Hole structure chemical mechanical polishing method and method for manufacturing semiconductor device

Abstract

The present application relates to a kind of hole structure chemical mechanical polishing method and the manufacturing method of semiconductor device, the hole structure chemical mechanical polishing method includes: obtaining the semiconductor structure formed with hole structure, the semiconductor structure is formed with hole filling metal, the semiconductor structure includes the barrier layer under the hole filling metal and the oxidation layer under the barrier layer, the hole filling metal fills in the hole structure;The first chemical mechanical polishing is carried out to the hole filling metal, and the first signal window is set in the way of end point monitoring, and the polishing end point is set at the transition interface of the hole filling metal and the barrier layer;Second chemical mechanical polishing is carried out after the first chemical mechanical polishing, and the barrier layer is removed, and the second signal window is set in the way of end point monitoring, and the polishing end point is set at the transition interface of the barrier layer and the oxidation layer.The present application can reduce the thickness and uniformity of first dielectric layer are influenced by external factors Fluctuation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and in particular to a pore structure chemical mechanical polishing method, and also to a method for manufacturing a semiconductor device polished using the pore structure chemical mechanical polishing method. Background Technology

[0002] In tungsten chemical mechanical polishing (W-CMP), tungsten contact holes serve as the first metal layer connecting to the device and remain the mainstream process in integrated circuits at various nanoscales (<130nm). The height and morphology (roughness) of the tungsten plug protrusion affect its contact with the metal layer, and the thickness of the first dielectric layer around the contact hole influences the device's electrical performance (Rc / Rs, ferromagnetic hysteresis, and memory function, etc.). Furthermore, the uniformity and defects of the wafer surface film (seam / dishing / roughness, etc.) directly affect the focusing accuracy and critical width (CD) of the photolithography process. Summary of the Invention

[0003] Therefore, it is necessary to provide a chemical mechanical polishing method for pore structures with accurate control of residual film thickness and a method for manufacturing semiconductor devices.

[0004] A chemical mechanical polishing (CMP) method for a porous structure includes: obtaining a semiconductor structure with a porous structure, wherein a pore-filling metal is formed on the semiconductor structure, the semiconductor structure includes a barrier layer under the pore-filling metal and an oxide layer under the barrier layer, and the pore-filling metal is filled into the porous structure; performing a first CMP on the pore-filling metal, setting a first signal window using termination point monitoring, and setting the polishing termination point at the transition interface between the pore-filling metal and the barrier layer; performing a second CMP after the first CMP to remove the barrier layer, setting a second signal window using termination point monitoring, and setting the polishing termination point at the transition interface between the barrier layer and the oxide layer; wherein the first CMP has a first polishing rate, the second CMP has a second polishing rate, and the first polishing rate is higher than the second polishing rate.

[0005] The aforementioned chemical mechanical polishing (CMP) method for porous structures, for film structures filled with metal / barrier layer / oxide layer during CMP, accurately obtains the termination points between different interface layers at different polishing rates by setting monitoring termination points for multi-step polishing at different polishing rates, thereby reducing the fluctuations in the thickness and uniformity of the first dielectric layer due to external factors.

[0006] A method for manufacturing a semiconductor device includes: obtaining a semiconductor structure having a porous structure; the semiconductor structure includes a substrate, a metal layer on the substrate, a first dielectric layer covering the metal layer, a first polishing-stop oxide layer on the first dielectric layer, a first barrier layer on the first polishing-stop oxide layer, and a first hole-filling metal on the first barrier layer, the semiconductor structure further having a porous structure extending through the first barrier layer, the first polishing-stop oxide layer, and the first dielectric layer to the metal layer, the first hole-filling metal filling the porous structure; and polishing the first hole-filling metal, the first barrier layer, and the first polishing-stop oxide layer using the aforementioned porous structure chemical mechanical polishing method. Attached Figure Description

[0007] Figure 1a This is a schematic diagram of the tungsten plug gap. Figure 1b This is a schematic diagram of the dents and corrosion on the tungsten plug. Figure 1c These are electron microscope images of the dents and corrosion on the tungsten plug. Figure 1d These are electron microscope images of multiple sets of defective tungsten plugs. Figure 1e These are electron microscope images showing gaps in the tungsten plugs. Figure 1f These are electron microscope images of tungsten plugs with high morphological roughness;

[0008] Figure 2 This is a flowchart of a pore structure chemical mechanical polishing method in one embodiment;

[0009] Figure 3 This is a schematic diagram of a semiconductor structure that requires chemical mechanical polishing in one embodiment;

[0010] Figure 4 This is a schematic diagram of a chemical mechanical grinding (CMP) grinding device.

[0011] Figure 5a This is an example of the EPD signal curve and signal window of a CMP. Figure 5b This is a schematic diagram showing the shape (slope) of the signal curves corresponding to different film layer combinations. Figure 5c This is a schematic diagram illustrating the overlap between the signal window and the signal curve. Figure 5d Setting the actual signal window for a single step in one embodiment;

[0012] Figure 6a and Figure 6b This is a schematic diagram of the contact between the polishing slurry and the polishing pad in step S152 of one embodiment;

[0013] Figure 7a and Figure 7b This is a schematic diagram of the contact between the mixture and the grinding pad in step S154 of one embodiment;

[0014] Figure 8 This is a schematic diagram of the grinding process in step S156 of one embodiment;

[0015] Figure 9 The comparison is an electron microscope image of the pore structure after chemical mechanical polishing of an embodiment of this application;

[0016] Figure 10a This is a flowchart of a method for manufacturing a semiconductor device in one embodiment. Figure 10b This is a flowchart of some steps in a method for manufacturing a semiconductor device in one embodiment;

[0017] Figures 11a~11k This is one embodiment of the method used. Figure 10a and Figure 10b The diagram shows a cross-sectional view of the device during the manufacturing process of the semiconductor device using the method shown. Detailed Implementation

[0018] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0019] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0021] In tungsten chemical mechanical polishing (CMP), different multilayer film combinations (such as W / TIN / TI / SiON / SiO2 or W / TIN / TI / SiON / TiN / SiO2) exist, and the polishing rates of different layers vary under the same conditions. Especially during the interface transition process of wafer surface film polishing, uneven mixing of different interface layers can easily occur at the wafer center / edge. In schemes using endpoint detection (EPD) technology to monitor the polishing termination point, this will delay and cause failure in capturing the automatic termination signal during interface state transition. Simultaneously, it will cause a significant deviation in film thickness between the die region and the test region, affecting the stability of the device's electrical performance.

[0022] In tungsten chemical mechanical polishing (CMP) processes, under appropriate polishing parameters, extending the overpolishing time and using novel slurries with different selectivity ratios are typically employed to control the amount of oxide removal, thereby obtaining tungsten plugs with a certain protrusion height. However, there are polishing differences in the pattern and center-edge position of the wafer surface, and the wafer surface film is affected by the slurry flow rate, concentration, and distribution of the slurry on the polishing pad during the polishing process. Therefore, simply adjusting the polishing time and using slurries with different selectivity ratios cannot effectively control the uniformity of the overall oxide removal on the wafer surface, resulting in significant fluctuations in the uniformity of the tungsten plug protrusion height.

[0023] Furthermore, due to the limitations of the previous tungsten filling process, tungsten plug seams and large morphological roughness are prone to occur, which remains a challenge for the industry. This poses a severe challenge to subsequent W-CMP processes in addressing the tungsten plug seams and ensuring a smooth morphology. At the same time, these problems also affect the growth quality and uniformity of subsequent film layers, posing a risk of instability in the device's electrical performance (RC).

[0024] Unreasonably extending the overpolishing time will increase the risk of tungsten plug gap defects in areas with denser patterns, such as erosion, dishing, and high roughness in the tungsten plug gaps and morphology. Figures 1a-1f As shown. Furthermore, extending the overpolishing time will correspondingly increase the production cost and reduce production efficiency.

[0025] The exemplary W-CMP scheme uses EPD for endpoint monitoring. Monitoring the termination point at the interface of different dielectric films typically involves setting only one main polishing pressure step to obtain the over-polishing stage at the stop layer endpoint. This method suffers from significant fluctuations in the control of the thickness of WTW (wafer-to-wafer) and WIW (wafer-in-wafer) dielectric layers (e.g., DRAC / SiO2), limiting its accuracy. Furthermore, due to limitations in the preceding tungsten film filling process, W CMP is prone to the risk of tungsten plug gaps.

[0026] Improving the morphology and roughness of tungsten plugs currently typically involves using new polishing slurries with smaller abrasive particle sizes (<100nm). This requires high-quality polishing slurries, and the industry has a long development and evaluation cycle, resulting in relatively high costs.

[0027] This application primarily addresses inherent defects (seam, roughness, etc.) arising from variations in pattern design and deposition processes of different preceding layers. These defects introduce potential fluctuations into the W-CMP process, affecting the uniformity of the grinding stop layer (oxides) and the precise control of the tungsten plug morphology. The inventors aim to overcome the limitations in EPD stop point setting caused by differences in selectivity between different layer combinations (e.g., W / TIN / TI / SiO2 / SiON), and to eliminate the risk of excessive dielectric film removal during W-CMP due to patterning differences in the preceding tungsten plug filling, leading to tungsten plug gaps.

[0028] Figure 2 This is a flowchart of a chemical mechanical polishing method for porous structures in one embodiment, including the following steps:

[0029] S110, to obtain a semiconductor structure with a porous structure.

[0030] Figure 3This is a schematic diagram of a semiconductor structure requiring chemical mechanical polishing in one embodiment. A hole-filling metal 140 is formed on the semiconductor structure, filling the hole structure 121. In one embodiment of this application, the hole-filling metal 140 is made of tungsten. The semiconductor structure includes a barrier layer 134 under the hole-filling metal 140 and an oxide layer 132 under the barrier layer. In one embodiment of this application, the barrier layer 134 is made of titanium and / or titanium nitride. The Ti film layer can act as an adhesive layer, mainly alleviating stress problems between the dielectric layers it contacts; the TiN film layer mainly prevents metal particles from diffusing to other film layers (such as metals W, Ti, etc.). In other embodiments, the barrier layer 134 can also be a Ta / TaN film layer. The oxide layer 132 serves as a polishing termination oxide layer. In one embodiment of this application, the oxide layer 132 is made of silicon oxide (e.g., silicon dioxide) and / or silicon oxynitride (e.g., silicon oxynitride).

[0031] exist Figure 3 In the illustrated embodiment, the semiconductor structure further includes a substrate 110 and a first dielectric layer 120.

[0032] S120, perform the first chemical mechanical polishing, and set the polishing termination point at the transition interface between the hole-filling metal and the barrier layer.

[0033] The hole-filling metal 140 is subjected to chemical mechanical polishing. Step S120 sets the first signal window by means of termination point monitoring (EPD), and sets the polishing termination point of step S120 at the transition interface between the hole-filling metal 140 and the barrier layer 134. Figure 4 This is a schematic diagram of chemical mechanical polishing (CMP) equipment. CMP equipment includes a platen (…). Figure 4 (Not shown in the image) A polishing pad 12 on a pressure plate, a conditioner disc 16 on the polishing pad 12, a polishing head 14, and a polishing fluid channel 18. The wafer 20 is placed on the polishing pad 12, and the polishing head 14 applies downward pressure to press the wafer 12 onto the polishing pad 12. The polishing fluid channel 18 is used to spray polishing fluid onto the polishing pad 12.

[0034] In one embodiment of this application, the first chemical mechanical polishing is a bulk tungsten film polishing stage, in which polishing slurry for tungsten polishing and high polishing rate (e.g., high polishing pressure, high polishing speed) are used to remove the tungsten film, and a signal window (#1-window out) is set in a termination point monitoring manner to obtain the transition stage of the interface between W and the barrier layer 134 (TIN / Ti).

[0035] S130, perform the second chemical mechanical polishing, and set the polishing termination point at the transition interface between the barrier layer and the oxide layer.

[0036] Remove the barrier layer 134. Step S130 sets the second signal window by means of termination point monitoring, and sets the grinding termination point of step S130 at the transition interface between the barrier layer 134 and the oxide layer 132.

[0037] In one embodiment of this application, the second chemical mechanical polishing is a transitional polishing stage of the mixed interface between W and the barrier layer 134 (TIN / Ti). The polishing slurry used for tungsten polishing and the low polishing rate (e.g., low polishing pressure, high polishing speed) are used to remove the TiN / Ti film. A signal window (#2-window In) is set in a termination point monitoring manner to obtain the interface transition between the barrier layer 134 (TIN / Ti) and the oxide layer 132.

[0038] The aforementioned chemical mechanical polishing (CMP) method for porous structures, for film structures filled with metal / barrier layer / oxide layer during CMP, accurately obtains the termination points between different interface layers at different polishing rates by setting monitoring termination points for multi-step polishing at different polishing rates, thereby reducing the fluctuations in the thickness and uniformity of the first dielectric layer due to external factors.

[0039] Specifically, the monitoring termination point setting employs a two-step independent signal algorithm: high-grinding pressure and low-grinding pressure steps each use different signal windows to capture the interface stop layer. Properly setting the signal window ensures accurate acquisition of the termination point corresponding to different grinding stages; improperly set signal windows will cause failure to capture the termination point, thus hindering precise control of the film thickness and interface. The signal mode uses either optical (laser) or torque (torque) methods, and the signal data calculation algorithm uses the average method. Figure 5a This is an example of the EPD signal curve and signal window of CMP. Figure 5a The horizontal axis represents time in seconds; the vertical axis represents the relative intensity of the signal, which indicates the relative change in reflected light or torsional current on the film surface, measured in Arb. Units (AU). The height of the signal window represents the amplitude intensity of the signal, which is the percentage of different signals from the material (film) within the detector's frequency range.

[0040] In one embodiment of this application, step S130 is followed by step S140: performing a third chemical mechanical polishing (CMP) to remove the remaining barrier layer 134 and part of the oxide layer 132. In one embodiment of this application, the third CMP is a transitional polishing stage at the interface between the barrier layer 134 and the oxide layer 132. It uses a polishing slurry for tungsten polishing and a low polishing rate (e.g., low polishing pressure, high polishing speed) to remove the TiN / Ti film, and sets the over-polishing time using a by-time / endpoint detection method. In one embodiment of this application, the over-polishing time is 0-15 seconds. In one embodiment of this application, the thickness of the oxide layer 132 removed by the third CMP is 100-300 Å.

[0041] In one embodiment of this application, the grinding parameters for the first chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 4.5~5.0 psi, internal tube pressure 6.0~6.8 psi, membrane pressure 3.0~3.8 psi, polishing slurry flow rate 100~150 ml / min, and tungsten / oxide 132 selectivity ratio 3~3.7.

[0042] In one embodiment of this application, the grinding parameters for the second chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 2.0~2.5psi, internal tube pressure 2.0~2.5psi, membrane pressure 1.0~1.5psi, polishing slurry flow rate 100~130ml / min, and tungsten / oxide 132 selectivity ratio 2~2.5.

[0043] In one embodiment of this application, the grinding parameters for the third chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 2.0~2.5psi, internal tube pressure 2.0~2.5psi, membrane pressure 1.0~1.5psi, polishing slurry flow rate 100~130ml / min, and tungsten / oxide 132 selectivity ratio 2~2.5.

[0044] In one embodiment of this application, the sizes of the first signal window and the second signal window are set based on the slope of the signal curve. In another embodiment, the horizontal axis of the first signal window and the vertical axis of the second signal window represent time, and the vertical axis represents the relative intensity of the signal. The relative intensity of the signal in the first signal window decreases with increasing time, while the relative intensity of the signal in the second signal window increases with increasing time.

[0045] The slope k of the signal curve is represented by tanα or tanβ, see [reference]. Figure 5b Where α is the positive angle between the signal curve and the horizontal axis when the relative signal intensity increases with time; β is the negative angle between the signal curve and the horizontal axis when the relative signal intensity decreases with time. The overlapping region between the signal curve and the signal window is denoted by θ, see [reference needed]. Figure 5c As shown. The actual signal window setting for a single step can be found in [reference needed]. Figure 5d . Figure 5d The window setting is expressed as the relationship between tanθ = |a| / (|b|×10), or tanθ = (|b|×10) / |a|, and tanα or tanβ:

[0046] 1) When 45°≤α or 45°≤β<90°, θ should satisfy: 45°≤θ≤60°, that is, 1≤|a| / (|b|×10)≤√3;

[0047] 2#) When 0°≤α<45° or β<45°, θ should satisfy: 30°≤θ≤45°, that is, √3 / 3≤(|b|×10) / |a|≤1.

[0048] In one embodiment of this application, the height of the first signal window 1# is -0.3 to -0.4, the width is 2 to 4 seconds, and the number of windows is 1 to 3; the height of the second signal window 2# is 0.17 to 0.35, the width is 1 to 3 seconds, and the number of windows is 1 to 3.

[0049] The above-mentioned chemical mechanical polishing method for porous structures sets different polishing stages according to the number of film interfaces involved in the polishing process, and sets polishing parameters and signal windows for polishing termination points for different polishing stages. It can flexibly combine and accurately obtain the interface termination points under different polishing rates in multiple steps, and then accurately set the over-polishing time of the automatic polishing stop layer termination point, controlling the film thickness fluctuation of the polishing termination layer (i.e., oxide layer 132) within 50~100Å, and significantly reducing the risk of tungsten plug gaps.

[0050] In one embodiment of this application, step S140 is followed by step S150: over-polishing of the oxide layer 132. The polishing speed in step S150 is lower than the polishing speed of the first and second chemical mechanical polishing processes. The polishing speed may include the pressure plate speed and / or the polishing head speed.

[0051] In one embodiment of this application, step S150 includes:

[0052] S152, polishing is performed by passing polishing fluid through the polishing pad, and the selection ratio of oxide layer 132 / hole filling metal 140 is 12~15.

[0053] In one embodiment of this application, the grinding parameters for step S152 are set as follows: pressure plate / grinding head speed 50~65 rpm / min, retaining ring pressure 4.0~4.5 psi, internal tube pressure 2.5~3 psi, membrane pressure 2~2.5 psi, grinding slurry flow rate 150~200 ml / min, oxide layer 132 / W selectivity ratio 12~15.

[0054] In one embodiment of this application, the distance from the landing point of the polishing slurry on the polishing pad to the center of the polishing pad is 8.5-9 cm. See [link to relevant documentation]. Figure 6a .

[0055] S154, after mixing the polishing slurry and cleaning water, it is introduced onto the polishing pad for polishing, and the selection ratio of oxide layer 132 / hole filling metal 140 is 8~10.

[0056] In one embodiment of this application, the grinding parameters in step S154 are set as follows: pressure plate / grinding head speed 95~105 rpm / min, retaining ring pressure 3~3.5 psi, internal tube pressure 2~2.5 psi, membrane pressure 1.5~2 psi, grinding slurry flow rate 150~200 ml / min, and oxide layer 132 / W selectivity ratio 8~10.

[0057] In one embodiment of this application, the outlets of the polishing slurry and the cleaning water are positioned close together to form a mixture. The distance from the center of the polishing pad to the landing point of the mixture on the polishing pad is 9.5 to 10 centimeters. See [link to relevant documentation]. Figure 7a The outlets of the grinding slurry and the cleaning water can be positioned at the same horizontal level. In one embodiment of this application, the cleaning water is high-pressure deionized water (DIW).

[0058] S156, Grinding is performed by passing cleaning water through the grinding pad.

[0059] In one embodiment of this application, the distance from the point where the cleaning water falls on the abrasive pad to the center of the abrasive pad is 8-10 cm. See [link to relevant documentation]. Figure 8 .

[0060] Step S150 uses an abrasive slurry for oxide layer polishing and a low polishing rate (e.g., low polishing pressure, low polishing speed) to remove a small amount of oxide layer 132. The polishing steps are primarily set up by coordinating the polishing slurry and high-pressure deionized water pipelines, and the arrangement of single and double pipelines is adjusted. In one embodiment of this application, the thickness of the oxide layer 132 removed in step S150 is 50~250 Å.

[0061] In one embodiment of this application, the grinding speed in step S152 is less than the grinding speed in step S154, and the grinding pressure in step S152 is greater than the grinding pressure in step S154. The grinding pressure may include the downward pressure of the grinding head.

[0062] In one embodiment of this application, the contact angle between the polishing slurry column and the polishing pad in step S152 is 80-90 degrees, see [link to relevant documentation]. Figure 6b .

[0063] In one embodiment of this application, the contact angle between the mixed liquid column and the grinding pad in step S154 is 45-60 degrees, see [link to relevant documentation]. Figure 7b .

[0064] Step S150 involves adjusting the polishing slurry and high-pressure deionized water pipelines to adjust the landing point of the polishing slurry and / or deionized water and mixture on the polishing pad. This reduces the friction between the polishing slurry particles and the tungsten plug surface, improving the uniformity of the wafer surface film and the roughness of the tungsten plug morphology. See [link to relevant documentation]. Figure 9 .

[0065] The aforementioned chemical mechanical polishing (CMP) method for porous structures effectively controls the thickness stability and uniformity of the dielectric layer in wafer-to-wafer and wafer-in-wafer processes by using a multi-step monitoring method for the termination points of the multilayer film interface states and improving the coordination between the polishing slurry and high-pressure deionized water pipelines. This results in a highly smooth, damage-free W-plug surface morphology, thereby improving the electrical performance stability of the device. This method also improves the stability of precise alignment in the photolithography process while saving on consumable costs.

[0066] Understandably, the above-described pore structure chemical mechanical polishing method is applied to the manufacture of semiconductor devices. Accordingly, this application provides a method for manufacturing a semiconductor device using the above-described pore structure chemical mechanical polishing method. Figure 10a This is a flowchart of a method for manufacturing a semiconductor device in one embodiment, including the following steps:

[0067] S210 forms a metal layer on the substrate.

[0068] See Figure 11a Various device structures known in the art, such as active regions, well regions, and contact regions, can be formed on the substrate 210. Other device structures known in the art, such as gates and dielectric layers, can also be formed on the substrate 210. Figure 11a In the illustrated embodiment, an oxide layer 212 is formed on the substrate 210; the material of the oxide layer 212 can be an oxide of silicon, such as silicon dioxide. The substrate 210 can be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, or other III / V compound semiconductors, or a multilayer structure composed of these semiconductors, or silicon-on-insulator (SOI), silicon-on-insulator stacked (SSOI), silicon-on-insulator stacked (S-SiGeOI), silicon-on-insulator (SiGeOI), and germanium-on-insulator (GeOI), etc.

[0069] In one embodiment of this application, the manufactured semiconductor device is a ferroelectric memory (FRAM).

[0070] exist Figure 11a In the embodiment shown, the metal layer 214 includes a conductive body and Ti / TiN layers located on the upper and lower surfaces of the conductive body.

[0071] In one embodiment of this application, a metal film layer can be formed on the oxide layer 212 by processes such as chemical vapor deposition (CVD) or physical vapor deposition (PVD), and then a metal layer 214 can be formed by patterning processes (such as photolithography and etching processes). In one embodiment of this application, an anti-reflective layer (DARC) can also be formed on the metal layer 214 before performing the patterning process.

[0072] S220, forming the first dielectric layer covering the metal layer.

[0073] In one embodiment of this application, a first dielectric layer 220 covering the metal layer 214 is formed by chemical vapor deposition. See [link to relevant documentation]. Figure 11b .

[0074] S230, a first polishing termination oxide layer is formed on the first dielectric layer.

[0075] exist Figure 11c In the illustrated embodiment, after step S220, a step of forming an anti-reflective layer (DARC) 232 on the first dielectric layer is further included. In one embodiment of this application, the material of the anti-reflective layer 232 includes SiON, and the anti-reflective layer 232 can be formed by chemical vapor deposition. Figure 11c In the illustrated embodiment, after forming the antireflective layer 232, a step of forming a thin oxide layer 233 on the antireflective layer 232 is further included. In one embodiment of this application, the first polishing termination oxide layer includes the antireflective layer 232 and the thin oxide layer 233.

[0076] S240, patterning the first polishing termination oxide layer and the first dielectric layer to form a hole structure extending to the metal layer at the bottom.

[0077] exist Figure 11d In the embodiment shown, a hole structure 221 of Ti / TiN layer extending to the metal layer 214 is formed by photolithography and etching of thin oxide layer 233, anti-reflection layer 232 and first dielectric layer 220.

[0078] S250, a first barrier layer is formed on the first grinding termination oxide layer.

[0079] In one embodiment of this application, the first barrier layer is a Ti / TiN layer. In another embodiment, the first barrier layer is formed on a thin oxide layer 233 using physical vapor deposition. During deposition, plasma bombardment is applied to the corners at the top of the hole structure 221, partially removing the corners and resulting in an inverted trapezoidal cross-section at the top of the hole structure. In one embodiment, the angles of the two corners at the top of the inverted trapezoid are approximately 30-60°. The corners at the top of the hole structure 221 with a certain angle facilitate tungsten filling.

[0080] S260, forming a first hole-filling metal on the first barrier layer.

[0081] In one embodiment of this application, a first via-filling metal 240 is formed on a barrier layer using a process such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). The first via-filling metal 240 fills the via structure 211. See [link to relevant documentation]. Figure 11e . Figure 11e The first barrier layer is not shown, and the hole structure 211 is not indicated. In one embodiment of this application, the material of the first hole filling metal 240 is tungsten.

[0082] S270, perform CMP.

[0083] CMP is performed using the pore structure chemical mechanical polishing method described in any of the foregoing embodiments to achieve precise film thickness control of the dielectric layer, stopping at the antireflective layer 232. Specifically, CMP may include the following steps:

[0084] Step A: Perform the first chemical mechanical polishing, and set the polishing termination point at the transition interface between the first hole filling metal and the first barrier layer.

[0085] The first hole-filling metal 240 is subjected to chemical mechanical polishing. Step A sets the first signal window using end-point monitoring (EPD) and sets the polishing end point of step A at the transition interface between the first hole-filling metal 240 and the first barrier layer.

[0086] In one embodiment of this application, the first chemical mechanical polishing is a bulk tungsten film polishing stage, in which polishing slurry for tungsten polishing and high polishing rate (e.g., high polishing pressure, high polishing speed) are used to remove the tungsten film, and a signal window (#1-window out) is set in a termination point monitoring manner to obtain the transition stage of the W and barrier layer (TIN / Ti) interface.

[0087] Step B involves performing a second chemical mechanical polishing process, with the polishing termination point set at the transition interface between the first barrier layer and the first polishing termination oxide layer.

[0088] Remove the first barrier layer. Step B sets the second signal window by monitoring the termination point, setting the grinding termination point of Step B at the transition interface between the first barrier layer and the first grinding termination oxide layer.

[0089] In one embodiment of this application, the second chemical mechanical polishing is a transitional polishing stage of the mixed interface between W and the first barrier layer (TIN / Ti). The polishing slurry used for tungsten polishing and the low polishing rate (e.g., low polishing pressure, high polishing speed) are used to remove the TiN / Ti film. A signal window (#2-window In) is set in a termination point monitoring manner to obtain the interface transition between the first barrier layer (TIN / Ti) and the first polishing termination oxide layer.

[0090] Specifically, the monitoring termination point setting employs a two-step independent signal algorithm: high grinding pressure and low grinding pressure steps respectively capture the interface stop layer by setting different signal windows. The signal mode uses optical or torque methods, and the signal data calculation algorithm uses the averaging method.

[0091] In one embodiment of this application, step C is included after step B: performing a third chemical mechanical polishing to remove the remaining first barrier layer and part of the first polishing termination oxide layer. In one embodiment of this application, the third chemical mechanical polishing is a transitional polishing stage at the interface between the first barrier layer and the first polishing termination oxide layer. It uses polishing slurry for tungsten polishing and a low polishing rate (e.g., low polishing pressure, high polishing speed) to remove the TiN / Ti film, and sets the over-polishing time using a time / termination point monitoring method. In one embodiment of this application, the over-polishing time is 0-15 seconds. In one embodiment of this application, the thickness of the first polishing termination oxide layer removed by the third chemical mechanical polishing is 100-300 Å.

[0092] In one embodiment of this application, the grinding parameters for the first chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 4.5~5.0 psi, internal tube pressure 6.0~6.8 psi, membrane pressure 3.0~3.8 psi, polishing slurry flow rate 100~150 ml / min, and tungsten / first polishing termination oxide layer selectivity ratio 3~3.7.

[0093] In one embodiment of this application, the grinding parameters for the second chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 2.0~2.5psi, internal tube pressure 2.0~2.5psi, membrane pressure 1.0~1.5psi, polishing slurry flow rate 100~130ml / min, and tungsten / first polishing termination oxide layer selectivity ratio 2~2.5.

[0094] In one embodiment of this application, the grinding parameters for the third chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 2.0~2.5psi, internal tube pressure 2.0~2.5psi, membrane pressure 1.0~1.5psi, polishing slurry flow rate 100~130ml / min, and tungsten / first polishing termination oxide layer selectivity ratio 2~2.5.

[0095] In one embodiment of this application, the sizes of the first signal window and the second signal window are set based on the slope of the signal curve. In another embodiment, the horizontal axis of the first signal window and the vertical axis of the second signal window represent time, and the vertical axis represents the relative intensity of the signal. The relative intensity of the signal in the first signal window decreases with increasing time, while the relative intensity of the signal in the second signal window increases with increasing time.

[0096] Figure 5d The window setting is expressed as the relationship between tanθ = |a| / (|b|×10), or tanθ = (|b|×10) / |a|, and tanα or tanβ:

[0097] 1) When 45°≤α or 45°≤β<90°, θ should satisfy: 45°≤θ≤60°, that is, 1≤|a| / (|b|×10)≤√3;

[0098] 2#) When 0°≤α<45° or β<45°, θ should satisfy: 30°≤θ≤45°, that is, √3 / 3≤(|b|×10) / |a|≤1.

[0099] In one embodiment of this application, the height of the first signal window 1# is -0.3 to -0.4, the width is 2 to 4 seconds, and the number of windows is 1 to 3; the height of the second signal window 2# is 0.17 to 0.35, the width is 1 to 3 seconds, and the number of windows is 1 to 3.

[0100] In one embodiment of this application, step D is included after step C: performing a first polishing to terminate the over-polishing of the oxide layer. The polishing speed in step D is lower than the polishing speed of the first and second chemical mechanical polishing processes. A cross-sectional schematic diagram of the device after step D is shown below. Figure 11f As shown.

[0101] In one embodiment of this application, step D includes:

[0102] Step D1: Polishing is performed by passing polishing fluid through the polishing pad. The ratio of the first polishing termination oxide layer to the first hole filling metal 240 is 12~15.

[0103] In one embodiment of this application, the grinding parameters for step D1 are set as follows: pressure plate / grinding head speed 50~65 rpm / min, retaining ring pressure 4.0~4.5 psi, internal tube pressure 2.5~3 psi, membrane pressure 2~2.5 psi, grinding fluid flow rate 150~200 ml / min, first grinding termination oxide layer / W selectivity ratio 12~15.

[0104] In one embodiment of this application, the distance from the landing point of the polishing slurry on the polishing pad to the center of the polishing pad is 8.5-9 cm. See [link to relevant documentation]. Figure 6a .

[0105] Step D2 involves mixing the polishing slurry and cleaning water, then introducing the mixture onto the polishing pad for polishing. The first polishing termination oxide layer / W ratio is 8~10.

[0106] In one embodiment of this application, the grinding parameters in step S154 are set as follows: pressure plate / grinding head speed 95~105 rpm / min, retaining ring pressure 3~3.5 psi, internal tube pressure 2~2.5 psi, membrane pressure 1.5~2 psi, grinding fluid flow rate 150~200 ml / min, and first grinding termination oxide layer / W selectivity ratio 8~10.

[0107] In one embodiment of this application, the outlets of the polishing slurry and the cleaning water are positioned close together to form a mixture. The distance from the center of the polishing pad to the landing point of the mixture on the polishing pad is 9.5 to 10 centimeters. See [link to relevant documentation]. Figure 7a In one embodiment of this application, the cleaning water is high-pressure deionized water (DIW).

[0108] Step D3: Pour cleaning water through the grinding pad and grind the material.

[0109] In one embodiment of this application, the distance from the point where the cleaning water falls on the abrasive pad to the center of the abrasive pad is 8-10 cm. See [link to relevant documentation]. Figure 8 .

[0110] Step D uses an abrasive slurry for oxide layer polishing and a low polishing rate (e.g., low polishing pressure, low polishing speed) to remove a small amount of the first polishing termination oxide layer. The polishing steps are primarily set up by coordinating the polishing slurry and high-pressure deionized water pipelines, and the arrangement of single and double pipelines is adjusted. In one embodiment of this application, the thickness of the first polishing termination oxide layer removed in step D is 50~250 Å.

[0111] In one embodiment of this application, the grinding speed in step D1 is less than the grinding speed in step D2, and the grinding pressure in step D1 is greater than the grinding pressure in step D2.

[0112] In one embodiment of this application, the contact angle between the polishing slurry column and the polishing pad in step D1 is 80-90 degrees, see [link to relevant documentation]. Figure 6b .

[0113] In one embodiment of this application, the contact angle between the mixed liquid column and the grinding pad in step D2 is 45-60 degrees, see [link to relevant documentation]. Figure 7b .

[0114] See Figure 10b In one embodiment of this application, the following steps are included after step S270:

[0115] S310, a capacitor is formed on the first hole filling metal.

[0116] exist Figure 11gIn the illustrated embodiment, capacitor 250 is a MIM (metal-dielectric-metal) cap, including a top electrode 254, a bottom electrode 252, and a dielectric layer 253 disposed between the top electrode 254 and the bottom electrode 252. The bottom electrode 252 is in direct contact with the first via-filling metal 240. Capacitor 250 can be formed by deposition and patterning processes. Deposition can employ processes such as physical vapor deposition or atomic layer deposition (ALD), and patterning can include photolithography and etching processes. In one embodiment of this application, an anti-reflective layer 242 can also be formed on the top of capacitor 250 before photolithography.

[0117] In one embodiment of this application, the semiconductor device is a hafnium oxide ferroelectric material memory device, and the dielectric layer 253 is made of HfO2 and / or HfZrO. By applying an external voltage to the device, the atomic structure of the dielectric layer 253 can be changed to reflect different ferroelectric storage characteristics (hysteresis loops).

[0118] S320, a second dielectric layer is formed on the capacitor and the first dielectric layer.

[0119] In one embodiment of this application, a step of forming a silicon nitride layer 244 on the capacitor 250 is included before step S320. The silicon nitride layer 244 can be formed by a chemical vapor deposition process. Figure 11h In the illustrated embodiment, the silicon nitride layer 244 is also formed on the antireflective layer 232, and correspondingly, the second dielectric layer 260 is formed on the silicon nitride layer 244. The second dielectric layer 260 can be formed by chemical vapor deposition (CVD), and the gas source for CVD can be TEOS (tetraethyl orthosilicate).

[0120] S330, a second polishing termination oxide layer is formed on the second dielectric layer.

[0121] The second polishing termination oxide layer may include an anti-reflective layer 262, which can be formed by a chemical vapor deposition process. In one embodiment of this application, a thin oxide layer 263 may be formed on the anti-reflective layer 262.

[0122] S340, patterning the second polishing termination oxide layer and the second dielectric layer to form the first through-hole and the second through-hole.

[0123] See Figure 11i The bottom of the first through-hole 271 extends to the top electrode of the capacitor 250, and the bottom of the second through-hole 273 extends to the top of the first hole filling metal 240. Therefore, in Figure 11iIn the illustrated embodiment, during patterning step S340, the silicon nitride layer 244 and the anti-reflection layer 242 also need to be patterned, that is, the silicon nitride layer 244 and the anti-reflection layer 242 at the locations of the first via 271 and the second via 273 need to be removed. In one embodiment of this application, the first via 271 and the second via 273 are formed by photolithography and etching.

[0124] S350, a second barrier layer is formed on the second grinding termination oxide layer.

[0125] In one embodiment of this application, the second barrier layer is a Ti / TiN layer. In another embodiment, the first barrier layer is formed on the thin oxide layer 263 by physical vapor deposition. During the deposition process, plasma is used to bombard the corners at the top of the first via 271 and the second via 273, and a portion of the corners is removed, resulting in an inverted trapezoidal cross-section at the top of the hole structure. In one embodiment, the angles of the two corners at the top of the inverted trapezoid are approximately 30-60°.

[0126] S360, a second hole-filling metal is formed on the second barrier layer.

[0127] In one embodiment of this application, a second via-filling metal 270 is formed on the second barrier layer using a process such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). The second via-filling metal 270 fills the first via 271 and the second via 273. See [link to relevant documentation]. Figure 11j . Figure 11j The second barrier layer is not shown, and the first through hole 271 and the second through hole 273 are not labeled. In one embodiment of this application, the material of the second hole filling metal 270 is tungsten.

[0128] S370, perform CMP.

[0129] CMP is performed using the pore structure chemical mechanical polishing method described in any of the foregoing embodiments. In one embodiment of this application, after CMP, the tungsten plug protrudes 200-500 Å relative to the surrounding structure (dielectric layer). Specifically, CMP may include the following steps:

[0130] Step A: Perform the first chemical mechanical polishing, and set the polishing termination point at the transition interface between the second hole filling metal and the second barrier layer.

[0131] The second hole-filling metal 270 is subjected to chemical mechanical polishing. Step A sets the first signal window using end-point monitoring (EPD) and sets the polishing end point of step A at the transition interface between the second hole-filling metal 270 and the second barrier layer.

[0132] In one embodiment of this application, the first chemical mechanical polishing is a bulk tungsten film polishing stage, in which polishing slurry for tungsten polishing and high polishing rate (e.g., high polishing pressure, high polishing speed) are used to remove the tungsten film, and a signal window (#1-window out) is set in a termination point monitoring manner to obtain the transition stage of the W and barrier layer (TIN / Ti) interface.

[0133] Step B involves performing a second chemical mechanical polishing process, with the polishing termination point set at the transition interface between the second barrier layer and the second polishing termination oxide layer.

[0134] Remove the second barrier layer. Step B sets the second signal window by monitoring the termination point, setting the grinding termination point of Step B at the transition interface between the second barrier layer and the second grinding termination oxide layer.

[0135] In one embodiment of this application, the second chemical mechanical polishing is a transition polishing stage between the W and the second barrier layer (TIN / Ti) interface. The TiN / Ti film is removed by using polishing slurry for tungsten polishing and a low polishing rate (e.g., low polishing pressure, high polishing speed). A signal window (#2-window In) is set in a termination point monitoring manner to obtain the interface transition between the second barrier layer (TIN / Ti) and the second polishing termination oxide layer.

[0136] Specifically, the monitoring termination point setting employs a two-step independent signal algorithm: high grinding pressure and low grinding pressure steps respectively capture the interface stop layer by setting different signal windows. The signal mode uses either optical (laser) or torque (torque) methods, and the signal data calculation algorithm uses the average method.

[0137] In one embodiment of this application, step C is included after step B: performing a third chemical mechanical polishing to remove the remaining second barrier layer and part of the second polishing termination oxide layer. In one embodiment of this application, the third chemical mechanical polishing is a transitional polishing stage at the interface between the second barrier layer and the second polishing termination oxide layer. It uses polishing slurry for tungsten polishing and a low polishing rate (e.g., low polishing pressure, high polishing speed) to remove the TiN / Ti film, and sets the over-polishing time using a time / termination point monitoring method. In one embodiment of this application, the over-polishing time is 0-15 seconds. In one embodiment of this application, the thickness of the second polishing termination oxide layer removed by the third chemical mechanical polishing is 100-300 Å.

[0138] In one embodiment of this application, the grinding parameters for the first chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 4.5~5.0 psi, internal tube pressure 6.0~6.8 psi, membrane pressure 3.0~3.8 psi, polishing slurry flow rate 100~150 ml / min, and tungsten / second polishing termination oxide layer selectivity ratio 3~3.7.

[0139] In one embodiment of this application, the grinding parameters for the second chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 2.0~2.5psi, internal tube pressure 2.0~2.5psi, membrane pressure 1.0~1.5psi, polishing slurry flow rate 100~130ml / min, and tungsten / second polishing termination oxide layer selectivity ratio 2~2.5.

[0140] In one embodiment of this application, the grinding parameters for the third chemical mechanical polishing are set as follows: pressure plate / grinding head speed 110~120 rpm / min, retaining ring pressure 2.0~2.5psi, internal tube pressure 2.0~2.5psi, membrane pressure 1.0~1.5psi, polishing slurry flow rate 100~130ml / min, and tungsten / second polishing termination oxide layer selectivity ratio 2~2.5.

[0141] In one embodiment of this application, the sizes of the first signal window and the second signal window are set based on the slope of the signal curve. In another embodiment, the horizontal axis of the first signal window and the vertical axis of the second signal window represent time, and the vertical axis represents the relative intensity of the signal. The relative intensity of the signal in the first signal window decreases with increasing time, while the relative intensity of the signal in the second signal window increases with increasing time.

[0142] Figure 5d The window setting is expressed as the relationship between tanθ = |a| / (|b|×10), or tanθ = (|b|×10) / |a|, and tanα or tanβ:

[0143] 1) When 45°≤α or 45°≤β<90°, θ should satisfy: 45°≤θ≤60°, that is, 1≤|a| / (|b|×10)≤√3;

[0144] 2#) When 0°≤α<45° or β<45°, θ should satisfy: 30°≤θ≤45°, that is, √3 / 3≤(|b|×10) / |a|≤1.

[0145] In one embodiment of this application, the height of the first signal window 1# is -0.3 to -0.4, the width is 2 to 4 seconds, and the number of windows is 1 to 3; the height of the second signal window 2# is 0.17 to 0.35, the width is 1 to 3 seconds, and the number of windows is 1 to 3.

[0146] In one embodiment of this application, step D is included after step C: performing a second polishing to terminate the over-polishing of the oxide layer. The polishing speed in step D is lower than the polishing speeds of the first and second chemical mechanical polishing. A cross-sectional schematic diagram of the device after step D is shown below. Figure 11k As shown.

[0147] In one embodiment of this application, step D includes:

[0148] Step D1: Polishing is performed by passing polishing slurry through the polishing pad. The ratio of the second polishing termination oxide layer to the second hole filling metal 270 is 12~15.

[0149] In one embodiment of this application, the grinding parameters for step D1 are set as follows: pressure plate / grinding head speed 50~65 rpm / min, retaining ring pressure 4.0~4.5 psi, internal tube pressure 2.5~3 psi, membrane pressure 2~2.5 psi, grinding slurry flow rate 150~200 ml / min, and second grinding termination oxide layer / W selectivity ratio 12~15.

[0150] In one embodiment of this application, the distance from the landing point of the polishing slurry on the polishing pad to the center of the polishing pad is 8.5-9 cm. See [link to relevant documentation]. Figure 6a .

[0151] Step D2 involves mixing the polishing slurry and cleaning water, then introducing the mixture onto the polishing pad for polishing. The selection ratio of the oxide layer / W at the end of the second polishing process is 8-10.

[0152] In one embodiment of this application, the grinding parameters in step S154 are set as follows: pressure plate / grinding head speed 95~105 rpm / min, retaining ring pressure 3~3.5 psi, internal tube pressure 2~2.5 psi, membrane pressure 1.5~2 psi, grinding slurry flow rate 150~200 ml / min, and second grinding termination oxide layer / W selectivity ratio 8~10.

[0153] In one embodiment of this application, the outlets of the polishing slurry and the cleaning water are positioned close together to form a mixture. The distance from the center of the polishing pad to the landing point of the mixture on the polishing pad is 9.5 to 10 centimeters. See [link to relevant documentation]. Figure 7a In one embodiment of this application, the cleaning water is high-pressure deionized water (DIW).

[0154] Step D3: Pour cleaning water through the grinding pad and grind the material.

[0155] In one embodiment of this application, the distance from the point where the cleaning water falls on the abrasive pad to the center of the abrasive pad is 8-10 cm. See [link to relevant documentation]. Figure 8 .

[0156] Step D uses an abrasive slurry for oxide layer polishing and a low polishing rate (e.g., low polishing pressure, low polishing speed) to remove a small amount of the second polishing termination oxide layer. The polishing steps are primarily set up by coordinating the polishing slurry and high-pressure deionized water pipelines, and the arrangement of single and double pipelines is adjusted. In one embodiment of this application, the thickness of the second polishing termination oxide layer removed in step D is 50~250 Å.

[0157] In one embodiment of this application, the grinding speed in step D1 is less than the grinding speed in step D2, and the grinding pressure in step D1 is greater than the grinding pressure in step D2.

[0158] In one embodiment of this application, the contact angle between the polishing slurry column and the polishing pad in step D1 is 80-90 degrees, see [link to relevant documentation]. Figure 6b .

[0159] In one embodiment of this application, the contact angle between the mixed liquid column and the grinding pad in step D2 is 45-60 degrees, see [link to relevant documentation]. Figure 7b .

[0160] It should be understood that although the steps in the flowchart of this application are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart of this application may include multiple steps or multiple stages, which are not necessarily completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps.

Claims

1. A method for chemical mechanical polishing of porous structures, comprising: A semiconductor structure with a porous structure is obtained, wherein a porous filling metal is formed on the semiconductor structure, and the semiconductor structure includes a barrier layer under the porous filling metal, an oxide layer under the barrier layer, a first dielectric layer under the oxide layer, and a substrate under the first dielectric layer. The porous filling metal is filled into the porous structure, and the barrier layer serves to prevent metal particles from diffusing to other film layers. The hole-filling metal is subjected to a first chemical mechanical polishing process, and a first signal window is set by an termination point monitoring method, with the polishing termination point set at the transition interface between the hole-filling metal and the barrier layer. After the first chemical mechanical polishing, a second chemical mechanical polishing is performed to remove the barrier layer. A second signal window is set by a termination point monitoring method, and the polishing termination point is set at the transition interface between the barrier layer and the oxide layer. The oxide layer is used as the polishing termination oxide layer. A third chemical mechanical polishing is performed after the second chemical mechanical polishing to remove the remaining barrier layer and part of the oxide layer; The third chemical mechanical polishing is the interface transition polishing stage between the barrier layer and the oxide layer; Wherein, the first chemical mechanical polishing has a first polishing rate, the second chemical mechanical polishing has a second polishing rate, and the third chemical mechanical polishing has a third polishing rate. The first polishing rate is higher than the second polishing rate and the third polishing rate. The first, second, and third chemical mechanical polishing use polishing slurries for tungsten polishing. The selectivity ratio of the pore-filling metal to the oxide layer in the second chemical mechanical polishing is 2 to 2.5, and the selectivity ratio of the pore-filling metal to the oxide layer in the third chemical mechanical polishing is 2 to 2.

5.

2. The chemical mechanical polishing method for porous structures according to claim 1, characterized in that, The barrier layer is made of titanium and / or titanium nitride, the hole filling metal is tungsten, the horizontal axis of the first signal window and the vertical axis of the second signal window are time, and the vertical axis is the relative intensity of the signal; the height of the first signal window is negative, and the height of the signal in the second signal window is positive.

3. The chemical mechanical polishing method for porous structures according to claim 2, characterized in that, The height of the first signal window is -0.3 to -0.4, and the width is 2 to 4 seconds; the height of the second signal window is 0.17 to 0.35, and the width is 1 to 3 seconds.

4. The chemical mechanical polishing method for porous structures according to claim 3, characterized in that, The first signal window and the second signal window satisfy the following relationship: When 45°≤α or 45°≤β<90°, 45°≤θ≤60°; When 0°≤α<45° or β<45°, 30°≤θ≤45°; Where θ is the overlapping area between the signal curve and the signal window, α is the positive angle of the signal curve relative to the horizontal axis when it rises, and β is the negative angle of the signal curve relative to the horizontal axis when it falls.

5. The chemical mechanical polishing method for porous structures according to claim 1, characterized in that, The grinding pressure of the first chemical mechanical polishing is greater than that of the second chemical mechanical polishing; the selectivity ratio of the pore-filling metal to the oxide layer in the first chemical mechanical polishing is 3 to 3.

7.

6. The chemical mechanical polishing method for porous structures according to claim 1, characterized in that, The thickness of the oxide layer removed by the third chemical mechanical polishing is 100~300 Å.

7. The chemical mechanical polishing method for porous structures according to claim 6, characterized in that, It also includes a step of over-polishing the oxide layer after the third chemical mechanical polishing, wherein the polishing speed of the over-polishing of the oxide layer is less than the polishing speed of the first chemical mechanical polishing and the second chemical mechanical polishing; The over-polishing of the oxide layer includes: In the first grinding step, grinding fluid is introduced into the grinding pad for grinding, and the selection ratio of the oxide layer to the pore filling metal is 12~15. The second grinding step involves mixing the grinding fluid and cleaning water and then passing it onto the grinding pad for grinding. The selection ratio of the oxide layer to the pore-filling metal is 8 to 10. The third grinding step involves passing cleaning water through the grinding pad for grinding.

8. The chemical mechanical polishing method for porous structures according to claim 7, characterized in that, In the first grinding step, the distance between the landing point of the grinding liquid on the grinding pad and the center of the grinding pad is 8.5-9 cm; in the second grinding step, the outlets of the grinding liquid and the cleaning water are positioned close to each other to form a mixture, and the distance between the landing point of the mixture on the grinding pad and the center of the grinding pad is 9.5-10 cm; in the third grinding step, the distance between the landing point of the cleaning water on the grinding pad and the center of the grinding pad is 8-10 cm.

9. The chemical mechanical polishing method for porous structures according to claim 7, characterized in that, The grinding speed in the first grinding step is lower than the grinding speed in the second grinding step, and the grinding pressure in the first grinding step is greater than the grinding pressure in the second grinding step; and / or In the first grinding step, the contact angle between the grinding liquid column and the grinding pad is 80-90 degrees; and / or In the second grinding step, the contact angle between the mixed liquid column and the grinding pad is 45 to 60 degrees.

10. A method for manufacturing a semiconductor device, comprising: Obtain a semiconductor structure with a porous structure; The semiconductor structure includes a substrate, a metal layer on the substrate, a first dielectric layer covering the metal layer, a first polishing-stopping oxide layer on the first dielectric layer, a first barrier layer on the first polishing-stopping oxide layer, and a first hole-filling metal on the first barrier layer. The semiconductor structure also forms a hole structure that extends through the first barrier layer, the first polishing-stopping oxide layer, and the first dielectric layer to the metal layer. The first hole-filling metal is filled into the hole structure. The first pore-filling metal, the first barrier layer, and the first grinding termination oxide layer are ground using the pore structure chemical mechanical polishing method as described in any one of claims 1-9.

11. The method for manufacturing a semiconductor device according to claim 10, characterized in that, The step of obtaining the semiconductor structure with a porous structure includes: The metal layer is formed on the substrate; Forming a first dielectric layer covering the metal layer; The first polishing termination oxide layer is formed on the first dielectric layer; Pattern the first polishing termination oxide layer and the first dielectric layer to form the hole structure extending to the metal layer at the bottom; The first barrier layer is formed on the first grinding termination oxide layer; The first hole-filling metal is formed on the first barrier layer and fills the hole structure.

12. The method for manufacturing a semiconductor device according to claim 11, characterized in that, The step of forming a first barrier layer on the first grinding-terminated oxide layer employs a deposition process including plasma bombardment treatment, which removes the corners at the top of the pore structure, resulting in an inverted trapezoidal cross-section at the top of the pore structure.

13. The method for manufacturing a semiconductor device according to claim 11, characterized in that, After the step of forming a first dielectric layer on the metal layer, the method further includes the step of forming an anti-reflection layer on the first dielectric layer; The first polishing-terminating oxide layer includes the anti-reflection layer; The step of patterning the first polishing termination oxide layer and the first dielectric layer includes patterning the antireflective layer.

14. The method for manufacturing a semiconductor device according to any one of claims 10-13, characterized in that, Also includes: After the pore structure chemical mechanical polishing method is completed, a capacitor is formed on the first pore filling metal; The capacitor includes a top electrode, a bottom electrode, and a dielectric layer disposed between the top electrode and the bottom electrode, wherein the bottom electrode is in direct contact with the metal filling the first hole; A second dielectric layer is formed on the capacitor and the first dielectric layer; A second polishing termination oxide layer is formed on the second dielectric layer; The second polishing termination oxide layer and the second dielectric layer are patterned to form a first through-hole extending to the top electrode at the bottom and a second through-hole extending to the first hole at the bottom and filled with metal. A second barrier layer is formed on the second grinding termination oxide layer; A second hole-filling metal is formed on the second barrier layer, and the second hole-filling metal fills the first through hole and the second through hole; The second hole filling metal, the second barrier layer, and the second grinding termination oxide layer are subjected to chemical mechanical polishing.

15. The method for manufacturing a semiconductor device according to claim 14, characterized in that, Before the step of forming a second dielectric layer on the capacitor and the first dielectric layer, the method further includes a step of forming a silicon nitride layer on the capacitor, wherein the second dielectric layer is formed on the silicon nitride layer; the patterning of the second polishing termination oxide layer and the second dielectric layer further includes patterning the silicon nitride layer.

16. A method for manufacturing a semiconductor device, characterized in that, The manufacturing process is carried out according to the method of claim 14 or 15; the step of performing chemical mechanical polishing on the second hole-filling metal, the second barrier layer and the second polishing termination oxide layer is performed by the method of any one of claims 1-9.

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