半導(dǎo)體制造裝備概述(編輯修改稿)
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【文章內(nèi)容簡介】 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 40 mm looping. Short wires are to ground. Long wires are to the leads. 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Wedge stitch bonding. 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Limitation of wirebonding For the application of wirebonding method, terminals of chips have to be arranged at the periphery of the chips, otherwise short circuit is easily caused. Therefore, wirebonding technique is difficult for high I/O(500) interconnections. 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Bonding parameters Bonding parameters are extremely important because they control the bonding yield and reliability directly. The key variables for wire bonding include: Bonding force and pressure uniformity Bonding temperature Bonding time Ultrasonic frequency and power 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Bond design Ball bonding Ball size is approximately 2 to 3 times the wire diameter, times for small ball applications with fine pitches, and 3 to 4 times for large bond pad application. Bond size should not exceed 3/4 of the pad size, about to 5 times the wire diameter, depending on the geometry and moving direction of capillary during bonding. Loop heights of 150 um are now mon, but very depending on the wire diameter and applications. Loop length should be less than 100 times the wire diameter. However, in some cases, high I/Os for instance, wire lengths have to increase to more than 5 mm. The wirebonder must suspend the length of wire between the die and lead frame without vertical sagging or horizontal swaying. 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Wedge bonding A highstrength wedge bond is possible even the bond is only 23 mm wider than wire diameter. Pad length must support the long dimension of the wedge bond as well as the tail. The pad39。s long axis should be oriented along the intended wire path. Bond pitch must be designed to maintain consistent distance between wires. 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Cleaning To ensure bondability and reliability of wirebond, one of the critical conditions is that the bonding surface must be free of any contaminants. Therefore cleaning is an important work before bonding. The method usually adapted is molecular cleaning method, plasma or UVozone cleaning method. 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Bond evaluation ?Destructive bond pull test (Method 2023) ?Internal visual (Method 2023。 Test condition A and B) ?Delay measurements (Method 3003) ?Nondestructive bond pull test (Method 2023) ?Ball bond shear test ?Constant acceleration (Method 2023。 Test condition E) ?Random vibration (Method 2026) ?Mechanical shock (Method 2023) ?Stabilization bake (Method 1008) ?Moisture resistance (Method 1004) 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 Destructive bond pull test (Method 2023) 華中科技大學(xué) 機(jī)械學(xué)院 機(jī)械電子信息工程系 If both thebonds are at the same level and the hook is applied at the center, the forces can be represented When the both angles are 30o, the pull force is equal to the breakload. The fai
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