New Product: Semilab SSM’s SRP metrology system provides density and resistivity depth profiling

Product Briefing Outline: Semilab SSM, a division of Semilab, has launched its newest member to the ‘NanoSRP’ family of metrology products. Designed for small and mid-tier sized semiconductor and solar cell manufacturers, the SRP Express 170 is a manual system that provides density and resistivity depth profiling using spreading resistance profiling technology (SRP).

Problem: To date, small and mid-tier companies have had to choose between high-end, high throughput systems designed to support multiple samples at a time or at least ten years old obsolete low-end manual systems. These old systems are DOS based, which younger operators are often no longer familiar with, and the PC hardware is prone to fail. The wear out of the complex pneumatic motion control often makes micro resolution probing unattainable. Moreover, spare parts are becoming increasingly difficult to source. High end systems don’t have these issues, but their price isn’t justifiable when only a small number of samples need to be measured per day.

Solution: With the SRP-Express 170 system manufacturers can replace their aging, manual systems or outsourced services to bring a cost-effective modern spreading resistance profiling system in house. The SRP-Express 170 features a modern touch screen based Windows computer interface, which provides a user friendly, time efficient operation and analysis platform. A vision system that incorporates an electronic camera makes operation faster and acquisitions of images possible. The use of a modern piezo drive allows for a very smooth operation with higher resolution and flexibility. SRP is one of the oldest, best understood, and established electrical measurement technique in the semiconductor industry. This technology provides a direct measurement of the resistivity and carrier density profiles of electrically active dopants – the same electrical properties that determine device performance. The carrier density is obtained in cross section of a single layer or an entire device. There are no practical limits on carrier density range, conductivity, or structure thickness. It is primarily used for process development and control in all Silicon processing steps from substrate through the doping of poly gates. Because it provides complete electronic information it is often used for investigative purpose.

Applications: SRP is used whenever an electronic semiconductor structure needs to be profiled. This could be to tune and control diffusion. In epi growth SRP is used to check on autodoping, outdiffusion, hydrogen annealing, and reactor problems like temperature instabilities. After ion-implantation SRP controls dose, depth, and sheet rho, and allows for transistor threshold adjustments. SRP can verify Silane or dopant gas cleanliness to avoid massive production scrap. The photovoltaic industry uses SRP for diffusion profiling, where diffusion depth is a critical parameter for cell efficiency.

Platform: The SRP Express 170 will be priced between $200,000-300,000 depending on system configuration and options. The probing setup is integrated into a light tight cabinet, with integrated electromagnetic, vibration and acoustic isolation. Automatic bevel angel measurement (BAM) is available as an option. This option allows for better depth accuracy. Semilab SSM provides all necessary sample preparation tools in an optional kit.

Availability: Currently available.