Introductory Information About Silicon Nitride Film Stress and Wafer Processing

Low Accent LPCVD Nitride with a Blur Accent of beneath than 250 MPa Compactness is generally acclimated for architecture Membranes film thickness, Cantilever Beams and added automated structures. Low Accent Nitride is additionally actual able as a KOH. The characteristics of silicon-nitride films deposited with plasma-enhanced actinic breath degradation (PECVD) can alter in agreement and concrete properties. An important constant in the artifact of micro-electro-mechanical systems (MEMS) accessories is the ascendancy and dressmaking of the blur stress. In fact, silicon-nitride blur accent can alter from compactness (up to 800 MPa) to compressive (-500 MPa), depending on the PECVD degradation conditions.

One of the basal architecture blocks in silicon dent processing and MEMS processing is the adeptness to drop attenuate films of actual assimilate a wafer. One such degradation action is LPCVD Silicon Nitride, a attenuate blur degradation action that coats all of the apparent areas of the wafer. The aberration in automated backdrop amid the nitride and the silicon dent will acquaint a "stress" in the dent + nitride system.

Tensile and Compressive Stress: If there is an according bulk of nitride on both abandon of the dent it will be in a counterbalanced accompaniment film thickness and abide flat.

If the nitride is removed from one ancillary of the dent the arrangement will no best be in calm and the dent will bow. If the dent curves up against the ancillary with the nitride, the nitride is advised to be tensile. If the dent curves bottomward abroad from the ancillary with the nitride, the nitride is advised to be compressive.

Selecting the Right Blur Stress: Choosing the actual blur accent can be acute to crop and achievement of the device. For instance, if Stoichiometric Nitride (800 Mpa Tensile) is acclimated as a KOH mask, too blubbery of a blur can advance to micro-cracking and blur failure. Switching to a Low Accent NItride (200 Mpa Tensile) will annihilate micro arise and advance yield.

Film Accent for MEMS: Having too low of a blur accent can additionally account problems for assertive applications. Many MEMS branch applications use silicon nitride as a membrane, diaphragm, or added abeyant structure. Insufficient compactness accent can aftereffect in structures that can "sag" or "droop". Typically, the thinner the nitride, the added compactness accent is bare to accumulate a abeyant anatomy flat.

Remember, the absolute abeyant anatomy charge be advised a "system". If added compressive films such as PECVD Oxide are added on top of the nitride, added accent charge be congenital into the nitride to atone for it. The absolute "system" charge be tensile.

Applications Guide: Here are some of our nitride recommendations for baddest applications:

KOH Etch Mask: Nitride Thickness (500 to 3000 A)
Film type: stoichiometric Nitride On Oxide Accent
Target (-300/800 Mpa)

Thickness (500 to 10,000 A)
Film type: Low Accent Nitride Accent
Target (200 Mpa)

Thickness (500 to 30,000 A)
Film type: Super Low Accent Nitride Accent
Target (50 Mpa)

Suspended Structures:
Nitride Thickness (Less than 500 A)
Film type: Low Accent Nitride Accent
Target (350 Mpa)

Thickness (500 to 1000 A)
Film type: Low Accent Nitride Accent
Target (300 Mpa)

Thickness (1000 to 5,000 A)
Film type: Low Accent Nitride Accent
Target (250 Mpa)

Thickness (5,000 to 10,000 A)
Film type: Low Accent Nitride Accent
Target (200 Mpa)

Thickness (10,000 to 15,000 A)
Film type: Low Accent Nitride Accent
Target (150 Mpa)

Thickness (15,000 to 20,000 A)
Film type: Super Low Accent Nitride Accent
Target (100 Mpa)

Thickness (20,000 to 30,000 A)
Film type: Super Low Accent Nitride Accent
Target (50 Mpa)

Jessica entered the Semiconductor film thickness Manufacturing acreage in 1998 and is now the architect of Rogue Valley Microdevices in 2003.