Component including two semiconductor elements, between which at least two hermetically sealed cavities are formed and method for establishing a corresponding bonding connection between two semiconductor elements

What is this patent about?

’000 is related to the field of semiconductor manufacturing and micro-electromechanical systems (MEMS). Specifically, it addresses the challenge of packaging multiple sensor components on a single chip when those components require different operating environments, such as the high-vacuum conditions needed for a gyroscope versus the higher damping pressure required for an accelerometer.

The underlying idea behind ’000 is to utilize the topography of the semiconductor substrate itself to facilitate a multi-stage sealing process. By etching or depositing material to create different surface levels on the wafer before applying the bonding material, the inventor ensures that bonding frames are physically offset from one another. This height differential allows a cap to be pressed down in increments, sealing one cavity at a first ambient pressure and then a second cavity at a different pressure.

The claims of ’000 focus on a component structure where at least two semiconductor elements are joined by a structured connecting layer to form multiple hermetically sealed cavities. The critical limitation is that the circumferential bonding frames for these cavities must be situated on different surface levels of at least one of the elements, enabling them to be closed at different times during the assembly process.

In practice, this is achieved by creating a trench-type recess or a pedestal on the surface of the MEMS wafer or the cap wafer. A bonding material of uniform thickness is then applied across these varying heights. When the two wafers are brought together, the most elevated bonding frame makes contact first, sealing the first sensor. As the wafers are pressed closer together, the recessed bonding frame eventually makes contact, sealing the second sensor under a new set of chamber pressure conditions.

This approach differs from prior methods that relied on depositing bonding layers of varying thicknesses, which is a complex and often unreliable process. By moving the height variation into the substrate topography, the invention allows for a single, uniform deposition of bonding material. This simplifies the manufacturing flow and makes the sequential bonding process compatible with standard materials like Al-Ge or Au-Si without requiring specialized, multi-thickness metal deposition.