Freescale Semiconductor,inc.

Asymchem Laboratories (tianjin) Co., Ltd.

Wei Shen

Zhigang Bai

Jiangping Lu

Hao Hong

Enxuan Zhang

Baoguan Yin

Jianhong Wang

Weimin Chen

Zhen Zhang

Wanming Yu

Honglei Yan

Yeqing Su

Provided is a preparation process of diazomethane. The preparation process includes: step S1, taking N-methylurea as a raw material to continuously prepare, in a continuous reactor, a first product system containing N-methyl-N-nitrosourea: step S2, performing continuous extraction and continuous back-extraction on the first product system to obtain an N-methyl-N-nitrosourea solution; step S3, enabling the N-methyl-N-nitrosourea solution to continuously react with an alkaline solution in a continuous reactor to obtain a second product system containing the diazomethane; and step S4, performing continuously liquid separation, water freezing and removal on the second product system, to obtain the diazomethane.

Preparation process of diazomethane

A method for manufacturing a thin semiconductor package includes providing a lead frame with a removable substrate that has an attaching surface attached to a first surface of the lead frame. The lead frame is formed from an electrically conductive sheet and has leads that extend inwardly from a lead frame boundary towards a central region of the lead frame. A semiconductor die is mounted on the removable substrate at the central region. The semiconductor die has a connection pad surface with die pads on it, and the connection pad surface is attached to the attaching surface of the removable substrate. The lead frame and die are encapsulated with a first encapsulant so that the lead frame is sandwiched between the first encapsulant and the removable substrate. The removable substrate is removed from the lead frame to expose the first surface of the lead frame and then the die pads are electrically connected to respective ones of the leads. The die and lead frame then are encapsulated with a second encapsulant so that the lead frame and die are sandwiched between the first and second encapsulants. Part of the first encapsulant is then removed to reduce the thickness of the package and expose the leads.

Thin semiconductor package and method for manufacturing same

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Tianjin, China

Wei Shen