Patent Application
20160178279
Embodiments of the invention relate generally to electronic device manufacturing including chemical mechanical planarization (CMP), and more particularly to substrate edge residue removal systems, apparatus and methods adapted to clean substrates after CMP.
After a chemical mechanical planarization (CMP) process is performed on a substrate, the substrate is typically cleaned to remove unwanted debris and particles therefrom. For example, slurry, polished substrate material or other residue may cling to the substrate, including the edge bevel of the substrate. Following CMP, substrates may be post-cleaned in a cleaning module such as a scrubber brush box, a megasonic tank, or the like to remove such unwanted material. Prior to the post-clean, and even after the post-clean, a rinse in a rinse tank may be used in some embodiments.
During the rinsing operations, the substrates can be dried upon being removed from a rinsing tank. Such drying is typically accomplished by use of an air or vapor (e.g., IPA vapor) knife, such as a Marangoni knife which directs gas at an interface (e.g., the meniscus formed) between the substrate and rinse fluid as the substrate is lifted out of a bath of the rinse fluid. In Marangoni drying, a substrate is raised in a vertical orientation from a fluid bath, and an alcohol vapor is delivered to a meniscus that is formed at the substrate/fluid interface. The alcohol vapor reduces the surface tension at the meniscus, thereby creating a “Marangoni” force resulting in a downward liquid flow opposite to the substrate lift direction. As a result, the substrate surface above the meniscus is dried. However, some bath residue may be difficult to remove using such conventional drying methods. Thus, improved systems, apparatus, and methods of removing residue from a substrate are desired.
In some embodiments, a substrate edge residue removal system is provided. The substrate edge residue removal system includes an assembly formed from a lower body including a gas cavity and an upper plate removably coupled to the lower body wherein the assembly includes a passageway leading from the gas cavity to a plenum and an output slit extending along a length of the plenum and in fluid communication with the plenum; a frame supporting the assembly; a Marangoni drying device coupled to the frame and disposed below the assembly; and a substrate holder operable to support and to lift a substrate past the output slit of the assembly.
In some embodiments, a substrate edge residue removal apparatus adapted to clean a substrate is provided. The substrate edge residue removal apparatus includes a lower body including a gas cavity; and an upper plate removably coupled to the lower body. The lower body and upper plate together form an assembly having a passageway leading from the gas cavity to a plenum and an output slit extending along a length of the plenum and in fluid communication with the plenum.
In some embodiments, a method of removing residue from a substrate edge is provided. The method includes supporting a substrate on a substrate holder in a vertical orientation while lifting the substrate upward past a drying device; activating a substrate edge residue removal apparatus to apply a curtain of gas to a lower portion of the substrate once the substrate has been lifted past the drying device; and continuing to lift the substrate upward past the substrate edge residue removal apparatus such that the curtain of gas removes substantially all of the liquid from the substrate without leaving a residue.
Other features and aspects of embodiments of the invention will become more fully apparent from the following detailed description of example embodiments, the appended claims, and the accompanying drawings.
Various embodiments of the invention are disclosed in the following detailed description and accompanying drawings.
In one or more embodiments of the present invention, a substrate edge residue removal apparatus is provided. The substrate edge residue removal apparatus especially aids in cleaning the lower edges of a substrate being held vertically, as well as around the substrate contact locations, and may therefore avoid residue buildup on a lower edge of the substrate, and/or around the substrate contact locations.
In some embodiments, following CMP, substrates may be rinsed in a post-CMP rinse, and then may be transferred directly to a post-cleaning module, such as a scrubber brush box, a megasonic tank, or the like, for further cleaning. However, during the rinsing and conventional drying process, as the substrate is retracted from the rinse bath, some adhered particles and/or residues may still remain, especially on contact points, and along a bottom edge of the substrate. Thus, embodiments of the present invention provide a substrate edge residue removal apparatus and operational methods that provide improved residue removal after a substrate has, for example, been removed from a rinsing bath and dried using conventional processes.
In some embodiments, a substrate edge residue removal apparatus is configured and adapted to eliminate or minimize liquid entrapment at the bottom of the substrate (and/or at finger contact points of a substrate holder) that may remain even after a conventional substrate drying process, such as a surface tension Marangoni process. Prior art systems typically rely on evaporation to remove liquid left behind on the substrate edge by the Marangoni or other processes. However, if such liquid residue is permitted to merely evaporate, a solid residue (e.g., a water mark) may remain, adhered to the substrate edge location where the liquid evaporated. This residue can result in contamination of the substrate and introduction of defects.
Instead of evaporatively drying liquid residue after a Marangoni or other process, embodiments of the present invention blow the liquid off (e.g., physically displace the liquid) via force from pressurized gas (e.g., nitrogen (N2)) flowed from the substrate edge residue removal apparatus so that neither liquids nor solids remain. In some embodiments, the gas used can be an N2 and isopropyl alcohol (IPA) vapor mix (e.g., with a relatively high moisture content) that insures the liquid residue is blown-off without first drying.
Some embodiments include a two piece assembly formed from a lower body removably coupled to an upper plate. Gas is flowed through the assembly and exits via a thin output slit formed by a gap between the two pieces of the assembly. In some embodiments, the gas is flowed at a rate sufficiently low enough to maintain an even laminar flow. In some embodiments, the slit's output direction is angled downward and the apparatus is only activated as the lower third of the substrate is passed by the output slit. After the substrate has passed the conventional drying process devices (e.g., a Marangoni dryer), the substrate edge residue removal apparatus is activated directing a vapor or gas curtain on the major surface of the substrate that blows any residue off of the substrate face and edge, as well as off of the fingers of the substrate holder as the substrate is lifted past the apparatus.
In some embodiments, the substrate holder may include vacuum slots adapted to draw in liquid that is blown off of the substrate by the substrate edge residue removal apparatus. Operation of the vacuum slots can be synchronized with operation of the substrate edge residue removal apparatus. In other words, at the same time the gas curtain is activated and applied to a passing substrate but the substrate edge residue removal apparatus, vacuum pressure can be applied to the substrate edge from the vacuum slots in the substrate holder.
As used herein unless otherwise specified, the term “clean” is intended to mean the removal of solids, liquids, residues, or other particles that are on, in contact with, or have become adhered to a substrate. These and other features and embodiments of the invention will be described in more detail below with reference to the drawings.
Turning now to
As can be seen in
The substrate edge residue removal apparatus 104 of embodiments of the present invention provides means to remove the remaining residue. Once the bottom of the substrate has been moved past the waterfall heads 202, 204 and the Marangoni dryer device 208, the substrate edge residue removal apparatus 104 is activated and a gas curtain 210 (e.g., as represented by a dashed line in
An angle adjustment knob 308 is disposed at the end of the apparatus 104 opposite the gas channel 306. The angle adjustment knob 308 includes a pointer 402 that indicates the angle setting of the apparatus 104 on an indexed scale 310. In some embodiments, the angle of the apparatus 104 (i.e., the angle of the gas curtain 210 relative to the major surface of the substrate 108) can be adjusted manually and in others, an actuator under the control of controller 150 can set the angle.
The apparatus 104 is supported and rotatably secured to the frame 102 (
Turning now to
The width of the gas curtain 210 is defined by the length of the output slit 504 which can be approximately 5 mm (+/−1 mm) to approximately 300 mm (+/−30 mm). This width is selected to accommodate cleaning the lower portion of 300 mm substrates. Other widths can be used. The thickness of the gas curtain 210 is defined by the height of the output slit 504 which can be approximately 0.025 mm (+/−0.001 mm) to approximately 3 mm (+/−0.5 mm). The output slit can be dimensioned to allow a volume to flow at a rate of approximately 1 slm (+/−0.2 slm) to approximately 100 slm (+/−10 slm) at a pressure in the range of approximately 68947.57 Pa (+/−500 Pa) to approximately 689475.7 Pa (+/−500 Pa). The plenum 500 can have a volume in the range of approximately 0.0626 mm3 (+/−0.005 mm3) to approximately 90000 mm3 (+/−500 mm3). Other practicable dimensions are possible. The various components of the substrate edge residue removal apparatus 104 can be made of any practicable materials such as rigid metals (e.g., stainless steel, aluminum, etc.), ceramic, or various plastics (e.g., PEEK). Other suitable materials may be used.
More or fewer contact fingers can be used and can be disposed in different locations than the three shown in
The substrate holder 106 has utility for holding a substrate 108 in a vertical orientation, lowering the substrate 108 into a bath (e.g., into a rinsing bath), and aiding in the removal of the substrate 108 from the bath in semiconductor device processing. In some embodiments as shown in
In some embodiments, a substrate holder 106′ may include multiple substrate contact supports 802a-d configured to contact and support a substrate 108. These supports 802a-d may be v-shaped or otherwise-shaped to facilitate draining of fluid from the substrate holder 106′ when the substrate holder 106′ is removed from a fluid bath. In some embodiments, one or more of the substrate contact supports 802a-d may include a vacuum port (not shown) for applying a vacuum at one or more of the supports 802a-d, to further assist in fluid removal. Additionally or alternatively, a slit-shaped vacuum port 804 may be provided between supports 802b and 802c, at the bottom edge of the substrate 108. Vacuum may be applied to the one or more vacuum ports via vacuum inlets 810, 812, for example. The one or more vacuum ports may be operable to apply a vacuum at one or more locations along the bottom edge of a substrate. As such, liquid residue, which formerly could collect at such substrate supports and/or along a bottom edge of a substrate, may be removed. Example substrate holders are described in previously incorporated U.S. application Ser. No. 14/593,841, filed Jan. 9, 2015. Any other suitable substrate holders may be employed.
The various methods described herein may be implemented by, or under the control of, the controller 150, which may be, for example, an appropriately programmed general purpose computer or other computing device. Typically a processor (e.g., one or more microprocessors) will receive instructions from a memory or like device, and execute those instructions via, for example, various actuators, thereby performing one or more methods defined by those instructions. Further, programs that implement such methods may be stored and transmitted using a variety of media (e.g., computer readable media) in any manner. In some embodiments, hard-wired circuitry or custom hardware may be used in place of, or in combination with, software instructions for implementation of the processes of various embodiments. Thus, embodiments of the controller 150 are not limited to any specific combination of hardware and software. The controller 150 may include various components and devices (e.g., a processor, input and output devices, sensors, displays, actuators, and the like) appropriate to perform the method.
A substrate edge residue removal system 100 can be part of a larger post-CMP modular cleaning system. In operation, a substrate 108 can be loaded into the substrate holder 106 and lowered into a cleaning module via a robot, which attaches to and moves the substrate holder 106. The robot may be any suitable robot, such as a gantry robot, a beam robot, or the like. The robot lowers the substrate 108 into a rinsing tank of the cleaning module, and optionally past the waterfall heads 202, 204, which may rinse both sides of the substrate 108. The substrate 108 is fully immersed in the cleaning liquid contained in the rinsing tank for a suitable time, and then is retracted from the tank. The tank may include megasonic or other energized cleaning capabilities in some embodiments.
As the substrate 108 exits the tank, it again passes by the waterfall heads 202, 204 where the substrate 108 may optionally receive a rinse of cleaning liquid. The substrate 108 can be concurrently moved past a Marangoni dryer device 208. The Marangoni dryer device 208 can be an air knife, such as taught in U.S. Pat. Nos. 8,869,422 and 8,322,045, for example. Other configurations of the Marangoni dryer device 208 can be used. After the substrate 108 has been moved past the Marangoni dryer device 208 (e.g., the gas from the Marangoni dryer device 208 is no longer aimed at or contacting the substrate 018), the substrate edge residue removal apparatus 104 can be activated by the controller 150 to deliver a gas curtain 210 starting at the lower third of the substrate 108 while the substrate 108 continues to be lifted. In some embodiments, the substrate can be lifted at a rate of approximately 1 mm/s (+/−0.5 mm/s) to approximately 30 mm/s (+/−1 mm/s). Substantially all of the liquid remaining on the substrate after the Marangoni drying process can be removed by the substrate edge residue removal apparatus 104. In some embodiments, concurrently with the substrate edge residue removal apparatus 104 being activated, vacuum pressure can be applied by the controller 150 to the substrate via the substrate holder 106.
With reference to
The foregoing description discloses only example embodiments of the invention. Modifications of the above-disclosed assemblies, apparatus, and methods which fall within the scope of the invention will be readily apparent to a person of ordinary skill in the art. While embodiments of the invention have been described primarily with regard to cleaning a substrate after CMP, it will be understood that embodiments of the invention may be employed for other substrate cleaning and/or pre-cleaning applications.
Accordingly, while the invention has been disclosed in connection with example embodiments thereof, it should be understood that other embodiments may fall within the scope of the invention, as defined by the following claims.
The present application claims priority from U.S. Application Ser. No. 62/094,938, filed Dec. 19, 2014, and titled “SUBSTRATE RINSING SYSTEMS AND METHODS” (Docket No. 22585), which is hereby incorporated by reference herein in its entirety for all purposes. The present application is related to U.S. application Ser. No. 14/593,841, filed Jan. 9, 2015, and titled “SUBSTRATE HOLDER ASSEMBLY, APPARATUS, AND METHODS” (Docket No. 22564), which is hereby incorporated by reference herein in its entirety for all purposes. The present application is related to U.S. Application Ser. No. ______, filed ______, and titled “SUBSTRATE GRIPPER APPARATUS AND METHODS” (Docket No. 22600), which is hereby incorporated by reference herein in its entirety for all purposes. The present application is related to U.S. application Ser. No. ______, filed ______, and titled “SYSTEMS AND METHODS FOR RINSING AND DRYING SUBSTRATES” (Docket No. 22586), which is hereby incorporated by reference herein in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 62094938 | Dec 2014 | US |
