March 23, 2007
NTT Advanced Technology Corporation
NTT Advanced Technology Corporation
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December 4, 2002 Accurate measurement of electrical resistance in a tiny area of one-square millimeter has become possible
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The probe has been developed jointly with Kiyota Manufacturing Co. (headquartered in Kita-ku, Tokyo, Japan; President: Shigeo Kiyota) under an R&D Business Contract*1 for an Immediate-Effect Regional Renovation Consortium sponsored by the Kanto Bureau of Economy, Trade and Industry, Ministry of Economy, Trade and Industry. The probe has been applied to the measurement of the electrical resistance of a silicon chip, and it has been confirmed that this probe can accurately measure the sheet resistance at position 1 mm from the chip edge. This successful measurement is a big step towards the development of a high resolution resistance measurement system.
[Background and history]
The 4-point probe is widely used today because it can measure the electrical resistance of semiconductors or metal films easily, without any patterning processes. However, the probes of conventional systems are spaced at a pitch of around 1 mm. Probes with a smaller pitch have not been available. In the fabrication of semiconductors and liquid crystal displays, higher controllability and yield are required, and this fine-pitch 4-point probe will be a powerful tool in monitoring fabrication processes. NTT laboratories have sophisticated semiconductor fabrication process technology and material evaluation methods, while Kiyota Manufacturing Co., has technologies for conventional 4-point probe manufacturing and hyperfine material processing. They have collaborated with each other in looking at the possibility of measuring the resistance of a tiny area with a fine-pitched 4-point probe system, and have developed a hyperfine diameter wire processing method*2, which consists of primary electrolytic polishing followed by secondary polishing with a mechanism to prevent vibration. This method has made it possible to manufacture this probe.
 [Outline of the probe system]<Basic performance> The pitch between probes is 0.1 mm, making it possible to measure the electrical resistance in a tiny area of 1 mm2. <Basic configuration> Each needle is made of tungsten carbide alloy and has a diameter of 0.05 mm. The tip is curved with a radius of 0.02 mm. Each needle is connected to a metal leaf spring. The probe consists of four needles and springs whose surface is coated with. |
<Main application areas>
The probe can be used for measuring the resistance of a tiny area on a semiconductor or a metal film, the distribution of resistance in a chip, the resistance of wafer edges, the resistance of a test element on a wafer, etc. In particular, the probe system is expected to find application in small semiconductor samples produced for R&D purposes. It can also be applied to fault analysis of circuits, such as identifying a broken wire or a short circuit.
[Properties of the probe system]
| - | Excellent precision in spacing: 0.1mm ± 5 . |
| - | Excellent durability: The probe endures 150 thousand repetition tests (horizontal direction) |
| - | Ease of handling: The probe can be used as easily as conventional 1mm-pitch probes. |
<Glossary>
| *1: | R&D Business Contract for an Immediate-Effect Regional Renovation Consortium |
| This contract was adopted as one of the proposal-based business projects in the fiscal 2001 supplementary budget, which aimed to revitalize the regional economy through the creation of new industries by promoting practical technology development directly conducive to the emergence of new businesses through cooperation between regional universities and industries. The projects were sponsored by the Kanto Bureau of Economy, Trade and Industry, Ministry of Economy, Trade and Industry. "The development of the prototype of a 4-probe system for measuring the resistance of a minute semiconductor surface area" has been managed by NTT-AT, and parts of the project were contracted out to Kiyota Manufacturing Co., National Institute of Advanced Industrial Science and Technology (headquartered in Tsukuba-shi, Ibaraki, Japan), and Keio University (headquartered in Yokohama-shi, Kanagawa, Japan). | |
| *2: | Hyperfine diameter wire processing method. Patent pending by NTT-AT. |
For inquiries, please contact
| Dr. Yoshiyuki Sato Materials Analytical Technology Department Electronics Division Leading-edge Key Technology Business Headquarters NTT Advanced Technology Corporation TEL: +81-46-250-3678; +81-46-250-1678 |
