Strain gauge mapping of die surface stresses

Error analysis for piezoresistive stress sensors used in flip chip packaging

“…Multi-element resistor rosettes on silicon have been widely utilized by many groups to measure integrated circuit die stress in electronic packages and other applications [1][2][3][4][5][6][7][8]. This work utilizes resistor rosettes on the (111) surface that respond to all six components of the stress state and therefore can measure the complete three-dimensional state of stress at points on the surface of a die by using properly designed silicon sensors [9,10].…”

Smart Brackets for 3D-Force-Moment Measurements in Orthodontic Research and Therapy – Developmental Status and Prospects*

“…possi-ble to integrate these sensors with circuit blocks into a compact single-chip system, allowing multiple stress sensors to be driven, sensor signals to be filtered, amplified and combined in-situ, and undesirable cross-sensitivity to be compensated for. In addition to their widespread use in the automobile industry as pressure and acceleration sensors [58], these piezoresistive stress sensors are also used in test chips to characterize the mechanical stress occurring during the "packaging" of microelectronic chips [23,48,54,55,56,61], whereby the reproducibility and reliability of processing technologies are primarily analyzed. Further developments in such integrated systems include arrays of up to 32 × 32 stress sensors distributed over the chip surface [24] for representative determination of mechanical stress distribution in that sensor chip region.…”

“…Neben ihrer weit verbreiteten Anwendung in der Automobilindustrie als Druck-und Beschleunigungssensoren [58] werden piezoresistive Stress-Sensorstrukturen z.B. auch in Testchips zur Charakterisierung der mechanischen Stressverhältnisse bei der "Verpackung" von mikroelektronischen Chips eingesetzt [23,48,54,55,56,61], wobei primär Aspekte der Reproduzierbarkeit und Zutromechanical sensor system with 32 stress-sensor elements measuring 6 × 3 mm 2 (scale of ca. 2.5:1).…”

Importance of molding compound chemical shrinkage in the stress and warpage analysis of PQFPs

“…The development of low stress molding compounds, "softer" die attach materials, and the use of die coatings are among the most commonly adopted approaches of achieving this aim [3], [4]. Although stress sensing test chips can be difficult to calibrate accurately [5], they are widely used as a means of confirming whether the material or structural changes to packages do indeed reduce the magnitude of stress on the chip [6], [7].…”