MOCVD device

Abstract

The utility model provides an MOCVD (Metal Organic Chemical Vapor Deposition) device. The MOCVD device comprises a reaction chamber, a sample table, a lifting mechanism, an induction coil and a plasma generating device, the sample table is positioned in the reaction chamber, and an edge ring is arranged around the sample table; the lifting mechanism is connected with the edge ring and can adjust the up-down displacement of the edge ring; the plasma generating device is used for generating longitudinal plasma, and the induction coil is arranged in the edge ring so as to provide a magnetic field to adjust the motion state of charged particles in the plasma and increase the horizontal component of the charged particles, so that the side wall processing effect of the plasma in the wafer is improved; the damage to the bottom due to high energy of particles in the vertical direction is also reduced; meanwhile, the position of the induction coil can move relative to the horizontal plane of the wafer, the directions of magnetic induction lines in the middle and edge areas in the wafer plane are changed correspondingly, the motion trails of charged particles in the middle and horizontal positions of the wafer are changed, and the uniformity of the quality of a wafer film is further improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of wafer processing equipment relates to a kind of MOCVD device. BACKGROUND

[0002] MOCVD (Metal-Organic Chemical Vapor Deposition) is a kind of chemical vapor phase epitaxy growth technology developed on the basis of VPE (Vapor Phase Epitaxy) technology.

[0003] In the field of semiconductors, titanium nitride (TiN) structure mainly refers to titanium nitride film, which is widely used in integrated circuit manufacturing due to its unique physical and chemical properties. Especially in copper interconnection structure, TiN is used as a barrier layer to enhance the adhesion of aluminum-copper alloy interconnection lines on silicide, reduce the contact resistance and stress between interconnection lines and contact holes, and prevent the mutual diffusion between silicon and aluminum, avoid aluminum puncture, and also be used as a barrier layer in other interconnection processes to prevent metal electromigration.

[0004] As a barrier layer in the contact hole, due to the high C content in TiN film, the film is loose and has high resistivity. After vacuum deposition, more water vapor and oxygen will be present on the surface of the TiN film, further increasing the resistivity and affecting its performance. To avoid this problem, in the existing MOCVD equipment, a layer of TiN film is formed by chemical reaction on the substrate surface through heating the substrate. However, the C and O content in the TiN film formed by CVD in this step is high, and the film quality is poor. Therefore, the deposited TiN film needs to be treated by plasma. For example, the C content in the treated TiN film can be reduced by about 41%, and the O content can be reduced by about 95%, which greatly improves the film quality and resistivity. However, referring to Figure 1 In the process of plasma treatment of the film, the plasma is generated by the plasma generating device 130 in the existing MOCVD machine, and the collimation of the generated plasma is good. The side wall treatment ability is much weaker than the longitudinal treatment ability. Therefore, the thickness of the TiN film on the side wall is much larger than the thickness of the film in the longitudinal direction, and the step coverage reaches 150-180%, which causes the TiN film on the side wall to absorb more water vapor and oxygen, causing the resistivity to increase, and further affecting the filling of subsequent metals such as tungsten. At the same time, due to the strong vertical treatment ability of the longitudinal ability, although the TiN film in the longitudinal direction is improved, it is also likely to penetrate the TiN film and nitride the tungsten and other metals at the bottom of the contact hole, increasing the impedance.

[0005] In addition, due to the change of process or uneven distribution of film stress in the film forming process, the temperature of the edge or middle of the wafer is different, and the film layer and film quality of the wafer in the middle and edge are also obviously different, so that the quality of the TiN film in the contact hole is correspondingly different between the edge and the middle, thereby affecting the uniformity of the device performance.

[0006] Therefore, it is necessary to provide a MOCVD device to increase the collision between particles by realizing the oscillation of particles on the wafer surface, on the one hand, to reduce the bombardment damage to the bottom by reducing the particle energy, and on the other hand, to increase the probability of particle impact on the sidewall, improve the improvement ability of the sidewall film quality, and improve the in-plane uniformity of the film quality.

[0007] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application and facilitating the understanding of those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art only because it is described in the background section of the present application. Practical new type content

[0008] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide a MOCVD device to improve the quality problem of the existing film.

[0009] To achieve the above-mentioned purpose, the present application provides a MOCVD device, which comprises:

[0010] a reaction chamber;

[0011] a sample stage, which is located in the reaction chamber, and the periphery of the sample stage is provided with an edge ring;

[0012] a lifting mechanism, which is connected with the edge ring, and the up-down displacement of the edge ring is adjusted through the lifting mechanism;

[0013] an induction coil, which is arranged in the edge ring, and a magnetic field is provided through the induction coil to adjust the motion state of the charged particles;

[0014] a plasma generating device, which comprises a radio frequency power supply and an adapter, and the adapter is connected with a showerhead device.

[0015] Optionally, the edge ring is in inverted L shape, and the sample stage has a step corresponding to the edge ring.

[0016] Optionally, the lifting rod of the lifting mechanism penetrates the sample stage and is connected with the edge ring.

[0017] Optionally, the step height of the sample stage is h0, the horizontal part of the edge ring is h1 away from the step position, and h1≤h0.

[0018] Optionally, the induction coil is annularly arranged in the edge ring; or the induction coil is spaced apart in the edge ring.

[0019] Optionally, N>1 of the lifting mechanisms are included, and the N lifting mechanisms are annularly and equidistantly distributed.

[0020] Optionally, the fixing member between the induction coil and the edge ring is a ceramic fixing member.

[0021] Optionally, the MOCVD device includes a controller, and the lifting mechanism communicates with the controller.

[0022] Optionally, the communication mode of the lifting mechanism and the controller includes wired communication and / or wireless communication; and the driving member of the lifting mechanism includes a servo motor or a stepping motor.

[0023] Optionally, the induction coil is connected with a power supply, and the power supply includes an alternating current power supply and / or a direct current power supply.

[0024] The utility model provides a kind of MOCVD device, including reaction chamber, sample stage, lifting mechanism, induction coil and plasma generating device;Sample stage is located in reaction chamber, and the periphery of sample stage is equipped with edge ring;Lifting mechanism is connected with edge ring, and the up-down displacement of edge ring can be adjusted;Plasma generating device is used to generate longitudinal plasma, induction coil is arranged in edge ring, and then magnetic field is provided to adjust the movement state of charged particle in plasma, increase the horizontal component of charged particle, to improve the sidewall processing effect of plasma in wafer, also reduce the damage to bottom due to high particle energy in vertical direction;At the same time, the relative motion of induction coil position can occur relative to wafer horizontal plane, the direction of magnetic induction line corresponding wafer surface middle and edge area changes, changes the movement track of charged particle in wafer middle and horizontal position, further improves the uniformity of wafer film quality. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is shown as MOCVD device diagram in prior art.

[0026] Figure 2 It is shown as MOCVD device diagram provided by the utility model.

[0027] Figure 3 It is shown as the local enlarged schematic view of edge ring structure of the utility model.

[0028] Figure 4A top view of the MOCVD device is shown.

[0029] Figures 5a to 5d A working principle diagram of the induction coil is shown.

[0030] Figures 6a to 6c A magnetic field distribution diagram corresponding to the wafer edge and the middle under different positions of the edge ring is shown.

[0031] Figures 7a to 7c A structure diagram in the process of preparing a TiN layer in the existing MOCVD device is shown.

[0032] Figures 8a to 8c A structure diagram in the process of preparing a TiN layer in the MOCVD device of the present application is shown.

[0033] BRIEF DESCRIPTION OF DRAWINGS

[0034] 100 reaction chamber

[0035] 110 isolation ring

[0036] 120 ceramic fixing part

[0037] 130 plasma generating device

[0038] 131 radio frequency power supply

[0039] 132 adapter

[0040] 140 sample table

[0041] 150 edge ring

[0042] 161 induction coil

[0043] 162 lifting mechanism

[0044] 163 hollow groove

[0045] 164 support table

[0046] 165 driving part

[0047] 170 power supply

[0048] 200 showerhead device

[0049] 210 TiN layer DETAILED DESCRIPTION

[0050] The following describes the embodiments of the present application by specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present application. The present application can also be implemented or applied by different specific embodiments, and the details in the present application can be modified or changed based on different viewpoints and applications without departing from the spirit of the present application.

[0051] It should be noted that the diagrams provided in the present embodiment only schematically illustrate the basic concept of the present application, and only the components related to the present application are shown in the diagrams, not the number, shape and size of the components when actually implemented. The shape, number and proportion of the components when actually implemented can be arbitrarily changed, and the layout of the components can be more complex.

[0052] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0053] Referring to Figures 2 to 4 The present embodiment provides a MOCVD device, which comprises a reaction chamber 100, a sample table 140, a lifting mechanism 162, an induction coil 161 and a plasma generating device 130. The sample table 140 is located in the reaction chamber 100, and the sample table 140 is provided with an edge ring 150 around the periphery. The lifting mechanism 162 is connected with the edge ring 150, and the up-down displacement of the edge ring 150 is adjusted through the lifting mechanism 162. The induction coil 161 is arranged in the edge ring 150, and a magnetic field is provided through the induction coil 161 to adjust the motion state of charged particles. The plasma generating device 130 comprises a radio frequency power supply 131 and an adapter 132, and the adapter 132 is connected with a showerhead device 200.

[0054] Specifically, the plasma generating device 130 generates a high-frequency electric field through the radio frequency power supply 131, so that the electrons in the gas molecules sprayed by the showerhead device 200 obtain energy and are ionized to generate plasma. The impedance matching between the radio frequency power supply 131 and the plasma load is ensured through the adapter 132, so as to ensure the uniform distribution of the gas and improve the uniformity and stability of the subsequent generated plasma.

[0055] As a further example of the above example, the induction coil 161 can be arranged in the edge ring 150 in a ring shape.

[0056] Referring to Figures 2 to 3 In the embodiment, the annular inductive coil 161 is arranged in the edge ring 150, and a magnetic field is generated under the action of the power supply 170, so that the generated magnetic field binds and adjusts the motion state of the charged particles near the sample table 140.

[0057] In some other embodiments, the inductive coil 161 is arranged in the edge ring 150 in a spaced manner, and can be arranged at different positions of the edge ring 150, so as to control different positions of the wafer on the sample table 140.

[0058] For example, the power supply 170 connected to the inductive coil 161 can be direct current or alternating current, and preferably, the power supply 170 can be alternating current. Specifically, when the power supply 170 is connected to alternating current, the inductive coil 161 generates an alternating magnetic field under the action of alternating current. In the embodiment, referring to Figure 5a According to Ampere's rule, the direction of the alternating magnetic field can be determined. When the current of the power supply 170 is alternating current, the charged particles will enter the alternating magnetic field, and the alternating magnetic field will further change the motion trajectory of the charged particles. Referring to Figures 5b to 5d According to the left-hand rule of Lorentz force, the motion trajectory of the charged particles can be determined. Since the motion directions of the charged particles are different, acceleration, deceleration, deflection, collision and other motions will occur.

[0059] Referring to Figure 2 and Figures 8a to 8c In the embodiment, when the TiN layer 210 is prepared in the MOCVD device, the wafer surface is first heated on the sample table 140 to cause a chemical reaction to form a thin film, and then plasma treatment is performed. Since the plasma generated by the plasma generating device 130 is concentrated in the longitudinal direction, the inductive coil 161 arranged in the edge ring 150 generates an alternating magnetic field under the action of the power supply 170, so that the motion direction of the charged particles changes. In the prior art, referring to Figures 7a to 7c Since the motion direction of the plasma is concentrated in the longitudinal direction, the thickness of the bottom of the TiN layer 210 in the contact hole is much smaller than the thickness of the sidewall, and the film quality of the TiN layer 210 will also be affected. In the embodiment, referring to Figures 8a to 8cSince the cutting magnetic induction line direction component can improve the oscillation and collision probability of the charged particles, thereby improving the processing effect of the particles on the sidewall in the structure, to a certain extent, the damage to the bottom caused by high particle energy is reduced, the high-energy particles penetrate the TiN film in the longitudinal direction to cause the metal nitride of the bottom contact hole, thereby improving the impedance of the TiN layer 210 of the bottom, and further optimizing the film quality of the TiN layer 210.

[0060] In order to ensure that the induction coil 161 has conductivity, temperature resistance and corrosion resistance, the induction coil 161 can be made of copper wire, ferrite and the like. In the present embodiment, the induction coil 161 is made of copper wire, so as to provide stable inductance value and low resistance loss.

[0061] As an example, the edge ring 150 is a ring-shaped component, the edge ring 150 is in an inverted L shape, and the sample table 140 has a step corresponding to the edge ring 150. The above arrangement is to avoid that in the semiconductor process, the plasma enters the back of the wafer through the edge of the wafer or reacts to form a polymer at the edge of the sample table 140, so as to maximize the protection of the sample table 140 from the plasma.

[0062] Specifically, in the reaction chamber 100, in order to prevent the deposition of the film layer and the accumulation of the polymer at the edge and the sidewall of the sample table 140, referring to Figure 3 , the edge ring 150 is in an inverted L shape, so as to be embedded with the sample table 140; the vertical part of the edge ring 150 is used to protect the side of the sample table 140, and the horizontal part of the edge ring 150 is used to protect the horizontal position of the periphery of the sample table 140. Of course, the shape of the edge ring 150 is not limited to this, and the edge ring 150 can also adjust the shape structure according to the sample table 140, so as to protect the side and the periphery of the sample table 140.

[0063] As an example, the material of the edge ring 150 includes silicon carbide, boron carbide, quartz, high-conductivity composite material and the like. Considering the high-temperature resistance, corrosion resistance and good heat conduction performance, in the present embodiment, the edge ring 150 preferably adopts a silicon carbide edge ring.

[0064] As an example, referring to Figure 3 , the sample table 140 is provided with a step, and the height of the step of the sample table 140 is h0. In some embodiments, in order to facilitate the installation of the edge ring 150 and prevent the aggregation of contaminated particles at the step position of the sample table 140, the h0 is in the range of 6-16 mm, such as 6 mm, 8 mm, 10 mm, 14 mm, 16 mm and the like. Of course, other height value ranges can also be used, which are not limited here.

[0065] Further, the lifting mechanism 162 drives the edge ring 150 to move, so that the horizontal part of the edge ring 150 is at a distance h1 from the step position. In order to ensure the protection of the sample table 140 by the edge ring 150, h1≤h0; when h1 is 0, the top of the edge ring 150 is at least flush with the wafer, so as to prevent unnecessary film deposition or pollution on the side of the wafer or the sample table 140. In the embodiment, the top of the edge ring 150 is flush with the wafer. Of course, in some other embodiments, the top of the edge ring 150 can be higher than the wafer. This can not only change the gas flow distribution inside the reaction chamber 100, so that the gas flow distribution is more uniform, but also effectively adjust the concentration and incident angle of the wafer edge plasma, so that the plasma density of the edge and the middle region is more uniform, effectively reducing the risk of merging of holes and holes, trenches and trenches.

[0066] In order to enable the magnetic field generated by the induction coil 161 to accurately control the motion state of the charged particles in the wafer edge or middle region, referring to Figure 3 , the induction coil 161 is arranged at the middle region of the horizontal part of the edge ring 150. In some other embodiments, the position of the induction coil 161 can be at the upper position or the lower position of the horizontal part of the edge ring 150, which is set according to the actual situation.

[0067] As an example, referring to Figure 3 , the lifting rod of the lifting mechanism 162 penetrates the sample table 140 and is connected with the edge ring 150;

[0068] Specifically, the MOCVD device can include N>1 lifting structures, and the N lifting mechanisms 162 are arranged in a ring shape at equal intervals. The arrangement of multiple lifting mechanisms 162 helps to maintain the lifting stability of the sample table 140, and is conducive to the uniformity of the gas flow distribution and the temperature field distribution in the reaction chamber 100, so as to ensure the uniform growth of the epitaxial layer. In order to protect the lifting mechanism 162 from the plasma, the lifting rod of the lifting mechanism 162 penetrates the sample table 140.

[0069] Further, the lifting mechanism 162 includes a thimble mechanism or a slide rod mechanism. Preferably, in the embodiment, the lifting mechanism 162 is a thimble mechanism; the lifting mechanism 162 further includes a driving member 165 and a support table 164, so as to realize the driving of the lifting mechanism 162. The thimble mechanism is connected with the driving member 165 through the support table 164 and is driven by the driving member 165.

[0070] As an example, the driving member 165 includes a stepper motor and a servo motor. The driving member 165 drives the edge ring 150 to move up and down; in the embodiment, the driving member 165 preferably adopts a stepper motor to achieve high-precision control of the position of the edge ring 150. In other embodiments, the controller 165 can also select a servo motor, and the specific type is not limited here.

[0071] As an example, the MOCVD device further includes a controller (not identified), and the lifting mechanism 162 communicates with the controller.

[0072] Further, the communication mode of the lifting mechanism 162 with the controller includes one or a combination of wired communication and wireless communication. Through the controller, signal reception, processing, and command issuance are achieved. The communication mode of the controller and the lifting mechanism 162 can be set according to actual needs.

[0073] Further, through the up and down displacement of the edge ring 150, the horizontal position of the induction coil 161 relative to the wafer changes, thereby increasing the adjustable freedom of the edge and middle regions of the wafer. The horizontal position of the induction coil 161 relative to the wafer generally includes three cases; refer to Figures 6a to 6c The position of the induction coil 161 is different from the position of the wafer, Figure 6a The position of the induction coil 161 is flush with the position of the wafer, in which state, the magnetic field directions of the edge and middle regions of the wafer are consistent, and the magnetic field direction is perpendicular to the wafer horizontal plane. After the charged particles are injected into the reaction chamber 100, other particles except the particles perpendicular to the electric field direction are deflected at a certain angle under the action of the magnetic field. Figure 6b The position of the induction coil 161 is higher than the position of the wafer, Figure 6c The position of the induction coil 161 is lower than the position of the wafer. In Figure 6b and Figure 6c In the state, the magnetic field directions of the edge and middle regions of the wafer are different, and the magnetic field direction of the edge region of the wafer is at a certain angle with the magnetic field direction of the center region of the wafer, so that the charged particle motion collision probability of the edge region of the wafer is higher than that of the center region of the wafer, thereby increasing the adjustable freedom of the edge and middle regions of the wafer.

[0074] Further, during the maintenance of the device, the edge ring 150 is usually disassembled, replaced or cleaned. The manual replacement of the edge ring 150 can cause the edge ring 150 to be displaced in the up-down direction. When the device is maintained, the change in the position of the edge ring 150 can change the distribution of the in-plane magnetic field of the wafer, which can further affect the uniformity of the film quality in the deep hole of the wafer. On the other hand, when different products are applied to the same device, the distribution of the deep holes between the products is different, so that the different products correspond to the micro-differences in the horizontal position of the induction coil 161. These differences cannot be immediately discovered and corrected. Most production personnel judge the uniformity of the film quality in the wafer by testing the in-plane electrical properties of different products. In order to further avoid the micro-displacement of the edge ring 150 and the micro-difference between the deep holes of different products, the fine adjustment of the lifting mechanism 162 can reduce the above errors and problems. In addition, in the same product, due to the non-uniformity of the process temperature, film stress and other factors in the process, the deep hole film and the film quality of the edge and the middle region of the wafer are obviously different. By fine adjustment of the relative position of the induction coil 161 to the wafer, the magnetic field direction of the edge and the middle region of the wafer is controlled, and then the motion track and collision probability of the charged particles in the edge and the middle region of the wafer are controlled, and the uniformity of the in-plane deep hole of the wafer is optimized.

[0075] As an example, refer to Figure 3 and Figure 4 The fixing member between the induction coil 161 and the edge ring 150 is a ceramic fixing member 120.

[0076] Specifically, the MOCVD device further comprises the ceramic fixing member 120 and a hollow groove 163; and the ceramic fixing member 120 is uniformly dispersed on the inner wall of the hollow groove 163, and is used to fix the induction coil 161. Further, the ceramic fixing member 120 usually needs to have corrosion resistance, high purity and high density, and good thermal stability. Therefore, the ceramic fixing member 120 can be made of high-purity alumina ceramic, aluminum nitride ceramic, silicon carbide ceramic, etc. In the present embodiment, the ceramic fixing member 120 is preferably made of high-purity alumina ceramic fixing member.

[0077] Refer to Figure 2 The MOCVD device further comprises an isolation ring 110. In order to protect the inner wall of the reaction chamber 100, the isolation ring 110 is located around the sample table 140, and is easily disassembled to ensure that it can be disassembled and cleaned during normal maintenance.

[0078] In summary, the utility model provides a kind of MOCVD device, including reaction chamber, sample stage, lifting mechanism, induction coil and plasma generating device;Sample stage is located in reaction chamber, and periphery is equipped with edge ring;Lifting mechanism is connected with edge ring, can adjust the up and down displacement of edge ring;Plasma generating device is used to generate longitudinal plasma, and induction coil is arranged in edge ring, and then provide magnetic field to adjust the movement state of charged particle, increase the horizontal component of charged particle, to improve the sidewall processing effect of plasma in wafer, also reduced the damage to bottom due to high particle energy in vertical direction;At the same time, the relative motion of induction coil position relative to wafer horizontal plane can occur, and the magnetic induction line direction of corresponding wafer surface middle and edge area changes, changes the movement trajectory of charged particle in wafer middle and horizontal position, further improves the uniformity of wafer film quality.The utility model effectively overcomes the shortcomings in the prior art and has high industrial utilization value.

[0079] The above embodiments only exemplarily illustrate the principles and effects of the utility model, and are not used to limit the utility model. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the utility model should be covered by the claims of the utility model.

Claims

1. A MOCVD apparatus, characterized by comprising: The MOCVD device comprises: a reaction chamber; a sample stage located in the reaction chamber and provided with a flange ring around the periphery of the sample stage; a lifting mechanism connected with the flange ring, which is used to adjust the up-and-down displacement of the flange ring; an induction coil arranged in the flange ring, which is used to provide a magnetic field to adjust the movement state of charged particles; a plasma generating device comprising a radio frequency power supply and an adapter, and the adapter is connected with a showerhead device.

2. The MOCVD apparatus according to claim 1, wherein: The flange ring is in an inverted L shape, and the sample stage is provided with a step corresponding to the flange ring.

3. The MOCVD apparatus according to claim 2, wherein: The lifting rod of the lifting mechanism penetrates the sample stage and is connected with the flange ring.

4. The MOCVD apparatus according to claim 2, wherein: The step height of the sample stage is h0, the distance between the horizontal part of the flange ring and the step position is h1, and h1≤h0.

5. The MOCVD apparatus of claim 1, wherein: The induction coil is arranged in the flange ring in a ring shape; or the induction coils are arranged in the flange ring in a spaced manner.

6. The MOCVD apparatus of claim 1, wherein: There are N>1 lifting mechanisms, and the N lifting mechanisms are distributed in a ring shape at equal intervals.

7. The MOCVD apparatus of claim 1, wherein: The fixing member between the induction coil and the flange ring is a ceramic fixing member.

8. The MOCVD apparatus of claim 1, wherein: The MOCVD device comprises a controller, and the lifting mechanism communicates with the controller.

9. The MOCVD apparatus of claim 8, wherein: The communication mode between the lifting mechanism and the controller comprises wired communication and / or wireless communication; the driving member of the lifting mechanism comprises a servo motor or a stepping motor.

10. The MOCVD apparatus of claim 1, wherein: The induction coil is connected with a power supply, and the power supply comprises an alternating current power supply and / or a direct current power supply.

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