Company Events

Becoming a semiconductor manufacturer now is a tricky process. In previously low-cost industrial areas, wages and energy prices have risen, while capital expenditures have risen. At the same time, competition is heating up, and a large number of new businesses have entered the market in recent years. It is understandable that industry participants are anxious about these changes, and they have been pursuing a record number of mergers and acquisitions in order to take advantage of the next wave of productivity growth.

Semiconductor manufacturing is divided into two stages: "front end" and "back end". After all the circuits are formed on the wafer, back-end semiconductor manufacturing refers to manufacturing operations. Revolutionary technology is created by combining extraordinary accuracy and precision with tremendous throughput.

Many operations in back-end semiconductor production use servo drives because of their excellent performance and repeatability, which is exactly what high-end semiconductor processing requires.

Most of the back-end factories in emerging countries have not yet used Industry 4.0 technology in their key operations, including wafer dicing, assembly, testing, and packaging of individual semiconductors. Many of these factories are still struggling to implement lean methods common in front-end factories. Even if back-end manufacturers get some benefits from lean programs, they often struggle to keep improving.

In the face of increasing consumer demand and the improvement of industry competitiveness, the relevance of back-end activities in semiconductor production continues to increase. More effective tools are needed to assist machine setup and batch scheduling decisions to achieve short cycle times, high throughput, and high utilization, while improving expiration date performance.

Leaderboard back-end tool process

Wafer inspection

Optical wafer inspection looks for defects that may cause problems in the final product. Defects and annoyances as small as 30 nanometers can be detected, and the effective use is as small as 10 nanometers. Electron beam detection overcomes the limitations of optical detection and is accurate to sub-3 nanometer resolution. Compared with optical inspection, electron beam inspection can identify the smallest faults, but has lower throughput. When defects and troubles are discovered, they will be mapped and corrected or avoided.

Wafer test/wafer probe

These chips are tested for the first time throughout the semiconductor manufacturing process to ensure that they perform as expected. Perform a functional inspection while the chip is still on the wafer, using a test fixture with pins to contact the circuit on the surface of the chip. The signal response of the chip is sent and measured by the probe. If feasible, repair the defective chips; otherwise, they will be destroyed after the cutting process.

Dicing wafer

In this back-end semiconductor manufacturing process, the finished wafer is cut into individual chips. Mechanical sawing and laser cutting are two automated methods. The cutting saw uses a circular cutting blade to cut the mold into a size of 35mm to 0.1mm for mechanical sawing. The chip is then transferred to the chip bonding process using chip processing equipment.

Servo motion is suitable for aligning the dicing saw and wafer and adjusting the dicing blade.

Chip bonding

A single chip is too small and fragile to handle alone. They must be protected, and there must be an easy way to electrically connect to the chip. The process of bonding the bare chip to the substrate is called chip bonding or chip bonding.

In the next process, the substrate will serve as the interface between the tiny size of the chip and large-scale electronic processing. It will also serve as the basis for PC board protection chip packaging.

Wire connector

Wire bonding uses fine gold wires to connect each pad on the die to a corresponding pad on the substrate after die bonding. This connects the silicon chip in the chip container to the external pins through electrical connections. Wire bonding is used in traditional chip packaging, such as dual in-line packaging (DIP), which has a characteristic black rectangular rectangle with silver pins protruding like bug legs, and PLCC packages, which have conductors on all four sides.

Wire bonders run at extremely fast speeds to maintain the large number of connections required for each chip. In fact, this is one of our most bandwidth-intensive applications.

Flip Chip/Solder Ball

Flip chips are mounted "backwards" as a modern alternative to wire bonding. As a result, the term "flip chip" was coined. Unlike the wires that are connected around the edge of the chip in wire bonding, an array of "bumps" is created on the surface of the chip. These bumps are used as connectors between the chip and surrounding containers. The following are some of the benefits of flip chip technology:

    A better connection to the chip, rather than wire bonding, will add extra length, capacitance and inductance, all of which will reduce signal speed.
    Since the entire chip is exposed, not just the border, more connection sites can be accessed.
    Increase production speed
    The overall package size is small.

Encapsulation

When the back-end semiconductor manufacturing process is completed, a molded plastic compound or a sealing cover is used to seal the bonded chip and frame. The silicon chip is now ready to be used in the electronics industry.

How to optimize the back-end tools?

Utilize the full potential of the workforce

Operator contact time The time employees spend in contact with materials or running machines accounts for 30% to 50% of all work in the back-end factory. Employees often sit idle for the remainder of the working day while waiting for the machine to complete its manufacturing cycle. Even if the production line is not running at full capacity, the ratio of employees to machines is the same, which increases the duration of employees not actively participating in the work.

Standard lean practices, such as changing the ratio of workers to machines based on operator contact time or adopting flexible staffing to ensure that the number of people in the workshop is sufficient to meet the current capabilities of the factory, has helped some back-end manufacturers increase labor productivity. These initiatives have produced some benefits, but they are difficult to maintain, which means that back-end production is still labor-intensive.

Improve quality without delaying the production line

The engineering team must study machine data and communicate with colleagues on the production line to determine the specific production steps that will cause losses in the event of production peaks or losses or unexpected quality problems in the back-end facilities. However, engineers may only collect data once a week, which makes it more difficult to pinpoint the root cause long after the problem occurs.

Engineers may need to interview production line employees to obtain information, and workers may recall some basic data about tool settings or other operating environments, which may cause delays.

Establishing a dedicated production and quality improvement team and daily lean "meetings" may be a more desirable approach. These organized discussions can help engineers grasp output stability and unpredictability and other issues, so as to make improvements.

Consider throughput in a more proficient way

Most back-end factories rely on absolute indicators of available or unavailable uptime equipment, ignoring subtle results, such as small shutdowns that do not result in a complete shutdown when evaluating OEE. In addition, back-end manufacturers use manual procedures to track production losses, which will only reveal a wide range of patterns over time. These high-level conclusions do not allow engineers to fully understand the factors that cause production problems, so it is difficult to formulate improvement strategies.

In order to solve these problems, some return to the basic principles of lean are needed. For example, a manufacturer may form a continuous improvement team to prioritize and identify the source of throughput bottlenecks. Many organizations have these teams, although they are not always present in the back-end factories.

Consider a simple idea: Machines can be equipped with sensors to track major events that affect OEE, such as production failures or equipment failures. The operator will then enter contextual data through the touch screen interface, saving time for manual data entry and providing engineers with higher-level detailed information.

All in all, the semiconductor business is the leader in data collection; the problem is that companies only use part of the data they obtain. For the first time, advanced technology can help manufacturers tap their vast knowledge base and provide specific and practical insights needed to develop solutions.

In addition, Industrial Revolution 4.0 tools can automate many time-consuming processes that are now done manually in back-end factories. Together, these enhancements help managers execute lean plans faster and more effectively, and some organizations have seen meaningful cost, throughput, and quality advantages within a few months.

Back-end factories that integrate smart manufacturing technologies may stand out in the highly competitive semiconductor industry, surpassing companies that use more traditional lean methods.