Semiconductor manufacturing method

Abstract

The invention provides a semiconductor manufacturing method. The semiconductor manufacturing method comprises the steps that under masking of a photoresist mask layer, a metal material layer is etched to form a metal wire, and polymers are left on the surface of the photoresist mask layer; carrying out plasma bombardment on the polymer to dissociate and take away the polymer; and removing the photoresist mask layer. Therefore, the residual polymer after metal etching can be effectively removed, the process defects of photoresist residue, metal corrosion and the like are reduced, and the quality, the performance and the reliability of the product are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a semiconductor manufacturing method. Background Art

[0002] Dry etching is an essential part of the semiconductor manufacturing process. It is a technology that uses plasma and reactive gases to etch solid materials on the wafer surface that are not covered by mask patterns. Dry etching of metal materials is the main process for forming interconnect wires made of aluminum, copper and other materials in semiconductor manufacturing. In metal aluminum etching, photoresist is often used as a mask to define the pattern, and gases such as Cl2 / BCl3 are used to etch metal materials. In the actual production process, it is found that the AlCl3 type polymer produced during aluminum etching is not easy to volatilize, and it is very easy to adhere to the photoresist to form a solid polymer shell on the surface of the photoresist. It cannot be removed after the subsequent stripping and wet cleaning processes, and the polymer shell remains on the surface of the aluminum wire, which is also easy to cause metal corrosion (the residual Cl2 in the polymer and the H2O in the environment generate HCl, which continues to react with Al to generate AlCl3, and AlCl3 and H2O react to generate HCl, and a cyclic reaction is carried out), etc., which affects the quality, performance and reliability of the product. Summary of the invention

[0003] One of the purposes of the present invention is to provide a semiconductor manufacturing method that can effectively remove polymer residues after metal etching, reduce the generation of process defects such as photoresist residues and metal corrosion, and improve product quality, performance and reliability.

[0004] In order to achieve the above-mentioned object, the present invention provides a semiconductor manufacturing method. The semiconductor manufacturing method comprises: etching a metal material layer to form a metal line under the mask of a photoresist mask layer, a polymer remaining on the surface of the photoresist mask layer; plasma bombarding the polymer so that the polymer is dissociated and carried away; and removing the photoresist mask layer.

[0005] Optionally, the semiconductor manufacturing method further includes: after etching the metal material layer to form the metal wire and before plasma bombarding the polymer, removing part of the thickness of the photoresist mask layer so that at least part of the polymer is peeled off from the surface of the photoresist mask layer.

[0006] Optionally, the semiconductor manufacturing method further includes: after removing the photoresist mask layer, performing a dechlorination treatment using H2 and N2.

[0007] Optionally, in the step of plasma bombarding the polymer, the gases used include Ar and BCl3.

[0008] Optionally, in the step of plasma bombarding the polymer, the dissociated polymer is taken away by pumping out gas in the chamber.

[0009] Optionally, the step of etching the metal material layer to form the metal wire and the step of plasma bombarding the polymer are performed in the same chamber.

[0010] Optionally, in the step of removing the photoresist mask layer, gases used include O2 and N2.

[0011] Optionally, the material of the metal wire includes Al; and the light transmittance of the metal wire is lower than 30%.

[0012] Optionally, in the step of etching the metal material layer to form the metal wire, etching gases used include Cl2 and BCl3.

[0013] Optionally, the polymer comprises AlCl3.

[0014] In the semiconductor manufacturing method provided by the present invention, after etching the metal material layer to form the metal wire, the polymer is plasma bombarded so that the polymer is dissociated and taken away, which can effectively remove the polymer remaining after the metal etching, reduce the adhesion between the polymer and the photoresist, reduce the generation of process defects such as photoresist residue and metal corrosion, and improve the quality, performance and reliability of the product.

[0015] Furthermore, after the metal material layer is etched to form the metal wire and before the polymer is plasma bombarded, a portion of the thickness of the photoresist mask layer is removed so that at least a portion of the polymer is peeled off from the surface of the photoresist mask layer. Since after the portion of the thickness of the photoresist mask layer is removed, at least a portion of the polymer is suspended on the photoresist mask layer and is easily peeled off and removed, the purpose of peeling off the polymer firmly adhered to the surface of the photoresist mask layer can be achieved, and combined with the subsequent plasma bombardment of the polymer, the polymer remaining after the metal etching can be effectively removed, thereby improving the quality, performance and reliability of the product.

[0016] Furthermore, after removing the photoresist mask layer, dechlorination treatment is performed using H2 and N2. H2 can react with residual chlorine (Cl) to form gaseous HCl and be taken away, thereby reducing metal corrosion defects on the surface of the metal wire and improving product quality, performance and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The schematic diagram is a schematic diagram of polymer residue after directly removing the photoresist mask layer in the prior art.

[0018] Figure 2A schematic flow chart of a semiconductor manufacturing method provided in accordance with an embodiment of the present invention.

[0019] Figures 3 to 6 A schematic diagram of a semiconductor manufacturing method according to an embodiment of the present invention.

[0020] Explanation of reference numerals: 101 - dielectric layer; 102 - bottom barrier layer; 103 - metal line; 104 - top barrier layer; 105 - anti-reflective coating layer; 106 - photoresist mask layer; 107 - polymer. DETAILED DESCRIPTION

[0021] Figure 1 FIG. 1 is a schematic diagram of the polymer residue after directly removing the photoresist mask layer in the prior art. Figure 1 As shown, in the prior art, after the aluminum-containing metal material layer is etched by dry etching process to form the metal wire 103, the photoresist mask layer 106 on the metal wire 103 is directly removed. As mentioned in the background art, in the actual production process, it is found that the polymer 107 of the type AlCl3 and the like generated in the aluminum etching process is not easy to volatilize, and the polymer 107 is easy to adhere to the photoresist mask layer 106 to form a solid polymer shell layer. However, the combustion reaction of O2 / N2 and the photoresist in the photoresist stripping chamber under a relatively high pressure still cannot effectively remove the adhered large polymer. After removing the photoresist mask layer 106, as shown in the background art, Figure 1 As shown, the polymer 107 collapses and adheres to the surface of the metal line 103 and cannot be removed in the wet cleaning process, resulting in process defects such as photoresist residue and metal corrosion.

[0022] In order to solve the above problems, the present invention provides a semiconductor manufacturing method. In the semiconductor manufacturing method, after etching a metal material layer to form a metal line, plasma bombardment is performed on a polymer so that the polymer is dissociated and taken away, so that the polymer remaining after metal etching can be effectively removed, the adhesion of the polymer and the photoresist can be reduced, and the generation of process defects such as photoresist residue and metal corrosion can be reduced, thereby improving the quality, performance and reliability of the product.

[0023] Furthermore, after the metal material layer is etched to form the metal wire and before the polymer is plasma bombarded, a portion of the thickness of the photoresist mask layer is removed so that at least a portion of the polymer is peeled off from the surface of the photoresist mask layer. Since after the portion of the thickness of the photoresist mask layer is removed, at least a portion of the polymer is suspended on the photoresist mask layer and is easily peeled off and removed, the purpose of peeling off the polymer firmly adhered to the surface of the photoresist mask layer can be achieved, and combined with the subsequent plasma bombardment of the polymer, the polymer remaining after the metal etching can be effectively removed, thereby improving the quality, performance and reliability of the product.

[0024] Furthermore, after removing the photoresist mask layer, dechlorination treatment is performed using H2 and N2. H2 can react with residual chlorine (Cl) to form gaseous HCl and be taken away, thereby reducing metal corrosion defects on the surface of the metal wire and improving product quality, performance and reliability.

[0025] The semiconductor manufacturing method proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0026] It should be understood that, unless otherwise specified or indicated, spatial relationship terms in the specification, such as "under", "below", "below", "under", "above", "above", etc., may be used here for convenience of description to describe the relationship between an 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, the spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, then the elements or features described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0027] Figure 2 FIG. 1 is a flow chart of a semiconductor manufacturing method provided by an embodiment of the present invention. Figure 2 As shown, the semiconductor manufacturing method provided in this embodiment includes: Step S1, under the mask of a photoresist mask layer, etching the metal material layer to form a metal line, wherein a polymer remains on the surface of the photoresist mask layer; Step S2, plasma bombarding the polymer so that the polymer is dissociated and carried away; and Step S3, removing the photoresist mask layer.

[0028] It should be understood that although Figure 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 2At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0029] Figures 3 to 6 The following is a schematic diagram of a semiconductor manufacturing method according to an embodiment of the present invention. Figure 2 , Figures 3 to 6 The semiconductor manufacturing method of the present application is described.

[0030] refer to Figure 3 As shown, step S1 is performed to etch the metal material layer under the mask of the photoresist mask layer 106 to form the metal line 103 , and polymer remains on the surface of the photoresist mask layer 106 .

[0031] In this embodiment, a dry etching process is used to etch the metal material layer to form the metal line 103. The material of the metal line 103 may include Al, but is not limited thereto. The etching gas used when etching the metal material layer to form the metal line 103 may include Cl2 and BCl3, but is not limited thereto.

[0032] It should be noted that the polymer including AlCl3 produced in the process of etching the aluminum metal material layer using Cl2 and BCl3 is not easy to volatilize and is very easy to adhere to the photoresist mask layer 106 to form a solid polymer shell layer. The polymer shell layer cannot be effectively removed in the conventional process of removing the photoresist mask layer. Therefore, it is necessary to use the semiconductor manufacturing method provided by the present application to plasma bombard the polymer 107 before step S3 of removing the photoresist mask layer to improve the removal effect of the polymer.

[0033] Since the thicker the metal material layer or the metal wire 103 is, the more polymer 107 is generated, which makes it more difficult to remove the polymer 107. Therefore, when the thickness of the metal wire 103 is greater than 3000nm or greater than 3300nm, after etching the metal material layer to form the metal wire 103, the polymer 107 is plasma bombarded by the semiconductor manufacturing method of the present application, so that the polymer is dissociated and taken away, and then the photoresist mask layer 106 is removed, so that the residual polymer can be effectively removed.

[0034] Since there is a high probability that the polymer 107 will adhere to the photoresist mask layer 106 and cause defects when the transmittance of the metal line 103 is lower than 30%, the semiconductor manufacturing method provided in the present application can be used to effectively remove the residual polymer when the transmittance of the metal line 103 is lower than 30%.

[0035] refer to Figure 3 As shown, although at the angle shown, the polymer 107 covers the top surface and side walls of the metal line 103 and the photoresist mask layer 106, in practice, the polymer 107 will not completely wrap the photoresist mask layer 106 and the metal line 103, that is, part of the photoresist mask layer 106 and part of the metal line 103 will still be exposed from the polymer 107.

[0036] Exemplarily, step S1 may include: forming a metal material layer on the dielectric layer 101 ; coating a photoresist on the metal material layer; exposing and developing the photoresist to form a photoresist mask layer 106 ; and etching the metal material layer under the mask of the photoresist mask layer 106 to form a metal line 103 .

[0037] Exemplarily, the material of the dielectric layer 101 includes but is not limited to silicon dioxide.

[0038] refer to Figure 3 As shown, in this embodiment, a bottom barrier layer 102 may be provided under the bottom surface of the metal line 103, and a top barrier layer 104 may be provided on the top surface of the metal line 103. The bottom barrier layer 102 is located between the dielectric layer 101 and the metal line 103, and the top barrier layer 104 may be located between the metal line 103 and the dielectric layer thereon. The top barrier layer 104 and the bottom barrier layer 102 may prevent the metal in the metal line 103 from diffusing into the dielectric layer 101 above and below it, which helps to ensure the electrical performance stability of the product. Exemplarily, the top barrier layer 104 and the bottom barrier layer 102 may be a single-layer structure or a double-layer structure; for example, the top barrier layer 104 and the bottom barrier layer 102 both include a stacked Ti layer and a TiN layer.

[0039] refer to Figure 3 As shown, an anti-reflective coating 105 may be provided below the photoresist mask layer 106, and the anti-reflective coating 105 may be used to absorb the light irradiated thereon to improve the pattern accuracy of the formed photoresist mask layer 106. Exemplarily, the material of the anti-reflective coating 105 includes but is not limited to silicon oxynitride (SiON) or carbon-doped silicon oxide (SiCO).

[0040] It should be noted that, under the mask of the photoresist mask layer 106 , during the process of etching the metal material layer to form the metal line 103 , the anti-reflective coating 105 , the top barrier layer 104 and the bottom barrier layer 102 may also be etched until the dielectric layer 101 is exposed.

[0041] Next, refer to Figure 4 As shown, a portion of the thickness of the photoresist mask layer 106 is removed, so that at least a portion of the polymer 107 is peeled off from the surface of the photoresist mask layer 106 .

[0042] Specifically, part of the thickness of the photoresist mask layer 106 below the polymer 107 is removed, so that at least part of the polymer 107 is suspended on the photoresist mask layer 106 and can be easily peeled off, that is, the polymer 107 firmly adhered to the surface of the photoresist mask layer 106 can be peeled off, which is beneficial to the subsequent dissociation of the polymer, improves the final polymer removal effect, and improves the quality, performance and reliability of the product.

[0043] Exemplarily, gas such as O2 may be used to remove a portion of the thickness of the photoresist mask layer 106. During the process of removing a portion of the thickness of the photoresist mask layer 106, the chamber where the product is located may be evacuated, and the stripped polymer may be moved out of the chamber along with the evacuated gas.

[0044] Exemplarily, the step of etching the metal material layer to form the metal line 103 and the step of removing part of the thickness of the photoresist mask layer 106 can be performed in the same chamber, for example, both are performed in a metal etching chamber. In this way, there is no need to remove the wafer after etching to form the metal line 103, which is convenient to operate and can save time, and there is no need to add new equipment.

[0045] Next, refer to Figure 5 As shown, step S2 is performed to perform plasma bombardment on the polymer 107 so that the polymer 107 is dissociated and taken away.

[0046] Exemplarily, the gas used for plasma bombardment of the polymer 107 includes Ar. Since Ar has a large molecular weight, bombarding the polymer 107 with Ar can effectively dissociate the polymer 107. The gas used for plasma bombardment of the polymer 107 can also include BCl3. Since BCl3 also has a large molecular weight, bombarding the polymer 107 with BCl3 can effectively dissociate the polymer 107. In addition, BCl3 can react with Al-containing components in the polymer to improve the dissociation effect.

[0047] During the plasma bombardment of the polymer 107 , a polymer pump may be used to evacuate the chamber where the product is located, so that the chamber maintains a certain vacuum degree, and the polymer dissociated into particles can be pumped away along with the gas.

[0048] In this embodiment, the step of etching the metal material layer to form the metal wire 103 and the step of plasma bombarding the polymer 107 can be performed in the same chamber (ie, the metal etching chamber), which is convenient to operate and can save time without adding new equipment.

[0049] In this embodiment, the power used for plasma bombardment of the polymer 107 may be greater than or equal to 200 W and less than or equal to 500 W, so that high-energy plasma bombardment can be formed, which can improve the dissociation rate of the polymer 107 .

[0050] Next, refer to Figure 6 As shown, step S3 is performed to remove the photoresist mask layer 106. Since the polymer 107 is stripped and plasma bombarded before, in step S3 of removing the remaining photoresist mask layer 106, the polymer 107 and the photoresist mask layer 106 can be completely removed, which can reduce the generation of process defects such as photoresist residue and metal corrosion caused by the adhesion of the polymer 107 and the photoresist, thereby improving the quality, performance and reliability of the product.

[0051] Exemplarily, step S3 can be performed in a stripping chamber. The gases used to remove the photoresist mask layer 106 include, but are not limited to, O2 and N2. Among them, N2, O2, the photoresist mask layer 106, and water vapor can undergo a combustion reaction in the stripping chamber to remove the photoresist mask layer 106.

[0052] In this embodiment, after removing the photoresist mask layer 106, H2 and N2 can also be used for dechlorination treatment, so that the residual chlorine can react with H2 to form gaseous HCl, thereby avoiding the residual chlorine from reacting with the metal wire 103 to cause metal corrosion, thereby improving the quality, performance and reliability of the product.

[0053] The above description is only a description of the preferred embodiment of the present invention, and is not any limitation on the scope of rights of the present invention. Any technical personnel in this field can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A semiconductor manufacturing method, characterized in that: include: Under the mask of a photoresist mask layer, etching the metal material layer to form a metal line, wherein a polymer remains on the surface of the photoresist mask layer; Plasma bombarding the polymer causes the polymer to dissociate and be carried away; as well as The photoresist mask layer is removed.

2. The semiconductor manufacturing method according to claim 1, wherein: Also includes: After etching the metal material layer to form the metal line and before plasma bombarding the polymer, a portion of the thickness of the photoresist mask layer is removed so that at least a portion of the polymer is peeled off from the surface of the photoresist mask layer.

3. The semiconductor manufacturing method according to claim 1, wherein: Also includes: After removing the photoresist mask layer, dechlorination treatment is performed using H2 and N2.

4. The semiconductor manufacturing method according to claim 1, wherein: In the step of plasma bombarding the polymer, the gases used include Ar and BCl3.

5. The semiconductor manufacturing method according to claim 1, wherein: In the step of plasma bombarding the polymer, the dissociated polymer is taken away by pumping out the gas in the chamber.

6. The semiconductor manufacturing method according to claim 1, wherein: The step of etching the metal material layer to form the metal line and the step of plasma bombarding the polymer are performed in the same chamber.

7. The semiconductor manufacturing method according to claim 1, wherein: In the step of removing the photoresist mask layer, the gases used include O2 and N2.

8. The semiconductor manufacturing method according to claim 1, wherein: The material of the metal wire includes Al; and the light transmittance of the metal wire is lower than 30%.

9. The semiconductor manufacturing method according to claim 1, wherein: In the step of etching the metal material layer to form the metal wire, the etching gas used includes Cl2 and BCl3.

10. The semiconductor manufacturing method according to any one of claims 1 to 9, characterized in that: The polymer includes AlCl3.

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