Controlling electrical properties of dielectrics and the interfaces they form with semiconductors is imperative for achieving high IC device performance and yield. Semilab offers metrology solutions to electrically characterize the critical dielectric layers and processes that span process modules ranging from FEOL to BEOL.
The most common implementation of Semilab’s in-line electrical metrology is replacement of the IC MOS short-loop, which alleviates the need for expensive and time-consuming processing. The in-line methods provide rapid feedback without the need for preparing devices; resulting in increased process tool utilization time for critical product. The two primary MOS measurements being replaced are; 1) Capacitance – Voltage (C-V) method for determination of Dielectric Capacitance, Dielectric Charges, and Dielectric/Semiconductor Interface Quality; and 2) the Current – Voltage (I-V) method that measures Dielectric Leakage and Breakdown.
The below table summarizes the dielectric properties measured by Semilab systems, the associated critical IC device parameters that are affected, and the process areas in which the issues are commonly encountered.
Measured properties of dielectrics and interfaces:
|Measured Property||Affected Device Parameter||Process Module|
|Dielectric/ Semiconductor Interface Quality (Dit, Qit, Nit)||Threshold voltage (Vt), Carrier Mobility, Reliability/ Hysteresis||Diffusion,
|Dielectric Charge (Qf, Qm, Qot, Vfb)||Vt, Reliability/ Hysteresis||Diffusion
|Dielectric Capacitance (CD, CET, EOT)||Vt, Reliability/ GOI, RC||Diffusion
|Surface Charge (VPDM, NVD, Vsurf)||Reliability/ GOI||Cleaning
|Dielectric Leakage (I-V, I-E, SILC, Etunnel)||Reliability/ GOI||Diffusion
In order to meet the individual requirements of our diverse customer base, Semilab offers various versions of these techniques using multiple approaches; including the non-contact Corona-Kelvin method (FAaST system) and the contact methods using Elastic Metal Probe (FCV system) and Mercury Probe (MCV system).
Semilab SDI FAaST systems represent state-of-the-art non-contact electrical metrology used in manufacturing control and development of semiconductor devices and materials. Employing non-contact surface potential probing techniques combined with illumination and/or non-invasive surface charging, these powerful techniques measure a broad range of parameters characterizing semiconductor wafers, dielectrics and interfaces with astounding precision, while saving the cost and time involved in fabricating dedicated test devices.
The major application of the Non-Contact C-V profiling metrology is monitoring of dielectrics during IC manufacturing. The most important feature, differentiating it from conventional electrical measurements, is its preparation free non-contact nature, which eliminates preparation of MOS capacitors, thereby reducing metrology cost and facilitating fast data feedback in both Manufacturing and R&D environments.
The non-contact corona-Kelvin metrology uses corona discharge in air to place an electric charge on a semiconductor wafer. The wafer response is monitored with a vibrating capacitor probe, typically a Kelvin-probe, which measures the surface voltage (Vcpd). Surface voltage monitoring in both the dark and under strong illumination enables separation of two important voltage components:
Analysis of the acquired charge-voltage data provides electrical parameters such as Dit, Vfb, Qtot (dielectric charge), CD, EOT, and Dielectric Leakage.
Example Vcpd vs Qcorona data for dielectric on p-type Si
Example Dit spectra for various dielectrics on Si
The major application of this metrology is monitoring of dielectrics during IC manufacturing. The most important feature, differentiating it from conventional electrical measurements, is its preparation free non-contact nature, which eliminates preparation of MOS capacitors, thereby reducing metrology cost and facilitating fast data feedback in both Manufacturing and R&D environments.
FAaST metrology includes best in the world Semilab SDI unique capabilities:
Semilab SDI FAaST system’s offer:
The WT product line is a powerful measurement platform for performing many different semiconductor material characterization measurements. The base system includes all the overhead functions necessary to perform characterization measurements, including power supplies, computer and operating software, XY measurement stage, etc. The WT-2000 is typically used to make maps, where the wafer is scanned at a programmable raster. Each system is configured to the user’s requirements by adding treatment and measurement capabilities.
The FAaST 300 SL system is the cutting-edge non-contact electrical metrology system that combines both of Semilab SDI’s patented Micro and Macro corona-Kelvin methods into a single platform designed to support advanced R&D as well as the most demanding high-volume manufacturing environment.
Features and System specifications:
WT series are powerful stand-alone tools specifically designed for high volume 300 mm facilities with full factory automation and OHT included.
Features and System Specifications:
|Wafer Size||up to 200 mm||150/200 mm or 200/300 mm||200/300 mm|
|Loading options||up to 4 pieces of 200 mm open cassette||
||Double FOUP platform|
SECS/GEM communication option
|SECS/GEM communication option||Fully automated software|
|Factory automation||Not available, designed for mid-range fabs||Not available, designed for mid-range fabs||Yes, specifically designed for high volume facilities with full factory automation, OHT option|
It is possible to integrate all of the following measurement techniques into one mapping instrument:
WT product line is designed to meet SEMI standards.
The FAaST 350 C-V / I-V system applies Semilab SDI’s advanced C-V / I-V measurements based on patented corona-Kelvin methods to non-contact imaging of dielectrics and interface properties. This workhorse platform is designed with automated wafer handling from dual FOUP Loadport loading stations fully capable of supporting in-line measurements in the most demanding high-volume manufacturing environment.
Features and System specifications:
FAaST 330/230 C-V / I-V systems apply Semilab SDI’s advanced C-V / I-V measurements based on patented corona-Kelvin methods to provide non-contact imaging of dielectric and interface properties on monitor wafers. These platforms include automated wafer handling that is suitable for the medium to high-volume manufacturing environment. These models feature:
FAaST 310/210 C-V / I-V systems apply Semilab SDI’s advanced C-V / I-V measurements based on patented corona-Kelvin methods to provide non-contact imaging of dielectric and interface properties on monitor wafers. The platforms are suitable for R&D and low-volume manufacturing environments. These models feature: