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Printing preparation of mini gap reversed-mounting welded convex templates with lead/tin or leadless solder

A template and technology technology, which is applied in the field of preparing flip-chip bump solder balls, can solve the problems of poor reliability, affecting the life of solder balls, process limitations, etc., and achieve the effect of reducing solder ball spacing and improving process controllability

Inactive Publication Date: 2004-12-08
THE HONG KONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the requirements of the printing process, the volume of solder paste is generally 40-60% larger than the volume of solder balls after reflow, which limits the reduction of the distance between solder balls
When preparing small-pitch solder balls, the process faces great limitations, low yield, and poor reliability
In addition, due to the different interconnection metal materials in the semiconductor wafer, there are also process control problems in the electroless plating under-bump metal layer, which reduces the connection reliability of the metal layer and affects the life of the solder ball.

Method used

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  • Printing preparation of mini gap reversed-mounting welded convex templates with lead/tin or leadless solder
  • Printing preparation of mini gap reversed-mounting welded convex templates with lead/tin or leadless solder
  • Printing preparation of mini gap reversed-mounting welded convex templates with lead/tin or leadless solder

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Embodiment Construction

[0033] The UBM layer 2 to be prepared, such as figure 1 Shown as round or figure 2 is a square. Wherein, a pair of rectangular metal layers formed in two opposite directions of the UBM layer 2 is called the solder reflow guide layer 1 . The width W of the rectangular solder reflow guide layer 1 and the side length of the square ( figure 2 ) or circle diameter D( figure 1 ) ratio is between 0.08-0.15, and the ratio between the length L of the rectangular solder reflow guiding layer 1 and the side length or circle diameter D of a regular square is between 0-1.2.

[0034] Such as image 3 As shown, that is, the printing template 3 used in FIG. 8( a ) is designed in such a way that the size of the template opening 4 needs to match the size of the UBM layer 2 and the reflow guide layer 1 .

[0035] As shown in Figure 4, the volume of 4 holes (V2) at the opening of the template is related to the thickness T of the template and the area of ​​the opening, and the ratio of the v...

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Abstract

The invented technique of preparing solder ball for encapsulating semiconductor includes following steps: preparing metal level and back flow leading metal level under salient point by using technique of nickel-vanadium alloy and float pulling off technique; designing and preparing printing template based on size of solder ball and technological requirements; printing soldering paste on chip by using printing machine; based on requirement of soldering paste material, forming solder ball under certain temperature by back flow. The invention raises possibility of technical control for preparing solder ball through template printing technique, reduces space between solder balls and provides reliable solder ball for upside down mounting solder in different sizes and materials.

Description

technical field [0001] The invention relates to electronic packaging, and is a technology for preparing flip-chip soldering bump solder balls on wafers or chips in the semiconductor process. Background technique [0002] As the size of integrated circuit chips continues to shrink, electronic packaging technology is gradually developing in the direction of high performance, high density, high input / output ports, low cost, and miniaturization. New packaging technologies are becoming more and more widely used in the industry. Compared with packaging technologies such as surface mount (SMT), tape automatic bonding (TAB), quad flat package (QFP), pin grid array (PGA) and solder ball array (BGA), flip chip welding technology can meet the needs of electronic products. The high performance, small shape, high speed and high frequency requirements make the product have good electrical performance and heat transfer performance. In bump flip chip technology, bumps are metal solder ball...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/28H01L21/44H01L21/60H01L21/768H01L23/485
CPCH01L2924/01023H01L2924/0001H01L2924/01082H01L2924/01047H01L2924/01079H01L24/13H01L2924/14H01L2924/01005H01L2924/01033H01L2924/01322H01L2924/01006H01L2924/01029H01L2224/13099H01L2924/01074H01L2924/01078H01L2924/01022H01L2224/131H01L24/11H01L2924/014H01L2924/01024H01L24/03H01L24/05H01L2224/05001H01L2224/05022H01L2224/05571H01L2224/05644H01L2924/00014H01L2224/05099
Inventor 陈正豪肖国伟
Owner THE HONG KONG UNIV OF SCI & TECH
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