Resources

A discussion about semiconductor facilities’ environmental footprint in relation to water consumption, energy usage, and site selection considerations.

Despite the technological advancements in online analytical metrologies for ultrapure water (UPW) quality monitoring, offline measurements of grab samples are critical to assess certain quality parameters to date not yet available for online analyzers (i.e. metals and ions). The current recommendations from IRDS (2021 yield enhancement) for metals in UPW to is <1 ppt, for critical metals for image sensors even <0.2 ppt at POP. Therefore, high performance analytics is required in terms of limit of quantification and analytical range. To be able to reliably measure such low concentrations of metals in grab samples, clean sampling strategies are absolutely required to avoid cross contamination onsite. In this work, we present a simple and effective tool helping to bring the samples from the facility to the lab in a clean and reliable way, minimizing main cross-contamination normally occurring during sampling in an industrial environment.

Modern semiconductor devices face tremendous manufacturing challenges due to the ever increasing complexity of the device. In today's most advanced fabs, bulk gases, such as nitrogen, oxygen, argon, helium etc., which are used throughout the manufacturing process have to meet sub-part-per-billion (ppb) impurity specifications; however, semiconductor companies constantly push for lower limits and therefore demand improved analytical devices. At the same time, systems should be low on maintenance and operating costs. For instance, helium carrier gas required by sub-ppb gas chromatographs (GCs) is a huge cost factor that fabs seek to eliminate.

Nanoparticles represent one of the most critical contaminations in ultrapure supplies for semiconductor fabrication addressing ultrapure water (UPW), gasses and chemicals as well as materials of construction decreasing yield on the wafer. Along the UPW generation process, there are sources (e.g. materials) and sinks (e.g. filter) for nanoparticles. As final barrier for nanoparticles in the polishing step, ultrafilters are commonly used on UPW plants. However, the performance of the ultrafilters in the field in terms of removal performance for particles need to be investigated to come up with pro-active approaches for particle removal. Especially for UPW, there is a lack of online particle metrologies down to particle size of sub 50 nm. This study aims to give an overview on different particle metrologies to better understand the particle removal performance by ultrafilters on the market.

Particle contamination in ultrapure water (UPW) remains a high challenge in yield enhancement to achieve more functional die per wafer. IRDS requirement on acceptable particle size in UPW is getting more stringent year by year as semiconductor technology advances. Besides native particles, IRDS also shows growing concern on particle precursors such as dissolved molecular compound which may form solid particles when dried on wafer surface. Our study on the particle types released through a UPW system and its comparison to those found on wafers helps us identify the target particles and particle precursors to be removed from UPW. One of the target process consumables to be studied on the release of particles and particle precursors to UPW is ion exchange resin. Through our investigation on two different ion exchange resins, resin selection is shown to be critical in reducing the release of particles and particle precursors in both short and long terms.

Critical feature sizes of modern semiconductor devices have surpassed the capabilities of traditional optical-based methods to measure particle concentrations in process chemicals and on wafers. Without adequate metrology for quantifying particle and particle precursor concentration in process chemicals, device makers face challenges correlating component failures and fabrication steps. This is especially true for organic material released by Final Polish Ion Exchange resin during a rinse cycle, which is not detected efficiently using optical methods. In this work, we describe two state-of-the-art measurement methods that can detect organic particles and particle precursors to 3 nm using Aerosolization and Threshold Particle Counting (TPC) and defects from UPW deposited on a wafer surface down to 8 nm using Surfaced Enhanced Particle Sizing (SEPS)

Organic contamination present in Ultrapure Water (UPW) and other liquids pose a risk of depositing on the wafer surface during processing and cleaning. Of greatest concern are those deposits that are non-volatile. These are designated as “Critical Organics”. The objectives of this study are to quantify the extraction of critical organics from high-purity piping in hot UPW; specifically, PFA and PVDF, assess the affinity of the organic contaminants to the wafer surface during spin processing and to determine the relative concentrations of organic contamination remaining on the wafer surface as a function of temperature.

In the yield enhancement report 2021 there is a call for highly controlled deposition experiments to determine the particle deposition rate on the wafer compared to the known particle count in the ultrapure water (UPW) to gain better understanding about the contamination sources on-wafer. The goal of this collaborative study between Lam Research as a tool supplier and Ovivo Switzerland as an UPW engineering company is to investigate potential correlation between UPW quality form a full scale UPW plant and particle deposition on standard silicon 300 mm wafer.

Ultrapure water (UPW) is extensively used for cleaning and dilution purposes in fabs. A problem in UPW can have a fatal effect on wafer defectivity so that the final die yield. Therefore, it is crucial to characterize the risk of on-wafer defectivity of UPW at different stages of purification. The current 12-inch wafer testing methods are capital intensive requiring special equipment for both sample preparation and on-wafer particle scanning. Therefore, extensive application of on-wafer analysis of UPW is not a financially viable solution. This presentation will introduce a practical and economically feasible methodology to analyze the on-wafer defectivity of UPW using small wafers (2-inch or 4-inch). The method is based on applying the spin-drying process successively on the same wafer, increasing the particle density to a level higher than the existing particle baseline of the wafer.

For the dimensional scaling and performance enhancement of upcoming semiconductor devices, metal wire lines and space minimization are required. However, due to the technical limitation of mask locational alignment accuracy, wiring layer has short circuits and semiconductor performance deteriorates. To prevent short circuit by the misalignment, metal recess technology with etch back metal layer as atomic scale to fill dielectrics and create allowable gap length is required. Furthermore, wire metal has been changed to make interconnect line resistance lower from copper (Cu) to cobalt (Co) and molybdenum (Mo), new wet solutions which are optimize for each is demanded