Method for improving process stability of atomic layer deposition cavity and heated pedestal

Abstract

The application provides a method for improving process stability of an atomic layer deposition cavity and a heating base. The method comprises the following steps: providing a heating base comprising a plurality of independently controlled heating sub-pans, the heating sub-pans being provided with convex points; conveying a substrate above the heating base; adjusting the heating sub-pans respectively to change the height of the convex points protruding from the surface of the heating base, so that the convex points are in contact with the back surface of the substrate; and performing a thin film deposition process on the substrate. By using the modularized heating base with sub-pans capable of independently changing the height of the contact convex points, the actual thermal field distribution can be flexibly and accurately matched, the problem of uneven local heat transfer efficiency of the heating base is effectively improved, the uniformity of the thin film deposition thickness is significantly improved, the overall stability of the atomic layer deposition cavity process is improved, and the equipment maintenance time is reduced.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing, and in particular to a method for improving the stability of atomic layer deposition cavity processes and a heating base. Background Technology

[0002] As semiconductors demand higher step coverage, metal deposition processes have evolved to include not only traditional PVD physical sputtering deposition but also ALD (Atom layer deposition).

[0003] ALD deposition is a chemical reaction, and the heating efficiency of the substrate directly affects the intensity of the chemical reaction, thus affecting the thickness, speed, and uniformity of the film deposition.

[0004] The heating mode of the heating base for the wafer mainly relies on the heat conduction between the bumps on the surface of the heating base and the back of the wafer. The process steps require first grabbing the wafer to the cavity to the pin (ejector pin) position, and then slowly retracting the pin to make the wafer rest on the bumps of the base.

[0005] The existing technology has a fixed height and position of the protrusions, which cannot match the actual heating distribution of the heating base, resulting in poor deposition uniformity and affecting product performance. Summary of the Invention

[0006] The technical problem this invention aims to solve is that, in existing technologies, the height and position of the bumps on the surface of the heating base inside the atomic layer deposition chamber are fixed, which cannot flexibly match the varying thermal field distributions in different areas of the heating base during actual processes. This fixed structure leads to uneven local heat transfer efficiency, resulting in poor uniformity of thin film deposition on the wafer surface, severely affecting the performance of the final semiconductor product and reducing the overall stability of the atomic layer deposition chamber process.

[0007] To achieve the above and other related objectives, the present invention provides a method for improving the stability of atomic layer deposition cavity processes, comprising:

[0008] A heating base is provided, the heating base including multiple independently controlled heating plates, the surface of the heating plates being provided with protrusions;

[0009] The substrate is transferred above the heating base;

[0010] Adjust the heating discs to change the height of the protrusions extending from the surface of the heating base, so that the protrusions contact the back of the base;

[0011] A thin film deposition process is performed on the substrate.

[0012] Preferably, the plurality of heating plates are arranged in a concentric ring structure, including a circular heating plate located in the central region and at least a single-layer outer ring heating plate surrounding the circular heating plate; or, the plurality of heating plates are arranged in a fan-shaped array structure around the center point of the heating base.

[0013] Preferably, the heating plates are arranged in a concentric ring structure, and the heating base includes a first heating plate, a second heating plate, and a third heating plate.

[0014] Preferably, the substrate comprises a wafer.

[0015] Preferably, the base is gripped by a pin and placed in the cavity at a preset position above the heating base, and the pin is slowly retracted so that the base rests on the protrusion of the heating base.

[0016] Preferably, temperature distribution data or film thickness distribution data of the substrate deposition area are obtained, and the corresponding heating disks are independently raised and lowered according to the temperature distribution data or film thickness distribution data to adjust the height of the protrusions in the corresponding areas.

[0017] Preferably, the height of the protrusions on each of the heating discs can be adjusted in a way that does not affect each other.

[0018] To address the aforementioned technical problems, the present invention also provides a heating base for atomic layer deposition, comprising:

[0019] Multiple heating plates are assembled to form a base support surface;

[0020] The protrusions are distributed on the base support surface of each of the heating sub-discs;

[0021] Each of the heating discs can be independently height-adjusted to change the height at which the protrusions on the heating discs abut against the back of the base.

[0022] Preferably, the plurality of heating plates are arranged in a concentric ring structure, including a circular heating plate at the center and at least a single-layer annular heating plate surrounding the circular heating plate.

[0023] Preferably, the plurality of heating discs are arranged in a fan-shaped array structure around the center of the base support surface.

[0024] Preferably, it further includes an independent lifting drive assembly connected to each of the heating sub-plates, the lifting drive assembly being used to drive the corresponding heating sub-plate to move independently in a direction perpendicular to the base support surface.

[0025] As described above, the method and heating base for improving the process stability of atomic layer deposition chambers of the present invention have the following beneficial effects:

[0026] This invention breaks through the physical limitations of traditional single fixed bump bases by introducing a heating base composed of multiple heating discs, achieving localized dynamic adjustment of the height of the surface contact bumps. This design allows the equipment to precisely match the actual temperature field distribution of the base and independently compensate for local heat transfer deviations, effectively improving the problem of uneven heating efficiency of the heating base on the substrate. This not only fundamentally improves the uniformity and thickness consistency of thin film deposition but also provides a wider operating window for complex deposition processes. Furthermore, during routine preventative maintenance, maintenance personnel do not need to spend time grinding the chassis or replacing the entire unit; they can quickly correct process drift simply by adjusting the height using the drive components. This effectively reduces equipment downtime and improves the long-term stability and mass production capacity of atomic layer deposition chamber processes. Attached Figure Description

[0027] Figure 1 The diagram shows a flow chart of the method for improving the stability of atomic layer deposition cavity process according to the present invention.

[0028] Figure 2 The diagram shows the structure of the heating base of the present invention in the grasping position;

[0029] Figure 3 The diagram shows the structure of the heating base of the present invention in the position of the protrusion adjustment point;

[0030] Figure 4 The diagram shows the heating base of the present invention in a process position.

[0031] Figure 5 The diagram shown is a top view of the heating discs of the present invention, which are arranged in a concentric ring structure.

[0032] Figure 6 The diagram shows a comparison of deposition uniformity between embodiments of the present invention and prior art. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] Please refer to Figure 1 A method for improving the stability of atomic layer deposition cavity processes, comprising:

[0035] Step 1: Provide a heating base 101, which includes multiple independently controlled heating discs, and the surface of the heating discs is provided with protrusions 103; In semiconductor manufacturing processes, the heat transfer efficiency in the reaction chamber is directly related to the chemical reaction rate.

[0036] Traditional, single, fixed heating bases often exhibit uneven temperature distribution due to localized differences in heat conduction. By introducing heating discs with multiple independently controllable zones, independent temperature or contact status management can be achieved for different areas. The heating discs can be made of materials such as aluminum nitride, silicon carbide, alumina, or other ceramics and metals with high thermal conductivity and corrosion resistance. (Refer to reference...) Figure 2 The bumps 103 are evenly distributed on the substrate support surface. Their main function is to reduce the direct contact area on the back of the substrate, prevent particle contamination on the back of the wafer, and establish a stable heat conduction path between the substrate and the heating disk.

[0037] In some embodiments, in step one, multiple heating disks are arranged in a concentric ring structure, including a circular heating disk 201 located in the central region and at least a single-layer outer ring heating disk surrounding the circular heating disk 201. The arrangement of the concentric ring structure closely matches the radial symmetry characteristics of the semiconductor substrate during spin deposition or in a gas radial distribution state. The central circular heating disk 201 is typically used to control the temperature of the substrate core region, while the outer ring region is used to compensate for heat loss at the edges due to airflow or radiative heat dissipation, thereby improving the uniformity of the overall temperature distribution.

[0038] In some embodiments, please refer to Figure 5 In step one, the heating base 101 includes a first heating plate 201, a second heating plate 202, and a third heating plate 203. The arrangement of the first heating plate 201, the second heating plate 202, and the third heating plate 203 is not limited to three parts. It can also be expanded to four or five, or more independent areas, depending on the internal space of the actual equipment or the base size, to provide more dimensional process control nodes.

[0039] In some embodiments, in step one, multiple heating plates are arranged in a fan-shaped array around the center point of the heating base 101. The specific arrangement of the heating plates can be flexibly adjusted according to the airflow distribution characteristics or heat conduction laws inside the cavity.

[0040] In some embodiments, in step one, the substrate 104 includes a wafer. Specific types of substrate 104 include, but are not limited to, silicon wafers, silicon-on-insulator wafers, germanium wafers, glass substrates, or other substrates suitable for advanced integrated circuit manufacturing processes.

[0041] Step 2: Transfer the substrate 104 to the heating base 101. The process of transferring the substrate 104 is usually completed by an external robotic arm in conjunction with a lifting mechanism inside the chamber. After the robotic arm sends the substrate 104 into the reaction chamber, the lifting mechanism located below the heating base 101 will take over the substrate 104 and maintain it at the preset process preparation height.

[0042] In some embodiments, in step two, the ejector pin 102 is used to grasp the base 104 to a preset position above the heating base 101 within the cavity, and the ejector pin 102 is slowly retracted, so that the base 104 rests on the protrusion 103 of the heating base 101. Figure 2 As shown in the gripping position, the ejector pin 102 passes upward through the reserved hole in the heating base 101 to perform the gripping operation.

[0043] Step 3: Adjust the heating plates separately to change the height of the protrusion 103 extending out of the surface of the heating base 101, so that the protrusion 103 contacts the back of the base 104;

[0044] like Figure 3 The adjustment position of the protrusions shown, through fine-tuning the internal heating discs, essentially directly adjusts the height of the corresponding protrusion 103 on its surface. Adjusting the height of the protrusion 103 is a key means of changing the local heat transfer efficiency. When the height of the protrusion 103 in a certain area is increased, the distance between the base 104 and the heat source surface of the base changes, thereby adjusting the heat transfer efficiency of that specific area; conversely, decreasing the height of the protrusion 103 will make the base 104 closer to the heated surface, thus enhancing the heat transfer in the corresponding area. Subsequently, as... Figure 4 As shown in the process position, after the height of the protrusions 103 in each area is adjusted to be ready, the ejector pins 102 are slowly retracted, allowing the substrate 104 to descend smoothly and be fully positioned on the protrusions 103 distributed at different heights. Slowly retracting the ejector pins 102 helps prevent the substrate 104 from shifting or sliding during descent, ensuring precise alignment between the center of the substrate 104 and the center of the heating base 101. The ejector pins 102 are typically made of high-temperature resistant quartz or ceramic materials that are less prone to generating microparticles. Precise alignment improves the uniformity of edge venting in subsequent deposition processes, thereby enhancing the stepped coverage of the film in the edge region of the substrate 104.

[0045] In some embodiments, in step three, temperature distribution data or film thickness distribution data of the deposition area of ​​the substrate 104 are acquired, and the corresponding heating plates are independently raised and lowered according to the temperature distribution data or film thickness distribution data to adjust the height of the protrusions 103 in the corresponding areas. The methods for acquiring temperature distribution data or film thickness distribution data include using an in-situ temperature sensor integrated inside the cavity to read a real-time thermal distribution map, or obtaining a film thickness mapping map by performing offline measurements on the previously processed substrate 104. Through this closed-loop feedback control mechanism, the equipment control system can automatically calculate the heat areas that need compensation and send raising and lowering commands to the corresponding heating plates.

[0046] In some embodiments, in step three, the height of the protrusions 103 of each heating plate can be adjusted independently. Figure 3 It can be seen that the independent adjustment mechanism of each disk does not affect each other, ensuring that the compensation action in a local position will not cause cross-interference with the process conditions of the adjacent area, thereby improving the deposition uniformity of the entire substrate 104 surface and the long-term repeatability of the equipment process.

[0047] Please refer to Figure 6 , Figure 6 A comparison chart showing the uniformity of substrate surface deposition (temperature or film thickness thermal distribution) after using existing technology and the method of the embodiments of this application is presented. Figure 6 In the existing technology on the left, which uses a single fixed-height convex point, the distribution diagram cannot flexibly match the actual heat field distribution. This results in obvious localized areas of excessive and insufficient heat transfer on the substrate surface (manifested as a clear contrast between light and dark color blocks and edge aggregation in the distribution diagram), leading to poor overall uniformity. However, by applying the embodiment of this application, the aforementioned differences in heat conduction are effectively compensated for by independently adjusting the height of the heating plates in multiple zones. Figure 6 As shown in the distribution diagram of the embodiment of this application on the right, the extreme distribution deviation areas are effectively eliminated, and the overall distribution diagram is smoother and more uniform in color, which intuitively proves that the method provided by this application effectively improves the global stability and consistency of the atomic layer deposition process on the entire substrate surface.

[0048] Step 4: Perform thin film deposition on substrate 104. Atomic layer deposition (ALD) relies on the alternating chemisorption and self-limiting reaction of precursor and reactive gases on the surface of substrate 104. In high aspect ratio interconnect structures in advanced processes, uniform temperature distribution ensures a highly consistent adsorption rate of the precursor at the bottom and top of trenches or vias, preventing overhangs or internal voids. The flexible and scalable height of the bumps 103 not only applies to the production of films of specific single thicknesses but also provides a wider process operating window for various film stack combinations with different thermal budget requirements.

[0049] In some embodiments, step four, the thin film deposition process includes a metal thin film deposition process. Specifically, the metal thin film deposition process encompasses the formation of conductive layers, work function layers, or barrier layers such as tungsten, titanium, tantalum, ruthenium, molybdenum, titanium nitride, and tantalum nitride. Besides metal thin films, the deposition process can also be applied to the formation of high-dielectric-constant insulating materials such as alumina, hafnium dioxide, and zirconium oxide.

[0050] A heating base 101 for atomic layer deposition includes:

[0051] Multiple heating plates are combined to form a base support surface;

[0052] The protrusions 103 are distributed on the base support surface of each heating plate;

[0053] Each heating plate can be independently height-adjusted to change the height at which the protrusion 103 on the heating plate abuts against the back of the base 104.

[0054] This multi-modal heating base hardware architecture breaks through the physical limitations of traditional single fixed chassis. Tiny thermal isolation gaps can be set between the heating panels to reduce heat conduction interference between adjacent panels. Through configuration such as... Figure 3 The variable-height base shown eliminates the need for equipment maintenance engineers to frequently sand the chassis surface or spend money replacing entire components during routine preventative maintenance. This provides an effective alternative for reducing equipment downtime and increasing overall production line capacity.

[0055] In some embodiments, multiple heating disks are arranged in a concentric ring structure, including a central circular heating disk 201 and at least a single-layer annular heating disks surrounding the circular heating disk 201. For example... Figure 5 As shown, the arrangement of the concentric ring structures matches the radial symmetry characteristics of the semiconductor substrate 104 during the spin deposition process or in a gas radial distribution state. The central circular heating disk 201 is typically used to control the temperature of the core area of ​​the substrate 104, while the outer ring areas such as the second heating disk 202 and the third heating disk 203 are used to compensate for heat loss at the edges due to airflow or radiation.

[0056] In some embodiments, multiple heating disks are arranged in a fan-shaped array around the center of the base support surface. The fan-shaped array arrangement provides a means to solve the temperature drift caused by non-centrosymmetry inside the cavity. For example, the temperature difference caused by the asymmetry of the flow field between the air inlet and the exhaust port can be compensated by adjusting the height of the fan-shaped disks at different azimuth angles.

[0057] In some embodiments, the system further includes independent lifting drive components connected to each heating plate, which drive the corresponding heating plate to move independently in a direction perpendicular to the substrate support surface. These independent lifting drive components include, but are not limited to, stepper motors or servo motors combined with ball screw mechanisms, or precision linear actuation devices such as pneumatic lifting cylinders or piezoelectric actuators. To maintain a high vacuum and clean environment inside the atomic layer deposition reaction chamber, the motion axis of the lifting drive component is typically isolated from the reaction chamber using a metal bellows or magnetohydrodynamic sealing assembly. Process drift can be quickly corrected simply by adjusting the position coordinates of the drive component using software formulation parameters.

[0058] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0059] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for improving the stability of atomic layer deposition cavity processes, characterized in that, include: A heating base is provided, the heating base including multiple independently controlled heating plates, the surface of the heating plates being provided with protrusions; The substrate is transferred above the heating base; Adjust the heating discs to change the height of the protrusions extending from the surface of the heating base, so that the protrusions contact the back of the base; A thin film deposition process is performed on the substrate.

2. The method for improving the stability of atomic layer deposition cavity processes according to claim 1, characterized in that: The multiple heating plates are arranged in a concentric ring structure, including a circular heating plate located in the central region and at least a single-layer outer ring heating plate surrounding the circular heating plate; or, the multiple heating plates are arranged in a fan-shaped array structure around the center point of the heating base.

3. The method for improving the stability of atomic layer deposition cavity processes according to claim 2, characterized in that: The heating plates are arranged in a concentric ring structure, and the heating base includes a first heating plate, a second heating plate, and a third heating plate.

4. The method for improving the stability of atomic layer deposition cavity processes according to claim 1, characterized in that: The substrate includes a wafer.

5. The method for improving the stability of atomic layer deposition cavity processes according to claim 1, characterized in that: The base is grasped by the ejector pin and placed in the cavity at a preset position above the heating base. The ejector pin is then slowly retracted so that the base rests on the protrusion of the heating base.

6. The method for improving the stability of atomic layer deposition cavity processes according to claim 1, characterized in that: The temperature distribution data or film thickness distribution data of the substrate deposition area are obtained, and the corresponding heating disks are independently raised and lowered according to the temperature distribution data or film thickness distribution data to adjust the height of the protrusions in the corresponding areas.

7. The method for improving the stability of atomic layer deposition cavity processes according to claim 1, characterized in that: The height of the protrusions on each of the heating discs can be adjusted in a telescoping manner without affecting each other.

8. A heating base for atomic layer deposition, characterized in that, include: Multiple heating plates are assembled to form a base support surface; The protrusions are distributed on the base support surface of each of the heating sub-discs; Each of the heating discs can be independently height-adjusted to change the height at which the protrusions on the heating discs abut against the back of the base.

9. The heating base for atomic layer deposition according to claim 8, characterized in that: The plurality of heating plates are arranged in a concentric ring structure, including a circular heating plate at the center and at least a single-layer annular heating plate surrounding the circular heating plate; or, the plurality of heating plates are arranged in a fan-shaped array structure around the center point of the heating base.

10. The heating base for atomic layer deposition according to claim 8, characterized in that: It also includes an independent lifting drive assembly connected to each of the heating sub-plates, the lifting drive assembly being used to drive the corresponding heating sub-plate to move independently in a direction perpendicular to the base support surface.

Images