What is wafer microbumping packaging?

Wafer microbumping packaging, more commonly expressed as Wafer Microbumping or Wafer Bumping, is an advanced semiconductor packaging technology.The following is a detailed explanation of Wafer Bumping:

I. Definitions and rationale

Wafer micro-bump packaging refers to the formation or installation of tiny bumps (also known as bumps) at pre-determined locations on the wafer before it is cut into individual chips, which will serve as interfaces between the chip and external circuitry.The principle involves creating a series of bumps on the surface of the wafer to interconnect the chip to a PCB (printed circuit board) or substrate.

II. Methods of Bump Formation

Wafer bumping technology includes a number of different bump formation methods, such as:

Printed bumps: Bumps are formed on wafers by printing.

Electroplated bumps: Bumps are formed by depositing metal on a wafer using electroplating technology.

Other methods: e.g. eutectic plating type drop balls, lead-free alloys and copper pillar alloy bumping techniques.

III. Material and structure of bumps

Bumps are available in a variety of material choices, including gold (Au), copper/nickel/gold (Cu/Ni/Au), copper pillar, tin/lead (Sn/Pb) and tin/silver/copper (Sn/Ag/Cu).Bumps are also available in a variety of structures and shapes, such as mushroom, straight, cylindrical, spherical, etc., to suit different packaging needs.

IV. Technical advantages and applications

Wafer micro-bump packaging technology has significant technical advantages, including:

High Integration: Tiny bump sizes enable high density bumps to be formed on wafers, resulting in increased integration.

High-frequency performance: Gold bump-based thermosonic bonding technology offers excellent high-frequency performance.

Precise control: Allows precise control of the height, shape and position of the bump, improving the quality and reliability of the bump.

In addition, wafer micro-bumping technology can be used in various packaging types, such as flip chip packaging, three-dimensional integrated circuit packaging, etc., which are widely used in the electronics industry.

V. Technical challenges and development trends

Despite its many advantages, wafer microbump packaging technology faces a number of technical challenges, such as high manufacturing costs, complex technical difficulties and possible reliability issues.In the future, wafer microbump packaging technology will continue to develop in the direction of miniaturisation, small pitch, lead-free and high reliability.As the functions and feature sizes of heterogeneous integration modules continue to increase, three-dimensional integration technology has emerged, and interconnections between bumps will become the key to realising three-dimensional stacking of chips.

In summary, wafer micro-bump packaging technology is an important technology in the field of semiconductor packaging, which is of great significance for improving the performance and integration of integrated circuits.With the continuous progress and innovation of technology, wafer micro bump packaging technology will play a more important role in the future.