Method for manufacturing contact hole adhesive barrier layer

Abstract

This invention provides a method for manufacturing a contact hole adhesion barrier layer. The method includes providing a semiconductor substrate with contact holes formed thereon; forming a first metal layer covering the contact holes on the semiconductor substrate; forming a first TICxNyHz layer on a titanium layer; then bombarding the first TICxNyHz layer with plasma to remove some carbon and hydrogen elements to form a buffer layer; and forming a second metal layer on the buffer layer, wherein the stress of the buffer layer is less than the stress of the second metal layer. This method significantly reduces the defect of adhesion barrier layer detachment by forming a low-stress buffer layer between the Ti and TIN layers of the contact hole adhesion barrier layer, thereby improving silicon wafer defects and yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for manufacturing a contact hole adhesion barrier layer. Background Technology

[0002] Currently, the contact hole adhesion barrier layer process widely uses TI (titanium) and TIN (titanium nitride) as adhesion barrier layers. TI reduces contact resistance, and TIN isolates TI to prevent Ti from reacting with W (tungsten) to form WF6 (tungsten hexafluoride), thereby preventing the strong oxidizing WF6 from eroding the TI film.

[0003] Current technology typically uses MOCVD (Metal-Organic Chemical Vapor Deposition) to fill TIN. MOCVD has good filling ability, but the resulting film has poor density and purity. Therefore, a plasma treatment is added to the process to remove impurities such as C and H from the TIN film. However, the final TIN film has high tensile strength, which leads to defects such as bulging and detachment at the wafer edges where adhesion is poor. These defects have been found on multiple platforms, and in severe cases, they can even affect product yield.

[0004] To solve the above problems, a novel method for manufacturing the contact hole adhesion barrier layer is needed. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for manufacturing a contact hole adhesion barrier layer, which solves the problem of using metal-organic chemical vapor deposition (MOCVD) to fill TIN in the prior art. MOCVD has good filling ability, but the resulting film has poor density and purity. Therefore, a plasma treatment is added to the process to remove impurities such as C and H in the TIN film. However, the final TIN film has high tension, which leads to defects such as bulging and detachment at the wafer edges with poor adhesion, affecting the product yield.

[0006] To achieve the above and other related objectives, the present invention provides a method for manufacturing a contact hole adhesion barrier layer, comprising:

[0007] Step 1: Provide a semiconductor substrate, on which contact holes are formed;

[0008] Step 2: Form a first metal layer on the semiconductor substrate that covers the contact hole;

[0009] Step 3: Form the first TIC on the titanium layer. x N y H z The first layer, then the first TIC is bombarded with the first plasma. x N y Hz The layer removes some of the carbon and hydrogen elements to form a buffer layer;

[0010] Step 4: Form a second metal layer on the buffer layer, wherein the stress of the buffer layer is less than the stress of the second metal layer.

[0011] Preferably, the contact hole in step one is used to form a common pad in subsequent processes.

[0012] Preferably, the material of the first metal in step two is titanium.

[0013] Preferably, in step two, the first metal layer covering the contact hole is formed by physical vapor deposition.

[0014] Preferably, in step three, the first TIC is formed on the titanium layer by a metal-organic chemical vapor deposition method. x N y H z layer.

[0015] Preferably, the first TIC in step three x N y H z The thickness of the layer is 20 to 40 angstroms.

[0016] Preferably, in step three, the first plasma uses nitrogen and hydrogen as ion sources.

[0017] Preferably, in step three, the first plasma is used to bombard the first TIC. x N y H z The layer has a radio frequency first plasma power of 900 to 1200 W.

[0018] Preferably, in step three, the buffer layer is formed by bombarding the first plasma layer with the plasma gas for 20 to 50 seconds.

[0019] Preferably, the material of the second metal layer in step four is titanium nitride.

[0020] Preferably, the method for forming the second metal layer in step four includes: forming a second TIC on the buffer layer. x N y H z The second TIC is then bombarded with a second plasma layer. x N y H z A titanium nitride layer is formed.

[0021] Preferably, in step four, the second plasma uses hydrogen and nitrogen as ion sources.

[0022] Preferably, in step four, the second plasma is used to bombard the second TICxNyHz layer, and the radio frequency plasma power is 1700 to 1800W.

[0023] As described above, the method for manufacturing the contact hole adhesion barrier layer of the present invention has the following beneficial effects:

[0024] The method of the present invention forms a low-stress buffer layer between the TI and TIN of the contact hole adhesion barrier layer, which greatly reduces the defect of adhesion barrier layer detachment, and can improve silicon wafer defects and improve yield. Attached Figure Description

[0025] Figure 1 The diagram shown is a schematic representation of the process flow of the present invention.

[0026] Figure 2 The diagram shown illustrates the formation of the first metal layer according to the present invention.

[0027] Figure 3 The diagram shown illustrates the formation of the first TICxNyHz layer according to the present invention.

[0028] Figure 4 The diagram shown is a schematic diagram of the first TICxNyHz layer processed by plasma according to the present invention.

[0029] Figure 5 The diagram shown illustrates the formation of the second metal layer according to the present invention. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] Please see Figure 1 The present invention provides a method for manufacturing a contact hole adhesion barrier layer, comprising:

[0032] Step 1: Provide a semiconductor substrate, on which contact holes are formed;

[0033] In an embodiment of the present invention, the contact hole in step one is used to fill conductive metal in the subsequent process to form a common pad. That is, the semiconductor substrate 10 can be a structure used in the subsequent process to form a common pad, such as a metal interconnect layer or a dielectric layer between two metal interconnect layers.

[0034] Step two, a first metal layer 11 covering the contact hole is formed on the semiconductor substrate 10, forming as shown in the figure. Figure 2 The structure shown;

[0035] In an embodiment of the present invention, the material of the first metal in step two is titanium.

[0036] In an embodiment of the present invention, in step two, a first metal layer 11 covering the contact hole is formed by physical vapor deposition.

[0037] Step 3: A first TICxNyHz layer 12 is formed on the titanium layer. The chemical name of the first TICxNyHz layer 12 is tetramethylamine titanium, which forms as follows: Figure 3 The structure shown will be referred to later. Figure 4 The first TICxNyHz layer 12 is bombarded with the first plasma 13 to remove some of the carbon and hydrogen elements to form a buffer layer 14. Since the C, H and other impurities in the TIN film are completely removed, its tension is relatively large. By removing some of the carbon and hydrogen elements in the first TICxNyHz layer 12 with the first plasma 13, a buffer layer 14 with less tension than the TIN film can be formed.

[0038] In an embodiment of the present invention, in step three, a first TICxNyHz layer 12 is formed on the titanium layer by means of metal-organic chemical vapor deposition. Typically, the substrate needs to be heated to 380 to 450 degrees Celsius before deposition.

[0039] In an embodiment of the present invention, the thickness of the first TICxNyHz layer 12 in step three is 20 to 40 angstroms, for example 20 angstroms, 25 angstroms, 30 angstroms, 35 angstroms and 40 angstroms.

[0040] In an embodiment of the present invention, in step three, the first plasma 13 uses nitrogen and hydrogen as ion sources.

[0041] In an embodiment of the present invention, in step three, the first TICxNyHz layer is bombarded with a first plasma 13, the radio frequency power of which is 900 to 1200W, that is, nitrogen and hydrogen are ionized into the first plasma 13 at a radio frequency power of 900 to 1200W.

[0042] In an embodiment of the present invention, in step three, the first TICxNyHz layer 12 is bombarded with the first plasma 13 for 20 to 50 seconds to form a buffer layer 14, that is, the carbon and hydrogen elements in the first TICxNyHz layer 12 are precipitated by the first plasma 13 to form a low-stress film.

[0043] Step four: A second metal layer 15 is formed on the buffer layer 14, wherein the stress in the buffer layer 14 is less than the stress in the second metal layer 15, resulting in the following... Figure 5 The structure shown.

[0044] In an embodiment of the present invention, the material of the second metal layer 15 in step four is titanium nitride. The second metal layer 15 is formed using the conventional contact hole filling TIN method, the specific method of which is determined by the characteristics of different process nodes and process platforms. The present invention forms a low-stress buffer layer 14 between the TI and TIN of the contact hole adhesion barrier layer, which greatly reduces the defects caused by the adhesion barrier layer falling off, thereby improving silicon wafer defects and yield.

[0045] In an embodiment of the present invention, the method for forming the second metal layer in step four includes: forming a second TICxNyHz layer on the buffer layer 14, and then bombarding the second TICxNyHz layer with a second plasma to form a titanium nitride layer. Typically, the substrate needs to be heated to 380 to 450 degrees Celsius before deposition.

[0046] In an embodiment of the present invention, the second plasma in step four uses hydrogen and nitrogen as ion sources.

[0047] In an embodiment of the present invention, in step four, the second TICxNyHz layer is bombarded with a second plasma with a radio frequency plasma power of 1700 to 1800W, typically 1750W, which is the traditional contact hole filling TIN method.

[0048] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0049] In summary, the method of this invention significantly reduces the defect of adhesion barrier layer detachment by forming a low-stress buffer layer between the TI and TIN layers of the contact hole adhesion barrier layer, thereby improving silicon wafer defects and yield. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0050] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a contact hole adhesive barrier layer, characterized in that, At least including: Step 1: Provide a semiconductor substrate, on which contact holes are formed; Step 2: Form a first metal layer on the semiconductor substrate to cover the contact hole, wherein the first metal layer is a titanium layer; Step 3: A first TICxNyHz layer is formed on the titanium layer, and then the first TICxNyHz layer is bombarded with a first plasma to remove some of the carbon and hydrogen elements to form a buffer layer. Step 4: Form a second metal layer on the buffer layer, wherein the stress of the buffer layer is less than the stress of the second metal layer.

2. The method for manufacturing the contact hole adhesion barrier layer according to claim 1, characterized in that: The contact hole mentioned in step one is used to form a common pad in subsequent processes.

3. The method for manufacturing the contact hole adhesion barrier layer according to claim 2, characterized in that: In step two, the first metal layer covering the contact hole is formed by physical vapor deposition.

4. The method for manufacturing the contact hole adhesion barrier layer according to claim 1, characterized in that: In step three, the first TICxNyHz layer is formed on the titanium layer by a metal-organic chemical vapor deposition method.

5. The method for manufacturing the contact hole adhesion barrier layer according to claim 1, characterized in that: The thickness of the first TICxNyHz layer in step three is 20 to 40 angstroms.

6. The method for manufacturing the contact hole adhesion barrier layer according to claim 1, characterized in that: In step three, the first plasma uses nitrogen and hydrogen as ion sources.

7. The method for manufacturing the contact hole adhesion barrier layer according to claim 6, characterized in that: In step three, the first TICxNyHz layer is bombarded with the first plasma, and the radio frequency first plasma power is 900 to 1200W.

8. The method for manufacturing the contact hole adhesion barrier layer according to claim 7, characterized in that: In step three, the first TICxNyHz layer is bombarded with the first plasma for 20 to 50 seconds to form the buffer layer.

9. The method for manufacturing the contact hole adhesion barrier layer according to claim 1, characterized in that: The material of the second metal layer in step four is titanium nitride.

10. The method for manufacturing the contact hole adhesion barrier layer according to claim 9, characterized in that: The method for forming the second metal layer in step four includes: forming a second TICxNyHz layer on the buffer layer, and then bombarding the second TICxNyHz layer with a second plasma to form a titanium nitride layer.

11. The method for manufacturing the contact hole adhesion barrier layer according to claim 10, characterized in that: In step four, the second plasma uses hydrogen and nitrogen as ion sources.

12. The method for manufacturing the contact hole adhesion barrier layer according to claim 11, characterized in that: In step four, the second TICxNyHz layer is bombarded with the second plasma, with a radio frequency plasma power of 1700 to 1800 W.

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