What has now become a very tricky process for Chinese semiconductor producers. In previously low-cost industrial zones, wages and energy consumption prices are rising, while capital cost expenditures climb. At the same time, competitiveness is heating up, and a large number of new businesses have joined the world market in recent years. Industry participants are understandably anxious about these data changes, and they themselves have been pursuing a record number of mergers and acquisitions in a bid to capitalize on the next wave of productivity growth.
Semiconductor manufacturing is divided into two stages, the "front-end" and the "back-end". After all the circuits are formed on the wafer, back-end semiconductor manufacturing refers to the fabrication operation. Revolutionary technology is created by combining extraordinary accuracy with precision and tremendous throughput.
Many of the operations in back-end semiconductor manufacturing utilize servo drives because of their superior performance and repeatability, which is exactly what is needed for high-end semiconductor processing.
Most back-end fabs in emerging countries have yet to utilize industry 4.0 technologies in their key operations, including wafer dicing, wafer test assembly, testing, and packaging of individual semiconductors. Many of these fabs are still trying to implement lean methods common in front-end fabs. Even when back-end manufacturers benefit from lean programs, they often struggle to keep up.
The relevance of back-end management activities in semiconductor manufacturing continues to struggle to improve in the face of the problematic development of growing consumer demand and increased market competitiveness in the education industry. More effective tools are needed to assist machines can setup and batch scheduling decisions to achieve short cycle times, high throughput and high utilization, but also to improve due date performance.
The process of line list back-end tools
Wafer Inspection
Optical wafer inspection will look for defects that could cause problems for the final product. Defects and faults as small as 30 nanometers can be detected with effective use as small as 10 nanometers. E-beam inspection overcomes the limitations of optical inspection and can be accurate to sub-3 nanometer resolution. E-beam inspection recognizes the smallest faults but has low throughput compared to optical inspection. Defects and faults are mapped and corrected or avoided as they are found.
Wafer Test/Wafer Probe
These chips are tested for the first time in the semiconductor manufacturing process to make sure they work as intended. While the chip is still on the die, a functional check is performed and a test fixture with pins is used to make contact with the circuitry on the die surface.failure analysis The signal response of the chip is sent and measured by the probes. If feasible, defective chips are repaired; otherwise, they are destroyed after the dicing process.
Dicing Wafers
In this back-end semiconductor manufacturing process, finished wafers are cut into individual chips. Mechanical sawing and laser dicing are the two automated methods. Dicing saws use circular cutting blades to cut the die into sizes of 35mm to 0.1mm for mechanical sawing. Subsequently, the die is transferred to the die bonding process using die handling equipment.
Servo motions are applied to align the saw and wafer blades and to adjust the dicing blades.
Chip Bonding
Individual chips are too small and fragile to be handled individually. They must be protected and there must be an easy way to electrically connect them to the chip. The process of bonding a bare chip to a substrate is called chip bonding or chip attachment.
In the following process, wafer level testing the substrate will act as an interface between the tiny dimensions of the chip and the large-scale development of electronic information processing companies. It will also serve as the basis for the PC board to protect the management chip for encapsulation.
Wire Bonding
Each pad on the lead bonding die is connected to the corresponding pad on the substrate with a fine gold wire after bonding the die. This connects the silicon chip in the chip container to the external pins via an electrical connection. Lead wire bonding is used for conventional chip packages such as DIP, which is characterized by a black rectangle with silver pins protruding like bug legs, and PLCC packages with conductors on all four sides.
The lead bonding machine runs at extremely fast speeds to maintain the large number of connections required for each chip. In fact, this is one of our most bandwidth-hungry applications.
Flip Chip/Solder Balls
FLIP chips are mounted "backwards" as an alternative to modern soldering. Hence the term "flip chip" was coined. Unlike wire bonding, wires are connected around the edge of the chip, creating an array of "bumps" on the chip surface. These bumps act as connectors between the chip and the surrounding container. Here are some of the benefits of flip chip technology.
A better connection to the chip, rather than wire bonding, would add extra length, capacitance, and inductance, all of which would reduce signal speed.
Since our entire Chinese chip is exposed, not just the border, companies can connect more sites by accessing them.
Increased production speed
Smaller overall package size.
Packaging
When the back-end semiconductor manufacturing process is complete, the bonded chips and frames are sealed using molded plastic compounds or by connecting sealing caps. Silicon chips are now ready for use in the electronics industry.
How can back-end tooling be optimized?
Utilizing the full potential of the workforce
Operator Contact Time: Employees spend 30 to 50 percent of their time touching materials or running machines in the back-end plant. Employees typically spend the rest of the workday doing nothing, waiting for machines to complete their manufacturing cycles. Even when production lines are not running at full capacity, the ratio of employees to machines is consistent, which increases the duration of employee disengagement.
Standard Lean practices, such as the ability to change the worker-to-machine ratio in China by varying it based on operator contact hours or employing flexible staffing allocations to ensure that a certain number of a company's shop-floor managers are sufficient to meet the plant's current capacity, have helped student certain back-end manufacturers improve social labor productivity. These important initiatives have yielded some benefits, but they are difficult to sustain, meaning that back-end production methods remain labor-intensive.
Improving quality without delaying the production line
Engineering teams must study machine data and communicate with their colleagues on the production line to determine the specific production steps that will be taken in the event of production spikes or losses, or unexpected quality issues at back-end facilities. However, engineers may only collect data once a week, making it more difficult to determine the root cause long after the problem has occurred.
Engineers may need to interview line employees for information, while workers may recall some basic data about tool settings or other operating environments, which can cause delays.
Establishing a dedicated output and quality improvement team and daily Lean "meetings" may be a better approach. These organized discussions can help engineers get a handle on issues such as output stability and unpredictability so they can make improvements.
Consider throughput in a more skillful way.
Most back-end factories rely on absolute metrics of available or unavailable uptime devices, ignoring subtle results such as small interruptions that don't result in complete shutdown when evaluating OEE. In addition, back-end manufacturers use manual programs to track production losses, which only show a broad pattern over time. These advanced findings do not give engineers a comprehensive understanding of the factors that contribute to production problems, which makes the development of improvement strategies difficult.
To address these issues, some return to the basic principles of Lean is needed. For example, manufacturers can form a continuous improvement team to prioritize and identify sources of production bottlenecks. Many organizations have these teams, although they are not always present in the back-end plant.
Consider a simpler idea: machine learning could be equipped with sensors to track significant historical events that affect OEE, such as the failure of an organization's manufacturing operations or equipment system failures. Operators would then enter contextual data through a touchscreen interface, which could save time on manual data as input and provide engineers with higher-level details.
In short, the semiconductor business is a leader in data collection; the problem is that companies only use a fraction of the data they acquire. For the first time ever, advanced technology can help manufacturers tap into their vast knowledge base and provide the specific, practical insights they need to develop solutions.
In addition, Industrial Revolution 4.0 tools can automate many of the time-consuming processes that now need to be done manually in back-end factories. Overall, these improvements have helped managers implement lean initiatives faster and more efficiently, with some organizations seeing meaningful cost, throughput, and quality benefits within months.
Back-end factories that integrate smart manufacturing techniques may stand out in the competitive semiconductor industry, outperforming those that utilize more traditional lean methods.
