Formation method of semiconductor device

Abstract

The invention discloses a method for forming a semiconductor device, which comprises the following steps of: S1, providing a semiconductor device which comprises a plurality of back side grooves, and arranging a silicon oxide layer on the surface of each back side groove; s2, introducing a first processing gas, and performing surface modification on the silicon oxide layer under the action of a radio frequency power supply to form an amination interface; wherein the first treatment gas comprises nitrogen and hydrogen, and the volume ratio of the nitrogen is 50%-88%. According to the method, the silicon oxide interface is subjected to amination treatment before the tungsten nitride adhesion layer is formed, so that the reaction gas for forming the tungsten nitride and the silicon oxide are bonded in a chemical adsorption manner, and the adhesion between the product tungsten nitride and the silicon oxide layer is enhanced. Furthermore, by adjusting the proportion of nitrogen and hydrogen in the first processing gas, the adhesion of the tungsten nitride layer and the silicon oxide layer is effectively improved, after the tungsten layer and the aluminum film are sequentially formed subsequently, the defect that the aluminum gasket falls off due to layering of the tungsten layer and the silicon oxide layer in the FAB on-line process of the wafer can be avoided, and the product yield is improved.

Description

Technical Field

[0001] The present invention relates to a semiconductor device manufacturing process, and in particular to a method for forming a semiconductor device. Background Art

[0002] In back-illuminated CMOS image sensors, tungsten (W) is often used to form a light-blocking metal grid to prevent light irradiating one pixel from diffusing to adjacent pixels and causing optical signal crosstalk. Tungsten nitride (WN) is often used as an adhesion layer and / or barrier layer between the W layer and its underlying film layers (such as silicon oxide layers).

[0003] However, due to the varying properties of different material layers, such as thermal expansion coefficients and lattice defects, conventional deposition methods for tungsten nitride adhesion layers cannot meet the evolving demands of semiconductor processes. Poor adhesion of tungsten nitride can cause the tungsten layer to separate from the underlying silicon oxide (SiO2) layer, leading to product shedding defects. To prevent this separation from the underlying film layer, which can damage product performance, it is necessary to effectively improve the adhesion of the tungsten nitride layer to the underlying film layer. Summary of the Invention

[0004] The purpose of the present invention is to provide a pre-treatment process for a WN adhesion barrier layer, thereby improving the adhesion between the tungsten nitride layer and the underlying film layer and increasing the product yield.

[0005] In order to achieve the above object, the present invention provides a method for forming a semiconductor device, comprising:

[0006] Step S1, providing a semiconductor device comprising a plurality of backside trenches, wherein a silicon oxide layer is provided on the surface of the backside trenches;

[0007] In step S2, a first processing gas is introduced to modify the surface of the silicon oxide layer under the action of a radio frequency power supply to form an amino interface; wherein the first processing gas contains nitrogen and hydrogen, wherein the volume ratio of nitrogen is 50% to 88%.

[0008] Optionally, the semiconductor device further includes a plurality of backside through holes, and the bottoms of the backside through holes are a conductive metal layer.

[0009] Optionally, the conductive metal layer includes a tungsten layer or a copper layer.

[0010] Optionally, the formation method further comprises a reduction pretreatment step: introducing a second processing gas to perform a reduction treatment on the conductive metal layer.

[0011] Optionally, the second process gas comprises hydrogen.

[0012] Optionally, the second process gas further contains an inert gas.

[0013] Optionally, the inert gas includes argon.

[0014] Optionally, in step S2, the RF power source includes a first RF power, and the first RF power is 1800W to 2200W.

[0015] Optionally, in step S2, the RF power supply further includes a second RF power, and the second RF power is 180W to 260W.

[0016] Optionally, the formation method further comprises: step S3, introducing process gas to form a tungsten nitride layer on the surface of the silicon oxide.

[0017] Optionally, the process gas includes WF6, NH3 and B2H6.

[0018] Optionally, the tungsten nitride layer has a thickness of 50 angstroms to 100 angstroms.

[0019] Optionally, the forming method further comprises: step S4, depositing a tungsten layer on the surface of the tungsten nitride layer.

[0020] Optionally, the forming method further comprises: step S5, depositing an aluminum film on the surface of the tungsten layer.

[0021] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0022] 1) Before forming a tungsten nitride adhesion layer on the surface of the silicon oxide layer, the present invention first introduces a first processing gas to perform interface modification on the surface of the silicon oxide layer. Under the action of the radio frequency electric field, the plasma formed by the dissociation of the first processing gas chemically bonds with the Si atoms of the silicon oxide layer to form an amino interface. The nucleophilic N atoms in the amino interface attack the electrophilic W atoms in the tungsten-containing precursor to form chemical bonds, thereby promoting the adsorption of the tungsten-containing precursor gas at the interface of the silicon oxide layer, thereby enhancing the adhesion of the reaction product tungsten nitride to the silicon oxide layer, avoiding the aluminum liner falling off defect caused by the separation of the W layer and the silicon oxide layer formed in the subsequent process, and thus improving the product yield.

[0023] 2) The first processing gas contains nitrogen and hydrogen. The volume ratio of nitrogen is 50% to 88%. Experiments have found that increasing the ratio of N2 to H2 molecules can increase the probability of molecular collisions, thereby increasing the degree of dissociation of N2 and H2 and generating NH 2+As the plasma concentration increases, the probability of combining with Si atoms in SiO2 increases, thereby enhancing the degree of amination at the SiO2 interface, and further promoting the chemical adsorption of the tungsten-containing precursor and the SiO2 interface, increasing the adhesion between the adhesion layer WN and SiO2, and improving the delamination defects between the high-stress W layer and the dielectric film layer (silicon oxide layer).

[0024] 3) When the semiconductor device also includes a backside via structure and the conductive metal layer at the bottom of the backside via is Cu, the present invention also introduces a second process gas before modifying the surface of the silicon oxide layer to form an amino interface, thereby reducing the conductive metal layer and removing any copper oxide that may have formed on the surface of the conductive metal layer, thereby improving signal transmission efficiency. The second process gas is a mixture of hydrogen and an inert gas. The higher molecular weight of the inert gas increases the collision and dissociation efficiency of hydrogen molecules, thereby improving the reduction rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flow chart of a method for forming a semiconductor device.

[0026] Figure 2 It is a partial schematic diagram of a semiconductor device with backside trenches according to the present invention.

[0027] Figure 3 For Figure 2 Schematic diagram of the state where the back-side groove forms an amino interface.

[0028] Figure 4 The present invention is a flowchart of a method for forming a semiconductor device.

[0029] Figure 5 It is a partial schematic diagram of a semiconductor device with a backside through hole and a backside trench.

[0030] Figure 6 The present invention is a flowchart of a method for forming a semiconductor device.

[0031] Figure 7 The figure is a schematic diagram of a semiconductor device having a backside through hole and a backside trench undergoing a reduction treatment.

[0032] Figure 8 For passing Figure 7 Schematic diagram of the surface modification state after reduction treatment.

[0033] Figure 9 The present invention is a flowchart of a method for forming a semiconductor device.

[0034] Figure 10Schematic diagram of slice analysis of the BSST trench portion of the wafer prepared in Examples 1-5 using focused ion beam (FIB) technology.

[0035] Figure 11 Schematic diagram of dark defect detection results of wafers prepared in Example 1 and Example 3 on the FAB line.

[0036] Figure ID

[0037] Back side through hole 1

[0038] Back groove 2

[0039] Base 21

[0040] Etching the main layer 22

[0041] Insulation layer 23

[0042] Bottom silicon oxide layer 231

[0043] Silicon nitride layer 232

[0044] Surface silicon oxide layer 233

[0045] Amination interface 234

[0046] W floor 51

[0047] Aluminum film 52

[0048] Conductive metal layer 53

[0049] CuO layer 531

[0050] Tungsten nitride layer 54 . DETAILED DESCRIPTION

[0051] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0052] In the description of the present invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0053] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical connections; direct connections or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0054] The “tungsten-containing precursor” described herein refers to a tungsten-containing process gas for forming a tungsten nitride layer, for example, WF6.

[0055] To improve the adhesion of the tungsten layer to the underlying silicon oxide layer, the present invention performs an amination treatment on the surface of the silicon oxide layer before forming the tungsten nitride adhesion layer, forming an amination interface. When a tungsten-containing precursor gas used to form tungsten nitride is introduced, the -NH2 at the amination interface acts as a nucleophilic group and undergoes a nucleophilic reaction with the positively charged W in WF6, forming a chemical bond. This allows the tungsten-containing precursor gas (e.g., WF6 gas to form WN) to chemically adsorb to the silicon oxide layer. The strong chemical adsorption enhances the adhesion of the resulting WN to the underlying silicon oxide layer. This is described in detail below with reference to the accompanying figures and examples.

[0056] like Figure 1 As shown, the present invention provides a method for forming a semiconductor device, comprising:

[0057] In step S1 , a semiconductor device is provided, which comprises a plurality of backside trenches, wherein a silicon oxide layer is provided on the surface of the backside trenches.

[0058] like Figure 2 As shown, a local structure of a semiconductor device with a backside trench is illustrated. An etching body layer 22 is formed on a substrate 21, and a backside trench 2 is formed in the etching body layer 22. As an example, the etching body layer 22 can be a silicon (Si) layer. An insulating layer 23 is deposited on the backside trench 2. As an example, the insulating layer 23 can be an underlying silicon oxide (SiO2) layer 231, a silicon nitride (SiN) layer 232 and a surface silicon oxide layer 233 in sequence. The process requires that when an adhesion layer WN and a W layer are formed on the surface silicon oxide layer 233 of the backside trench 2, in order to avoid separation of the W layer and the surface silicon oxide layer 233, the processing method of step S2 of the present invention is adopted to improve the adhesion of the tungsten nitride layer.

[0059] In step S2, a first processing gas is introduced to modify the surface of the silicon oxide layer under the action of a radio frequency power supply to form an amino interface; wherein the first processing gas contains nitrogen and hydrogen, wherein the volume ratio of nitrogen is 50% to 88%.

[0060] The RF power supply includes a first RF power of 1800W to 2200W (low frequency, LF), which is used to dissociate the first processing gas into plasma.

[0061] In some embodiments, in step S2, the RF power source further includes a second RF power having a power of 180W to 260W (high frequency, HF) for increasing the plasma density and thereby improving the density of the amination.

[0062] The state of modifying the surface of the back side groove 2 to form an aminated interface is shown as follows: Figure 3 As shown, under the action of the first radio frequency, nitrogen dissociates into nitrogen ions, and hydrogen dissociates into hydrogen ions. The nitrogen ions and hydrogen ions react with silicon oxide on the surface of the surface silicon oxide layer 233 to form Si-NH2 (as shown in the following formula 1), forming an aminated interface 234 on the surface of the backside trench.

[0063]

[0064] like Figure 4 As shown, the method for forming a semiconductor device of the present invention further includes: step S3, introducing process gas to form a tungsten nitride layer on the surface of the silicon oxide.

[0065] As an example, the process gas may include WF6 (tungsten-containing precursor), NH3, and B2H6.

[0066] The N atoms in the aminated interface are nucleophilic and easily attack the W atoms (electrophilic) in the tungsten-containing precursor. The two bond, resulting in strong chemical adsorption of the tungsten-containing precursor gas to the silicon oxide layer, thereby enhancing the adhesion of the resultant WN to the SiO2 dielectric film layer. The mechanism is shown in the following formula 2:

[0067]

[0068] It can be seen that after the above-mentioned aminated interface is formed, the tungsten-containing precursor is chemically adsorbed to the silicon oxide layer, which is closer than the usual physical adsorption, so that the product WN has strong adhesion to the silicon oxide, and the subsequent tungsten film deposited on the WN is not easy to fall off.

[0069] The thickness of the tungsten nitride layer is determined according to the resistance value required by the device connection. As an example, the thickness of the tungsten nitride layer can be 50 angstroms to 100 angstroms.

[0070] It is understood that the method of the present invention can be used to improve the adhesion of tungsten nitride in various scenarios where it is necessary to form a tungsten nitride adhesion layer on the silicon oxide surface to prevent the silicon oxide layer from separating and falling off from the subsequently deposited W layer. For example, for semiconductor devices with backside trenches and / or backside vias, it is necessary to form a tungsten nitride adhesion layer on the silicon oxide layer before filling the W layer to prevent the W layer from separating from the silicon oxide layer.

[0071] like Figure 5 As shown, in some backside illumination (BSI) processes, a W layer 51 exists in the backside via 1 (BVIA) and the backside shallow silicon trench 2 (BSST), and an aluminum film 52 is deposited on the W layer 51. Among them, the W layer 51 in the BVIA part needs to contact the conductive metal layer 53 of the frontside illumination (FSI) structure to achieve signal transmission. The conductive metal layer can be a tungsten layer or a copper layer. When the conductive metal layer 53 includes a copper layer, after the Cu in the FSI structure is exposed to the air, a CuO layer 531 is easily formed on the surface, and the CuO layer 531 will hinder signal transmission. In addition, the W layer 51 in the backside shallow trench 2 also needs to consider the adhesion with the underlying film layer (surface silicon oxide layer 233) to prevent the W layer from separating from the underlying film layer due to poor adhesion, thereby forming defects and damaging product performance. Therefore, it is necessary to form a tungsten nitride layer 54 as an adhesion layer before forming the W layer 51. To meet the application requirements of the W layer in both structures, the present invention first performs a reduction pretreatment on the conductive metal layer (e.g., copper) at the bottom of the backside via before forming the tungsten nitride layer 54, and then performs a surface modification treatment in step S2 to form an amino interface.

[0072] When the conductive metal layer includes a copper layer, copper oxide is easily formed when copper is exposed to air, which affects signal transmission. The present invention provides a method for forming a semiconductor device, such as Figure 6 As shown, before the tungsten nitride pretreatment process of the present invention is performed, a reduction pretreatment step is required: Step S1', introducing a second processing gas to perform a reduction treatment on the conductive metal layer. The reaction mechanism of the reduction treatment is shown in Formula 3 below.

[0073]

[0074] The second processing gas is a reducing gas, for example, may contain hydrogen.

[0075] Since hydrogen is light and has a very low ionization rate, it requires a strong energy to achieve the desired ionization effect. Therefore, the present invention also adds a heavier inert gas, such as argon, to the second processing gas. Under the bombardment and collision of the heavier Ar ions, the ionization degree of hydrogen can be increased to form more hydrogen plasma, which can fully reduce the copper oxide on the surface of the conductive metal layer. The state of the reduction treatment is shown in the figure below. Figure 7 It is understood that inert gases (helium, neon, argon, krypton, xenon) can achieve the purpose of the present invention. The present invention selects argon from the perspective of cost-effectiveness.

[0076] After the reduction treatment step, the first treatment gas is introduced to modify the surface of the silicon oxide layer to form an amino interface 234, as shown in the schematic diagram. Figure 8 shown.

[0077] like Figure 9 As shown, the method for forming a semiconductor device of the present invention further forms a W layer on the tungsten nitride layer, and further, an aluminum thin film can be formed on the W layer. That is, the formation method further includes:

[0078] Step S4, depositing a tungsten layer on the surface of the tungsten nitride layer;

[0079] Step S5: depositing an aluminum film on the surface of the tungsten layer.

[0080] The tungsten layer is deposited using conventional methods, for example, by depositing a thin tungsten seed layer on the nitride adhesion layer using SiH4 / WF6; and then using H2 / WF6 to deposit a bulk tungsten layer to fill the backside vias or backside trenches.

[0081] Aluminum thin film is deposited using conventional methods, for example, a PVD method, in which plasma is used to bombard an Al target material, knocking Al atoms from the target material and depositing them on the tungsten layer of the wafer.

[0082] The present invention also found that too high or too low a ratio of nitrogen to hydrogen in the first processing gas will also affect the adhesion performance of the tungsten nitride adhesion layer. When the ratio of N2 to H2 in the WN pre-treatment process is increased, the concentration of N2 and H2 molecules will change, the probability of molecular collision will increase, and the degree of dissociation of N2 and H2 will increase, and the generated -NH2 + As the plasma concentration increases, the probability of bonding with Si atoms in SiO2 increases, thereby enhancing the degree of amination at the SiO2 interface. This promotes chemical adsorption of the tungsten-containing precursor gas at the SiO2 interface, further enhancing the adhesion of the resulting WN to SiO2 and improving delamination defects between the high-stress W film and the dielectric film. The following explores the appropriate ratio of N2 to H2 through Examples 1-5.

[0083] Example 1

[0084] A wafer with a backside trench and a backside through hole is provided. The surfaces of the backside through hole and the backside trench have a silicon oxide layer, and the conductive metal layer at the bottom of the backside through hole is a Cu layer.

[0085] To prevent the Cu layer from naturally oxidizing and forming CuO on the surface, which could affect signal transmission, a reduction treatment was first performed to remove the CuO. A second treatment gas was introduced, and the conductive metal layer was reduced under a 200W high-frequency RF power source for 40 seconds. The second treatment gas consisted of 50 sccm Ar and 50 sccm H₂.

[0086] The first processing gas containing 150 sccm N2+20 sccm H2 was introduced for 50 seconds, and a 2000W low-frequency RF power supply and a 220W high-frequency RF power supply were applied respectively to dissociate N2 and H2 to form a large amount of N + and H + Plasma state; N + and H + The plasma reacts to form NH 2+ Plasma, NH 2+ The plasma forms an Si-NH2 amino interface with the Si atoms of SiO2 on the wafer surface.

[0087] Process gases (WF6, NH3 and B2H6) are introduced to form a tungsten nitride layer with a thickness of 80 angstroms on the amino interface of the silicon oxide surface.

[0088] After depositing a 3000 angstrom tungsten layer and an 8000 angstrom aluminum film using conventional methods, the BSST trench was sliced ​​and analyzed using focused ion beam (FIB) technology to characterize the shedding of the W layer in the BSST trench. Figure 10 shown.

[0089] Example 2

[0090] The same method as in Example 1 is used, wherein the first processing gas is 150 sccm N2+75 sccm H2.

[0091] Example 3

[0092] The same method as in Example 1 is used, where the first processing gas is 150 sccm N2+100 sccm H2.

[0093] Example 4

[0094] The same method as in Example 1 is used, wherein the first processing gas is 150 sccm N2+150 sccm H2.

[0095] Example 5

[0096] The same method as in Example 1 is used, wherein the first processing gas is 190 sccm N2+150 sccm H2.

[0097] The FIB results of Examples 1-5 are as follows: Figure 10 As shown, under the conditions of Example 1 (150 sccm N2+20 sccm H2), the W in the BSST trench portion is separated from the underlying SiO2 dielectric layer, forming a delamination defect, as shown in FIG. Figure 10 As shown in the red dotted circle in a. It can be seen that the larger the ratio of N2 to H2, the better. When the ratio of N2 to H2 is greater than 88%, although an amino interface is formed, the adhesion of the final tungsten nitride layer cannot meet the process requirements, and delamination defects occur between the tungsten layer and the silicon oxide layer. When the N2 content is kept constant, the H2 content is increased to 75 sccm (Example 2, see Figure 10 b), 100 sccm (Example 3, see Figure 10 c), 150 sccm (Example 4, see Figure 10 Under the conditions of d), no delamination was found between W and the underlying SiO2 at the BSST trench; and when the H2 content was 150 sccm, the N2 content was increased to 190 sccm (Example 5, see Figure 10 In figure e), FIB results show a tight bond between W and SiO2 in the BSST trench. These results indicate that when the N2 ratio in the N2-H2 gas mixture during the WN pretreatment process is greater than 50% and less than 88%, the W in the BSST trench is tightly bonded to the underlying film, with no delamination defects.

[0098] Considering the cost and capacity of mass production FAB, the wafers prepared in Example 1 and Example 3 were selected to be put into the manufacturing plant (FAB) and the detachment defect of the aluminum pad in the BSST groove was detected using a dark field defect inspection machine. The long-term data was collected. The results are as follows: Figure 11 As shown. Among them, Figure 11 a shows the dark field defect detection data of the wafer prepared in Example 1 on the FAB line. Figure 11 Figure b shows the dark field defect detection of the wafer prepared in Example 3 on the FAB line. The horizontal axis represents the detection time point, and the vertical axis represents the number of defects. Figure 11As can be seen, compared to wafers prepared using a first process gas of 150 sccm N₂ + 20 sccm H₂, wafers prepared using a first process gas of 150 sccm N₂ + 100 sccm H₂ exhibited virtually no delamination defects during long-term monitoring. Therefore, the present invention provides a solution to the delamination defect commonly seen in mass production FABs, which occurs due to poor adhesion between the W layer and the underlying dielectric film layer. This also reduces the potential impact of delamination defects on product reliability, thereby improving product quality and reducing production costs.

[0099] In summary, the present invention performs an amination treatment on the silicon oxide interface before forming the tungsten nitride adhesion layer, promoting chemical adsorption bonding between the tungsten-containing precursor gas and the silicon oxide. By adjusting the ratio of nitrogen to hydrogen in the first process gas, the adhesion between the tungsten nitride layer and the silicon oxide layer is effectively improved, thereby preventing the occurrence of AL pad detachment defects during the wafer fabrication process. Furthermore, to prevent oxidation of the copper in the conductive metal layer at the bottom of the backside vias, which could affect signal transmission, the present invention introduces a second process gas before introducing the first process gas to form the amination interface, thereby reducing the conductive metal layer.

[0100] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for forming a semiconductor device, characterized in that: Include: Step S1, providing a semiconductor device comprising a plurality of backside trenches, wherein a silicon oxide layer is provided on the surface of the backside trenches; In step S2, a first processing gas is introduced to modify the surface of the silicon oxide layer under the action of a radio frequency power supply to form an amino interface; wherein the first processing gas contains nitrogen and hydrogen, wherein the volume ratio of nitrogen is 50% to 88%.

2. The method for forming a semiconductor device according to claim 1, wherein: The semiconductor device further comprises a plurality of backside through holes, and the bottoms of the backside through holes are a conductive metal layer.

3. The method for forming a semiconductor device according to claim 2, wherein: The conductive metal layer includes a tungsten layer or a copper layer.

4. The method for forming a semiconductor device according to claim 2, wherein: The forming method further comprises a reduction pretreatment step: introducing a second processing gas to perform a reduction treatment on the conductive metal layer.

5. The method for forming a semiconductor device according to claim 4, wherein: The second process gas includes hydrogen.

6. The method for forming a semiconductor device according to claim 5, wherein: The second process gas further includes an inert gas.

7. The method for forming a semiconductor device according to claim 6, wherein: The inert gas includes argon.

8. The method for forming a semiconductor device according to claim 1, wherein: In step S2, the radio frequency power supply includes a first radio frequency power, and the first radio frequency power is 1800W to 2200W.

9. The method for forming a semiconductor device according to claim 8, wherein: In step S2, the RF power supply further includes a second RF power, and the second RF power is 180W to 260W.

10. The method for forming a semiconductor device according to claim 1, wherein: The forming method further includes: step S3, introducing process gas to form a tungsten nitride layer on the surface of the silicon oxide.

11. The method for forming a semiconductor device according to claim 10, wherein: The process gas includes WF6, NH3 and B2H6.

12. The method for forming a semiconductor device according to claim 10, wherein: The thickness of the tungsten nitride layer is 50 angstroms to 100 angstroms.

13. The method for forming a semiconductor device according to any one of claims 1 to 12, wherein: The forming method further includes: step S4, depositing a tungsten layer on the surface of the tungsten nitride layer.

14. The method for forming a semiconductor device according to claim 13, wherein: The forming method further comprises: step S5, depositing an aluminum film on the surface of the tungsten layer.

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