Fluid handling – Systems – Multiple inlet with single outlet
Reexamination Certificate
1999-06-25
2001-07-31
Lee, Kevin (Department: 3753)
Fluid handling
Systems
Multiple inlet with single outlet
C137S896000, C134S094100, C134S095100
Reexamination Certificate
active
06267142
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to fluid pressure regulating systems, and more particularly to systems for stabilizing the delivery flow of water and chemicals to a wafer preparation station.
2. Description of the Related Art
As is well known, semiconductor devices are fabricated from semiconductor wafers, which are subjected to numerous processing operations. These operations include, for example, impurity implants, gate oxide generation, inter-metal oxide depositions, metallization depositions, photolithography pattering, etching operations, chemical mechanical polishing (CMP), etc. Although these processes are performed in ultra clean environments, the very nature of many of the process operations is to blame for the generation of surface particles and residues. For instance, when CMP operations are performed, a film of particles and/or metal contaminants are commonly left behind.
Because surface particles can detrimentally impact the performance of an integrated circuit device, wafer cleaning operations have become a standard procedural requirement after certain process steps. Although cleaning operations are rather procedural, the equipment and chemicals implemented to perform the actual cleaning are highly specialized. This specialization is important because each wafer, being at different stages of fabrication, represents a significant investment in terms of raw materials, equipment fabrication time, and associated research and development.
To perform the cleaning operations in an automated manner, fabrication labs typically employ a cleaning system. A typical cleaning system may be, for example, a Synergy™ cleaning system from OnTrak™ of Lam Research Corporation, Fremont, Calif. A typical Synergy™ cleaning system employs two brush stations, where each brush station has a set of brushes for cleaning the top and bottom surfaces of a wafer. Each of the brushes are commonly configured to deliver chemicals and DI water Through-The-Brush (TTB) or by way of a drip dispensing bar, to enhance the cleaning ability of the system. The system typically also includes a spin-rinse station, where a wafer, after being cleaned in the brush stations is rinsed with DI water and dried before completing the cleaning cycle.
As can be appreciated, it is very important that facility lines, which supply the DI water to the cleaning system supply the water at substantially steady water pressure levels. Unfortunately, the facility lines in different fabrication labs vary substantially. Thus, the delivered water can have fluctuating pressures that cause more or less water to be supplied during a wafer preparation operation. On the same token, it is very important for facility lines, which supply chemicals to a system deliver a steady flow to internal modules that mix DI water with the delivered chemicals.
For instance, in cases where the chemical solution is hydrofluoric (HF) acid, if too much HF acid may be mixed with DI water, the resulting solution can be too strong and therefore cause over etching to occur. In other cases, not enough DI water is mixed with HF acid, which can also produce an over concentrated solution. The possibility of over etching, under etching, or just simply inappropriate wafer surface preparation can cause dies of a prepared wafer to be unreliable or damaged.
In view of the foregoing, there is a need for systems and methods for stabilizing DI water and chemical delivery to wafer preparing systems.
SUMMARY OF THE INVENTION
Broadly speaking, the present invention fills these needs by providing systems and methods for stabilizing DI water delivery and chemical delivery to wafer preparation systems. By stabilizing the DI water and chemical delivery, more precision chemical solutions can be produced, thus improving wafer preparation operations, such as, cleaning operations, and combined cleaning and etching operations. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device, or a method. Several inventive embodiments of the present invention are described below.
In one embodiment, a solution delivery system for use with a wafer preparation system is disclosed. The solution delivery system includes a de-ionized water (DIW) dispense drawer having an input for receiving an initial flow of DIW from a facility water supply. The DIW dispense drawer further includes a first pressure regulator for stabilizing the initial flow of DIW and producing a substantially steady flow of DIW as a DIW output of the DIW dispense drawer. A chemical drawer is also provided as part of the solution delivery system. The chemical drawer is configured to receive the substantially steady flow of DIW from the DIW dispense drawer. The chemical drawer is further configured to receive an initial flow of chemicals from a chemical source. The chemical drawer also includes a second pressure regulator for stabilizing the initial flow of chemicals from the chemical source and thus producing a substantially steady flow of chemicals. In this preferred embodiment, the chemical drawer further includes a mix manifold for mixing the substantially steady flow of DIW received from the DIW dispense drawer and the substantially steady flow of chemicals. The mix manifold being configured to output a chemical solution having a controlled concentration.
In another embodiment, a fluid delivery system for controllably channeling fluids to at least one wafer preparation station is disclosed. The fluid delivery system includes a de-ionized water (DIW) dispense drawer having an input for receiving an initial flow of DIW from a facility water supply. The DIW dispense drawer includes a first pressure regulator for stabilizing the initial flow of DIW and therefore produce a first substantially steady flow of DIW as a first DIW output of the DIW dispense drawer. The DIW dispense drawer also includes a second pressure regulator for stabilizing the initial flow of DIW and to produce a second substantially steady flow of DIW as a second DIW output of the DIW dispense drawer. The DIW dispense drawer can then be coupled to one or more chemical drawers to perfect the delivery of a chemical solution to a wafer preparation system, such as brush box.
In yet a further embodiment, a chemical delivery system for channeling fluids received from a water source and a chemical source to a chemical wafer preparation station is disclosed. The chemical deliver system includes a chemical module being configured to receive a flow of DIW from the water source. The chemical module is configured to receive an initial flow of chemicals from the chemical source. The chemical module further includes a pressure regulator for stabilizing the initial flow of chemicals from the chemical source and producing a substantially steady flow of chemicals. The stabilizing is configured by adjusting a pressure of the initial flow of chemicals to a reduced pressure.
Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
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deLarios John Martin
Wong Larry Ping-Kwan
Lam Research Corporation
Lee Kevin
Martine & Penilla LLP
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