Patent Application
20090212093
Embodiments are generally related to sensor devices and components. Embodiments are also related to pressure sensors that incorporate IC (Integrated Circuit) components. Embodiments are additionally related to methods for direct die-to-die wire bonding.
Many processes and devices have been used in the field of pressure sensing. Pressure sensors are generally used and deployed wherever a need for monitoring and responding to pressure changes is necessary. Pressure sensors are commonly used in a variety of automotive, aerospace, commercial, industrial, and consumer applications.
The operational environments in which pressure sensors are required to operate in these applications with high accuracy and repeatability can be very demanding. For example, extreme thermal conditions including thermal shocks in ranges from 150 C to −55 C, and extreme conditions of shock and vibration.
Pressure sensors may typically include a substrate, a silicon pressure sense die with a diaphragm movable in response to pressure programmable compensation IC die, a cover to enclose the diaphragm, and terminals extending through some part of the base or cover to supply power and to measure a pressure signal. The programmable compensation IC die can be utilized for adjusting the output of the sensor die to obtain the pressure signal. In such a configuration, wire bonds can be utilized to provide an electrical connection between bonding pads on a top surface of the silicon sense die and compensation IC die and conductor paths on the ceramic substrate.
In the majority of prior art applications, the silicon pressure sense die is bonded to the compensation integrated circuit die by bonding each die separately to the ceramic substrate and utilizing traces on the substrate to connect the two die. Hence, these wire bonds require area on the ceramic substrate for bond pads which increases the number of the wire bonds. Two wire bonds, with an intervening conductive trace on the ceramic substrate are required to make each connection between the pressure sense die and the programmable compensation IC. The inductance of the connective path increases as the length of the path increases. The increase in the number and length of the wire bonds further increases package size and manufacturing cost. Further, the reliability of the sensor can also be affected by the number of wire bonds required. In general, it is desirable to reduce the length and number of the wire bonds and conductive traces utilized to connect the pressure sense die wire bond pads to the compensation integrated circuit die.
Based on the foregoing it is believed that a need exists for an improved method for direct die-to-die wire bonding. It is also believed that a need exists for an improved pressure die pad layout that is compatible with different compensation integrated circuit dies.
The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments disclosed and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole.
It is, therefore, one aspect of the present invention to provide for improved sensor devices and components.
It is another aspect of the present invention to provide for improved pressure sensor die pad layout that is compatible with different compensation IC dies.
It is further aspect of the present invention to provide for improved methods for direct die-to-die wire bonding.
The aforementioned aspects and other objectives and advantages can now be achieved as described herein. A method for direct die-to-die wire bonding incorporates a pressure sense die and a programmable compensation IC (Integrated Circuit) die that can be mounted on a ceramic substrate. The two die can be positioned beside each other such that wire bond pads on the pressure sense die and bonding leads on the compensation IC die are sufficiently close to each other to wire bond directly between the two die. For this to be possible, the bond pads must be in the same order. The pressure sense die and the compensation IC can be connected directly with wire bonds in order to reduce the number of wire bonds and improve reliability. The pressure sense die can be designed with multiple wire bond pad patterns in order to be utilized with different programmable compensation IC dies. The method and pressure sense die layout as disclosed in greater detail herein reduces the number of wire bonds required to connect the pressure sense die and the compensation IC die.
The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the embodiments and, together with the detailed description, serve to explain the embodiments disclosed herein.
The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof.
Referring to
Note that the term “power supply” as utilized herein is intended to include both power and ground. The pressure sense die 105 includes only a few representative bonding pads however, it should be understood that the pressure sense die 105 can possess a multiplicity of both signal bond pads and power supply bond pads. Similarly, the second set of wire bond pad pattern 120 also includes signal bond pads 145, 165, 185 and power supply bond pads 135 and 155. The pressure sense die 105 further includes bonding lines 130, 150, 140 and 160 for the power supply bond pads 135 and 155 and signal bond pads 145 and 165 respectively.
The pressure sense die pad system 100 includes bond pads only along the edges for illustrative purpose of clarity however, bond pads can also be provided along the remaining edges of the die 105 so that the sense die 105 can be compatible with different programmable compensation IC dies. Bond pads on the pressure sense die can provide signals other than pressure, bond pads 175 and 185 could be connected to a diode device that provides a signal proportional to temperature, for example.
Referring to
The pressure sense die 105 such as shown in
A programmable compensation IC die 250 can be mounted on the ceramic substrate 230 as depicted in
The bond pads 135, 145, 155, 165 and 170 of the pressure sense die 105 can be connected to respective bonding leads of the programmable compensation IC die 250 on a one-to-one basis utilizing bond wires 220, 222, 224, 226 and 228. For example, the power supply-bonding pad 135 and 155 on the pressure sense die 105 can be electrically connected to a power supply-bonding leads 260 and 265 of the programmable compensation IC die 250 with wire bonds 224 and 228. Very thin bond wires usually formed of aluminum or gold can be utilized to connect the bond pads on the pressure sense die 105 on a one-for one basis with the bond leads on the integrated circuit die 250. In this way, electrical connections can be established from the bond pads to the package leads.
Referring to
It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
