Combining Sealed and Exposed Sensors on One Microchip

This patent describes a microchip design that integrates multiple tiny sensors on the same side, where one sensor is exposed to the outside world through a backside hole while others remain protected by a sealed cap.

What it covers

This patent describes a microelectromechanical systems (MEMS) sensor device that integrates multiple sensors on a single chip. It includes a substrate with a 'first side' and an opposing 'second side' (claim 1). A 'first sensor' and a 'second sensor' are both placed on the 'first side' of this substrate, at different locations (claim 1). The 'second sensor' contains a 'sense element' (claim 1), which is the part that detects physical changes. A key feature is a 'cavity' that extends through the substrate from the 'second side' (the back) to expose this 'sense element' of the second sensor to the external environment (claim 1). This allows the sense element, for example a diaphragm in a pressure sensor, to move in response to an external stimulus like pressure (claim 2). Both the first and second sensors are then enclosed together within a 'hermetically sealed chamber' formed by a cap coupled to the 'first side' of the substrate (claim 1). This setup allows for sensors with different environmental exposure needs to be manufactured on the same chip, such as an inertial sensor (first sensor) and a pressure sensor (second sensor) (claim 3).

What it doesn't cover

• —Does not cover a device where the first and second sensors are placed on opposite sides of the substrate, as both are required to be on the 'first side' (claim 1).
• —Does not cover a device where the cavity for the second sensor's sense element does not extend completely through the substrate from the 'second side' (claim 1).
• —Does not cover a device where both the first and second sensors are directly exposed to the external environment via through-substrate cavities.
• —Does not cover a device that lacks a 'hermetically sealed chamber' enclosing both the first and second sensors (claim 1).
• —Does not cover a device where the sensors are not 'laterally spaced apart' on the substrate, meaning they are at distinct locations (claim 1).

The clever bit

The clever part is integrating sensors with fundamentally different environmental requirements on the same side of a microchip. It allows one sensor (like a pressure sensor) to be exposed to the outside through a precisely etched hole from the back of the chip, while other sensors (like accelerometers) remain protected within a single, shared hermetically sealed chamber, simplifying manufacturing and packaging.

Why it matters

This patent addresses a common challenge in microchip manufacturing: how to combine different types of sensors, some needing to be sealed from the outside world (like accelerometers) and others needing direct exposure (like pressure sensors), onto a single, compact chip. By providing a method to expose only specific parts of one sensor through a backside cavity while keeping others sealed under a common cap, it enables the creation of smaller, more efficient multi-sensor modules. This integration is vital for reducing the size, cost, and power consumption of devices that require multiple types of environmental sensing.

Real-world examples

• 1.Integrated pressure and inertial sensors in smartphones
• 2.Multi-sensor modules in smartwatches and fitness trackers
• 3.Environmental monitoring sensors in Internet of Things (IoT) devices
• 4.Combined altimeter and motion sensors in drones