《Microelectronics Process》MEMS LAB SESSION 3

MEMS LAB SESSION 3 (Mechanical Characterization) OVERVIEW OF LAB SESSION: In this lab session, the cantilever and fixed-fixed beams will be mechanically tested to determ material and device performance characteristics. The structures will be mechanically loaded the corresponding deflection measured. From the load versus deflection curves, an effective spring constant can be calculated. This spring constant is used to analytically determine a fundamental material property, the Young's Modulus, of the silicon nitride. etermine a LAB OBJECTIVES This lab session has the following primary objectives Cleave wafers to prepare samples for testing Perform load versus deflection tests on silicon nitride beams act s pring constant. Calculate the Youngs Modulus, a basic material property, of the silicon nitride Initial instruction on the following major piece of lab equipment Hysitron Triboindenter LAB PROCEDURES MEMS Lab Session 3 has 2 major steps 3.1 CLEAVE WAFER MOUNT DIE 3.1.1 Tool: Diamond Scribe 3. 1.2 USing the diamond scribe, carefully push down on the edges of the wafer at the ends of dice lanes to separate the wafer into individual dies. Pick groups of four dies from different parts of wafers to be glued to a 1"x 1 "steel (not stainless steel) mounting plate. It is important that the plate be magnetic 3.2 LOAD VS DEFLECTION TEST 3.2.1 Tool: Hysitron Triboindenter 3.2.2 Since we will be deflecting the beams versus actually indenting them, use a conical shaped diamond tip with a 10 micron radius of curvature. If necessary, do an air indent to calibrate the piezoelectric transducer that moves the indenter tip. Trace pure Al sample to set the x-y safety limits for the stage movement. Make a H-shape Pattern to calibrate the x-y stage offset(this yields the registration between the tip and the optical microscope employed to image the cantilevers). Finally find the cantilever of interest and perform a load-deflection experiment(the maximum displacement is around 5 microns and the maximum load, 10 mN) PRE-LAB QUESTIONS 1. How is the indenter transducer actuated?

MEMS LAB SESSION 3 (Mechanical Characterization) OVERVIEW OF LAB SESSION: In this lab session, the cantilever and fixed-fixed beams will be mechanically tested to determine material and device performance characteristics. The structures will be mechanically loaded and the corresponding deflection measured. From the load versus deflection curves, an effective spring constant can be calculated. This spring constant is used to analytically determine a fundamental material property, the Young’s Modulus, of the silicon nitride. LAB OBJECTIVES: This lab session has the following primary objectives: ¾ Cleave wafers to prepare samples for testing. ¾ Perform load versus deflection tests on silicon nitride beams. ¾ Extract spring constant. ¾ Calculate the Young’s Modulus, a basic material property, of the silicon nitride. ¾ Initial instruction on the following major piece of lab equipment: Diamond Scribe Hysitron TriboIndenter LAB PROCEDURES: MEMS Lab Session 3 has 2 major steps: 3.1 CLEAVE WAFER & MOUNT DIE 3.1.1 Tool: Diamond Scribe 3.1.2 Using the diamond scribe, carefully push down on the edges of the wafer at the ends of dice lanes to separate the wafer into individual dies. Pick groups of four dies from different parts of wafers to be glued to a 1” x 1” steel (not stainless steel) mounting plate. It is important that the plate be magnetic. 3.2 LOAD VS. DEFLECTION TEST 3.2.1 Tool: Hysitron TriboIndenter 3.2.2 Since we will be deflecting the beams versus actually indenting them, use a conical shaped diamond tip with a 10 micron radius of curvature. If necessary, do an air indent to calibrate the piezoelectric transducer that moves the indenter tip. Trace a pure Al sample to set the x-y safety limits for the stage movement. Make a H-shaped Pattern to calibrate the x-y stage offset (this yields the registration between the tip and the optical microscope employed to image the cantilevers). Finally find the cantilever of interest and perform a load-deflection experiment (the maximum displacement is around 5 microns and the maximum load, 10 mN). PRE-LAB QUESTIONS: 1. How is the indenter transducer actuated? Page 1 of 2

2. Why is the periphery of the aluminum sample traced 3. What is the maximum spring constant that can be measured by the Hysitron Triboindenter? 4. What is the relationship between the effective spring constant and Young's modulus for a cantilever beam? For a fixed-fixed beam? Page 2 of 2

2. Why is the periphery of the aluminum sample traced? 3. What is the maximum spring constant that can be measured by the Hysitron TriboIndenter? 4. What is the relationship between the effective spring constant and Young’s modulus for a cantilever beam? For a fixed-fixed beam? Page 2 of 2