As the chip manufacturing process becomes smaller and smaller, the process difficulty also increases exponentially. Taking the 10nm process as an example, the total number of process steps exceeds 1,300, and the 7nm process exceeds 1,500. Any error in any process may lead to unqualified integrated circuits produced and lower the yield rate.
Therefore, in order to detect unstable factors in time and improve production yield, the testing process runs through the integrated circuit production process, and testing equipment is the key.
This article comes from the semiconductor testing equipment report of Yangtze Securities, which explains in detail the semiconductor testing process, equipment classification, and domestic and foreign market patterns.
1. Testing equipment runs through the production process: probe station, sorting machine, testing machine
As mentioned at the beginning, there are many and complicated integrated circuit processes, and any one of the process errors may lead to unqualified integrated circuits produced and lower the yield rate. Therefore, the test link is very important for integrated circuit production.
Integrated circuit test equipment can not only be used to judge the eligibility of the tested chip or device, but also provide information about the weak links in the design and manufacturing process, which will help improve the level of chip manufacturing and improve the performance and reliability of the chip from the source.
The testing of integrated circuits mainly includes design verification in chip design, wafer testing in wafer manufacturing (CP testing), and finished product testing after packaging (FT testing).
IC testing equipment mainly includes testing machines, probe stations and sorting machines. The testing machine is used in all the testing links, and the testing machine needs to be used in conjunction with the sorting machine or probe station in different links.
1. Design verification stage: verify the effectiveness of the chip design, with less demand for test equipment
Chip design companies usually use semiconductor test equipment to test wafers or chip samples to verify the effectiveness of the function and performance of the chip samples and guide chip design. The design verification stage requires less test equipment.
2. Wafer testing stage: testing machine + probe station, testing wafer, saving packaging cost
Wafer testing, also known as CP testing, refers to the function and electrical parameter performance testing of each chip die on the wafer through the use of a probe station and a testing machine after the wafer is manufactured and before packaging. The process is the last process of wafer manufacturing. Wafer testing is generally carried out in fabs, packaging and testing plants or special test foundries. The main equipment used is testers and probe stations, in addition to customized test circuit boards and probe cards, probe cards The probe is installed on it.
Wafer test process: first fix the probe card to the test circuit board, then install the test circuit board on the head of the tester, and then put the test head upside down on the probe station. There are holes in the upper part of the probe station for inserting the probe card. Once installed, the tester, test circuit board, probe card and probe station are all fixed. The robot arm inside the probe station controls wafer movement and aligns the contact holes on each chip die with the probe. The needle is then pushed up so that the probe is accurately inserted into the contact hole of the die, and finally the test is completed.
The diameter of the contact hole is usually 1-2um. Therefore, the precision of the probe station is very high for wafer testing. If there is a slight deviation, the probe will be more likely to damage the wafer. Therefore, the probe station’s The technology is more difficult.
The purpose of wafer testing is to pick out the good and bad dies separately and mark them to form a map map of the wafer. After that, only the dies with good performance are packaged to save subsequent packaging costs.
3. Finished product testing stage: testing machine + sorting machine, testing chips, improving yield
Packaging test is also called FT test or final test. It is generally completed in the packaging and testing factory. It means that after the chip is packaged, the electrical parameter performance test of each chip is performed through the cooperation of the sorting machine and the testing machine to ensure that each chip is delivered. The function and performance index of the integrated circuit can meet the design specification requirements, and the purpose is to improve the yield of the factory chip. Packaging and testing mainly use testing machines and sorting machines, in addition to customized test circuit boards and bases.
The process of finished product testing: the sorting machine automatically transfers the chips to be tested one by one and puts them into the test base. The base and the test circuit board connect the pins of the chip with the test board of the tester, and the tester applies input signals to the integrated circuit, collects output signals, and judges the effectiveness of the functions and performance of the integrated circuit under different working conditions. Finally, the test result is transmitted to the sorting machine through the communication interface, and the sorting machine marks, sorts, receives or taps the tested integrated circuits accordingly.
The purpose of finished product testing is to select good and bad chips separately, and only good chips will be sold to end customers to ensure the yield rate of the chips when they are shipped.
Second, the testing machine is customized, the probe station, the sorting machine general test machine, the probe station, and the sorting machine are used in different links, and their technical difficulties are also different. The testing machine is a customized equipment, and the probe station and sorting machine are more versatile.
1. The test machine is composed of a body and an internal test board, which are all designed and manufactured by the test machine factory.
The body of the tester is a standardized device, and different test boards can be inserted inside. The test machine factory will design a series of test boards. Each test board can meet the test of certain functions. When testing the chip, the test factory needs to choose different test boards according to the functional characteristics of the chip. Match.
In addition, each chip needs to write a unique test program. Therefore, the customization of the test machine is mainly reflected in the customization of the test board and the customization of the test program. When a chip is updated, the body of the test machine does not need to be replaced, the internal test board will be adjusted according to the chip to be tested next, and the test program must be updated.
2. The probe station and the sorting machine are relatively general equipment with a wide range of applications.
The probe station is selected based on the wafer size, and the sorting machine is selected based on the chip packaging method and test parallelism requirements. Different wafers and chips usually do not need to make much changes to the probe station and the sorting machine.
In the testing industry, especially the testing machine industry, more work is the writing of software, including the control program of the device at the bottom level and the test program for the chip at the upper level.
The control program of the bottom layer is similar to the operating system, and the control systems of different brands of test machines are different, while the test program of the upper layer is similar to the application software. It is written on the basis of the control system of the test machine. Each chip has its own customization. The test procedure of the change.
From the comparison of the technical difficulty of the three types of testing equipment: testing machine, probe station and sorting machine, the technical difficulty of testing machine and probe station is higher than that of sorting machine.
Testing machine, probe station and sorting machine are equipment sold independently. Manufacturers of testing machine, probe station and sorting machine have considered the feasibility of using products of different manufacturers in their research and development. There are industry common interfaces on the connection line settings, which can realize the combination of different types of equipment from different manufacturers, without the need to purchase from the same manufacturer.
But in the actual purchase of equipment, the customized nature of test equipment determines the special business model of the industry, that is, general equipment is usually purchased by fabs and packaging and testing plants, while customized equipment is led by chip design companies. s Choice:
1) The probe station and the sorting machine are general equipment, which are usually purchased independently by the fab or packaging and testing plant;
2) The tester, probe card, test circuit board and base are all customized equipment. The chip design company will designate the supplier according to the characteristics of its own chip, and then the fab and packaging and testing plant will purchase. Packaging and testing plants and fabs independently decide to purchase relatively few customized equipment.
3. The difficulty of testing equipment is relatively low, and Youli is the first to break through international barriers
Integrated circuit equipment mainly includes silicon wafer manufacturing equipment, wafer processing equipment, packaging equipment, and testing equipment. Due to the complex and long process of integrated circuit manufacturing, the equipment required for different links is different, and the technical difficulty and value also exist Significant differences.
In general, wafer processing equipment such as lithography machines and etching machines has higher technical barriers and greater difficulty, and is monopolized by a few giants in the world. The technical threshold of test equipment is relatively low, and domestic test equipment is expected to be the first to break through among various semiconductor equipment.
From the perspective of the market share of semiconductor equipment by product, the market share of semiconductor equipment is basically proportional to the technical difficulty, and products with higher technical difficulty enjoy a higher market premium. Wafer processing equipment accounts for the largest proportion. The reason is that in the integrated circuit manufacturing, packaging, testing and other links, the wafer manufacturing process is the most complicated, the process is the most, the technical barrier is the highest, and the equipment cost is also higher.
In 2018, the market size of wafer processing equipment, packaging equipment, test equipment, and other equipment was approximately 50,200, 54, 40, and 2.5 billion US dollars, respectively, and the market share was approximately 80.8%, 8.7%, 6.4%, and 4.0%, respectively.
At present, the manufacturing technology of advanced integrated circuit testing equipment in the world is basically in the hands of manufacturers in developed countries such as the United States and Japan.
In the test machine market, the United States Teradyne and Japan Advantest are two giants, which together account for more than 80% of the test machine market, and their share has been increasing in recent years.
The probe station has relatively high technical barriers, and the market is also in a dual monopoly situation. Tokyo Electronics and Tokyo Precision two Japanese companies occupy most of the market share.
The technical difficulty of the sorting machine is relatively low. At present, there is no leader in absolute technology or an absolute monopoly in market share. The competitive landscape is relatively scattered. The main participants include Cohu of the United States, EPSON of Japan, Advantech, Japan STI in Singapore, Hongjin in Taiwan, and Changchuan Technology in Mainland China. Looking back at the country, the current domestic testing equipment companies Changchuan Technology, Beijing Huafeng, Foshan Linkage, and Beijing Guanzhong have made certain breakthroughs and entered the famous domestic and foreign seals such as Changjiang Electronics Technology, Huatian Technology, Tongfu Microelectronics, and ASE. Test factory.
Domestic manufacturers have realized or partially realized domestic substitutions in the low-end and medium-end fields such as discrete device testers, analog testers, and sorting machines, and have established layouts in difficult test equipment fields such as digital testers and probe stations. Probe stations and high-end testing machines are still monopolized by overseas leaders.
In the context of the recent Sino-US trade frictions, the process of domestic substitution of semiconductor equipment may accelerate. Following the logic of easy first and difficult later, domestic test equipment is expected to take the lead in various semiconductor equipment.
Fourth, the demand for test equipment is on the rise. The developed test equipment in the mainland packaging and testing industry usually has a longer lifespan and requires less update. The main demand is new demand. The four major factors affecting the new demand for test equipment include downstream chip demand, chip complexity, semiconductor industry transfer, and test parallelism. The core influencing factors are downstream chip requirements and chip complexity.
In recent years, the complexity of chips has continued to increase, and the demand for test equipment has been affected by both the increase in chip complexity and the fluctuations in the downstream economy.
From 2015 to 2018, with the boom in the semiconductor industry, global semiconductor test equipment sales increased rapidly, reaching approximately US$5.4 billion in 2018.
With the supply chain destocking and 5G demand stimulating factors, it is expected that the semiconductor industry will recover in 2020, and the semiconductor test equipment market space is expected to exceed 6 billion US dollars. Looking back at China. In recent years, the demand for the semiconductor equipment market in mainland China has grown rapidly. According to SEMI's forecast, the semiconductor equipment market in mainland China will account for about 20% of the world in 2019.
In terms of products, in 2019, the market space for digital testing machines in mainland China is about RMB 3 to 3.5 billion, the market space for memory testing machines is about RMB 800 to 900 million, and the market space for analog testing machines is about RMB 500 to 600 million. The needle table market space is about 900 to 1 billion yuan each.
5. Industry competition is fierce and domestic substitution accelerates
The test equipment market has become increasingly competitive in recent years and industry integration has accelerated.
In 2011, Advantech acquired Feruijie, and the high-end test machine market formed a dual monopoly of Teradyne and Advantech. Testing machine companies other than Teradyne and Advantech are competing fiercely in the low-end market and are constantly integrating with each other. After a series of mergers, mergers and acquisitions, LXT, Credence, ECT and Multitest have become the world's third largest testing machine company Xcerra, but the revenue volume still has a large gap with Teradyne and Advantech. In 2018, Cohu acquired Xcerra. Since 2018, the expansion of domestic semiconductor test equipment to markets outside mainland China and the process of domestic substitution in the mainland China market have been significantly accelerated.
The acceleration of the domestic substitution process is due to the vigorous development of Chinese local chip design companies in recent years, and the rapid growth in demand for chip testing. However, due to the Sino-US trade friction, the security of the supply chain is increasingly valued, and domestic test equipment will get more trial opportunities , In the field of mid- and low-end analog test machines and sorting machines, domestically produced substitutions have been significantly accelerated. Domestic test equipment is accelerating overseas expansion. The short-term factor is the recent sluggish equipment procurement expenditures of mainland China's packaging and testing plants; the long-term factor is the strengthening of the technical strength of domestic equipment in the sub-fields of simulation and power supply and gradually participating in global competition.
Since 2018H2, the domestic packaging and testing industry investment has been sluggish, and equipment procurement expenditures have shrunk, prompting domestic test equipment companies to accelerate overseas expansion.
Beijing Huafeng’s simulation test machines have been sold in Taiwan and Southeast Asia in the early years, and offices have been established in the United States, Japan, and Italy. Currently, overseas revenue accounts for more than 30%.
Changchuan Technology established subsidiaries in Hong Kong, China and Japan, and set up an office in Taiwan, China to accelerate the company’s internationalization, promote its analog tester and sorting machine products, and acquire Singapore sorting machine manufacturing company STI has been approved by the Securities Regulatory Commission , Further enter the Southeast Asian market. Foshan United has good technology in power management and high-power discrete device testing. The testing machine has entered Southeast Asia packaging and testing plants.
In the long run, the semiconductor packaging and testing industry continues to shift to mainland China, especially the packaging and testing foundries in Southeast Asia. In recent years, with the rapid growth of China's packaging and testing industry, some packaging and testing plants in Southeast Asia are difficult to operate, so they are gradually being acquired. It has also become a trend for Chinese packaging and testing plants to go to Southeast Asia to purchase packaging and testing capacity.
Test equipment runs through the entire process of chip manufacturing and is essential to ensure the performance and reliability of the chip. In the current increasingly complex semiconductor manufacturing process, a complete test equipment process can detect unstable factors in time and improve production yield.
Compared with wafer processing and manufacturing, the packaging and testing industry in mainland China is more mature. Changjiang Electronics Technology, Tianshui Huatian, Tongfu Microelectronics, etc. have all achieved good market results in recent years, which has also led to the domestic market’s Increased demand for test equipment.
In the context of Sino-US trade frictions, domestic test equipment is expected to rise first among various semiconductor equipment, further accelerating the pace of localization.