Patent Application
20210210353
The present disclosure generally relates to a method of processing a semiconductor substrate having polysilicon layer. More specifically, the present disclosure relates to a method of post-CMP treatment of a polysilicon layer of a semiconductor substrate by non-ionic surfactants.
Chemical-mechanical polishing or chemical-mechanical planarization (CMP) is accomplished by holding the semiconductor wafer against a rotating polishing surface, or otherwise moving the wafer relative to the polishing surface, under controlled conditions of temperature, pressure, and chemical composition. The polishing surface, which may be a planar pad formed of a relatively soft and porous material such as a blown polyurethane, wetted with a chemically reactive and abrasive aqueous slurry. The aqueous slurry, which may be either acidic or basic, typically includes abrasive particles, reactive chemical agents such as transition metal chelated salts or oxidizers, and adjuvants such as solvents, buffers, and passivating agents. In the slurry, the salts or other agents provide the chemical etching action, whereas the abrasive particles, in cooperation with the polishing pad, provide the mechanical polishing action.
Polysilicon layers are commonly used as hard mask for forming patterns on a desired layer. The polysilicon layer has a hydrophobic surface. Organic contaminates (e.g., polish pad side product, clean brush debris, and surfactant of slurry) from subsequent planarization processes are likely to adhere to the surface of the polysilicon layer. Besides cleaning processes by using hydrogen fluoride (HF) solution and Standard Cleaning 1 (SC1) after the CMP process, an additional cleaning process by H2SO4 solution is usually required to remove the contaminates from the surface of the polysilicon layer to prevent defects.
Accordingly, there remains a need to provide a method of polishing and cleaning the polysilicon layer to overcome the aforementioned problems.
In view of above, the present disclosure is directed to a method of processing a substrate having a polysilicon layer and system thereof. The present disclosure uses a non-ionic surfactant solution to change the surface property of the polysilicon layer from hydrophobic to hydrophilic. Therefore, in the post-CMP cleaning process, organic contaminates on the surface of the polysilicon layer can be easily removed by HF solution and SC1 solution without an additional H2SO4 cleaning process.
An implementation of the present disclosure is directed to a method of processing a substrate having a polysilicon layer. As shown in
Another implementation of the present disclosure is directed to a processing system for processing a substrate having a polysilicon layer. The processing system includes a polishing module, a cleaning module, and a transfer region disposed between the polishing module and the cleaning module. The polishing module includes at least a first platen and a second platen. The first platen includes a first nozzle configured to provide an abrasive slurry for planarizing the polysilicon layer of the substrate. The second platen includes a second nozzle configured to provide a surfactant solution for treating the polysilicon layer. The cleaning module is coupled to the polishing module for cleaning the substrate. The transfer region includes a robot configured to transfer the substrate between the polishing module and the cleaning module.
As described above, the method and processing system of the implementations of the present disclosure use a non-ionic surfactant solution to change the surface property of the polysilicon layer from hydrophobic to hydrophilic. Therefore, in the post-CMP cleaning process, organic contaminates on the surface of the polysilicon layer can be easily removed by HF solution and SC1 solution without the need of an additional H2SO4 cleaning process.
Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.
The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which example implementations of the disclosure are shown.
This disclosure may, however, be implemented in many different forms and should not be construed as limited to the example implementations set forth herein. Rather, these example implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numerals refer to like elements throughout.
The terminology used herein is for the purpose of describing particular example implementations only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” or “has” and/or “having” when used herein, specify the presence of stated features, regions, integers, actions, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, actions, operations, elements, components, and/or groups thereof.
It will be understood that the term “and/or” includes any and all combinations of one or more of the associated listed items. It will also be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, parts and/or sections, these elements, components, regions, parts and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, part or section from another element, component, region, layer or section. Thus, a first element, component, region, part or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The description will be made as to the example implementations of the present disclosure in conjunction with the accompanying drawings in
The present disclosure will be further described hereafter in combination with the accompanying figures.
Referring to
The polishing module 100 includes a plurality of polishing platens (e.g., three platens 110, 120, 130; the number of platens may vary and is not limited thereto) and a carousel 140 supported above the platens 110-130. The platens 110-130 may be placed at substantially equal angular intervals around, and/or at substantially equal distances from a rotation axis 145 of the carousel 140. The carousel 140 is cross-shaped with carrier heads (e.g., four carrier heads 141, 142, 143, and 144) spaced at substantially equal angular intervals (e.g., at 90 degree intervals) around the rotation axis 145 of the carousel 140. Each of the carrier heads 141-144 secures one substrate, for example, by vacuum chucking or by a retaining ring. The carousel 140 rotates about the rotation axis 145 to transport the carrier heads 141-144 with the substrates between the platens 110-130. Each of the carrier heads 141-144 may be vertically movable, or include a vertically movable lower portion for lowering the substrate to one of the platens 110-130 for planarization. Each of the carrier heads 141-144 may be independently rotatable by a motor.
The cleaning module 200, in one implementation, is a rectangular-shaped cabinet. The cleaning module 200 washes the substrate after planarization to remove excess debris. As shown in
In another implementation, the cleaning module 200 may be a single-wafer cleaning module. While the batch type cleaning module washes several substrates in a tank, the single-wafer cleaning module is provided with a rotatable stage for cleaning one substrate in a chamber. Cleaning agents are provided to the surface of the substrate by nozzles in the chamber.
Referring to
Referring to
Referring to
In action S402, an abrasive slurry is applied on the first platen of the polishing module 100. In action S403, the polysilicon layer of the substrate is planarized on the polishing pad of the first platen by the abrasive slurry. The abrasive slurry includes at least one of silica, ceria, alumina, Mania, zirconia and germania. Preferably, the abrasive slurry includes at least one of silica and ceria. The planarization process may be referred to
In action S404, a surfactant solution is applied on the polishing pad of the second platen. In action S405, the polysilicon layer of the substrate is treated on the polishing pad of the second platen by the surfactant solution. The surfactant solution is an aqueous non-ionic surfactant solution. In an implementation, the non-ionic surfactant solution includes 0.1-5 wt % of alcohol ethoxylates. Alcohol ethoxylates are common non-ionic surfactants obtained from reacting alcohols with phoenols. The chemical structure of alcohol ethoxylates is R(OC2H4)nOH, wherein n ranges from 1 to 10. The non-ionic surfactant solution may be provided from the nozzles connected to the platens (such as the nozzle 131 or 132 for platen 130 shown in
In action S406, after the surface treatment of the polysilicon layer, the substrate is moved from the polishing module 100 to the cleaning module 200 by the robot 310. In action S407, the polysilicon layer of the substrate is cleaned in the cleaning module 200. As described above, since the surface treatment of the action S405 changes the surface property of the polysilicon layer from hydrophobic to hydrophilic, the surface of the polysilicon layer may be cleaned by HF solution and SC1 Standard Cleaning 1 (SC1) solution, without the need of an additional H2SO4 solution. A hydrophilic surface has reduced contact angles with aqueous HF solution and SC1 solution. Therefore, the organic contaminates can be easily removed by HF solution and SC1 solution. In one implementation, the cleaning module 200 may be a batch-type cleaning module as shown in
The present disclosure also is directed to a processing system for processing a substrate having a polysilicon layer. The processing system may be referred to the processing system 10 illustrated in
Each of the first platen 110, the second platen 120 and the third platen 130 includes a polishing pad (e.g., polishing pad 111 of platen 110 in
The polysilicon layer is cleaned by HF solution and SC1 solution in the cleaning module 200. In one implementation, the cleaning module 200 may be a batch type cleaning module having a plurality of tanks with different cleaning agents. By immersing the substrate in the tanks for a predetermined period of time, the polysilicon layer of the substrate is cleaned by HF solution and SC1 solution. In another implementation, the cleaning module may be a single-wafer cleaning module. While the batch type cleaning module washes several substrates in a tank, the single-wafer cleaning module is provided with a rotatable stage for cleaning one substrate in a chamber. Cleaning agents (e.g., HF solution and SC1 solution) are provided to the surface of the substrate by the nozzles in the chamber. Since the surface of the polysilicon layer of the substrate becomes hydrophilic after treated by the surfactant solution, organic contaminates on the surface of the polysilicon layer can be easily removed by HF solution and SC1 solution, without the need of an additional H2SO4 cleaning process.
The processing system 10 may further include a transfer region 300 disposed between the polishing module 100 and the cleaning module 200. The transfer region 300 includes a robot 310 configured to transfer the substrate between the polishing module 100 and the cleaning module 200.
As described above, the implementations of the present disclosure use a non-ionic surfactant solution to change the surface property of the polysilicon layer from hydrophobic to hydrophilic. Therefore, in the post-CMP cleaning process, organic contaminates on the surface of the polysilicon layer can be easily removed by HF solution and SC1 solution without the need of an additional H2SO4 cleaning process.
The implementations shown and described above are only examples. Many details are often found in the art such as the other features of a method of processing a substrate having a polysilicon layer and processing system thereof. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the implementations described above may be modified within the scope of the claims.
