Changho Han

The Novel Deflector for Multi Arrayed Microcolumn Using Microelectromechanical System (MEMS) Technology

This paper describes a new concept for a multiple arrayed deflector with a reduced amount of wiring by utilizing a fabrication technique using microelectromechanical system (MEMS) technology, such as multi wafer anodic bonding techniques and copper electroplating in order to produce a double layer structure. The double layer interconnection structure is a newly introduced interconnection method that reduces wiring among the components. A 3×3 arrayed deflector, which has an internal wiring structure, was fabricated. The deflection performance of the newly fabricated deflector displayed linear deflection results. Moreover, the difference in the signal delay between each deflector pole, which was caused by multiple interconnection structures, was calculated using a simulation program with integrated circuit emphasis (SPICE) simulator with an equivalent circuit model. The calculation results showed there was an approximate 3 ns signal delay difference. Therefore, this method is very useful for checking the difference in the signal delay. This work will be helpful for understanding the interconnections a multiple arrayed microcolumn system.

Full MEMS monolithic microcolumn for wafer-level arrayal

Recently, an advanced microcolumn concept for improved throughput was proposed. However, due to the complexity of the approach, the miniaturization was limited. In addition, microcolumns must run under ultrahigh vacuum conditions in order to obtain stable electron emission at the field-emission tip. Both signal and power lines need to be connected through the ultrahigh vacuum chamber. Therefore, increases in the number of microcolumn arrays necessitate more wiring from the external control unit to the internal units, and the number of wires can become prohibitive. To solve this problem, a new concept, exploiting the possibility of an arrayed microcolumn which uses microelectromechanical systems (MEMS) technology has been developed. This paper describes a monolithic (3×3 arrayed) microcolumn, which consists of a cold field-emission tip, an input lens, an einzel lens, and novel deflectors for multiple-arrayed microcolumns. We also describe its fabrication process, which relies on improved microfabrication a...

A miniaturized electron beam deflector and lens module with vertical interconnection using anodic bonding and Zn reflow

An 8x8 array of electron beam deflector and lens module was developed using a vertical interconnection based on anodic bonding and Zn reflow. It was fabricated using 4 inch wafers and the size of one module is 8x8mm . A uniform electroplating condition of Zn was developed and void-free anodic bonding of Si-glass-Si which included Zn metal was confirmed by IR image. Zn was successfully reflown and spread on the Ni above the melting temperature. This method can be applied to the various packaging or interconnection of devices composed of stacked wafers because the signal pad is easily extended to the top side using the vertical interconnection.

Self-Aligned Carbon Nanotubes for Field Emission Tip with Simple Process

Carbon nanotubes (CNTs) is one of the most attractive materials for field emission tip. Because of its low threshold voltage and high current density. In this article we introduce a new simple process to fabricate self-aligned carbon nanotubes for field emission tip with simple process. We can make the less than 200nm diameter hole with our one mask like process by which carbon nanotubes will be self-aligned with the gate layer. And then carbon nanotubes will be catalytically grown in PECVD chamber.

Wafer level vertical interconnection method for microcolumn array

A concept of miniaturized and arrayed electron beam system using vertical interconnection was proposed and fabrication with interconnection using metal reflow was performed. The interconnection of electron beam array is very important because all single columns should be controlled individually to obtain a uniformity of electron beam array. In addition, the interconnection area should be reduced to make the size of a single column smaller. Therefore, a vertical interconnection method was proposed and the schematic of vertically interconnected monolithic microcolumn is shown. The other advantages of this vertical interconnection method are controllable columns and removal of interference between columns (Han, 2005).

Fabrication of miniaturized electron beam system

A novel electron beam lithography system, microcolumn, was designed and fabricated using a wafer stacking and double metal interconnection process. This is the first monolithic microcolumn. All electrodes were made of highly doped Si wafer and Pyrex glass was used as an insulator. The system was assembled using a glass jig and several alignment methods including a conventional method using an aligner, laser diffraction image and refracted light were used and the misalignment was less than 10/spl mu/m. Anodic bonding was performed and the process condition was optimized to reduce the stress. The size of 3/spl times/3 arrayed microcolumn system including jig is 50mm /spl times/ 50mm and the height is 6.5mm. The size of 1 column is 6mm /spl times/ 6mm and it is the smallest size.

The novel deflector for multi arrayed microcolumn using MEMS technology

We present a novel design concept of deflectors for a 3 × 3 multiple arrayed microcolumn and its fabrication process using a improved microfabrication and novel MEMS technology, such as multi wafer anodic bonding techniques and copper electroplating for the double metallization process. The double metallization process is a newly introduced interconnection method to reduce wiring among the components. Moreover, a difference in the signal delay between pad site and each deflector pole, which was caused by multi interconnection structure, was calculated using the SPICE simulator with an equivalent circuit model. The calculation results were obtained with about 3ns signal delay difference. Therefore, in these arrayed systems, this method is very useful for checking the difference in signal delay.