are implemented on two polishing tables, the influence of dynamic balance error and chemical environment difference on the polishing quality can be reduced, and the polishing efficiency can be improved. The water-soluble polishing liquid is relatively more gentle. The chemical mechanical polishing based on the composite polishing pad can remove the oxide film while improving the polishing quality of the target plane. It can be understood that when the oxide layer film is deposited on the target plane of the wafer, the oxide and the silicon dioxide will penetrate each other with the target plane as the critical surface. In the microstructure, the oxide layer film above the target plane contains part of the silicon dioxide, but the content of the silicon dioxide in this area is less than the content of the oxide released by the deposition process; conversely, the wafer below the target plane contains part of the oxide released by the deposition process, but the content of the oxide in this area is less than the content of the silicon dioxide. When the removal ratio of the oxide and the silicon dioxide is 1:0.9-1.1, it indicates that the polishing position of the secondary polishing has reached the critical target plane, and the secondary polishing of the oxide layer film is stopped. The removal ratio of the oxide and the silicon dioxide is preferably 1:1. It can be understood that the removal ratio of the oxide and the silicon dioxide can be determined by a step tester, and the detection principle is not described here; the oxide content of the polished surface can be detected by spectrum (infrared or visible light) after the secondary polishing to perform end point detection, and the secondary polishing is stopped when the oxide film on the end point detection target plane is completely removed.

[0067] In a specific embodiment, the secondary chemical mechanical polishing of the oxide layer film is implemented by using a water-soluble polishing liquid and a composite polishing pad, which comprises:

[0068] The colloidal silicon dioxide with a particle size of 50-130 nm is arranged between the front surface of the wafer and the composite polishing pad; the polishing table and the polishing head are controlled to rotate in the same direction, and the rotating speed of each is not less than 90 RPM; the area pressure of the contact surface of the polishing table and the polishing head is controlled to be uniform and not more than 4 PSI.

[0069] Specifically, the colloidal silicon dioxide is an elliptical polishing material. The secondary chemical mechanical polishing can effectively reduce the surface defects of the target plane after the primary polishing. The sharp corners formed due to different removal rates are reduced by the colloidal silicon dioxide. The polishing speed is improved, the contact pressure is reduced, the surface quality of the polishing is improved, the polishing removal amount is accurately controlled, and the butterfly defects of the polished surface are effectively reduced by the above-mentioned process parameters to achieve the global planarization of the oxide layer film on the target plane.

[0070] In practical applications, the endpoint detection of the secondary polishing is usually implemented by spectral detection, but the spectral detection is implemented based on a detection point of the polishing surface, and cannot accurately represent the detection results of the entire polishing surface, resulting in the existence of the oxide layer film which is not completely removed above the target plane. Based on this, in a specific embodiment, after the removal ratio of the oxide of the oxide layer film and the silicon dioxide of the wafer front surface is detected to be 1:0.9-1.1, the method further comprises:

[0071] The secondary polishing is stopped after the oxide layer film of the target plane is continuously polished for 5-15s.

[0072] Specifically, the target plane as a whole can meet the quality requirements of removing the oxide layer film by continuously polishing the target plane for 5-15s, and the method can effectively further reduce the surface defects of the polishing surface and reduce the influence of spectral detection on the overall quality evaluation of the polishing surface.

[0073] In practical applications, the wafer needs to enter the next process after removing the oxide film, and since the secondary polishing has limited improvement on the roughness of the target plane, the removal method cannot be well adapted to the connection of the process. Based on this, in a specific embodiment, after the secondary polishing of the oxide layer film of the target plane is performed, the method further comprises:

[0074] moving the wafer after the secondary polishing to a tertiary polishing table; and performing tertiary chemical mechanical polishing on the target plane on the tertiary polishing table until the roughness of the target plane is less than 1nm.

[0075] Specifically, the tertiary polishing table has the same structure as the polishing tables of the primary polishing and the secondary polishing, the polishing tables of the primary polishing, the secondary polishing, and the tertiary polishing can be arranged in three independent closed spaces, and the purpose of the tertiary chemical mechanical polishing is to improve the surface roughness of the target plane. The polishing time is usually 10-60s, and the polishing is stopped when the roughness is less than 1nm to meet the needs of the next process, such as wafer bonding.

[0076] In a specific embodiment, the tertiary chemical mechanical polishing of the target plane on the tertiary polishing table comprises:

[0077] attaching a soft polishing pad to the target plane, moving the polishing head to the soft polishing pad, and spraying fine polishing liquid or pure water to the soft polishing pad; controlling the polishing table and the polishing head to rotate in the same direction, and the rotating speed of each is not less than 100RPM; and performing regional pressure control on the attached surface of the polishing table and the polishing head to make the attached pressure uniform and not greater than 3PSI, so as to perform the tertiary chemical mechanical polishing.

[0078] Specifically, the soft polishing pad can be a commercially available black pad, and the target plane is polished by high rotation speed and low pressure to improve the roughness of the target plane; wherein the regional pressure control is the same as the above embodiments to improve the uniformity of the polishing head and the target plane.

[0079] Based on the same inventive concept as the removal method, the embodiments of the present application also provide a semiconductor device, and the deposition layer during the preparation of the semiconductor device is removed by any of the methods.

[0080] Specifically, the semiconductor device can be a micro coaxial high frequency device, a micro flow device, or a band-pass filter, etc. Figure 2-5 and 2-6 After the removal of the oxide layer film is completed, Mo can be deposited on the target plane outside the groove by PVD (Physical Vapor Deposition) as the piezoelectric layer 4, and the deposition thickness is usually 2000-5000 angstroms. The piezoelectric layer is etched to form the required pattern; then the top electrode material is deposited and the electrode pattern is etched; the release window is obtained around the groove by dry etching, and the hydrogen fluoride (or HF) solution is injected from the release window to remove the oxide in the groove to form a cavity structure. It can be understood that the above process is only part of the semiconductor device manufacturing process, and the corresponding process can be completed according to the actual needs, and then the wafer is sliced and segmented into a single die, and the die is packaged to prepare a semiconductor device.

[0081] The technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0082] 1. The removal method described in the embodiments of the present application places the wafer to be processed with a groove etched on the front surface and an oxide layer film deposited on the front surface on the polishing table, polishes the oxide layer film on the target plane on the polishing table until the oxide layer film reaches the target thickness to preliminarily remove a large amount of oxide on the target plane, and then performs secondary polishing on the target plane until the oxide layer film on the target plane is completely removed. The polishing amount of secondary polishing is small, and the removal amount of the oxide layer film above the target plane can be accurately controlled during the secondary polishing process to accurately and completely remove the oxide layer film above the target plane, thereby improving the removal quality of the deposition layer on the wafer surface.

[0083] 2. Compared with the traditional manufacturing method of etching and planarizing the oxide layer film, the present method can shorten the process such as lithography, gluing, developing, reverse etching and cleaning of the semiconductor device, not only can greatly shorten the process time, but also can save a lot of cost.

[0084] 3. The removing method of the embodiment of the present application avoids long-time polishing in one polishing station, and avoids the adverse effects of chemical reaction imbalance and mechanical dynamic balance error on the removing quality of the deposited layer, so that the in-wafer non-uniformity is poor. The removing of the deposited layer is implemented in multiple polishing stations, which not only improves the removing efficiency but also further improves the removing quality.

[0085] 4. The three-step polishing of the target plane can not only effectively control the removing of the film on the target plane to achieve the control target, but also greatly improves the surface roughness of the wafer, which is very helpful for the implementation of the next process, such as wafer bonding (direct bonding requires very high surface roughness), thereby improving the overall process level of the semiconductor device.

[0086] Although the preferred embodiments of the present application have been described, those skilled in the art who have the basic inventive concept can make further changes and modifications to the embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0087] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for removing a deposited layer from a wafer surface, characterized by, The method comprises: placing a wafer to be processed on a polishing table, wherein the wafer to be processed is a wafer with a groove etched on the front surface and an oxide film deposited on the front surface; primary polishing the oxide film on the target plane on the polishing table until the oxide film reaches a target thickness, wherein the target plane is the front surface of the wafer to be processed outside the groove, and the primary polishing selects a coarse polishing liquid; secondary polishing the oxide film on the target plane until the oxide film above the target plane is completely removed; the primary polishing of the oxide film on the target plane on the polishing table until the oxide film reaches a target thickness comprises: performing primary chemical mechanical polishing of the oxide film on the target plane using a composite polishing pad, so that the oxide removal rate of the oxide film is not less than 6000 angstroms per minute; when the polishing time of the primary polishing reaches a preset time or the detection spectrum of the primary polishing surface is a target spectrum, determining that the oxide film reaches 0.5-1.5um, and stopping the primary polishing of the oxide film; the secondary polishing of the oxide film on the target plane comprises: moving the wafer completing the primary polishing to a secondary polishing table; performing secondary chemical mechanical polishing of the oxide film using a water-soluble polishing liquid and a composite polishing pad; when the removal ratio of the oxide of the oxide film and the silicon dioxide of the front surface of the wafer is detected to be 1:0.9-1.1, controlling to stop the secondary polishing of the oxide film; after the secondary polishing of the oxide film on the target plane, the method further comprises: moving the wafer completing the secondary polishing to a tertiary polishing table, wherein the tertiary polishing table has the same structure as the polishing tables of the primary polishing and the secondary polishing, and the polishing tables of the primary polishing, the secondary polishing and the tertiary polishing are arranged in three independent closed spaces; performing tertiary chemical mechanical polishing of the target plane on the tertiary polishing table until the roughness of the target plane is less than 1nm; the tertiary chemical mechanical polishing of the target plane on the tertiary polishing table comprises: attaching a soft polishing pad to the target plane, moving a polishing head to the soft polishing pad, and spraying fine polishing liquid or pure water to the soft polishing pad; controlling the polishing table and the polishing head to rotate in the same direction, and the rotating speed of each is not less than 100RPM; controlling the area pressure of the attached surface of the polishing table and the polishing head to be uniform and not greater than 3PSI, so as to perform tertiary chemical mechanical polishing.

2. The method of claim 1, wherein the primary chemical mechanical polishing of the oxide film on the target plane using a composite polishing pad comprises: placing smoke particles between the composite polishing pad and the target plane; controlling the polishing table and the polishing head to rotate in the same direction, and the rotating speed of each is not less than 80RPM; The contact surface of the polishing table and the polishing head is controlled by area pressure control, so that the contact pressure is uniform and not less than 5 PSI, to perform primary chemical mechanical polishing on the oxide film of the target plane.

3. The method of claim 1, wherein the removing is performed by a method selected from the group consisting of a chemical mechanical polishing, a dry etching, a wet etching, and a combination thereof. The secondary chemical mechanical polishing on the oxide film by using water-soluble polishing liquid and composite polishing pad comprises: Colloidal silica with abrasive particle diameter of 50-130 nm is placed between the wafer front surface and the composite polishing pad; The polishing table and the polishing head are controlled to rotate in the same direction, and the rotating speed is not less than 90 RPM; The contact surface of the polishing table and the polishing head is controlled by area pressure control, so that the contact pressure is uniform and not more than 4 PSI.

4. The method of claim 1, wherein After detecting that the removal ratio of the oxide of the oxide film and the silicon dioxide of the wafer front surface is 1:0.9-1.1, the method further comprises: The polishing on the oxide film of the target plane is continued for 5-15 s, and then the secondary polishing is stopped.

5. The method of claim 1, wherein The oxide film is phosphorus-silicon glass or boron-phosphorus-silicon glass with thickness not less than 3 μm.

6. A semiconductor device, characterized by comprising: The deposited layer during the preparation of the semiconductor device is removed by the method according to any one of claims 1-5. The deposited layer during the preparation of the semiconductor device is removed by the method according to any one of claims 1-5.

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