Chemical mechanical planarization (CMP) tools each of which uses a system of peristaltic pumps
for process fluid delivery. At various times during each CMP process, these pumps may be delivering tungsten or oxide slurries, DI water, or ammonium hydroxide. These fluids are dispensed onto the polishing substrate, and mechanical force is applied to create the desired planarized surface. The chemical interaction and the mechanical force combine to achieve the desired effect on each wafer. Peristaltic pumps have been used to dispense the necessary chemicals since the development of CMP tools. Before the advent of fab wide chemical delivery systems, many chipmakers simply pumped slurry and other chemicals out of nonpressurized drums, and the peristaltic pumps provided the necessary pressure to dispense the slurry onto the wafers. However, with the coming of state-of-the-art pressurized chemical delivery systems, pressure no longer needs to be provided by each tool.
Semiconductor manufacturing requires that the liquid flow in the process tool is always controlled, and one of the harsh applications is chemical mechanical planarization (CMP). When a CMP tool cannot distribute a consistent slurry rate to the polished substrate, it can have a huge negative impact on throughput, chemical use, and material integrity. Variations in wafer thickness, increased defect density, tool downtime, and increased wafer waste are just some of the problems that may be caused by poor process control.
The peristaltic pump is very suitable for the high purity and corrosive chemical environment of the semiconductor industry. For CMP, it provides the linearity and repeatability required for the distribution of slurry flow to the wafer at the best point of use during the polishing process. Low shear force is effective for CMP. The slurry is gentle, and its variable speed operation allows the flow or pressure to be controlled within a wide operating range to maintain the integrity of the process. If the flow rate of the polishing liquid is too high, it will cause orange peel. The flow rate of the CMP slurry pump
is adjustable, and it can be controlled by knob speed control, touch screen speed control, and external control speed control.
The performance of the slurry can achieve excellent wafer flatness, and the peristaltic pump
can help achieve this goal by controlling the slurry delivery and distribution. The non-invasive design of the peristaltic pump provides a straight flow path with no dead-flow areas, allowing the slurry to coalesce, harden and contaminate the process. The flow rate accuracy is ±0.5%. The stable fluid delivery not only ensures the continuous flow of slurry to the polishing pad, but also reduces the waste of slurry, chemicals, and deionized water. The conveyed medium does not contact the peristaltic pump body, which is conducive to conveying some media that are corrosive to metals, such as various acid and alkali solutions, or some salt solutions containing chloride ions. It is simple and quick to clean and disassemble. Since the medium only flows in the hose, cleaning is only for the hose, and the installation and disassembly of the peristaltic pump hose are relatively simple
The CMP slurry pump
has the same flow capacity in both directions. It will not cause damage to any parts of the peristaltic pump under the condition of no liquid and dry operation. It can generate up to 98% vacuum. Without valves, mechanical seals, and packing seals, there will be no such production. Leakage and maintenance factors can easily transport liquids or gas-liquid mixed fluids, allowing the fluid to contain solids up to 40% of the inner diameter of the hose, and can transport all kinds of materials or fluids that are abrasive, corrosive, and oxygen-sensitive.