Thin film deposition equipment and manufacturing method of NMOS (N-channel metal oxide semiconductor) device

Abstract

The invention provides thin film deposition equipment and a manufacturing method of an NMOS (N-channel metal oxide semiconductor) device, and belongs to the field of semiconductors. The thin film deposition apparatus includes a housing having a sputtering chamber. The target material is arranged opposite to the substrate, the target material comprises a first sputtering material and a second sputtering material, and the atomic weight of the first sputtering material is different from that of the second sputtering material. And the radio frequency power supply is used for generating plasma to bombard the target material and sputter the target material to the surface of the substrate to form a thin film. And the external member is arranged in the sputtering chamber, the external member is provided with a sputtering layer with a certain thickness, and the sputtering layer is made of the same material as the target material. Through the sputtering layer with a certain thickness deposited on the suite, the threshold voltage of the device is relatively stable, the performance of the product is improved, the process window of the product is also enlarged, the utilization rate of a machine table is improved, and the loss of a target material is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a thin film deposition device and a method for manufacturing an NMOS device. Background Art

[0002] In the 28nm high-k metal gate manufacturing process, the gate structure of the NMOS device is composed of a gate stack of titanium aluminum alloy (TiAL) / tantalum nitride (TAN) / titanium nitride (TiN) / high-k insulating layer (HK) / intermediate insulating layer (IL). Among them, the TiAL layer serves as the work function layer of the NMOS device, and the Al atoms in TiAl are easily diffused in the gate stack structure. Figure 1 As shown, Figure 1 The gate stack structure of the NMOS device includes 10-TiAL alloy layer, 20-TAN layer, 30-TiN layer, 40-HK layer, and 50-IL layer. The HK layer 40 is made of HfO2 material. In the TiAL alloy layer 10, the higher the ratio of Ti to AL, the easier it is for AL to diffuse. When AL diffuses to the interface between the TiN layer 30 and the HK layer 40 and replaces the Ti in the TiN layer 30, the interface dipole electric field is enhanced, the Schottky barrier height is increased, and the effective work function of the metal gate is reduced, resulting in a reduction in the threshold voltage of the NMOS. Figure 2 As shown, Figure 2 The work function changes with the AL content. Figure 2 It can be seen that with the increase of AL content, the work function decreases. Figure 3 As shown, Figure 3 The graph of the atomic ratio of Ti and Al versus the consumption of the target material is shown in Figure 2. Figure 3 It can be seen that the ratio of Ti and AL gradually decreases as the target material is consumed. The atomic ratio of Ti and AL decreases as the target material is consumed. In the early stage of target material consumption, the Ti / AL ratio is high, resulting in slow device speed. In order to ensure product performance, one-third of the target material needs to be consumed each time the target material is replaced. In order to ensure that the device performance meets the process requirements, target material waste and machine production capacity loss are caused.

[0003] How to control the stability of the Ti / Al ratio to ensure device performance is an important challenge currently facing high-K metal gate manufacturing process technology.

[0004] At present, there are many reports in the industry on the impact of process parameters on the atomic ratio of Ti and AL in Ti and AL deposition processes, but there are few studies on how to control the stability of the Ti / AL atomic ratio with the consumption of target material life when the process parameters are fixed. In order to ensure product performance, the target can only be used within the life range of the target when the Ti / AL ratio is relatively stable, resulting in waste of target materials.

[0005] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a thin film deposition device and a method for manufacturing an NMOS device, so as to solve the problem of how to control the stability of the Ti / AL ratio to ensure the performance of the device.

[0007] In order to solve the above technical problems, the present invention provides a thin film deposition device, comprising:

[0008] The housing has a sputtering chamber, the sputtering chamber is provided with a carrying platform, the carrying platform is used to carry the substrate to be sputtered, and the sputtering chamber is in a vacuum state;

[0009] A target material is disposed opposite to the substrate, the target material comprises a first sputtering material and a second sputtering material, the first sputtering material and the second sputtering material have different atomic weights;

[0010] A radio frequency power source is used to generate plasma to bombard the target material, sputtering the target material onto the surface of the substrate to form a thin film;

[0011] The kit is arranged in the sputtering chamber, and a sputtering layer is arranged on the surface of the kit. The material used in the sputtering layer is the same as that of the target material.

[0012] Preferably, the atomic ratio of the first sputtering material to the second sputtering material is 1:1, and the atomic ratio of materials used in the sputtering layer is 1:1.

[0013] Preferably, the first sputtering material and the second sputtering material are both metals.

[0014] Preferably, the first sputtering material is titanium and the second sputtering material is aluminum.

[0015] Preferably, the sputtered layer has a thickness of 1 to 1.5 μm.

[0016] Preferably, the sputtering layer is formed by a sandblasting process.

[0017] Preferably, the thin film deposition apparatus further comprises a vacuum pump system connected to the sputtering chamber, for extracting the gas in the sputtering chamber to maintain the sputtering chamber at a set vacuum degree.

[0018] Preferably, the kit is detachably connected to the housing.

[0019] Based on the same inventive concept, the present invention also provides a method for manufacturing an NMOS device, including providing a substrate, forming a gate structure on the substrate, the gate structure including a work function layer, the work function layer is made of an alloy material, and the work function layer is deposited using the above-mentioned thin film deposition equipment.

[0020] Preferably, the work function layer is made of metal titanium and metal aluminum alloy materials.

[0021] Compared with the prior art, the thin film deposition device of the present invention has the following advantages:

[0022] The present invention has a sputtering chamber by setting a shell, and the sputtering chamber is equipped with a carrier, and the carrier is used to carry the substrate to be sputtered, and the sputtering chamber is in a vacuum state. A target material is arranged opposite to the substrate, and the target material includes a first sputtering material and a second sputtering material, and the first sputtering material and the second sputtering material have different atomic weights. A radio frequency power supply is used to generate plasma to bombard the target material, and sputter the target material onto the surface of the substrate to form a thin film. A kit is arranged in the sputtering chamber, and a sputtering layer is arranged on the surface of the kit, and the material used in the sputtering layer is the same as that of the target material. Therefore, the thin film deposition equipment provided by the present invention can make the sputtering material with a light atomic weight on the kit deposited on the substrate, so as to increase the amount of the sputtering material with a light atomic weight deposited on the substrate. In this way, the ratio of the first sputtering material and the second sputtering material included in the target material can be kept relatively stable throughout the life cycle of the target material, and the device threshold voltage is also relatively stable, which improves the performance of the product, increases the process window of the product, improves the utilization rate of the machine and reduces the loss of the target material.

[0023] The manufacturing method of the NMOS device provided by the present invention and the thin film deposition equipment provided by the present invention belong to the same inventive concept. Therefore, the manufacturing method of the NMOS device provided by the present invention, by adopting the thin film deposition equipment provided by the present invention to deposit the work function layer of the gate structure, can control the stability of the ratio of the work function layer alloy, ensure the stability of the device performance, save target materials and improve the machine production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a gate stack structure of an NMOS device in one embodiment of the present invention;

[0025] Figure 2 is a graph showing the relationship between work function and AL content in one embodiment of the present invention;

[0026] Figure 3 is a graph showing the relationship between the atomic ratio of Ti and AL and the consumption of the target material in one embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of the structure of a thin film deposition device in one embodiment of the present invention;

[0028] Figure 5 is a graph showing the relationship between the threshold voltage of an NMOS device and target material consumption in one embodiment of the present invention;

[0029] In the figure,

[0030] 10-TiAL alloy layer; 20-TAN layer;

[0031] 30-TiN layer; 40-HK layer; 50-IL layer;

[0032] 100-sputtering chamber; 200-carrying platform;

[0033] 300-substrate; 400-target;

[0034] 500-Kit; 600-Magnetron;

[0035] 700-RF power supply; 800-housing;

[0036] 900-Protective parts. DETAILED DESCRIPTION

[0037] In order to make the purpose, advantages and features of the present invention clearer, the thin film deposition device and the method for manufacturing the NMOS device proposed by the present invention are further described in detail in combination with the drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. It should be understood that the drawings in the specification do not necessarily show the specific structure of the present invention in proportion, and the illustrative features used to illustrate certain principles of the present invention in the drawings in the specification will also adopt a slightly simplified drawing method. The specific design features of the present invention disclosed herein include, for example, specific dimensions, directions, positions and shapes, which will be determined in part by the specific application and use environment. And, in the embodiments described below, sometimes the same figure mark is used in common between different drawings to represent the same part or a part with the same function, and its repeated description is omitted. In this specification, similar numbers and letters are used to represent similar items, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0040] The core idea of ​​the present invention is to provide a thin film deposition device that can control the stability of the Ti / AL ratio when depositing the work function layer (i.e., TiAL alloy layer) of the NMOS device, so as to ensure the stability of device performance, save target materials and improve machine production capacity.

[0041] In order to realize the above-mentioned idea, the present invention provides a thin film deposition device, Figures 1 to 5 A specific embodiment of a thin film deposition device is disclosed. The thin film deposition device includes a housing 800, the housing 800 has a sputtering chamber 100, the sputtering chamber 100 is configured with a carrier 200, the carrier 200 is used to carry a substrate 300 to be sputtered, and the sputtering chamber 100 is in a vacuum state. A target material 400 is arranged opposite to the substrate 300, and the target material 400 includes a first sputtering material and a second sputtering material, and the first sputtering material and the second sputtering material have different atomic weights. An RF power supply 700 is used to generate plasma to bombard the target material 400, sputtering the target material 400 onto the surface of the substrate 300 to form a thin film. A kit 500 is arranged in the sputtering chamber 100. The kit 500 is arranged in the longitudinal direction (i.e., Figure 4 The kit 500 extends in the direction of the arrow b in the middle), and the kit 500 can extend to the position of the carrier 200 along the longitudinal direction, or can extend to the position below the carrier 200. A sputtering layer (not shown) is provided on the surface of the kit 500, and the material used in the sputtering layer is the same as that of the target 400.

[0042] The substrate 300 may be a substrate or a plate of a wafer waiting for sputtering. The following explanation will be given by taking a wafer as an example.

[0043] Among them, the materials used for the target 400 include a first sputtering material and a second sputtering material. The first sputtering material and the second sputtering material can both be sputtering materials such as metal Ti, metal Al, metal copper (Cu), metal oxide, etc. The atomic weights of the first sputtering material and the second sputtering material are different. In this embodiment, an alloy composed of the first sputtering material and the second sputtering material is selected as the work function layer of the metal gate, the first sputtering material selects metal Ti, and the second sputtering material selects metal Al. The following will be explained with the first sputtering material being metal Ti and the second sputtering material being metal Al. The atomic ratio of metal Ti and metal Al is 1:1. The atomic ratio is that the atomic number ratio of Ti and Al is 1:1.

[0044] Ginseng Figures 1 to 3 As shown, when the existing thin film deposition equipment deposits the TiAL alloy layer 10 on the surface of the wafer, since the atomic weight of metal Ti is heavier than that of metal AL, during the process of bombarding the target material to deposit the thin film, the path of metal Ti is not easy to change relative to metal AL, but metal AL is easy to grow on the kit 500, so the metal Ti deposited on the wafer is more than the metal AL. As the life of the target material is consumed, the metal AL on the kit 500 is more likely to be deposited on the wafer. Therefore, the atomic ratio of Ti and AL decreases as the target material is consumed, resulting in unstable performance of the device. In order to ensure stable product performance, it can only be used in the target material life range where the Ti / AL ratio is relatively stable, resulting in waste of target material.

[0045] However, the thin film deposition device disclosed in this embodiment deposits a TiAL alloy layer on the surface of the wafer by setting a sputtering layer on the kit 500, and the material of the sputtering layer is the same as the material of the target material, which is an alloy of metal Ti and metal AL. Although metal AL is easy to change the path, reducing the amount of metal AL on the target material deposited on the wafer, by depositing a certain thickness of Ti / AL alloy on the kit 500, the metal AL on the kit 500 can be deposited on the wafer, so that the Ti / AL ratio can be kept relatively stable throughout the life cycle of the target material, and the device threshold voltage is also relatively stable, which improves the performance of the product, increases the process window of the product, improves the utilization rate of the machine and reduces the loss of the target material.

[0046] Exemplarily, the sputtering layer is formed by a sandblasting process. The thickness of the sputtering layer formed in the kit 500 is 1.0-1.5 μm.

[0047] Specifically, refer to Figure 4As shown, a sputtering layer is formed on the kit 500 by a sandblasting process. Of course, the sputtering layer can also be formed by other methods, as long as a sputtering layer with a thickness of 1.0 to 1.5 μm can be formed on the surface of the kit 500. There is no specific limitation on the specific formation method. The thickness of the sputtering layer can be 1 μm, 1.2 μm, 1.3 μm, 1.4 μm, or 1.5 μm, or any value in the range of 1.0 to 1.5 μm. The atomic ratio of Ti and metal Al in the sputtering layer is 1:1.

[0048] In the thin film deposition equipment, a protective member 900 is also provided between the kit 500 and the wafer. In the actual experiment, by testing the kit 500 and the protective member 900 at the dotted line in the arrow a to deposit an alloy of metal Ti and metal AL with an atomic weight ratio of 1:1, it can be seen that when the kit 500 deposits an alloy of metal Ti and metal AL with a thickness of 1.0 to 1.5 μm, Figure 5 The experimental results shown. Figure 5 As shown, Figure 5 After the kit 500 is subjected to a sandblasting process to form a sputtering layer of 1.0 to 1.5 μm on the surface of the kit 500, an NMOS device is tested to obtain test data. Figure 5 It can be seen that as the target material is consumed, the threshold voltage tends to be stable. This means that during the life cycle of the target material, the Ti / AL ratio is relatively stable, and thus the threshold voltage is also relatively stable.

[0049] Exemplarily, the kit 500 is detachably connected to the housing 800 .

[0050] Specifically, refer to Figure 4 As shown, the kit 500 and the housing 800 can be detachably connected by bolts or by other means. As long as the kit 500 and the housing 800 can be detachably connected, the kit 500 can be taken out of the sputtering chamber 100 and replaced.

[0051] Exemplarily, the thin film deposition device is also provided with a radio frequency power supply 700 for generating plasma to bombard the target material 400, sputtering the target material 400 onto the surface of the wafer to form a thin film. In this embodiment, the radio frequency power supply 700 has a frequency of 13.56 MHZ. Of course, a frequency of 27.12 MHZ or higher can also be used. The thin film deposition device is also provided with a vacuum pump system (not shown in the figure). The vacuum pump system is connected to the sputtering chamber 100 and is used to extract the gas from the sputtering chamber 100 to maintain the sputtering chamber 100 at a set vacuum degree. The entire process of depositing the thin film is in a vacuum environment to reduce pollutants and unnecessary reactions. The thin film deposition device also includes other components such as a magnetron 600. It should be noted that since the present invention does not improve the components such as the radio frequency power supply 700, the vacuum pump system, the magnetron 600, and these components belong to the prior art, those skilled in the art are already familiar with their specific structures and principles, and will not be described in detail here.

[0052] To realize the above idea, this embodiment also discloses a method for manufacturing an NMOS device, including: providing a substrate, forming a gate structure on the substrate, the gate structure including a work function layer, and the work function layer is deposited by the thin film deposition device described above. The gate structure also includes an intermediate insulating layer and a high dielectric insulating layer, and the intermediate insulating layer, the high dielectric insulating layer and the work function layer are stacked to form a laminated structure as a gate structure. The work function layer is made of metal Ti and metal Al alloy materials.

[0053] Specifically, refer to Figure 1 As shown, when manufacturing the gate structure of the NMOS device, an intermediate insulating layer (i.e., IL layer 50) is first formed on the substrate. Then, a high-order insulating layer (HK layer 40) is formed on the surface of the intermediate insulating layer. Then, a titanium nitride layer (TiN layer 30) and a tantalum nitride layer (TAN layer 20) are sequentially formed on the surface of the high-order insulating layer, and finally, a TiAL alloy layer 10 is deposited on the surface of the tantalum nitride layer using the thin film deposition equipment provided in this embodiment. By using the thin film deposition equipment provided in this embodiment to deposit the TiAL alloy layer 10 on the surface of the tantalum nitride layer, the metal AL is prevented from diffusing to the interface between the titanium nitride layer and the HK layer, and the effective work function of the gate structure is prevented from being reduced, so that the performance of the NMOS device can be ensured to be stable. It should be noted that the sequential deposition of the IL layer 50, the HK layer 40, the TiN layer 30 and the TAN layer 20 on the substrate in this embodiment belongs to the prior art, and those skilled in the art are already familiar with the specific formation method thereof and will not be described in detail here.

[0054] In summary, the above embodiments have detailed descriptions of different configurations of thin film deposition equipment and methods for manufacturing NMOS devices. Of course, the above descriptions are only descriptions of preferred embodiments of the present invention, and are not any limitation to the scope of the present invention. The present invention includes but is not limited to the configurations listed in the above embodiments. Those skilled in the art can draw inferences based on the contents of the above embodiments. Any changes and modifications made by those of ordinary skill in the field of the present invention based on the above disclosures shall fall within the scope of protection of the claims.

Claims

1. A thin film deposition device, characterized in that: include: The housing has a sputtering chamber, the sputtering chamber is provided with a carrying platform, the carrying platform is used to carry the substrate to be sputtered, and the sputtering chamber is in a vacuum state; A target material is disposed opposite to the substrate, the target material comprises a first sputtering material and a second sputtering material, the first sputtering material and the second sputtering material have different atomic weights; A radio frequency power source is used to generate plasma to bombard the target material, sputtering the target material onto the surface of the substrate to form a thin film; The kit is arranged in the sputtering chamber, and a sputtering layer is arranged on the surface of the kit. The material used in the sputtering layer is the same as that of the target material.

2. The thin film deposition device according to claim 1, characterized in that: The atomic ratio of the first sputtering material to the second sputtering material is 1:1, and the atomic ratio of the materials used in the sputtering layer is 1:

1.

3. The thin film deposition device according to claim 1, characterized in that: The first sputtering material and the second sputtering material are both metals.

4. The thin film deposition device according to claim 1, characterized in that: The first sputtering material is titanium, and the second sputtering material is aluminum.

5. The thin film deposition device according to claim 1, characterized in that: The thickness of the sputtered layer is 1-1.5 μm.

6. The thin film deposition device according to claim 1, characterized in that: The sputtering layer is formed by using a sand blasting process.

7. The thin film deposition device according to claim 1, characterized in that: The thin film deposition equipment also includes a vacuum pump system connected to the sputtering chamber and used for pumping gas out of the sputtering chamber to maintain the sputtering chamber at a set vacuum level.

8. The thin film deposition device according to claim 1, characterized in that: The kit is detachably connected to the shell.

9. A method for manufacturing an NMOS device, characterized in that: include: A substrate is provided, a gate structure is formed on the substrate, the gate structure includes a work function layer, the work function layer is made of an alloy material, and the work function layer is deposited by a thin film deposition device as described in any one of claims 1 to 8.

10. The method for manufacturing an NMOS device according to claim 9, characterized in that: The work function layer is made of metal titanium and metal aluminum alloy materials.

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