NEC

About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.

Plasma processing method and equipment used therefor

Abstract: A plasma processing method is provided which suppresses the charge accumulation on a processing object such as a semiconductor substrate. An alternating excitation signal in the form of pulses for exciting the plasma is supplied to a reaction gas contained in a plasma chamber, each pulse having an on-period t on for supplying the excitation signal and an off-period t off for stopping the excitation signal. The off period ranges from 10 to 100 μsec. The on-period may be determined as needed. An alternating bias signal for biasing the processing object is also applied to the object in the chamber. The bias signal has a frequency of at most 600 kHz. As a result, an increased number of positive and negative ions impinge the object thus increasing the processing rate and reducing the charge accumulation compared to prior art processes.

Semiconductor device with plastic material covering a semiconductor chip mounted on a substrate of the device

Abstract: A plastic covered semiconductor device that enables to simplify the structure and fabrication to reduce the assembly cost of the device and to reduce the thickness or height of the device. This device contains a substrate having a first surface and a second surface opposite to the first surface, a semiconductor chip mounted on or over the first surface, lead fingers joined to the first surface, interconnecting conductors electrically interconnecting the semiconductor chip with the corresponding lead fingers, respectively, and a plastic covering material formed to cover the first surface. Each lead finger is made of an inner part bonded to the first surface of the substrate and an outer part protruding the covering material. The covering material confines the semiconductor chip, the interconnecting conductors and the inner parts of the lead fingers. The second surface of the substrate is exposed from the covering material. An edge of the covering material is substantially in accordance with an edge of the first surface. The substrate acts as a top or bottom of a package of the device.

Likelihood Function for QRM-MLD Suitable for Soft-Decision Turbo Decoding and Its Performance for OFCDM MIMO Multiplexing in Multipath Fading Channel

Abstract: This paper proposes likelihood function generation of complexity-reduced Maximum Likelihood Detection with QR Decomposition and M-algorithm (QRM-MLD) suitable for soft-decision Turbo decoding and investigates the throughput performance using QRM-MLD with the proposed likelihood function in multipath Rayleigh fading channels for Orthogonal Frequency and Code Division Multiplexing (OFCDM) multiple-input multiple-output (MIMO) multiplexing Simulation results show that by using the proposed likelihood function generation scheme for soft-decision Turbo decoding following QRM-MLD in 4-by-4 MIMO multiplexing, the required average received signal energy per bit-to-noise power spectrum density ratio (E b /N 0 ) at the average block error rate (BLER) of 10 -2 at a 1-Gbps data rate is significantly reduced compared to that using hard-decision decoding in OFCDM access with 16 QAM modulation, the coding rate of 8/9, and 8-code multiplexing with a spreading factor of 8 assuming a 100-MHz bandwidth Furthermore, we show that by employing QRM-MLD associated with soft-decision Turbo decoding for 4-by-4 MIMO multiplexing, the throughput values of 500 Mbps and 1 Gbps are achieved at the average received E b /N 0 of approximately 45 and 93 dB by QPSK with the coding rate of R= 8/9 and 16QAM with R = 8/9, respectively, for OFCDM access assuming a 100-MHz bandwidth in a twelve-path Rayleigh fading channel