Unlock instant, AI-driven research and patent intelligence for your innovation.

Metal thin film on the back of a wafer and preparation method thereof

A technology for backside metal and thin film preparation, applied in metal material coating process, vacuum evaporation plating, coating and other directions, can solve the problem of increasing wafer fragmentation rate, wafer electrical parameter testing, packaging dicing and other processes that cannot be achieved, Metal thin film wafer warpage and other problems, to achieve the effect of reducing the fragmentation rate, optimal electrical properties and warpage, and reducing warpage

Active Publication Date: 2019-11-12
ZHUZHOU CRRC TIMES SEMICON CO LTD
View PDF7 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of this, the purpose of the present invention is to provide a metal film on the back of the wafer and its preparation method, which solves the problem that the metal film formed by the existing process has a large stress and causes serious warping of the wafer, which makes the electrical parameters of the wafer at the back end Processes such as testing, packaging and dicing cannot be realized, and technical problems that increase the wafer fragmentation rate

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Metal thin film on the back of a wafer and preparation method thereof
  • Metal thin film on the back of a wafer and preparation method thereof
  • Metal thin film on the back of a wafer and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] as attached figure 1 Shown, a kind of specific embodiment of the metal film on the back of the wafer prepared according to the method of the present invention includes:

[0051]The first metal layer 3 formed on the surface of the high-concentration doped region 2 on the back of the wafer 1, the first metal layer 3 is an aluminum (Al) film, the thickness of the aluminum film is less than 5 μm, the typical value is 1 μm, the first metal layer 3 It can also be a titanium (Ti) layer or a nickel (Ni) layer, and the doped region 2 is a high-concentration P+ region or N+ region;

[0052] The second metal layer 4 formed on the surface of the first metal layer 3, the second metal layer 4 is a titanium (Ti) film, the thickness of the titanium film is controlled below 0.2 μm, the typical value is 0.1 μm, the second metal layer 4 can also For the chromium (Cr) layer;

[0053] The third metal layer 5 formed on the surface of the second metal layer 4, the third metal layer 5 is a n...

Embodiment 2

[0059] as attached figure 2 As shown, a specific embodiment of a method for preparing a metal thin film on the back of a wafer comprises the following steps:

[0060] S101: sputtering a layer of first metal on the back of wafer 1 to form first metal layer 3, the first metal layer 3 mainly plays the role of forming an alloy with the surface of wafer 1; the first metal is aluminum (Al ), the first metal layer 3 is an aluminum film, the thickness of the aluminum film is controlled below 5 μm, the typical value is 1 μm, the first metal can also be titanium (Ti) or nickel (Ni); the back of the wafer 1 is a doped area 2. The doped region 2 is a high-concentration P+ region or N+ region formed by ion implantation and annealing process. High-concentration doping means heavy doping, and the doping concentration is usually above the 18th power;

[0061] S102: Form a very thin layer of aluminum-silicon alloy (AlSi) at the contact between the doped region 2 and the first metal layer 3. ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
thermal stressaaaaaaaaaa
thicknessaaaaaaaaaa
thicknessaaaaaaaaaa
Login to View More

Abstract

The invention discloses a wafer back surface metal film and a preparation method thereof. The preparation method comprises: forming a first metal layer on the back surface of a wafer through sputtering; forming an alloy layer of a first metal and silicon at the contact position of the back surface of the wafer and the first metal layer; forming a second metal layer on the first metal layer throughsputtering; forming a third metal layer on the second metal layer through sputtering, controlling the wafer temperature at a temperature of less than a set value after the sputtering, and introducingprotection gas during the sputtering; closing the sputtering of the third metal, maintaining the gas flowing in the cavity, starting the sputtering of the third metal when the wafer temperature is lower than the set value, controlling the wafer temperature at the temperature of less than the set value after the sputtering, and repeatedly performing the step if the thickness of the third metal layer does not reach a target value; and if the thickness of the third metal layer does not reach the target value, forming a four metal layer on the third metal layer through sputtering. In the prior art, the high stress of the metal film formed through the existing process can cause the serious warpage of the wafer, such that the rear end wafer electrical parameter testing, the package scribing andother processes cannot be achieved, and the wafer breaking rate is increased. According to the present invention, the technical problems in the prior art can be solved.

Description

technical field [0001] The invention relates to the field of power electronic device manufacturing, in particular to a metal thin film on the back of a wafer and a preparation method thereof. Background technique [0002] Magnetron sputtering is a physical vapor deposition (Physical Vapor Deposition, PVD) process widely used in semiconductor device manufacturing processes. The magnetron sputtering process introduces a magnetic field on the surface of the target cathode, and uses the magnetic field to confine the charged particles to increase the plasma density to increase the sputtering rate. The working principle of magnetron sputtering is: under the action of electric field E, electrons collide with argon atoms in the process of flying to the substrate, so that they are ionized to produce Ar positive ions and new electrons. Among them, the new electrons fly to the substrate, and the Ar ions are accelerated to fly to the cathode target under the action of the electric fiel...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C23C14/16C23C14/34C23C14/48C23C14/58
CPCC23C14/165C23C14/3464C23C14/48C23C14/5806
Inventor 张大华黄建伟肖海波罗海辉谭灿健肖强
Owner ZHUZHOU CRRC TIMES SEMICON CO LTD