The volume manufacturing of electronics has been around since the early 1900s. The introduction of the printed wiring (or circuit) board has been the basis of most of the electronic/electrical products since before World War II. The vacuum tubes permitted the development of circuitry that could add new functionality to the circuitry and enabled the development of radio, radar, and many other advances. While television was demonstrated int eh 1930s, it wasn’t until the 1950s that it started to become commonplace.
Vacuum tubes had reliability problems with short lifetime and the constant need to replace them. Banks and banks of vacuum tubes were requi8red for applications and the heat generated by the vacuum tubes and the constant maintenance demonstrated the need for a better solution. Bell labs developed the transistor to replace the vacuum tubes and increase the reliability of the switching circuits for AT&T’s phone lines.
The development of mass production of the transistor enabled the creation of phone line connections that could automatically route calls to various destinations. In the early 1960, Texas Instruments (TI) patented the integrated circuit, which enabled the development of more complex circuits with advance functionality. The semiconductor industry is an outgrowth of these early pioneering efforts.
The semiconductors were applied to various designs for different capabilities. There was still a need to connect the semiconductors with various functionalities. This was done by using circuity boards and placing various semiconductor chips into the circuity in the board.
The semiconductor circuitry has grown more complex while the size of the transistor and related components in the semiconductor have decreased. The doubling of density of components followed a 70% shrinkage in linear size every 18 to 24 months. (70% width times 70% length yields a 49% area reductions or a doubling of density.)
The semiconductor components are still mounted into individual packages or multi-chip packages, which are them mounted on circuit boards. The manufacture of these semiconductor devices requires a package that can be handled by automated assembly equipment. The limit of circuit board assembly equipment is based on the size of the smallest component that can be picked up and accurately placed. Current automated electronic assembly equipment is limited to a component no smaller than 0.005 inch (127 µm) by 0.010 inch (254 µm).
Current small devices are in the millimeter range. Devices smaller than this can be obtained if the volume is very high (in the many millions of devices). There are examples of devices approaching the single digit millimeter and smaller sizes. Semiconductors need very high volume to be cost effective for most applications. The circuit board construction becomes problematic when the sizes shrink to the single digit millimeter and smaller range. Consequently, it is possible to manufacture devices using circuit boards (or other type of substrates, like thick and thin file substrates). Semiconductors can be produced effectively in the smaller sizes as long as the volume is large.
There is a gap, sub-millimeter devices, that does not have volume manufacturing capability available for producing quantities of devices that can have various different types of functionality that can be assembled as the mission need changes. This “in-between” size of manufacturing has not been addressed to date. There are devices being developed that will require this type of manufacturing capability. However, the development of this “devices” requires more than a sophisticated assembly mechanism.
This topic will be continued in future blogs. Stay “tuned”.