Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – For liquid etchant
Reexamination Certificate
2001-12-28
2003-11-25
Powell, William A. (Department: 1765)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
For liquid etchant
C216S088000, C156S345270, C438S692000, C438S745000
Reexamination Certificate
active
06652708
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the fabrication of structures on semiconductor wafers, and more specifically to methods and apparatus of chemical mechanical planarization and to the processing surfaces of chemical mechanical planarization apparatus.
2. Description of the Related Art
In the fabrication of semiconductor devices, integrated circuits are defined on semiconductor wafers by forming a plurality of layers over one another resulting in multi-level structures. As a result of the various layers disposed over one another, a surface topography of the wafer can become irregular, and an un-corrected irregularity increases with subsequent layers. Chemical Mechanical Planarization (CMP) has developed as a fabrication process utilized to planarize the surface of a semiconductor wafer, as well as to perform additional fabrication processes including polishing, buffing, substrate cleaning, etching processes, and the like.
In general, CMP processes involve the holding and rotating of a wafer against a processing surface under a controlled pressure. Typical CMP apparatus include linear belt processing systems in which a belt having a processing surface is supported between two or more drums or rollers which move the belt through a rotary path presenting a flat processing surface against which the wafer is applied. Typically, the wafer is supported and rotated by a wafer carrier, and a polishing platen is configured on the underside of the belt travelling in its circular path. The platen provides a stable surface over which the belt travels, and the wafer is applied to the processing surface of the belt against the stable surface provided by the platen.
Additional CMP apparatus include rotary CMP processing tools having a circular pad configuration for the processing surface, an orbital CMP processing tool similar to the circular CMP processing tool, a sub-aperture CMP processing tool, and other CMP processing systems providing a plurality of apparatus and configurations that, in general, utilize friction to planarize, polish, buff, clean, or otherwise process the surface of a semiconductor wafer having integrated circuits or other structures fabricated thereon.
CMP processing can include the use of varying degrees of abrasives, chemistries, fluids, and the like to maximize effective use of friction for wafer surface preparation, and several apparatus include providing for in-situ rinsing of wafers to reduce or remove the residue of CMP processing, as well as providing for cleaning and conditioning of processing surfaces during processing to maintain controllable and steady state processing.
In order to achieve and maintain controllable and steady state processing, environmental conditions such as, by way of example, temperature, pressure, and state of cleanliness (e.g., particle generation and filtration) are strictly monitored and manipulated to achieve optimum processing conditions. Additional processing variables such as speed of rotation or other movement of the processing surface, speed of rotation of the carrier supporting the wafer, amount of pressure used to apply the wafer to the processing surface, time of processing, and the like are monitored and manipulated as well. In a friction-based processing environment such as CMP, processing temperature significantly impacts removal rate on the surface of the wafer, and consequently, processing time for precise degrees of material removal. By way of example, failure to halt processing at precise points of material removal can result in overpolish, scratching, dishing, and other such defects in the wafer surface and structure fabrication.
Temperature variations on the processing surface vary widely depending on the process and apparatus. By way of example, the processing surface of the linear belt CMP tool is heated by the friction of processing, and by the friction of conditioning pads and pucks employed to condition and activate the belt. Cooling factors include agents used for processing, rinsing agents, and the ambient temperature of the processing environment as the belt travels around the rollers. Temperature variations effect the processing of the semiconductor wafer in general, and effect regions of the same semiconductor wafer differently during processing as some regions travel through more temperature variations than other regions.
Some prior art attempts to maintain processing surface temperature have included the introduction of steam to heat the processing surface to a desired processing temperature, but among other deficiencies, steam fails to address temperature variations across the processing surface. Prior art conditioning methods for linear belt systems include a sweeping conditioning pad travelling across the processing surface, but a sweeping conditioning pad fails to compensate for wave motions in belt systems, and introduces additional temperature variations.
What is needed are methods, processes, and apparatus to manipulate and control the temperature of the processing surface in CMP tools to maintain optimum and controllable processing over the entire surface of the semiconductor wafer.
SUMMARY OF THE INVENTION
Broadly speaking, the present invention fills these needs by providing methods, processes, and apparatus to achieve, maintain, and manipulate the temperature of the processing surface used in CMP processing operations. The present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device, and a method. Several embodiments of the present invention are described below.
In one embodiment, a temperature controller within a CMP system having a first roller, a second roller, and a linear belt circulating around the first and second rollers is disclosed. The linear belt of the CMP system spans between a first edge and a second edge. The temperature controller includes an array of thermal elements. Each of the thermal elements of the array is independently controlled. The array of thermal elements is positioned between the first roller and the second roller and is configured to contact a back surface of the linear belt. The array of thermal elements extends between the first edge and the second edge of the linear belt width.
In another embodiment, a method for controlling the temperature of a linear belt within a CMP system is disclosed. The CMP system includes a first roller, a second roller, and a linear belt which circulates around the first and second rollers. The linear belt has a width that spans between a first edge and a second edge, and further has an outer processing surface and an inner surface. The method for controlling the temperature of the linear belt includes applying thermal energy to a linear array of locations on the inner surface of the linear belt. The linear array of locations spans from the first edge to the second edge of the width of the linear belt. The method further includes controlling a degree of the applied thermal energy at each of the linear array of locations.
In still a further embodiment, a preparation surface conditioner is disclosed. The preparation surface conditioner is in a CMP system which includes a first roller, a second roller, and a linear belt circulating around the first and second rollers. The linear belt has a width that spans between a first edge and a second edge, and has an inner surface that contacts the first and second rollers and a preparation surface. The preparation surface conditioner includes an array of conditioning pucks for conditioning the outer preparation surface of the linear belt. Each of the conditioning pucks is independently controlled. The array of conditioning pucks extends between the first edge and the second edge of the linear belt width.
In yet another embodiment, a method for conditioning an outer processing surface of a linear belt is disclosed. The outer processing surface of the linear belt is in a CMP system having a first roller and a second roller. The linear belt circulates around the first and second rollers,
Lam Research Corporation
Martine & Penilla LLP
Powell William A.
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