CN116875961A

CN116875961A - Atomic layer deposition apparatus

Info

Publication number: CN116875961A
Application number: CN202311118197.4A
Authority: CN
Inventors: 王良栋; 龙风琴; 陈金良
Original assignee: Shanghai Betone Semiconductor Energy Technology Co ltd
Current assignee: Shanghai Betone Semiconductor Energy Technology Co ltd
Priority date: 2023-09-01
Filing date: 2023-09-01
Publication date: 2023-10-13

Abstract

The application provides an atomic layer deposition device, which comprises a deposition chamber and a gas supply device; the deposition chamber comprises a base, a substrate and a sealing cover plate; the substrate is arranged above the base, a spacing space between the base and the substrate is a deposition space, and two opposite ends of the deposition space are provided with an air inlet and an air outlet; the sealing cover plate is positioned above the substrate, the bottom surface is provided with an air groove with an opening facing the substrate, and the air groove surrounds the periphery of the deposition space; the gas supply device comprises an inert gas channel and a plurality of reaction gas channels, one end of the inert gas channel is respectively communicated with different reaction gas sources, and the other end of the inert gas channel is communicated with the deposition space; the inert gas channel both ends are linked together with the gas groove of inert gas source and sealed apron respectively, and inert gas's pressure is greater than the reaction gas pressure, and inert gas channel is provided with the opening to form the gas pressurize wall from this, in order to keep apart different reaction gas channels each other. The application is beneficial to improving the deposition uniformity and reducing the equipment maintenance cost.

Description

Atomic layer deposition apparatus

Technical Field

The application relates to the technical field of semiconductor manufacturing, in particular to semiconductor equipment, and in particular relates to atomic layer deposition equipment.

Background

Atomic layer deposition (Atomic Layer Deposition, ALD for short) refers to a method of forming a thin film by selectively pulsing two or more vapor phase chemical reaction precursors alternately into a reaction chamber and performing a vapor-solid phase chemisorption reaction on the surface of a deposition substrate. ALD techniques can deposit the desired material layer by layer on the substrate surface in the form of monoatomic films. Compared to chemical vapor deposition (Chemical Vapor Deposition, CVD) techniques, ALD techniques require that alternating pulse precursors be strictly performed. And extra reactants and byproducts in the reaction cavity are required to be purged by inert gas between precursor pulses, so that the problem that the precursor and the reaction gas are contacted in advance at the periphery of the reaction cavity to generate chemical compound particles in a CVD reaction, and accumulated in a gas injection pipeline to cause pipeline blockage is avoided. In addition, the gas pulse during the inert gas purging step may blow dust particles accumulated in the gas injection line into the reaction chamber, contaminating the substrates being produced, and causing product defects.

An ALD reaction chamber device and an ALD film plating device are provided in the patent application with publication number CN116103640A, wherein independent gas injection channels are arranged in the device, and precursor and reaction gas are in the independent channels and cannot react with each other before entering the reaction chamber, so that the generation of sediment generated by the reaction of the two gases is avoided from blocking a pipeline. In the ALD reaction cavity device, a gas collecting plate in a gas homogenizing unit and a gas injection piece in a gas injection unit are connected in a sealing manner through a mounting plate. In the prior art, the sealing part is usually sealed by sealing the mounting plate and the gas collecting plate in an isolated manner by using a perfluoro ether (FFKM) rubber sealing ring so as to ensure that two independent gas injection channels are formed at the gas inlet. However, the reaction temperature in the thermal ALD process is far higher than the highest temperature 327 ℃ which can be borne by the perfluoroether O-shaped rubber sealing ring (the current highest international technical level value), which can cause the O-shaped sealing ring to have high-temperature carbonization spalling phenomenon, so that the sealing effect between the mounting plate and the gas collecting plate can not be achieved, and the fallen particles are loaded into the reaction chamber by the reaction gas or the purge gas to pollute the substrate.

Furthermore, the substrate and the cover plate of the ALD deposition chamber in CN116103640a are sealed with a metal body. In the actual use process, as the surfaces of the two metal precision workpieces have certain roughness, the reaction gas has trace leakage, the reaction temperature in the thermal ALD is very high, and the contact gap is further enlarged due to thermal expansion after the metal materials are baked at high temperature for a long time, so that the air pressure difference between the inside and the outside of the chamber is increased, and the leakage of the reaction gas into the outside of the chamber is aggravated. The reaction gas accumulated outside cannot be discharged in a short time through a certain pulse purge gas, so that the film growth uniformity in the internal reaction cavity is affected, meanwhile, the leaked reaction gas is adsorbed on the outer cavity wall, and after long-time accumulation, the reaction gas can react outside the reaction cavity to generate sediment, so that the environment in the cavity is polluted.

Accordingly, there is a need to provide an improved solution based on the above-described shortcomings of ALD apparatus.

It should be noted that the foregoing description of the background art is only for the purpose of providing a clear and complete description of the technical solution of the present application and is presented for the convenience of understanding by those skilled in the art. The above-described solutions are not considered to be known to the person skilled in the art simply because they are set forth in the background of the application section.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present application is to provide an atomic layer deposition apparatus, which is used for solving the problems that in the prior art, a gas homogenizing unit of the atomic layer deposition apparatus adopts a perfluoroether O-shaped rubber ring to seal, and a metal body is used to seal between a substrate and a cover plate of a deposition chamber, so that ageing of a sealing member and/or gaps at sealing positions occur in a long-term high-temperature environment, resulting in reduced sealing performance and/or particle pollution of the apparatus.

To achieve the above and other related objects, the present application provides an atomic layer deposition apparatus including a deposition chamber and a gas supply device; the deposition chamber comprises a base, a substrate and a sealing cover plate; the substrate is arranged above the base, an interval space between the base and the substrate is a deposition space, and an air inlet and an air outlet are arranged at the opposite ends of the deposition space; the sealing cover plate is positioned above the substrate, the bottom surface of the sealing cover plate is provided with an air groove with an opening facing the substrate, and the air groove surrounds the periphery of the deposition space; the gas supply device comprises an inert gas channel and a plurality of reaction gas channels, one ends of the reaction gas channels are respectively communicated with different reaction gas sources, and the other ends of the reaction gas channels are communicated with the deposition space through gas inlets of the deposition chamber; the inert gas channel both ends are linked together with the gas groove of inert gas source and sealed apron respectively, and inert gas's pressure is greater than the reaction gas pressure, and inert gas channel is provided with the opening along length direction, from this at inert gas's flow path formation gas pressurize wall to keep apart different reaction gas channels each other.

Optionally, the gas supply device includes that the direction that is away from one side of deposition chamber laminating in proper order sets up transition board, even gas board, gas collecting plate and mounting panel, all is provided with a plurality of inlet channel on each board, and the inlet channel of each board corresponds the intercommunication and constitutes inert gas passageway and a plurality of reaction gas passageway, wherein, be provided with on the mounting panel around locating the annular groove of each reaction gas passageway circumference, the recess is linked together with the inert gas source and the opening surface of recess is covered by the gas collecting plate and becomes a part of inert gas passageway.

Optionally, a plurality of equipressure cavities and gas collecting ports are arranged on the gas collecting plate at intervals, each equipressure cavity extends along a first direction, one side of each equipressure cavity adjacent to the gas collecting plate is in an opening shape, one end of each gas collecting port is correspondingly communicated with a reaction gas inlet channel on the mounting plate, the other end of each gas collecting port is communicated with the corresponding equipressure cavity, a plurality of rows of gas homogenizing holes are arranged on the gas collecting plate at intervals along the direction of the parallel equipressure cavity, and each row of gas homogenizing holes is correspondingly communicated with each equipressure cavity so as to horizontally supply reaction gas into the deposition space along a second direction; the first direction and the second direction are perpendicular to each other and are all parallel to the horizontal plane of the substrate.

Optionally, the transition plate, the gas homogenizing plate, the gas collecting plate and the mounting plate are all metal plates, and the atomic layer deposition equipment further comprises a heating device connected with the gas supply device.

Optionally, the atomic layer deposition apparatus further comprises a lifting device connected with the base and/or the sealing cover plate.

Optionally, a groove for accommodating the substrate is arranged in the center of the base.

Optionally, an inert gas pipeline for connecting the inert gas source and the inert gas channel of the gas supply device is provided with a gas mass flow controller, a pressure sensor and pneumatic valves positioned at one end or two ends of the gas mass flow controller.

Optionally, the inlet and the outlet of the deposition chamber are located at the same height.

Optionally, a heating device is arranged at the bottom of the base.

Optionally, the atomic layer deposition apparatus further includes an external chamber, the deposition chamber and the gas supply device are located in the external chamber, an exhaust port communicated with the vacuum pump and a passage port for transferring the substrate are disposed on the external chamber, and the exhaust port of the deposition chamber is correspondingly communicated with the exhaust port of the external chamber up and down.

As described above, the atomic layer deposition apparatus of the present application has the following advantageous effects: according to the atomic layer deposition equipment disclosed by the application, through the improved structural design, the inert gas channels are arranged between different reaction gas source channels and between the deposition chamber and the sealing cover plate, and the inert gas with the pressure larger than that of the reaction gas is introduced, so that the precursor gases in the different channels are well separated, the precursor gases are prevented from reacting before entering the deposition chamber, and the precursor gases and the reaction gases are prevented from reacting in the channels to generate sediments to block the pipeline. Meanwhile, the formed gas wall ensures that chemical reaction is carried out in the inner reaction cavity, so that the equipment maintenance cost is reduced. The uniformity of the film is improved by an order of magnitude without increasing the reaction step time of the atomic layer deposition sequence.

Drawings

Fig. 1 is a schematic cross-sectional view showing an atomic layer deposition apparatus according to the present application.

Fig. 2 is a schematic diagram showing a positional relationship of each gas channel of a gas inlet device of an atomic layer deposition apparatus according to the present application.

Fig. 3 is an exemplary perspective view showing a gas collecting plate of an atomic layer deposition apparatus according to the present application.

Fig. 4 is a top view of a reaction chamber upper cover plate of an atomic layer deposition apparatus according to the present application.

Fig. 5 is a graph showing a comparison of uniformity of a thin film obtained by performing thin film deposition under the same conditions using a conventional apparatus and an atomic layer deposition apparatus provided by the present application.

Fig. 6 is a graph showing the comparison of the number of contaminant particles on the surface of a wafer obtained by thin film deposition under the same conditions using the conventional apparatus and the atomic layer deposition apparatus provided by the present application.

Detailed Description

Other advantages and effects of the present application will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present application with reference to specific examples. The application may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present application. As described in detail in the embodiments of the present application, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of explanation, and the schematic drawings are only examples, which should not limit the scope of the present application. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.

For ease of description, spatially relative terms such as "under", "below", "beneath", "above", "upper" and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Furthermore, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers or one or more intervening layers may also be present.

In the context of the present application, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, as well as embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present application by way of illustration, and only the components related to the present application are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex. In order to make the illustration as concise as possible, not all structures are labeled in the drawings.

In the existing atomic layer deposition equipment, different structures are sealed by adopting a sealing ring or a metal body. Both sealing modes have different problems, and long-term use of the sealing modes can lead to problems of reduced sealing performance of equipment, particle pollution and the like. In this regard, the present application proposes an improvement scheme.

In particular, the present application provides an atomic layer deposition apparatus having a structure as described with reference to fig. 1 to 4, which includes a deposition chamber and a gas supply device in communication with the deposition chamber. The gas supply device is communicated with a gas source and is used for supplying reaction source gas and inert gas into the deposition chamber.

The deposition chamber includes a pedestal 402, a substrate 304, and a sealing cover plate 301. The susceptor 402 is used to carry a substrate 400 to be deposited. The substrate 400 is, for example, a silicon wafer, but not limited thereto, and may be, for example, a wafer made of another material, and the shape of the substrate 400 is not limited to a circular shape, but may be other structures such as a square shape. It is important that the pedestal 402 topography match the substrate 400 topography. The substrate 304 is positioned above a pedestal 402. The space portion between the susceptor 402 and the substrate 304 constitutes a deposition space 102 where thin film deposition is performed, and opposite ends of the deposition space 102 are provided with an air inlet and an air outlet. That is, the pedestals 402 and the substrate 304 are spaced apart and the spacing is not exactly uniform in each region. The spacing between the two is typically maximized in the area corresponding to where the substrate 304 is placed, and the inlet and outlet may also be defined by a gap between the pedestal 402 and the substrate 304 (or the inlet and/or outlet may also be an opening provided in the pedestal 402 and/or the substrate 304), the longitudinal dimension of which is preferably smaller than the longitudinal dimension of the deposition space 102. The longitudinal dimension of the deposition space 102, i.e., the height of the largest region of the substrate 304 and pedestal 402, is preferably 0.5cm to 1.5cm, and the spacing is adjustable. Such as by lifting and lowering the substrate 304 and/or the pedestal 402.

In a preferred example, the center of the base plate 304 is provided with an upwardly concave groove. And preferably, the region of the pedestal 402 corresponding to the recess of the substrate 304 is also provided with a recess recessed downward, and the substrate 400 is placed in the recess of the pedestal 402. In other examples, substrate 400 may be secured to base 402 by some means of securing. For example, by a vacuum suction device, or by providing an edge pressure ring over the edge of the substrate 400 to press against the substrate 400. The grooves of the substrate 304 and the grooves of the susceptor 402 correspond up and down and together with a gap therebetween constitute the deposition space 102. That is, the pedestal 402 is relatively upwardly convex about the circumference of its recess, forming a sidewall around the substrate 400, and the annular sidewall of the pedestal 402 is preferably spaced from the substrate 400 by, for example, 0.5cm-1cm. This spacing facilitates the mounting and dismounting of the substrate 400. In some examples, an inert gas may also be introduced into the annular space between the substrate 400 and the pedestal 402, but the inert gas flow rate should not be excessive. The inert gas may provide some protection to the sidewalls of the substrate 400, such as helping to prevent the sides and bottom of the substrate 400 from being deposited. Or the inert gas can be heated, or a heater is additionally arranged in the annular space to heat the edge of the substrate 400, so that the problem that the heat at the edge of the substrate 400 is relatively easier to dissipate is solved, and the deposition uniformity is improved.

The sealing cover 301 is located above the base 304, and the sealing cover 301 is typically movable, e.g. at least up and down. The bottom surface of the sealing cover plate 301 is provided with an air groove 302 with an opening facing the substrate 304, and the air groove 302 surrounds the deposition space 102 (as shown in fig. 4). That is, the air groove 302 is an annular groove, and the central area of the air groove corresponds to the deposition space vertically. The number of air slots 302 may be single, the width of the air slots 302 is preferably 1cm-1.5cm, and the air slot pitch diameter is greater than the base pitch diameter, and the depth of the air slots 302 may be relatively small, such as within 1cm. In further examples, the air grooves may be more than 2 arranged in parallel spaced apart relation, thereby forming a multi-layered air curtain in the longitudinal direction, which helps to further enhance the sealing and insulating effect.

The gas supply device comprises an inert gas channel and a plurality of reaction gas channels. One end of each of the plurality of reactant gas channels is in communication with a different reactant gas source (particularly, the mutually reactive gases must be delivered through different channels), and the other end is in communication with the deposition space 102 via gas inlets in the deposition chamber walls. For example, the number of the reaction gas channels is 2, and the reaction gases which react with each other are supplied through different reaction gas channels. It should be noted that, most of the reaction gases used in the atomic layer deposition are evaporated from solid and/or liquid reaction sources, and the fluidity is relatively weak, so that in order to avoid sedimentation and/or recombination of molecules during the process of transferring the reaction gases, the reaction source materials are generally dispersed in a carrier gas for conveying in order to improve the diffusion uniformity. The carrier gas is a gas that does not react with the reaction source material, and more commonly used are nitrogen, argon and helium. The reaction gas mentioned in this embodiment is thus typically a mixed gas comprising a carrier gas and a reaction source material gas. The respective reactant gases typically complete their respective mixing with the carrier gas prior to entering the gas supply. In some examples, the inert gas may be separately re-introduced into the reaction gas channel to be re-mixed, thereby improving the dispersion uniformity of the reaction gas and ensuring that sufficient power is supplied to the deposition space 102.

The inert gas channel is connected at both ends to the inert gas source and the gas groove 302 of the sealing cover 301, respectively, and the inert gas is supplied at a pressure greater than the pressure of the reactive gas, and is provided with an opening along its length direction, for example, parallel to the reactive gas channel on the gas supply device, thereby forming a gas pressure maintaining wall in the flow path of the inert gas to isolate the different reactive gas channels from each other.

When the atomic layer deposition device provided in this embodiment is used for thin film deposition, different reaction source materials are conveyed to the deposition space 102 through different reaction gas channels, inert gas is introduced and the pressure of the inert gas is adjusted, so that the inert gas diffuses between the reaction gases along the inert gas channels between the reaction gas channels and enters the gas groove 302 of the sealing cover plate 301 through the gas inlet arranged on the deposition chamber, and therefore an inert gas pressure maintaining wall is formed between the different reaction gas channels and between the sealing cover plate 301 and the deposition space 102. The inert gases distributed among different reaction gas channels isolate different reaction gases from each other, so that the different reaction gases are prevented from reacting with each other when entering the deposition chamber, and the whole gas supply device is isolated from the external air; the inert gas between the sealing cover plate 301 and the deposition space 102 also isolates the deposition space 102 from the external environment, so that the gas in the reaction chamber is prevented from leaking outwards, and the external air is prevented from penetrating into the reaction chamber, so that the sealing performance of the equipment is greatly improved, the cleanliness of the equipment and the uniformity and stability of the deposition environment are improved, and the uniformity of thin film deposition is improved. Meanwhile, the application adopts inert gas to carry out isolation sealing, and the inside of the gas supply device can be free from sealing devices such as a sealing ring and the like, thereby being beneficial to reducing the maintenance cost of equipment.

In addition, using the atomic layer deposition apparatus of the present application, different reactant gases are preferably cyclically and alternately delivered to the deposition space 102 in a pulsed manner. And after the previous reaction gas is supplied for a preset period of time, inert gas is introduced into the deposition space 102 for purging, so as to sweep out the residual previous reaction gas, then another reaction gas for a preset period of time is introduced, and then inert gas is introduced for purging, so that the thin film with the required thickness is deposited on the surface of the substrate 400 in a sequential cycle. Inert gas as the purge gas may be introduced through the first reaction gas passage and/or the second gas passage, or may be introduced through a purge gas passage separately provided, without being strictly limited thereto.

The structure of the air supply device of the atomic layer deposition equipment provided by the application can be flexibly arranged according to the needs, or the atomic layer deposition equipment is suitable for atomic layer deposition in various air supply modes. For example, for a common top air supply. But in contrast, the present application is more suitable for side air supply. That is, the air supply device is arranged at one side of the reaction chamber and is communicated with the air inlet arranged at the same side of the deposition chamber.

In a preferred example provided by the application, the gas supply device comprises a transition plate 704, a gas homogenizing plate 703, a gas collecting plate 702 and a mounting plate 701 which are sequentially attached along a direction away from one side of the deposition chamber, wherein a plurality of gas inlet channels are arranged on each plate, and the gas inlet channels of each plate are correspondingly communicated to form an inert gas channel and a plurality of reaction gas channels. The mounting plate 701 is provided with an annular groove around the circumference of each reactant gas channel, and the groove may be a U-shaped groove or a rectangular groove. The recess communicates with an inert gas source and the open face of the recess is covered by a gas collection plate 702 to become part of the inert gas channel. That is, the inert gas channels on the mounting plate 701 are the annular grooves, the opening surfaces of the grooves are the surfaces adjacent to the gas collecting plate 702, and the inert gas channels on the other plates are the corresponding air holes penetrating each plate, and the air holes of the adjacent plates are correspondingly bonded to form the reaction gas flow passages. In the gas supply device with this structure, the mounting plate 701 mainly plays a role in tightly connecting the gas supply device with an external gas supply module, and the gas collecting plate 702 converges different reaction gases respectively, and then uniformly disperses different reaction gas flows converged in the gas collecting plate 702 again through different gas homogenizing holes on the gas homogenizing plate 703. Therefore, the matching of the gas collecting plate 702 and the gas homogenizing plate 703 can solve the problem of channel blockage caused by reaction when gases are mixed in a transmission pipeline in atomic layer deposition. While the transition plate 704 serves primarily to seal the supply to the deposition chamber. The 4 plates are independent and detachable, so that the equipment is convenient to maintain and clean. The gas is supplied through the cooperation of the plates and is supplied through the gas inlet located at the same side of the chamber, while the reactive gas is guided to uniformly diffuse into the deposition chamber in the horizontal direction by the suction force provided through the gas outlet located at the opposite side of the gas inlet, and finally deposited on the surface of the substrate 400. That is, the Cross Flow Type air supply is adopted in this embodiment. And in this embodiment, the inlet and outlet of the deposition chamber are preferably positioned at the same level so that the reactant gases can be sufficiently dispersed over the surface of the substrate 400.

The atomic layer deposition process is to alternately introduce a precursor reaction source and an inert gas into a reaction chamber in sequence, perform sequential reaction by the reaction source and purge residual gas by the inert gas, and deposit an atomic layer laminated film by using the principle of chemisorption and desorption, so that the atomic layer laminated film has the characteristics of self-limitation and self-saturation, and therefore, the gas molecules need to be controlled to keep a molecular flow state and enter a deposition chamber, and the gas flows through the surface of a substrate 400 (wafer) to perform chemisorption reaction, so that the leakage of the cavity is required to be ensured. The application forms the gas partition wall around the deposition space 102 by the inert gas, thereby avoiding the change of the diffusion path caused by the leakage of the reaction gas and being beneficial to improving the deposition uniformity.

Referring to fig. 2, two circular holes spaced apart from each other on the mounting plate 701 are a first reaction gas channel 7012 and a second reaction gas channel 7013, respectively, and a groove 7011 surrounding the first reaction gas channel 7012 and the second reaction gas channel 7013 is an inert gas channel. As an example, the width of the groove between the first and second reaction gas passages 7012 and 7013 may be larger than that of the other region, or each reaction gas passage may be surrounded by a separate annular groove (which may communicate with each other) so that there are two inert gas passages in parallel with each other between the first and second reaction gas passages 7012 and 7013, which may enhance the separation effect. Since the opening is formed on one side of the groove 7011, and the pressure of the inert gas in the groove 7011 is relatively high, after the opening of the groove 7011 is covered by the adjacent gas collecting plate 702, the inert gas in the groove 7011 completely surrounds different reaction gas channels under the action of the gas pressure, so that the separation is realized. Of course, the inert gas pressure should not be too high or too low to provide isolation, and too high may affect the proper supply of the reactant gas (e.g., may blow off the reactant gas flow). Preferably, the inert gas pressure and the reaction gas pressure ratio are controlled within 1.1.

In one example, for ease of management, multiple inlet lines for different reactant gases are integrated into a gas multi-manifold module 501 located outside the deposition chamber, the gas multi-manifold module 501 being in corresponding communication with reactant gas channels on the mounting plate 701 through multiple gas channels 502. The gas channel 502 typically employs a metal tube with a protective coating inside. In some examples, the gas channel 502 may employ a bellows.

In some examples, an inert gas source (e.g., a nitrogen source) is in communication with the inert gas channel of the gas supply via an inert gas line 601 at the bottom of the gas supply, such that inert gas is supplied into the inert gas channel of the gas supply from bottom to top, and inert gas is supplied into the recess 7011 of the mounting plate 701. To ensure that the inert gas maintains the desired pressure, a gas mass flow controller 603, a pressure sensor 605, and pneumatic valves at one or both ends of the gas mass flow controller 603 are provided on the inert gas line to precisely control the gas flow. Pneumatic valve 602 and pneumatic valve 604 are preferably provided at both ends of gas mass flow controller 603, respectively. In a further example, the pressure sensor and the pneumatic valve may be connected to a controller to adjust the opening and closing of the pneumatic valve according to the measurement result of the pressure sensor, and in combination with the measurement result of the gas mass flow controller 603 and the pressure sensor 605, adjust the gas flow in the inert gas channel 601 in time. The controller may be, for example, a control device such as a PLC controller or a host computer, and may be a control end of the entire apparatus, or the flow rate of the reaction source gas may be controlled by the controller (or the flow rate of each gas may be controlled uniformly by the overall controller of the apparatus).

In the preferred embodiment, transition plate 704, gas distribution plate 703, gas collection plate 702 and mounting plate 701 are all metal plates, such as stainless steel plates. The metal plates made of stainless steel not only enable each plate to have good mechanical strength and be convenient to process and shape, but also can bear certain deformation, and enable each plate to have good heat conduction performance. In order to avoid sedimentation and/or recondensing of the reaction gases in the transport path due to temperature drops, the atomic layer deposition apparatus may further be provided with a heating device connected to the gas supply device. The heating means are for example heating resistance wires arranged on at least one of the plates, the resistance wires for example being embedded in one or more of the plates. Or in other examples, the reaction gas may also be heated indirectly by heating the inert gas.

To further improve the uniformity of the distribution of the reaction gas, in an example, as shown in fig. 3, the gas collecting plate 702 is provided with a plurality of isopiestic chambers and gas collecting ports, which are arranged at intervals, and each isopiestic chamber extends along the first direction, so that the length of the isopiestic chamber is as close to the length of the substrate 400 in the direction parallel to the isopiestic chamber as possible. For example, the length of the isopipe is the same as the wafer diameter. The depth and width of the isopipe are as desired, for example 1-2cm. The cross section of the isostatic cavity can be rectangular or U-shaped, and the dimensions of the isostatic cavity can be completely consistent throughout. In other examples, the isopipe may be provided with a structure having a larger size at both ends than at the middle section. One side of the equipressure cavity adjacent to the equipressure plate 703 is in an opening shape, one end of each gas collecting port is correspondingly communicated with a reaction gas inlet channel on the mounting plate 701, the other end of each gas collecting port is communicated with the corresponding equipressure cavity, a plurality of rows of air homogenizing holes are arranged on the equipressure plate 703 at intervals along the direction of the parallel equipressure cavity, and each row of air homogenizing holes is correspondingly communicated with each equipressure cavity so as to horizontally supply the reaction gas into the deposition space 102 along the second direction; wherein the first direction and the second direction are perpendicular to each other and are all directions parallel to the horizontal plane of the substrate 400. For example, the number of the isostatic chambers is two, namely a first isostatic chamber 7021 for carrying a first reaction gas and a second isostatic chamber 7022 for carrying a second reaction gas, the first gas collecting port 7023 is communicated with the first isostatic chamber 7021, and the second gas collecting port 7024 is communicated with the second isostatic chamber 7022. The aperture of the gas collecting port is, for example, 0.5cm-1cm. The pore diameter of the air holes in the air distribution plate 703 is, for example, 0.1cm to 1cm, and the distance between the air holes is, for example, 0.5cm to 1cm. Inert gas passes through the gas collecting plate 702, the gas distributing plate 703, the transition plate 704 and the substrate 304 of the deposition chamber in sequence until being delivered to the gas groove 302 of the sealing cover plate 301, and the flow channel 303 thereof can be shown with reference to fig. 1. The reaction gas is sequentially delivered to the deposition space 102 through the mounting plate 701, the gas collecting plate 702, the gas distributing plate 703, the transition plate 704 and the gas inlet on the deposition chamber, and the residual gas and the reaction by-products are discharged through the gas outlet on the other end of the gas inlet, and the flow channel 705 in the reaction chamber and the flow channel 502 on the outside can be also referred to as shown in fig. 1. Also illustrated in fig. 1 are a first reactant gas channel 503 and a second reactant gas channel 504, respectively.

In some examples, the atomic layer deposition apparatus further includes a lifting device coupled to the pedestal 402 and/or the sealing cover plate 301. Such as in fig. 1, the pedestal 402 is connected at its bottom to a lifting support 405 that extends outside the deposition chamber and at its bottom to a lifting power structure 403, such as a cylinder. The lifting support 405 may be internally configured as a channel 404 for receiving a source wire such as an electrical wire. By driving the susceptor 402 to rise and fall, the distance of the substrate 400 in the longitudinal direction compared with the reactive gas can be changed, so that the distribution of the reactive gas on the surface of the substrate 400 can be adjusted as required, which contributes to the improvement of deposition uniformity. At the same time, lifting and lowering the susceptor 402 also facilitates moving the substrate 400 into and out of the deposition chamber. In other examples, a rotation drive structure coupled to the pedestal 402 may also be provided, such as a lift post on a turntable, to rotate the substrate 400 as desired, which also helps to improve deposition uniformity. In other examples, a driving means for driving the susceptor 402 to move horizontally may be provided, for example, a lifting support is provided on a guide rail, so that the susceptor 402 may be moved horizontally as needed, thereby changing the horizontal distance of the substrate 400 with respect to the reactive gas inlet port, which may also adjust the distribution of the reactive gas on the surface of the substrate 400, contributing to the improvement of deposition uniformity. Preferably, a plurality of power structures capable of driving the susceptor 402 to move up and down, rotate and horizontally may be simultaneously provided to flexibly adjust the position of the substrate 400 with respect to the air inlet as needed, thereby improving deposition uniformity.

In further examples, a lifting device may be provided in connection with the sealing cover plate 301 to cover or remove the sealing cover plate 301 from the deposition chamber, thereby releasing a gas retaining wall around the deposition chamber and also facilitating maintenance of the chamber. In addition, a horizontal moving device connected to the sealing cover 301 may be provided to more flexibly adjust the positions of the respective structures.

Preferably, lifting means connected to the base 402 and the sealing cover 301 may be provided, respectively.

In some examples, the base 402 is provided at its bottom with a heating device 401, the heating device 401 being disposed, for example, within the aforementioned lifting column. The heating means may be a resistive heater. In further examples, the heating device may also be other types of heaters, such as halogen lamp heaters. In the case of a halogen lamp heater, the susceptor 402 may be a transparent quartz disk with halogen lamps disposed at the bottom of the quartz disk recess to heat the substrate 400. Another advantage of using a transparent quartz disk as the pedestal 402 is that the thickness of the thin film deposited on the substrate 400 can be measured at the bottom of the pedestal 402 using an optical measurement device to adjust the deposition conditions in various areas of the substrate 400 according to the thickness profile, for example, to keep the thin film area as close to the gas inlet as possible. Since the temperature of the substrate 400 has a great influence on the thickness of the deposited film during the film deposition process, the film deposition condition can be improved by adjusting the heating temperature of each region of the substrate 400. For example, when heating with halogen lamps, the number of halogen lamps may be relatively increased and/or the heating power may be increased for substrates 400 relatively far from the gas inlet region, while other deposited films may be relatively thicker to relatively decrease the heating power and/or reduce the heater distribution. In other examples, cooling devices, such as water and/or air cooled lines, may also be provided at the bottom of the pedestal 402 to cool the substrate 400 when desired.

Most of the existing deposition apparatus are single-layer chamber. In a preferred embodiment of the present application, the atomic layer deposition apparatus further includes an external chamber 101, wherein the deposition chamber and the gas supply device are disposed in the external chamber 101 (or the deposition chamber is disposed in the external chamber 201, so that the deposition chamber may also be referred to as an inner cavity), and the external chamber 101 is provided with an exhaust port in communication with the vacuum pump 201 and a passage port 104 for transferring the substrate 400, and the exhaust port of the deposition chamber is correspondingly in up-down communication with the exhaust port of the external chamber 101, so that the residual gas and the reaction by-products 203 in the deposition space 102 are finally exhausted through the exhaust port.

Preferably, a passage port 104 for transferring the substrate 400 is provided at a side wall of the outer chamber 101, and a gate valve 103 is provided at an end of the passage port 104. The exhaust port provided at the bottom of the outer chamber 101 communicates with an outer exhaust line 202, and the other end of the exhaust line 202 communicates with a vacuum pump 201, i.e., the inner and outer chambers share a set of pumping system.

The deposition chamber is disposed within the outer chamber 101, and the deposition chamber is typically provided with different vacuum levels and cleanliness levels inside and outside the deposition chamber. The wafer can be subjected to vacuum environment of the outer cavity and advanced purification treatment before entering the inner cavity, so that wafer damage caused by environmental mutation is avoided, and the production yield is improved.

Of course, in the case of being provided with the inner and outer chambers, when the reaction gas is introduced into the inner chamber, the inner chamber pressure can be higher than the outer chamber, and if the sealing cover plate on the inner chamber can not be perfectly sealed, the gas can leak out of the outer chamber, and a gas turbulence state can be formed at the leaking position, so that the non-uniformity of the deposited film of the wafer is caused. By improving the structure, the gas pressure maintaining wall can effectively avoid the problems and ensure good sealing of the inner cavity and the outer cavity.

To verify the performance of the atomic layer deposition apparatus of the present application, the inventors conducted a number of experiments. The experimental contents include the case that other conditions such as gas flow rate, substrate heating temperature, etc. are the same, and the thin film deposition with the same film thickness is performed by using the present application as the existing atomic layer deposition apparatus. The results of the brief experiments are shown in fig. 5 and 6. Fig. 5 and fig. 6 are respectively a comparative graph of wafer film uniformity (standard deviation uniformity) and wafer surface contaminant particle number (> 65 nm) obtained by using the conventional atomic layer deposition apparatus and the atomic layer deposition apparatus with the gas pressure-maintaining sealing structure provided by the present application. As can be seen from the figure, the atomic layer deposition using the apparatus of the present application improves wafer film uniformity by one order of magnitude and reduces the number of particles on the wafer surface by more than 65 a nm by two orders of magnitude compared to the prior art.

In summary, according to the atomic layer deposition device disclosed by the application, through the improved structural design, the inert gas channels are arranged between different reaction gas source channels and between the deposition chamber and the sealing cover plate, and the inert gas with the pressure larger than that of the reaction gas is introduced, so that the precursor gases in the different channels are well separated, the precursor gases are prevented from reacting before entering the deposition chamber, and the precursor gases and the reaction gases are prevented from reacting in the channels to generate sediments to block the pipeline. Meanwhile, the formed gas wall ensures that chemical reaction is carried out in the inner reaction cavity, so that the equipment maintenance cost is reduced. The uniformity of the film is improved by an order of magnitude without increasing the reaction step time of the atomic layer deposition sequence. Therefore, the application effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present application and its effectiveness, and are not intended to limit the application. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that all equivalent modifications and variations of the application be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. An atomic layer deposition apparatus, characterized in that the atomic layer deposition apparatus comprises a deposition chamber and a gas supply device; the deposition chamber comprises a base, a substrate and a sealing cover plate; the substrate is arranged above the base, an interval space between the base and the substrate is a deposition space, and an air inlet and an air outlet are arranged at the opposite ends of the deposition space; the sealing cover plate is positioned above the substrate, the bottom surface of the sealing cover plate is provided with an air groove with an opening facing the substrate, and the air groove surrounds the periphery of the deposition space; the gas supply device comprises an inert gas channel and a plurality of reaction gas channels, one ends of the reaction gas channels are respectively communicated with different reaction gas sources, and the other ends of the reaction gas channels are communicated with the deposition space through gas inlets of the deposition chamber; the inert gas channel both ends are linked together with the gas groove of inert gas source and sealed apron respectively, and inert gas's pressure is greater than the reaction gas pressure, and inert gas channel is provided with the opening along length direction, from this at inert gas's flow path formation gas pressurize wall to keep apart different reaction gas channels each other.

2. The atomic layer deposition apparatus according to claim 1, wherein the gas supply device comprises a transition plate, a gas distribution plate, a gas collection plate and a mounting plate, which are sequentially attached to each other in a direction away from one side of the deposition chamber, a plurality of gas inlet passages are provided on each plate, the gas inlet passages of each plate are correspondingly communicated to form an inert gas passage and a plurality of reaction gas passages, wherein an annular groove is provided on the mounting plate around each reaction gas passage, the groove is communicated with an inert gas source, and an opening surface of the groove is covered by the gas collection plate to form a part of the inert gas passage.

3. The atomic layer deposition apparatus according to claim 2, wherein a plurality of equipressure cavities and gas collecting ports are arranged on the gas collecting plate at intervals, each equipressure cavity extends along a first direction, one side of each equipressure cavity adjacent to the gas collecting plate is in an opening shape, one end of each gas collecting port is correspondingly communicated with the reaction gas inlet channel on the mounting plate, the other end of each gas collecting port is communicated with the corresponding equipressure cavity, a plurality of rows of air homogenizing holes are arranged on the gas collecting plate at intervals along the direction parallel to the equipressure cavities, each row of air homogenizing holes is correspondingly communicated with each equipressure cavity, and the reaction gas is horizontally supplied into the deposition space along a second direction; the first direction and the second direction are perpendicular to each other and are all parallel to the horizontal plane of the substrate.

4. The atomic layer deposition apparatus according to claim 2, wherein the transition plate, the gas distribution plate, the gas collection plate, and the mounting plate are all metal plates, and the atomic layer deposition apparatus further comprises a heating device connected to the gas supply device.

5. The atomic layer deposition apparatus according to claim 1, further comprising a lifting device connected to the base and/or the sealing cover plate.

6. The atomic layer deposition apparatus according to claim 1, wherein a recess for receiving a substrate is provided in a center of the susceptor.

7. The atomic layer deposition apparatus according to claim 1, wherein a gas mass flow controller, a pressure sensor, and a pneumatic valve at one or both ends of the gas mass flow controller are provided on an inert gas line connecting an inert gas source and an inert gas passage of the gas supply device.

8. The atomic layer deposition apparatus according to claim 1, wherein the inlet and the outlet of the deposition chamber are located at the same level.

9. The atomic layer deposition apparatus according to claim 1, wherein the susceptor bottom is provided with heating means.

10. The atomic layer deposition apparatus according to any one of claims 1 to 9, further comprising an external chamber, wherein the deposition chamber and the gas supply device are located in the external chamber, and an exhaust port communicating with a vacuum pump and a passage port for transferring a substrate are provided in the external chamber, and the exhaust port of the deposition chamber communicates with the exhaust port of the external chamber vertically.