Method for improving stripping of film on inner surface of chamber

Abstract

The invention provides a method for improving stripping of a thin film on the inner surface of a cavity, which comprises the following steps of: performing process manufacturing in the cavity, and forming a first thin film layer on the inner surface of the cavity in the process of process manufacturing; forming a second thin film layer on the first thin film layer, wherein the stress of the second thin film layer is opposite to that of the first thin film layer; and repeating the steps in sequence. The stress of the first thin film layer is counteracted by forming the second thin film layer with the reverse stress, so that the overall stress of the thin film layers on the inner surface of the cavity is reduced, and the second thin film layer is formed after the first thin film layer is formed in the subsequent process manufacturing process. The interval formation of the second thin film layer can relieve the speed of stress accumulation of the first thin film layer on the inner surface of the chamber and delay stripping of the first thin film layer on the inner surface of the chamber caused by stress accumulation, so that the equipment maintenance period is prolonged, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuits, and in particular to a method for improving the peeling of a thin film on the inner surface of a chamber. Background Art

[0002] Before using sputtering equipment to deposit a metal layer on a wafer, it is usually necessary to bombard the wafer surface with argon ions to remove native oxide or residual byproducts / particles on the wafer surface. The chamber that completes this process is called a pre-clean chamber.

[0003] Oxides and other substances bombarded by argon ions will be sputtered onto the surface of the bare jar and / or Quartz dome in the pre-cleaning chamber. These oxide films adhere to the bare jar and / or Quartz dome. As the accumulated thickness increases, the stress (such as compressive stress) accumulates more and more, which can easily cause the adhesion between the oxide film and the bare jar and / or Quartz dome to decrease, thereby causing peeling defects.

[0004] In order to prevent the spalling defect from affecting the product, the pre-cleaning chamber must be maintained before the stress of the oxide adhesion layer reaches the critical value for spalling, and the bare jar and / or Quartz dome used to clean the oxide adhesion layer must be replaced. Therefore, how to effectively increase the oxide adhesion and reduce stress accumulation becomes a key factor in reducing spalling defects and extending the equipment maintenance cycle.

[0005] In the prior art, in order to prevent peeling defects from affecting the product, the pre-cleaning chamber will define the cumulative thickness threshold of the adhesion layer film. Taking the oxide adhesion film as an example, it is generally calculated by the number of wafers used, generally defined as about 2500 to 3000 wafers (for example, each wafer is bombarded Thickness: approx. ). Currently, when this thickness is reached, it is necessary to replace the bare jar or Quartz dome.

[0006] In order to delay the peeling of the adhesive layer in the pre-cleaning chamber, a special coating method can be used to increase the roughness of the inner surface of the bare jar or quartz dome. The rough surface can increase the adhesion of the oxide adhesive layer, thereby extending the replacement time of the bare jar or quartz dome (for example, it can be extended to about 5,000 pieces). However, this technology has relatively high requirements for surface treatment technology. Summary of the invention

[0007] The object of the present invention is to provide a method for improving the peeling of the inner surface film of the chamber, which can slow down the speed of stress accumulation of the inner surface film of the chamber and delay the peeling of the inner surface film of the chamber caused by stress accumulation.

[0008] In order to solve the above technical problems, the present invention provides a method for improving the peeling of the film on the inner surface of the chamber, comprising the following steps:

[0009] Performing a process in the chamber, and forming a first thin film layer on the inner surface of the chamber during the process;

[0010] forming a second thin film layer on the first thin film layer, wherein stress of the second thin film layer is opposite to stress of the first thin film layer; and,

[0011] Repeat the above steps in sequence.

[0012] Optionally, the method for forming the second thin film layer includes:

[0013] providing a substrate, and forming a second thin film material layer on the substrate;

[0014] The substrate is placed in the chamber and bombarded so that the material of the second thin film material layer is sputtered onto the first thin film layer to form the second thin film layer.

[0015] Optionally, the first film layer is under compressive stress, and the second film layer is under tensile stress; or, the first film layer is under tensile stress, and the second film layer is under compressive stress.

[0016] Optionally, the material of the second film layer is the same as that of the first film layer.

[0017] Optionally, the materials of the second thin film layer and the first thin film layer are both oxides or nitrides.

[0018] Optionally, the material of the second film layer is different from the material of the first film layer.

[0019] Optionally, after forming the second thin film layer, the method further includes: forming a third thin film layer on the second thin film layer, wherein a material of the third thin film layer is the same as a material of the first thin film layer.

[0020] Optionally, the materials of the first thin film layer and the third thin film layer are oxides, and the material of the second thin film layer is nitride.

[0021] Optionally, the thickness of the third film layer is smaller than the thickness of the second film layer.

[0022] Optionally, the chamber is a pre-cleaning chamber, and the chamber includes a Dome and / or a bare jar. Pre-cleaning of wafers is performed in the chamber, and the first thin film layer is formed on the surface of the Dome and / or the bare jar during the cleaning process.

[0023] In summary, in the method for improving the peeling of the film on the inner surface of the chamber provided by the present invention, a process is first performed in the chamber, and a first film layer is formed on the inner surface of the chamber during the process, and then a second film layer is formed on the first film layer, and the stress of the second film layer is opposite to the stress of the first film layer, and then the above steps are repeated in sequence. The present invention offsets the stress of the first film layer by forming a second film layer with reverse stress, thereby reducing the overall stress of the film layer on the inner surface of the chamber, and then forms the second film layer after the first film layer is formed during the process. The interval formation of the second film layer can alleviate the speed of stress accumulation of the first film layer on the inner surface of the chamber, delay the peeling of the first film layer on the inner surface of the chamber due to stress accumulation, thereby extending the equipment maintenance cycle and saving costs. At the same time, compared with the surface treatment method used in the prior art, the stress offset method has more flexibility, and the thickness or stress of the second film layer can be adjusted according to the different characteristics of the first film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0025] Figure 1 It is a flow chart of a method for improving the peeling of a thin film on the inner surface of a chamber provided by one embodiment of the present invention.

[0026] Figure 2 It is a schematic diagram of the structure of a thin film formed on the inner surface of a chamber provided by an embodiment of the present invention.

[0027] Figure 3 Schematic diagram of the stress of the film before the film peeling improvement on the inner surface of the chamber provided by one embodiment of the present invention.

[0028] Figure 4 It is a schematic diagram of the stress of the film after the film peeling of the inner surface of the chamber is improved according to one embodiment of the present invention.

[0029] Description of reference numerals:

[0030] 10 - chamber; 11 - first film layer; 12 - second film layer; 13 - third film layer. DETAILED DESCRIPTION

[0031] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0032] As used in the present invention, the singular forms "one", "an", and "the" include plural objects, unless the content clearly indicates otherwise. As used in the present invention, the term "or" is generally used in a sense that includes "and / or", unless the content clearly indicates otherwise. As used in the present invention, the term "several" is generally used in a sense that includes "at least one", unless the content clearly indicates otherwise. As used in the present invention, the term "at least two" is generally used in a sense that includes "two or more", unless the content clearly indicates otherwise. In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features.

[0033] There are generally several reasons for the generation of internal stress. The first is the thermal shrinkage effect. During the film formation process, the evaporated gas phase atoms deposited on the substrate have high kinetic energy, and the thermal radiation generated from the evaporation source will cause the film temperature to rise. When the deposition process is completed and the film temperature cools to room temperature, the atoms gradually become stable. The critical standard for whether the atoms inside the film can move is the recrystallization temperature. Thermal shrinkage below the recrystallization temperature is the cause of stress. The second is the phase transfer effect. During the film formation process, the transfer from gas phase to solid phase occurs. During the phase transition process, the volume generally changes, and the volume change will cause the formation of internal stress. The third is the elimination of lattice defects. There will be many lattice defects in the film. When defects such as vacancies and gaps are heated and cooled, the atomic surface diffusion eliminates the defects and absorbs energy to "self-heal", but at the same time, the volume shrinks to form internal stress of tensile stress nature. The fourth is interface mismatch. When a material with a different lattice structure from the substrate forms a thin film on the substrate, if the interaction between the two is strong, the film crystal structure will gradually approach the substrate crystal structure, and the film will be distorted to form internal stress. A smaller mismatch will produce elastic deformation, and a larger mismatch will produce interface dislocations to relieve most of the strain in the film. The generation of film internal stress is the result of the combined action of the above mechanisms.

[0034] After analyzing the causes of internal stress, the inventor proposed a method of eliminating stress by forming a reverse stress film to reduce the stress accumulation of the adhesion layer in the chamber, thereby delaying the peeling of the film, thereby extending the equipment maintenance cycle and saving costs.

[0035] After further research, the present invention provides a method for improving the peeling of the film on the inner surface of the chamber. Figure 1 This is a flow chart of a method for improving the peeling of a film on the inner surface of a chamber provided by an embodiment of the present invention. Figure 1 As shown, the method for improving the peeling of the film on the inner surface of the chamber provided in this embodiment includes the following steps:

[0036] Step S1: performing a process in a chamber, and forming a first thin film layer on the inner surface of the chamber during the process;

[0037] Step S2: forming a second thin film layer on the first thin film layer, wherein the stress of the second thin film layer is opposite to the stress of the first thin film layer; and

[0038] Step S3: Repeat the above steps in sequence.

[0039] Figure 2 FIG. 1 is a schematic diagram of the structure of a thin film formed on the inner surface of a chamber according to an embodiment of the present invention. Figure 1 and Figure 2 The method for improving the peeling of the film on the inner surface of the chamber provided by the embodiment of the present invention is described in detail.

[0040] In step S1 , a process is performed in a chamber, and a first thin film layer 11 is formed on the inner surface of the chamber 10 during the process.

[0041] Performing a process in a chamber means performing a process that the chamber should perform in the chamber. Exemplarily, the chamber may be a pre-cleaning chamber, and the process is pre-cleaning the wafer. The pre-cleaning chamber may perform pre-cleaning before vacuum sputtering.

[0042] During the process of manufacturing, a first thin film layer 11 is formed on the inner surface of the chamber 10. The first thin film layer 11 should be avoided as much as possible, but it is inevitable. For example, when the chamber is a pre-cleaning chamber, ion bombardment is performed on the wafer placed in the chamber to remove oxides or byproducts on the wafer. The oxides and other substances bombarded by ions will be sputtered to the inner surface of the chamber after being bombarded, forming the first thin film layer 11.

[0043] Please refer to Figure 2As shown, during the process of manufacturing in the chamber 10, a first thin film layer 11 is formed on the inner surface of the chamber 10. The material of the first thin film layer 11 is determined by the material bombarded on the wafer. In one embodiment of the present invention, the material of the first thin film layer 11 is an oxide or a nitride. As the process is carried out, the first thin film layer 11 is continuously accumulated on the inner surface of the chamber 10, and its stress will also accumulate. In this embodiment, the first thin film layer 11 has compressive stress. Of course, the first thin film layer 11 can also be tensile stress.

[0044] It should be noted that Figure 2 Only a portion of the chamber 10 is shown.

[0045] In this embodiment, the chamber is a pre-cleaning chamber, and the pre-cleaning chamber includes a Dome and / or a bare jar. The wafer is pre-cleaned in the chamber, and the first thin film layer is formed on the surface of the Dome and / or the bare jar during the cleaning process.

[0046] In step S2 , a second thin film layer 12 is formed on the first thin film layer 11 , and the stress of the second thin film layer 12 is opposite to the stress of the first thin film layer 11 .

[0047] When the second thin film layer 12 is formed on the first thin film layer 11, the chamber stops the process described in step S1, for example, the pre-cleaning chamber stops pre-cleaning the wafer. The second thin film layer 12 is actively formed on the first thin film layer 11, and is not formed by performing a certain process like the first thin film layer 11.

[0048] The stress of the second film layer 12 is opposite to the stress of the first film layer 11 to offset the stress of the first film layer 11. For example, the first film layer 11 is under compressive stress, while the second film layer 12 is under tensile stress; the first film layer 11 is under tensile stress, while the second film layer 12 is under compressive stress.

[0049] The material of the second film layer 12 may be the same as that of the first film layer 11, or may be different from that of the first material layer 11. In one embodiment of the present invention, the materials of the second film layer 12 and the first film layer 11 are both oxides or nitrides. In another embodiment of the present invention, the material of the first film layer 11 is oxide, and the material of the second film layer 12 is nitride. In another embodiment of the present invention, the material of the first film layer 11 is nitride, and the material of the second film layer 12 is oxide.

[0050] When the material of the second film layer 12 is different from that of the first film layer 11, after forming the second film layer 12, a third film layer 13 needs to be formed on the second film layer 12, and the material of the third film layer 13 needs to be the same as that of the first material layer 11, so as to avoid introducing substances irrelevant to the process described in step S1 into the chamber. In one embodiment of the present invention, the materials of the first film layer 11 and the third film layer 13 are oxides, and the material of the second film layer 12 is nitride.

[0051] In this embodiment, the method for forming the second thin film layer 12 includes: providing a substrate, forming a second thin film material layer on the substrate, and of course, the second thin film material layer is made of the same material as the second thin film layer 12. Then, the substrate is placed in the chamber, and the substrate is bombarded so that the material of the second thin film material layer is sputtered onto the first thin film layer 11 to form the second thin film layer 12. In other words, the method for forming the second thin film layer 12 can be the same as the method for forming the first thin film layer 11, except that when forming the second thin film layer 12, what is placed in the chamber is the substrate formed with the second thin film material layer, rather than the wafer used for process manufacturing.

[0052] The method for forming the third film layer 13 may be the same as the method for forming the second film layer 12. Since the third film layer 13 is only used to cover the second film layer 12 to prevent the introduction of substances irrelevant to the process into the chamber, the thickness of the third film layer 13 may be relatively thin, for example, the thickness of the third film layer 13 is less than the thickness of the second film layer 12, so as to save production time and production cost.

[0053] Figure 3 is a schematic diagram of the stress of the film before the film peeling improvement on the inner surface of the chamber provided by one embodiment of the present invention, Figure 4 It is a schematic diagram of the stress of the film after the film peeling of the inner surface of the chamber is improved according to one embodiment of the present invention. Figure 3 and Figure 4 The degree of completeness of the film layer is used to represent the magnitude of stress. Please refer to Figure 3 As shown, during the process of performing the process in the chamber, a first film layer 11 with internal stress is formed on the inner surface of the chamber. Since the chamber has been used to perform the process, as the process is continuously performed, the first film layer 11 accumulates continuously, and its stress also accumulates accordingly. The thicker the first film layer 11, the greater the stress. Please refer to Figure 4As shown, during the process of manufacturing in the chamber, a first film layer 11 with internal stress is formed on the inner surface of the chamber, and then a second film layer 12 with reverse stress is formed on the first film layer 11. Although the thickness of the film on the inner surface of the chamber increases, the overall stress of the film layer decreases due to the opposite stress. Figure 3 and Figure 4 It can be seen that by forming the second film layer 12 with reverse stress, the chance of peeling due to excessive stress can be reduced or delayed.

[0054] In step S3, the above steps are repeated in sequence, that is, step S1 and step S2 are repeated in sequence, that is, after the second thin film layer 12 is formed on the first thin film layer 11, the second thin film layer 12 offsets the stress of the first thin film layer 11 (for example, offsets a part or most of the stress), and then the normal process is continued to be carried out in the chamber. In this process, the first thin film layer 11 is inevitably formed on the second thin film layer 12, and then the process is stopped, and the second thin film layer 12 is continued to be formed on the re-formed first thin film layer 11 to offset the stress of the re-formed first thin film layer 11.

[0055] In the present invention, the stress of the first film layer 11 is offset by forming a second film layer 12 with reverse stress, thereby reducing the overall stress of the film layer on the inner surface of the chamber 10. The second film layer 12 is subsequently formed after the first film layer 11 is formed in the process. The interval formation of the second film layer 12 can alleviate the speed of stress accumulation of the first film layer 11 on the inner surface of the chamber, delay the peeling of the first film layer 11 on the inner surface of the chamber 10 caused by stress accumulation, thereby extending the equipment maintenance cycle and saving costs.

[0056] The above steps can be repeated once, twice or more than twice until the film layer on the inner surface of the chamber reaches the critical value of peeling, and then the equipment maintenance can be performed. Compared with the prior art, the equipment maintenance cycle can be significantly reduced. In addition, the surface treatment method in the prior art is a hardware change, which cannot be temporarily changed. The stress offset method used in the present invention has more flexibility, and the thickness or stress of the second film layer can be adjusted according to the characteristics of the first film layer.

[0057] In this embodiment, during normal process manufacturing in the chamber, the second thin film layer 12 can be formed periodically, for example, after pre-cleaning about 2,000 wafers in the pre-cleaning chamber, the second thin film layer 12 is formed on the first thin film layer 11 formed on the inner surface of the chamber, and then the wafers are pre-cleaned again. Alternatively, the process manufacturing can be stopped when the thickness of the first thin film layer 11 formed on the inner surface of the chamber reaches a set thickness, for example, when the thickness of the first thin film layer 11 reaches 20 μm, and the second thin film layer 12 is formed on the first thin film layer 11. Of course, the timing of forming the second thin film layer 12 is not limited to this.

[0058] In addition, the thickness of the second film layer 12 can be set according to actual needs. For example, the thickness of the second film layer 12 can be equal to the thickness of the first film layer 11 to offset as much stress as possible in the first film layer 11. Alternatively, the thickness of the second film layer 12 is less than the thickness of the first film layer 11 to prevent the film layer on the inner surface of the chamber from being too thick.

[0059] In summary, in the method for improving the peeling of the film on the inner surface of the chamber provided by the present invention, a process is first performed in the chamber, and a first film layer is formed on the inner surface of the chamber during the process, and then a second film layer is formed on the first film layer, and the stress of the second film layer is opposite to the stress of the first film layer, and then the above steps are repeated in sequence. In the present invention, the stress of the first film layer is offset by forming a second film layer with reverse stress, thereby reducing the overall stress of the film layer on the inner surface of the chamber. After the first film layer is formed during the process, the second film layer is formed again. The interval formation of the second film layer can alleviate the speed of stress accumulation of the first film layer on the inner surface of the chamber, delay the peeling of the first film layer on the inner surface of the chamber due to stress accumulation, thereby extending the equipment maintenance cycle and saving costs. At the same time, compared with the surface treatment method used in the prior art, the stress offset method has more flexibility, and the thickness or stress of the second film layer can be adjusted according to the different characteristics of the first film layer.

[0060] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for improving the peeling of a thin film on the inner surface of a chamber, characterized in that: The following steps are involved: Performing a process in the chamber, and forming a first thin film layer on the inner surface of the chamber during the process; forming a second thin film layer on the first thin film layer, wherein stress of the second thin film layer is opposite to stress of the first thin film layer; and, Repeat the above steps in sequence.

2. The method for improving the peeling of the film on the inner surface of the chamber according to claim 1, characterized in that: The method of forming the second thin film layer comprises: providing a substrate, and forming a second thin film material layer on the substrate; The substrate is placed in the chamber and bombarded so that the material of the second thin film material layer is sputtered onto the first thin film layer to form the second thin film layer.

3. The method for improving the peeling of the film on the inner surface of the chamber according to claim 1, characterized in that: The first film layer is under compressive stress, and the second film layer is under tensile stress; or, the first film layer is under tensile stress, and the second film layer is under compressive stress.

4. The method for improving the peeling of the film on the inner surface of the chamber according to claim 1, characterized in that: The material of the second film layer is the same as that of the first film layer.

5. The method for improving the peeling of the film on the inner surface of the chamber according to claim 4, characterized in that: The materials of the second film layer and the first film layer are both oxide or nitride.

6. The method for improving the peeling of the film on the inner surface of the chamber according to claim 1, characterized in that: The material of the second film layer is different from that of the first film layer.

7. The method for improving the peeling of the film on the inner surface of the chamber according to claim 6, characterized in that: After forming the second thin film layer, the method further includes: forming a third thin film layer on the second thin film layer, wherein a material of the third thin film layer is the same as a material of the first thin film layer.

8. The method for improving the peeling of the film on the inner surface of the chamber according to claim 7, characterized in that: The materials of the first film layer and the third film layer are oxides, and the material of the second film layer is nitride.

9. The method for improving the peeling of the film on the inner surface of the chamber according to claim 7, characterized in that: The thickness of the third film layer is smaller than that of the second film layer.

10. The method for improving the peeling of the film on the inner surface of a chamber according to any one of claims 1 to 9, characterized in that: The chamber is a pre-cleaning chamber, and the chamber includes a Dome and / or a bare jar. The wafer is pre-cleaned in the chamber, and the first thin film layer is formed on the surface of the Dome and / or the bare jar during the cleaning process.

Images