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Preparation method of three-dimensional micro-convex points

A micro-bump and three-dimensional technology, which is applied in the field of preparation of three-dimensional micro-bumps, can solve problems such as no technical support, and achieve the effects of low manufacturing cost, reduced cost, and simple manufacturing steps

Active Publication Date: 2018-11-23
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, there is no relevant patent that can provide technical support for the three-dimensional forming of micro-bumps

Method used

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  • Preparation method of three-dimensional micro-convex points
  • Preparation method of three-dimensional micro-convex points
  • Preparation method of three-dimensional micro-convex points

Examples

Experimental program
Comparison scheme
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preparation example Construction

[0035] The invention discloses a novel reflow soldering micro-bump preparation method, which belongs to the field of semiconductor chip packaging. The micro-bump structure is prepared by a method comprising the following steps: patterning a metal adhesion layer, a metal barrier layer, and a seed layer as metal pads on a substrate; then depositing a conductive layer required for electroplating on the entire substrate, and patterning; then spin-coat photoresist, and use exposure and development to form a micro-sized opening photoresist mask above the seed layer; then perform electroplating in a solder electroplating solution to form a layer of solder pillars; and then use Soak in an organic solution to remove the patterned photoresist; use an etching solution to remove the conductive layer required for electroplating; and finally reflow to obtain solder bumps with different heights.

[0036] Because the size of the patterned metal pad and the photoresist above the seed layer can...

Embodiment 1

[0057] The present invention obtains different area ratios by using the same pad area and different solder plating areas, and obtains three-dimensional solder bumps after reflow, including the following steps:

[0058] (1) A silicon dioxide oxide layer with a thickness of 200 nanometers is oxidized by dry method on a silicon substrate with a thickness of 500 micrometers.

[0059] (2) Prepare scattered metal pads on the surface of the silicon substrate by etching or stripping (as shown in FIG. 2( a )).

[0060] Further, step (2) includes the following steps:

[0061] (2-1) successively depositing a chromium film, a nickel film and a gold film on the oxide layer 101 on the silicon substrate 100 by thermal evaporation;

[0062] For example, the thickness of the chromium film is 20nm, the thickness of the nickel film is 80nm, and the thickness of the gold film is 300nm.

[0063] (2-2) Prepare a patterned photoresist mask on the gold film, the layout of the photoresist mask is re...

Embodiment 2

[0084] In the present invention, different area ratios are obtained by utilizing the same solder plating area and different pad areas, and three-dimensional solder bumps are obtained after reflow. The specific implementation steps refer to the steps in Embodiment 1, which will not be repeated here.

[0085] Wherein, it should be noted that, as shown in FIG. 3( a ), the areas of the metal pads are different, decreasing sequentially from left to right.

[0086] It should be noted that, as shown in Figure 3(d), the size of the opening of the photoresist inverted mold is the same, and the volume of solder electroplated on different metal pads is the same, while the area of ​​the metal pads decreases from left to right. Therefore, under the effect of the surface tension of the liquid, the solder balls formed by the same volume of solder show different sizes and different heights, and show a phenomenon of increasing and increasing from left to right.

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Abstract

The invention discloses a preparation method of three-dimensional micro-convex points. The preparation method comprises the steps that a plurality of metal welding pads are imaged on a substrate; a conductive layer required by electroplating is deposited on the substrate, the conductive layer of to-be-electroplated areas on all the metal welding pads is removed through an etching solution, photoresist is spin-coated, micro-sized open photoresist masks are formed in the to-be-electroplated areas on the upper portions of all the metal welding pads, and the area ratio of the area of the metal welding pad to the electroplating area of the metal welding pad is controllable; each metal welding pad with the corresponding open photoresist mask is electroplated in a solder electroplating solution to form a layer of solder column; soaking is conducted through an organic solution to remove the photoresist; the conductive layer for connecting all the metal welding pads during electroplating is removed through the etching solution; and the solder columns on all the metal welding pads are subjected to backflow to obtain the multiple solder convex points with different heights, and the smaller the area ratio of the area of the metal welding pad to the electroplating area of the metal welding pad is, the higher the solder convex point is. The solder convex points of the three-dimensional structures are obtained through a one-time process.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing and microelectronic device packaging, and more specifically, to a method for preparing three-dimensional micro-bumps. Background technique [0002] With the increasing demand for high integration, high performance, and miniaturization, micro-bump technology, as an interconnection technology between chips and packaging technology, relies on advanced packaging methods such as BGA, CSP, Flip Chip, and WLP. more attention. In the industry, micro-bump technology itself is also developing towards the direction of wafer level, micro-size, micro-pitch and high integration. [0003] The commonly used preparation techniques for micro-bumps include: preparing the seed layer required for electroplating, patterned photolithography mask, solder electroplating, and etching the seed layer. The height of the micro-bumps prepared by the existing micro-bump technology is basically the same. The...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/48
CPCH01L21/4853
Inventor 范继魏晓莉刘金全涂良成刘骅锋饶康
Owner HUAZHONG UNIV OF SCI & TECH