Deep hole filling method, preparation method of semiconductor device and semiconductor process equipment

Abstract

The invention provides a deep hole filling method, a preparation method of a semiconductor device and semiconductor process equipment. The deep hole filling method comprises the following steps: placing a semiconductor structure provided with a deep hole in a process chamber; introducing auxiliary gas into the process chamber; sputtering and depositing hot aluminum on the surface of one side, provided with the deep hole, of the semiconductor structure until the deep hole is completely filled; the auxiliary gas is used for improving the deep hole filling performance of the hot aluminum. According to the scheme, the productivity can be effectively improved under the condition that holes and gullies are reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing, and in particular to a deep hole filling method, a semiconductor device preparation method and semiconductor process equipment. Background Art

[0002] In the manufacturing process of power devices and power integrated circuits, a hot aluminum filling process is usually used to fill the deep holes of semiconductor structures. The hot aluminum filling process is usually carried out under high temperature conditions of 400℃ to 450℃. In order to prevent the hot aluminum from penetrating into the interior of the semiconductor structure at high temperature and causing a puncture (Spike) phenomenon, an adhesion layer, a barrier layer and a wetting layer are usually formed in sequence on the side of the semiconductor structure where the deep hole is set, and then a seed layer is formed on the side of the wetting layer away from the semiconductor structure, and finally hot aluminum is deposited. In order to improve the deep hole filling performance of hot aluminum, related technologies usually perform hot aluminum deposition at a lower deposition rate, and its filling efficiency is low, which reduces production capacity. Summary of the invention

[0003] The present application provides a deep hole filling method, a method for preparing a semiconductor device and a semiconductor process equipment to solve the problem of low production capacity caused by low deep hole filling efficiency existing in the related art.

[0004] The first aspect of the present application provides a deep hole filling method, comprising: placing a semiconductor structure provided with deep holes inside a process chamber; introducing an auxiliary gas into the interior of the process chamber; sputtering and depositing hot aluminum on a side surface of the semiconductor structure provided with the deep holes until the deep holes are completely filled; the auxiliary gas is used to improve the deep hole filling performance of the hot aluminum.

[0005] In one embodiment, a target material is disposed on the top of the process chamber. During the process of sputtering and depositing hot aluminum on a side surface of a semiconductor structure having a deep hole, the method further comprises: stepwise increasing the power loaded on the target material to increase the sputtering deposition rate of the hot aluminum.

[0006] In one embodiment, step-wise increasing the power loaded onto the target includes: sequentially loading a first power, a second power, and a third power onto the target, wherein the first power ranges from 2000W to 5000W, the second power ranges from 6000W to 10000W, and the third power ranges from 15000W to 20000W.

[0007] In one embodiment, loading multiple powers onto the target material in sequence includes: loading a first power onto the target material so that the hot aluminum fills the deep hole to a first target depth at a first deposition rate; loading a second power onto the target material so that the hot aluminum fills the deep hole to a second target depth at a second deposition rate; and loading a third power onto the target material so that the hot aluminum completely fills the deep hole at a third deposition rate and reaches a target thickness.

[0008] In one embodiment, a process gas is also introduced into the process chamber, and the flow rate of the process gas is greater than the flow rate of the auxiliary gas; sequentially loading the first power, the second power and the third power onto the target material comprises first cyclically loading the first power onto the target material, then cyclically loading the second power onto the target material, and then cyclically loading the third power onto the target material; each round of cyclic loading comprises the following steps: exciting the process gas to generate plasma; loading the target material with corresponding power so that the plasma bombards the target material to perform thermal aluminum deposition; stopping loading the corresponding power and cooling.

[0009] In one embodiment, the method further includes: when the third power is applied to the target, stopping the introduction of the auxiliary gas into the interior of the process chamber.

[0010] In one embodiment, a wafer carrier is disposed at the bottom of the process chamber, and the wafer carrier is used to carry the semiconductor structure. The auxiliary gas is also used to reduce the heating temperature of the semiconductor structure heated by the wafer carrier.

[0011] In one embodiment, the heating temperature ranges from 350°C to 450°C.

[0012] In one embodiment, the auxiliary gas is nitrogen, and the flow rate of the nitrogen is in the range of 1 sccm to 10 sccm.

[0013] In one embodiment, the depth of the deep hole is less than or equal to 1 μm, the width of the deep hole is greater than 1 μm, and the aspect ratio of the deep hole is greater than or equal to 0.5 and less than 1.

[0014] In a second aspect, an embodiment of the present application provides a method for preparing a semiconductor device, comprising: providing a semiconductor structure, the semiconductor structure having at least two semiconductor devices, and a deep hole being arranged between two adjacent semiconductor devices; and filling the deep hole using any of the methods in the above-mentioned embodiments to connect the two adjacent semiconductor devices in parallel.

[0015] In a third aspect, an embodiment of the present application provides a semiconductor process equipment, comprising: a process chamber and a controller, the controller comprising at least one processor and at least one memory, the memory storing a computer program, and when the computer program is executed by the processor, the process chamber implements any one of the above-mentioned methods.

[0016] The advantages or beneficial effects of the above technical solution include at least: by introducing auxiliary gas into the interior of the process chamber, the deep hole filling performance of hot aluminum is improved by utilizing the auxiliary gas, so that in the hot aluminum filling process, not only the occurrence of voids or grooves can be reduced, but also hot aluminum deposition can be performed at a higher sputtering deposition rate to achieve complete filling of the deep holes, which is more conducive to improving the deep hole filling efficiency, thereby increasing production capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application. In addition, these drawings and text descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application for those skilled in the art by referring to specific embodiments.

[0018] Figure 1 Shown is a technical roadmap of a hot aluminum filling process of the related art.

[0019] Figure 2A The figure is a schematic diagram of the structure of voids generated by hot aluminum filling in the related art.

[0020] Figure 2B Shown is an electron microscope image of voids generated by hot aluminum filling in the related art.

[0021] Figure 3A Shown is a schematic diagram of the structure of hot aluminum filling to produce grooves in the related art.

[0022] Figure 3B Shown is an electron microscope image of trenches produced by hot aluminum filling in the related art.

[0023] Figure 4 FIG. 1 is a schematic flow chart of a deep hole filling method according to an embodiment of the present application.

[0024] FIG. 5A to FIG. 5C Schematic diagram of the cross-sectional structure of each step of a deep hole filling method according to an embodiment of the present application.

[0025] Figure 5D Shown is an electron microscope image of an embodiment of the present application after hot aluminum filling.

[0026] Figure 5E for Figure 5D Partial rendering of area A in the middle.

[0027] Figure 6 Shown is a schematic diagram of the XRD spectrum of the thermal aluminum layer according to an embodiment of the present application.

[0028] Fig. 7A The figure shows the distribution of multiple square resistances in the thermal aluminum layer deposited when nitrogen is introduced.

[0029] Figure 7B The figure shows the distribution of multiple square resistances in the hot aluminum layer during the deposition process when no nitrogen gas is introduced.

[0030] Fig. 8A FIG. 1 is a schematic structural diagram of a semiconductor structure according to an embodiment of the present application.

[0031] Figure 8B Shown is a schematic structural diagram of a semiconductor device. DETAILED DESCRIPTION

[0032] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0033] In the manufacturing process of power devices and power integrated circuits, hot aluminum filling process is usually used to fill the deep holes of semiconductor structures. Since the material of the semiconductor structure contains silicon, and the solid solubility of silicon atoms in aluminum is very high, hot aluminum and semiconductor structures are easily miscible at high temperatures, causing hot aluminum to penetrate into the interior of the semiconductor structure and cause puncture. In order to prevent the puncture phenomenon, such as Figure 1 As shown, the hot aluminum filling process of the related art is usually: first, a layer of aluminum having a thickness of about The titanium (Ti) metal is used as the adhesion layer, and the deposition thickness is about Titanium nitride (TiN) is used as a barrier layer with a deposition thickness of approximately of titanium as a wetting layer and a deposition thickness of approximately The cold aluminum is used as the seed layer, and then hot aluminum is deposited to the thickness required for the power device.

[0034] In practical applications, such as Figure 2A and Figure 2B As shown in FIG. 1 , during the deposition of thermal aluminum, if the deposition rate is high, the thermal aluminum tends to grow rapidly at the opening of the deep hole 10A and close (overhang), so that a cavity 20A is generated inside the deep hole 10A. Figure 3A and Figure 3B As shown, during the deposition of hot aluminum, if the fluidity of the hot aluminum is poor, it is easy to generate gullies 20B inside the deep hole 10A. In both cases, the deep hole filling performance of hot aluminum is poor, which significantly increases the contact resistance of the power device finally formed, and reduces the stability and reliability of the device. In order to improve the deep hole filling performance of hot aluminum, the related technology usually deposits hot aluminum at a lower deposition rate, which not only avoids the generation of voids, but also increases the fluidity of hot aluminum by extending the flow time of hot aluminum, thereby preventing the generation of gullies. However, this method has a low filling efficiency and reduces production capacity.

[0035] In view of this, the present invention provides a deep hole filling method, a method for preparing a semiconductor device and a semiconductor process equipment to solve the problem of low production capacity caused by low deep hole filling efficiency in the related art. The present invention is described in detail below with reference to the accompanying drawings.

[0036] Figure 4FIG. 1 is a schematic flow chart of a deep hole filling method according to an embodiment of the present application.

[0037] like Figure 4 As shown, the deep hole filling method includes the following steps S110 to S130.

[0038] Step S110: placing a semiconductor structure provided with deep holes inside a process chamber, wherein the deep holes include but are not limited to contact holes.

[0039] Step S120 , introducing auxiliary gas into the process chamber.

[0040] Step S130, sputtering and depositing thermal aluminum on a surface of a side of the semiconductor structure where the deep hole is provided until the deep hole is completely filled; the auxiliary gas is used to improve the deep hole filling performance of the thermal aluminum.

[0041] For example, by introducing auxiliary gas into the process chamber, the effect of the thermal aluminum deposition rate on the counterbore filling performance of the thermal aluminum can be improved, so that when the thermal aluminum deposition rate is high, it is not easy to generate voids inside the deep hole; and / or, the auxiliary gas is also used to improve the fluidity of aluminum to prevent the formation of gullies inside the deep hole. In this way, the deep hole filling performance of the thermal aluminum can be improved.

[0042] The above scheme, by introducing auxiliary gas into the interior of the process chamber, utilizes the auxiliary gas to improve the deep hole filling performance of hot aluminum. In this way, in the hot aluminum filling process, not only can the occurrence of voids or grooves be reduced, but also hot aluminum deposition can be performed at a higher sputtering deposition rate to achieve complete filling of the deep holes, which is more conducive to improving the deep hole filling efficiency, thereby increasing production capacity.

[0043] In one embodiment, a target material is disposed on the top of the process chamber. During the process of sputtering and depositing hot aluminum on a side surface of a semiconductor structure having a deep hole, the method further comprises: stepwise increasing the power loaded on the target material to increase the sputtering deposition rate of the hot aluminum.

[0044] Exemplarily, the hot aluminum is sputtered and deposited by a magnetron sputtering process, and the target material can be aluminum. Since the power loaded on the target material is positively correlated with the sputtering deposition rate of the hot aluminum, the greater the power loaded on the target material, the greater the sputtering deposition rate of the hot aluminum. In the actual filling process, the sputtering deposition rate of the hot aluminum will affect the deep hole effect. For example, when the sputtering deposition rate of the hot aluminum is low, the deep hole filling effect of the hot aluminum is good and the deep hole filling efficiency is low; when the sputtering deposition rate of the hot aluminum is high, the deep hole filling effect of the hot aluminum is poor and the deep hole filling efficiency is high. In the related art, when the magnetron sputtering process is used for hot aluminum sputtering deposition, the sputtering deposition rate is usually set to a fixed value, so that the hot aluminum is deposited at a specific smaller sputtering deposition rate, and the filling effect is good but the filling efficiency is low. Compared with the related art, in the process of hot aluminum sputtering deposition, the present application can increase the sputtering deposition rate of the hot aluminum from small to large by step-by-step increasing the power loaded on the target material, thereby realizing step-by-step increasing of the sputtering deposition rate of the hot aluminum. In this way, thermal aluminum deposition is first performed at a lower sputtering deposition rate to reduce the occurrence of voids or grooves, and then thermal aluminum deposition is performed at a higher sputtering deposition rate, which ensures the deep hole filling ability of the thermal aluminum and greatly improves production capacity.

[0045] In one embodiment, step-wise increasing the power loaded onto the target includes: sequentially loading a first power, a second power, and a third power onto the target, wherein the first power ranges from 2000W to 5000W, the second power ranges from 6000W to 10000W, and the third power ranges from 15000W to 20000W.

[0046] Optionally, the first power is 4000W, the second power is 8000W, and the third power is 17500W.

[0047] It should be noted that in the related art, in order to ensure the filling performance of hot aluminum, a lower power, such as 1000W, is usually applied to the target to control the hot aluminum to be deposited at a lower sputtering deposition rate. Compared with the related art, the present application can improve the filling performance of hot aluminum by using the auxiliary gas introduced into the process chamber. In this way, the sputtering deposition efficiency of hot aluminum can be improved by increasing the initial power loaded on the target to at least 2000W while ensuring that the hot aluminum has good filling performance, thereby achieving the purpose of improving the deep hole filling efficiency of hot aluminum and improving production capacity.

[0048] In addition, by setting the first power range to 2000W to 5000W and the second power range to 6000W to 10000W, the first power and the second power can be both within 10000W, so that the increment from the first power to the second power can be limited, and the filling performance of the hot aluminum can be avoided to be reduced due to excessive increment. For example, if the increment of the first power and the second power is close to or exceeds 10000W, it is still easy to produce voids and gullies, which is conducive to further improving the deep hole filling effect of hot aluminum, such as improving the deep hole filling rate. Furthermore, by setting the third power range to 15000W to 20000W, deep hole filling can be performed at a relatively high deposition rate while ensuring that no voids and gullies are generated, further fully improving the deposition rate of hot aluminum, and achieving the purpose of fully improving production capacity.

[0049] In one embodiment, sequentially loading a plurality of powers onto the target material includes the following steps S210 to S230.

[0050] Step S210 , applying a first power to the target material to deposit hot aluminum at a first deposition rate to fill the deep hole to a first target depth.

[0051] Step S220: Apply a second power to the target material to deposit hot aluminum at a second deposition rate to fill the deep hole to a second target depth. The second target depth is less than the first target depth, that is, the depth of the deep hole becomes shallower, so that the deep hole can be nearly filled.

[0052] Step S230 , applying a third power to the target material, so that the hot aluminum is deposited at a third deposition rate until the deep hole is completely filled and the target thickness is reached.

[0053] Optionally, the first power is 4000W, the second power is 8000W, and the third power is 175000W.

[0054] In practical applications, if hot aluminum is deposited only at the first deposition rate to fill the deep hole, the production capacity is low; if hot aluminum is deposited at the third deposition rate to fill the deep hole, although the production capacity can be increased, it will cause the opening of the deep hole to close quickly, which is easy to produce voids and make the deep hole unable to be completely filled. The above scheme controls the hot aluminum to fill the deep hole to the first target depth at a lower first deposition rate, and then controls the hot aluminum to fill the deep hole to the second target depth at a moderate second deposition rate, so that the deep hole can be nearly filled. This can not only ensure the filling effect and avoid the generation of voids, but also improve the filling efficiency to a certain extent. Furthermore, on the basis of the deep hole being nearly filled, hot aluminum is deposited at a larger third deposition rate, which can greatly improve the deposition efficiency, so that the hot aluminum is quickly deposited to reach the target thickness, thereby achieving the effect of increasing production capacity.

[0055] In one embodiment, a process gas is also introduced into the process chamber, and the flow rate of the process gas is greater than the flow rate of the auxiliary gas. For example, the process gas includes argon gas, and the preferred flow rate of argon gas is in the range of 10 sccm to 50 sccm, and the auxiliary gas includes nitrogen gas, and the flow rate of nitrogen gas is in the range of 1 sccm to 10 sccm, and the flow rate of argon gas is greater than the flow rate of nitrogen gas.

[0056] Sequentially loading the first power, the second power and the third power to the target material includes first cyclically loading the first power to the target material, then cyclically loading the second power to the target material, and then cyclically loading the third power to the target material. Each cycle includes the following steps S310 to S330.

[0057] Step S310: exciting the process gas to generate plasma.

[0058] Step S320 , loading corresponding power onto the target material so that plasma bombards the target material to perform thermal aluminum deposition.

[0059] Step S330, cooling the semiconductor structure and stopping loading corresponding power.

[0060] The above scheme, by first cyclically loading the first power to the target material, then cyclically loading the second power to the target material, and then cyclically loading the third power to the target material, can ensure that the semiconductor structure has sufficient cooling time at the end of each cycle to prevent continuous deposition of particles from causing the temperature of the semiconductor structure to be too high.

[0061] In one embodiment, when the third power is applied to the target, the auxiliary gas is stopped from being introduced into the process chamber. In practical applications, after the first power and the second power are applied to the target in sequence, the deep hole is filled to the second target depth, and its depth becomes shallower, which reduces the demand for deep hole filling performance in the subsequent thermal aluminum deposition step. Therefore, when the third power is applied to the target, stopping the auxiliary gas from being introduced into the process chamber will not affect the filling performance, and it is more helpful to save the use of auxiliary gas and reduce costs.

[0062] In one embodiment, a wafer carrier is disposed at the bottom of the process chamber, and the wafer carrier is used to carry the semiconductor structure. The auxiliary gas is also used to reduce the heating temperature of the semiconductor structure heated by the wafer carrier.

[0063] In the related art, in order to improve the deep hole filling performance of hot aluminum, the wafer carrier is usually controlled to heat the semiconductor structure to increase the temperature of hot aluminum deposition, so that the hot aluminum has fluidity. The heating temperature of the wafer carrier is usually higher than 450°C, which shortens the service life of the wafer carrier. However, in the present application, the auxiliary gas can improve the fluidity of the hot aluminum, so there is no need for the wafer carrier to generate an excessively high heating temperature, thereby reducing the heating temperature of the wafer carrier, which helps to extend the service life of the wafer carrier.

[0064] In one embodiment, the heating temperature range of the wafer carrier is 350°C to 450°C (including the end points). Optionally, the heating temperature of the wafer carrier can be any value of 350°C, 400°C and 450°C. Since the heating temperature of the wafer carrier in the related art is usually higher than 450°C, by setting the heating temperature of the wafer carrier between 350°C and 450°C, the heating temperature of the wafer carrier can be lower than the heating temperature of the related art, thereby extending the service life.

[0065] In one embodiment, the auxiliary gas is nitrogen (N2), and the flow rate of nitrogen into the process chamber is in the range of 1 sccm to 10 sccm (including the end value). By setting the flow rate of nitrogen into the process chamber in the range of 1 sccm to 10 sccm, it is ensured that nitrogen is used to improve the deep hole filling performance of hot aluminum.

[0066] In one embodiment, Figure 5A As shown, the depth D of the deep hole 10A is less than or equal to 1 μm, the width W of the deep hole 10A is greater than 1 μm, and the aspect ratio of the deep hole 10A is greater than or equal to 0.5 and less than 1. Optionally, the depth D of the deep hole 10A is 1 μm, the width W of the deep hole 10A is 2 μm, and the aspect ratio of the deep hole 10A is 0.5. When the deep hole 10A is a circular hole, the width W of the deep hole 10A is the aperture of the deep hole 10A.

[0067] Optionally, before performing hot aluminum deposition, the embodiment of the present application may first deposit an adhesion layer, a barrier layer and a wetting layer in sequence on the surface of one side of the semiconductor structure where the deep hole is provided, then perform cold aluminum deposition to form a seed layer, and then perform hot aluminum deposition until the deep hole is completely filled. Among them, the material of the adhesion layer is usually metallic titanium, the material of the barrier layer is usually titanium nitride, and the material of the seed layer and the hot aluminum are both metallic aluminum. Due to the large difference in thermal expansion coefficient between aluminum and titanium nitride, the wettability is poor, which makes the fluidity of aluminum worse. Therefore, adding a wetting layer made of metallic titanium between the barrier layer and the seed layer can improve the fluidity of aluminum, thereby effectively improving the deep hole filling performance of cold aluminum and hot aluminum.

[0068] The deep hole filling method of the present application is described in detail below by using an example. The deep hole filling method may include the following first main step and second main step.

[0069] The first main step includes: inside the first process chamber, using a magnetron sputtering process to sequentially deposit an adhesion layer, a barrier layer and a wetting layer on a surface of a side of the semiconductor structure where the deep hole is arranged.

[0070] The first target is arranged at the top of the first process chamber, and the process conditions for depositing the adhesion layer, the barrier layer and the wetting layer include: the flow rate range of the process gas into the first chamber is 0 sccm to 100 sccm, and the power range of the first target is 0 W to 10000 W. The process gas includes argon (Ar) and nitrogen, the preferred flow rate range of argon into the first chamber is 40 sccm to 60 sccm, and the preferred flow rate range of nitrogen into the first chamber is 50 sccm to 90 sccm. The preferred power range of the first target is 6000 W to 8000 W.

[0071] For details, please refer to Figure 5A The first main step may include the following process steps 1 to 13, and the specific process parameters are shown in Table 1.

[0072] Step 1: Introduce argon gas into the first process chamber.

[0073] Step 2: Load low power, such as 1000W, to the first target material to ionize the argon gas to generate plasma and complete ignition; wherein the first target material is metal titanium.

[0074] Step 3: Load high power, such as 7000W, to the first target to attract plasma to bombard the first target, so that titanium atoms are sputtered out of the first target and deposited on the surface of the semiconductor structure 10 provided with the deep hole 10A. The thickness of the adhesive layer 31 is achieved.

[0075] Step 4: Introduce argon and nitrogen into the first process chamber.

[0076] Step 5: Load low power, such as 1000W, to the first target material to ionize the argon gas to generate plasma and complete ignition; wherein the first target material is metal titanium.

[0077] Step 6: Load high power, such as 7000W, to the first target to attract plasma to bombard the first target, so that titanium atoms sputtered from the first target react with nitrogen to produce titanium nitride, which falls on the surface of the adhesion layer 31 away from the semiconductor structure 10.

[0078] Step 7 to step 9, repeat step 4 to step 6 once, so that titanium nitride is deposited on the surface of the adhesion layer 31 away from the semiconductor structure 10 The thickness of the barrier layer 32 is achieved.

[0079] Step 10 to step 12, repeating step 1 to step 3 once, so that titanium atoms are deposited on the surface of the barrier layer 32 away from the semiconductor structure 10 The thickness of the film is 0.1 to achieve the deposition of the wetting layer 33. The adhesion layer 31, the barrier layer 32 and the wetting layer 33 constitute the interlayer film layer 30.

[0080] Step 13, stop applying power to the first target and stop introducing process gas into the first process chamber, thereby ending the process.

[0081] Table 1 Process parameters of the first main step

[0082]

[0083] The second main step includes: inside the second process chamber, using a magnetron sputtering process to sequentially deposit a seed layer and hot aluminum on a surface of a side of the semiconductor structure provided with the deep hole until the deep hole is completely filled.

[0084] A second target material is disposed on the top of the second process chamber, and a wafer carrier is disposed on the bottom of the second process chamber. The wafer carrier is used to adsorb the semiconductor structure on which the adhesion layer, barrier layer and wetting layer have been deposited. For example, the wafer carrier is provided with an electrostatic chuck, and the electrostatic chuck is used to adsorb the semiconductor structure so that the side surface of the semiconductor structure provided with the deep hole faces the second target material. It should be noted that since the target materials used in the magnetron sputtering process of the first main step and the second main step are different, the first main step and the second main step are performed in two different process chambers.

[0085] The process conditions for depositing cold aluminum include not introducing back-blowing gas to the back of the semiconductor structure, the flow rate of the process gas is in the range of 10sccm to 100sccm, and the power range of the second target material is 1000W to 20000W. The process conditions for depositing hot aluminum include introducing back-blowing gas to the back of the semiconductor structure, the flow rate of the process gas is in the range of 1sccm to 100sccm, and the power range of the second target material is 2000W to 20000W. Among them, when depositing cold aluminum, the preferred flow rate range of the process gas is 10sccm to 50sccm. When depositing hot aluminum, the process gas includes argon gas, the preferred flow rate range of argon gas is 10sccm to 50sccm, the auxiliary gas includes nitrogen gas, the preferred flow rate range of nitrogen gas is 1sccm to 10sccm, and the flow rate of the process gas is greater than the flow rate of the auxiliary gas.

[0086] For details, please refer to FIG. 5B to FIG. 5E The second main step may include the following process steps 1 to 59, and the specific process parameters are shown in Table 2.

[0087] Step 1: Introduce argon gas into the second process chamber.

[0088] Step 2: Load low power, such as 2000W, to the second target to ionize the argon gas to generate plasma and complete the ignition.

[0089] Step 3: Load the second target with high power, such as 19000W, to attract plasma to bombard the second target, such as metal aluminum, so that aluminum atoms are sputtered out of the second target and deposited on the surface of the wetting layer 33 facing away from the semiconductor structure 10. The thickness of the seed layer 40 is completed.

[0090] Step 4, introduce process argon gas, back-blowing argon gas and nitrogen gas into the interior of the second process chamber. The back-blown nitrogen gas is heated by the wafer carrier and then blown toward the back side of the semiconductor structure 10, that is, the surface of the semiconductor structure 10 facing the wafer carrier. It should be noted that during the deposition of the seed crystal layer 40, the heating temperature generated by the wafer carrier is 350°C. Since the back-blowing gas is not introduced, the wafer carrier only heats the back side of the semiconductor structure 10 by thermal radiation. Since the heat exchange efficiency of heat exchange is higher than that of thermal radiation, when depositing hot aluminum, the introduced back-blowing gas is first heated by the wafer carrier, and then heat exchange is performed with the back side of the semiconductor structure 10, so that the semiconductor structure 10 can be quickly heated to the required temperature, for example, 350°C to 450°C.

[0091] Step 5: Load low power, such as 2000 W, onto the second target to ionize the process argon gas to generate plasma gas to complete ignition.

[0092] Step 6: Load the second target with a first power, such as 4000 W, to attract plasma gas to bombard the second target, thereby achieving deposition at a first deposition rate.

[0093] Step 7: Cool the semiconductor structure 10 and stop loading the first power.

[0094] Step 8 to step 19, cyclically execute step 3 to step 5 4 times, so as to cyclically load the first power to the second target material, form the first hot aluminum layer 21 to fill the deep hole 10A to the first target depth d1. The number of cyclic executions can be any value between 3 and 5 times.

[0095] Steps 20 to 22 correspond to and are similar to steps 5 to 7, except that loading the first power onto the second target in step 21 is replaced by loading the second power onto the second target, for example, 8000W.

[0096] Step 23 to step 25, and step 20 to step 22 are executed once in a cycle to realize cyclic loading of the second power to the second target material, forming a second hot aluminum layer 22 to fill the deep hole 10A to a second target depth d2, so that the deep hole 10A is nearly filled.

[0097] Steps 26 to 28 correspond to and are similar to steps 5 to 7, except that the first power applied to the second target in step 27 is replaced by a third power, such as 175,000 W, and the nitrogen supply is stopped.

[0098] Step 29 to step 58, and step 26 to step 28 are performed 9 times in a loop, so as to realize the cyclic loading of the third power to the second target material, form the third thermal aluminum layer 23 to completely fill the deep hole 10A, and make the portion of the third thermal aluminum layer 23 outside the deep hole 10A reach the target thickness t. The first thermal aluminum layer 21, the second thermal aluminum layer 22 and the third thermal aluminum layer 23 constitute the thermal aluminum layer 20.

[0099] Step 59, stop introducing gas into the process chamber and stop loading power to end the process.

[0100] Table 2 Process parameters of the second main step

[0101]

[0102]

[0103] Figure 5D and Figure 5E 2 shows an electron microscope effect diagram of a semiconductor structure 10 having a deep hole 10A with a depth of 1 μm and a width of 2 μm after deep hole filling using an embodiment of the present application. It can be seen from the diagram that no voids or grooves are generated inside the deep hole 10A, and the surface of the formed thermal aluminum layer 20 is smooth.

[0104] In practical applications, the following differences exist in the deep hole filling of the semiconductor structure provided with the above-mentioned deep hole using the related technology and the embodiment of the present application respectively:

[0105] The related technology can only achieve deep hole filling by setting the heating temperature of the wafer carrier to above 450°C, loading 1000W of power onto the second target and continuously depositing hot aluminum for 3300S; however, after the auxiliary gas is introduced into the interior of the second process chamber, the heating temperature of the wafer carrier can be reduced to 350°C, and the power loaded onto the second target can be increased step by step from 4000W to 175000W, so as to shorten the time for depositing hot aluminum to 320S, which can effectively improve the deposition efficiency and thus increase the production capacity.

[0106] In addition, in the embodiment of the present application, when other process conditions remain unchanged, by comparing the deep hole filling effects of not introducing auxiliary gas into the second process chamber and introducing auxiliary gas into the second process chamber, it is found that:

[0107] When the auxiliary gas is not introduced into the second process chamber, even if the heating temperature of the wafer carrier is increased to 430°C, the deep hole cannot be completely filled; when the auxiliary gas is introduced into the second process chamber, the heating temperature of the wafer carrier is set to below 350°C to achieve complete filling, and the filling rate reaches more than 95%;

[0108] Furthermore, if Figure 6 As shown, the XRD (X-ray diffraction) spectrum of the hot aluminum layer reflects that when other process conditions remain unchanged, the crystal orientation peak positions of the hot aluminum layer deposited with nitrogen introduced into the second process chamber and the hot aluminum layer deposited without nitrogen introduced into the second process chamber are both close to 40°, indicating that the introduction of nitrogen has no effect on the crystallization characteristics of the hot aluminum layer. It can be seen that when nitrogen is introduced into the second process chamber as an auxiliary gas, nitrogen does not react with hot aluminum, and nitrogen plays a role in improving the deep hole filling effect of hot aluminum.

[0109] Furthermore, if Fig. 7A and Figure 7B As shown, Fig. 7A FIG. 1 shows a schematic diagram of the distribution of multiple sheet resistances in the thermal aluminum layer formed by deposition when nitrogen is introduced into the interior of the second process chamber while other process conditions remain unchanged, wherein Fig. 7A From the area selected by the dashed box in FIG, it can be seen that the average square resistance (Rs-avg) of the thermal aluminum layer is 4.471 mΩ / sq; Figure 7B FIG. 1 shows a schematic diagram of the distribution of multiple sheet resistances in the thermal aluminum layer formed by deposition when other process conditions remain unchanged and nitrogen is not introduced into the second process chamber, wherein Figure 7B The area selected by the dotted box in the figure shows that the average square resistance (Rs-avg) of the thermal aluminum layer is 4.335 mΩ / sq, and the difference between the average square resistances of the two thermal aluminum layers is very small, indicating that the introduction of nitrogen has no effect on the square resistance of the thermal aluminum layer and will not reduce the electrical properties of the thermal aluminum layer. The embodiment of the present application also provides a method for preparing a semiconductor device, which includes the following steps S410 to S420.

[0110] Step S410: Provide a semiconductor structure, wherein the semiconductor structure has at least two semiconductor devices, and a deep hole is provided between two adjacent semiconductor devices. Fig. 8AAs shown, the semiconductor device 11 in the semiconductor structure 10 can be a silicon carbide metal oxide semiconductor field effect transistor (SiC Metal-Oxide-Semiconductor Field-Effect Transistor, SiC MOSFET), and two adjacent semiconductor devices 11 form a multi-cell parallel structure without a source.

[0111] Step S420: fill the deep hole using any of the above-mentioned methods to connect two adjacent semiconductor devices in parallel. Figure 8B As shown, the deep hole filling method of the embodiment of the present application is used to fill the deep hole 10A between two adjacent semiconductor devices 11, so that the finally deposited thermal aluminum layer 20 can constitute the source of the two adjacent semiconductor devices 11, so that the two adjacent semiconductor devices 11 are connected in parallel. Figure 8B The interlayer film layer 30 and the seed layer 40 are omitted.

[0112] Optionally, the semiconductor device 11 may also be other types of power devices, and the embodiment of the present application does not limit the type of the semiconductor device 11 .

[0113] The above scheme uses the deep hole filling method of the embodiment of the present application to fill the deep hole 10A between two adjacent semiconductor devices 11, which can ensure that the hot aluminum 20 is quickly deposited without generating voids or grooves to realize the parallel connection of multiple semiconductor devices 11, which can not only improve the preparation efficiency of the device, but also reduce the contact resistance of the semiconductor device 11, improve the stability and reliability of the device, and improve the performance of the device.

[0114] The embodiment of the present application also provides a semiconductor process equipment. The semiconductor process equipment includes: a process chamber and a controller, the controller includes at least one processor and at least one memory, the memory stores a computer program, and when the computer program is executed by the processor, the process chamber implements any of the above-mentioned methods. It should be noted that since the semiconductor process equipment adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here. In addition, the process chamber and other components of the semiconductor process equipment can adopt various technical solutions known to ordinary technicians in this field now and in the future, which will not be described in detail here.

[0115] In addition, in this application, unless otherwise clearly specified and limited, the terms "connected", "connected", "stacked" and the like should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or integrated; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0116] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A deep hole filling method, characterized in that: include: Placing a semiconductor structure provided with a deep hole inside a process chamber; introducing an auxiliary gas into the interior of the process chamber; Thermal aluminum is sputtered and deposited on a surface of one side of the semiconductor structure where the deep hole is provided until the deep hole is completely filled; the auxiliary gas is used to improve the deep hole filling performance of the thermal aluminum.

2. The method according to claim 1, characterized in that A target material is arranged on the top of the process chamber, and in the process of sputtering and depositing hot aluminum on a side surface of the semiconductor structure where the deep hole is arranged, the method further comprises: The power applied to the target material is increased in a stepwise manner to increase the sputtering deposition rate of the hot aluminum.

3. The method according to claim 2, characterized in that The step-wise increase in power loaded onto the target includes: sequentially loading a first power, a second power and a third power onto the target, wherein the first power ranges from 2000W to 5000W, the second power ranges from 6000W to 10000W, and the third power ranges from 15000W to 20000W.

4. The method according to claim 3, characterized in that The sequentially loading a plurality of powers onto the target material comprises: Applying a first power to the target material so that the hot aluminum fills the deep hole to a first target depth at a first deposition rate; Applying a second power to the target material so that the hot aluminum fills the deep hole to a second target depth at a second deposition rate; A third power is applied to the target material so that the hot aluminum completely fills the deep hole at a third deposition rate and reaches a target thickness.

5. The method according to claim 3, characterized in that: A process gas is also introduced into the process chamber, and the flow rate of the process gas is greater than the flow rate of the auxiliary gas; sequentially loading the first power, the second power and the third power to the target material includes first cyclically loading the first power to the target material, then cyclically loading the second power to the target material, and then cyclically loading the third power to the target material; each round of cyclic loading includes the following steps: Exciting the process gas to generate plasma; Loading corresponding power to the target material so that the plasma bombards the target material to perform thermal aluminum deposition; Stop loading the corresponding power and perform cooling.

6. The method according to claim 4, characterized in that The method further comprises: When the third power is applied to the target, the auxiliary gas is stopped from being introduced into the process chamber.

7. The method according to claim 1, characterized in that A wafer carrying device is disposed at the bottom of the process chamber, and the wafer carrying device is used to carry the semiconductor structure. The auxiliary gas is also used to reduce the heating temperature of the semiconductor structure heated by the wafer carrying device.

8. The method according to claim 7, characterized in that The heating temperature ranges from 350°C to 450°C.

9. The method according to any one of claims 1 to 8, characterized in that The auxiliary gas is nitrogen, and the flow rate of the nitrogen is in the range of 1 sccm to 10 sccm.

10. The method according to claim 1, characterized in that The depth of the deep hole is less than or equal to 1 μm, the width of the deep hole is greater than 1 μm, and the aspect ratio of the deep hole is greater than or equal to 0.5 and less than 1.

11. A method for preparing a semiconductor device, characterized in that: include: A semiconductor structure is provided, wherein the semiconductor structure has at least two semiconductor devices, and a deep hole is provided between two adjacent semiconductor devices; The deep hole is filled with the method according to any one of claims 1 to 10, so that two adjacent semiconductor devices are connected in parallel.

12. A semiconductor process equipment, characterized in that: include: A process chamber and a controller, wherein the controller comprises at least one processor and at least one memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the process chamber implements the method according to any one of claims 1 to 10.

Images