What are the applications of slow wire electrical discharge machining technology in semiconductor packaging molds?

As semiconductor technology progresses towards 5-nanometer, 3-nanometer, and even smaller manufacturing processes, the performance and integration of chips are becoming increasingly superior. During this process, semiconductor packaging technology, as the final step in chip manufacturing, has become increasingly important.

The accuracy of semiconductor packaging molds directly determines the yield and performance of chip packaging. And the slow wire-cutting discharge machining technology, with its micrometer-level accuracy and ability to process complex contours, is playing an increasingly crucial role in this field.

Precise Foundation: The Technical Principle of Slow Wire Electrical Discharge Machining

Slow wire electrical discharge machining is a non-contact processing technology that uses a metal wire as the electrode and generates high temperatures through pulsed discharge to melt or gasify the material of the workpiece. Unlike traditional mechanical processing, it does not produce cutting force during the processing, making it particularly suitable for processing high-hardness and complex-shaped mold parts.

Its core advantage lies in the ability to achieve micrometer-level processing accuracy. Slow wire electrical discharge machining usually uses a one-time brass wire or galvanized wire as the electrode, with a relatively slow wire movement speed, typically ranging from several millimeters to several meters per second. This makes the processing process more stable and enables higher surface finish and dimensional accuracy.

The processing requirements for semiconductor packaging molds are extremely strict. For example, the clearance between the punch and the die of the lead frame mold usually needs to be controlled within a few microns, and the surface roughness requirement is Ra ≤ 0.8 μm. Only slow wire electrical discharge machining technology can simultaneously meet these requirements and has become an indispensable process method for semiconductor packaging mold manufacturing.

Application Scenario: The Specific Application of Slow Wire Cutting in Packaging Mold Manufacturing

In the manufacturing of semiconductor packaging molds, the application of slow wire cutting technology runs through the entire process from design to completion. For lead frame stamping molds, this technology can produce punches and dies with complex shapes and extremely high precision, ensuring the accuracy of the lead frame pin spacing and position.

The processing of plastic packaging molds also relies on slow wire cutting. The cavities of plastic packaging molds require extremely high surface finish to reduce plastic flow resistance and ensure the appearance quality of the chip packaging. Slow wire cutting can achieve mirror-like processing effects, with surface roughness reaching Ra ≤ 0.4 μm, meeting the requirements of high-end plastic packaging molds.

With the increase in chip integration and the continuous reduction of packaging sizes, the requirements for mold precision have also risen. For example, the micro-hole processing of ball grid array packaging molds, with hole diameters possibly less than 0.1 millimeters and a depth-to-diameter ratio of over 10:1, only slow wire cutting technology can complete such a highly challenging processing task.

Technical Breakthrough: Key Innovations in Semiconductor Packaging Mold Processing

In response to the trend of the semiconductor industry moving towards larger sizes and higher precision, the slow wire cutting technology has continuously made innovative breakthroughs. When processing large-sized packaging molds, traditional techniques encounter problems such as insufficient supply of inter-electrode working fluid and difficulty in discharging the etched products, resulting in low processing efficiency and poor surface quality.

To address these challenges, the latest technological advancements include a multi-channel high-pressure adaptive fluid supply system and a negative pressure-assisted chip removal device. These innovations ensure that the inter-electrode working fluid penetration rate is ≥ 95% when processing ultra-high-thickness workpieces of 1000 millimeters or more, effectively maintaining a stable discharge environment.

At the same time, the application of the new power supply plate technology significantly improves processing efficiency. The power supply plate with a three-dimensional topological conductive network structure enhances the uniformity of current density by 62%, and still maintains a ±0.001 millimeter accuracy stability during continuous processing. This breakthrough reduces the cutting time for complex molds by 40% and reduces electrode wear to 1/3 of the traditional process.

Equipment Evolution: Processing Equipment Optimized for Semiconductor Packaging

With the increasing demand for semiconductor packaging mold processing, equipment manufacturers have launched dedicated models. Mitsubishi Electric's electrical discharge machining machine SG8P is specifically designed to meet the processing requirements of the semiconductor packaging industry.

This model is equipped with semiconductor mold-specific processing conditions, adds high-quality semiconductor packaging surface fine processing circuits, and is configured with a dedicated processing fluid circulation system. It can be optimized for different packaging molds, reducing processing time while improving processing quality, and creating a high-quality processing surface most suitable for semiconductor packaging molds.

In addition, the emergence of non-metal wire cutting machines has further expanded the application scope of slow wire cutting technology. Traditional wire cutting relies on conductive materials, while non-metal wire cutting machines break this limitation and can process key semiconductor materials such as silicon carbide and silicon crystals.

These devices adopt a large and wide high-stiffness casting base design, effectively improving processing stability and accuracy, and the cutting speed is 300% to 600% higher than the previous generation. This provides more material options and process flexibility for semiconductor packaging mold manufacturing.

Future Challenges: The Tension Between Technical Barriers and Industrial Demand

Although the slow wire electrical discharge machining technology has made significant progress in semiconductor packaging mold processing, it still faces many challenges. As the chip packaging technology continues to develop, the requirements for mold accuracy and complexity will continue to increase, which requires the wire cutting technology to develop towards higher precision and higher efficiency.

The current main technical bottlenecks include insufficient supply of inter-electrode working fluid during high-energy and high-thickness cutting, as well as the difficulty in timely discharging the etching products. For ultra-high-thickness workpieces over 1000 millimeters, the existing process cannot fully meet the precision and efficiency requirements of the semiconductor industry.

In the future, the slow wire cutting technology will develop towards the direction of intelligence and integration. The next generation products are expected to be equipped with a self-learning current regulation system, which can automatically optimize the conductive network according to the processing parameters. At the same time, the introduction of biodegradable coating technology will enable the power board to decompose naturally, solving the environmental problems in the precision processing industry.

Xincheng is a professional manufacturer and purchaser of Wire EDM Parts in China. Welcome to consult！