CN115966473A

CN115966473A - Wafer processing technology

Info

Publication number: CN115966473A
Application number: CN202310038287.6A
Authority: CN
Inventors: 严立巍; 刘文杰; 朱亦峰; 马晴
Original assignee: Zhejiang Tongxinqi Technology Co ltd
Current assignee: Zhejiang Tongxinqi Technology Co ltd
Priority date: 2023-01-10
Filing date: 2023-01-10
Publication date: 2023-04-14
Also published as: CN117410227A

Abstract

The invention discloses a wafer processing technology, and belongs to the field of semiconductor manufacturing. A wafer processing process, comprising the steps of: completing a back metal process on the back of the wafer, and bonding the back of the wafer on the carrying disc; coating an aluminum metal layer on the front surface of the wafer and the upper end surface of the carrying disc, coating a photoresist on the aluminum metal layer, and exposing the aluminum metal layer above the reserved cutting channel of the wafer; etching the aluminum metal layer exposed out of the photoresist, and forming a metal ring at the joint of the wafer and the carrier disc; carrying out invisible cutting on the part of the wafer preset with the cutting channel, and heating the wafer to form ohmic alloy; carrying out chemical plating on the aluminum metal layer to form a noble metal layer; cutting the part of the wafer, which is preset with the cutting channel, to form the cutting channel, and cutting off and removing the metal ring; and carrying out film expansion and splitting to form crystal grains.

Description

Wafer processing technology

Technical Field

The invention relates to the field of semiconductor manufacturing, in particular to a wafer processing technology.

Background

In the processing technology of the wafer, the carrying difficulty of the thin wafer is high, and if the wafer is not fixed properly, the wafer is easy to warp, so that the yield of the whole product is influenced. On the other hand, in the noble metal chemical plating process of the wafer, the back surface of the wafer is easily plated with noble metal, resulting in an increase in production cost.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a wafer processing technology.

The purpose of the invention can be realized by the following technical scheme:

a wafer processing process, comprising the steps of:

completing a back metal process on the back of the wafer, and bonding the back of the wafer on the carrying disc;

coating an aluminum metal layer on the front surface of the wafer and the upper end surface of the carrying disc, coating a photoresist on the aluminum metal layer, and exposing the aluminum metal layer above the reserved cutting channel of the wafer;

etching the aluminum metal layer exposed out of the photoresist, and forming a metal ring at the joint of the wafer and the carrier disc;

invisible cutting is carried out at the position of the wafer preset with the cutting channel,

heating the wafer to form an ohmic alloy;

carrying out chemical plating on the aluminum metal layer to form a noble metal layer;

cutting off and removing the metal ring, positioning a preset cutting channel, and cutting the metal at the cutting channel part on the back of the wafer to form a cutting channel;

and carrying out film expansion and splitting to form crystal grains.

The material of the noble metal layer is one or more of nickel, palladium and gold.

The carrier disc is made of transparent materials, in the step of cutting the part of the wafer with the preset cutting channels to form the cutting channels, the bottom surface of the carrier disc is upward, the front surface of the wafer is downward placed on the transparent carrier, a device for positioning the part with the preset cutting channels is arranged on the carrier, and laser is projected above the carrier disc to cut the metal layer to be cut and the wafer to form the cutting channels through the transparent carrier disc.

The carrying disc is a glass carrying disc.

The invention has the beneficial effects that:

the metal ring can seal the joint of the wafer and the carrying disc, so that the plating solution does not contact the back of the wafer during chemical plating, and unnecessary waste is reduced. Meanwhile, the metal ring also has the function of fixing the wafer, and the wafer can be prevented from being fixed by using a bonding agent under the process of high temperature.

Drawings

The invention is further described below with reference to the accompanying drawings.

FIGS. 1-3 are process flow diagrams of the present application.

Parts in the figures with reference numbers:

1-wafer, 2-carrying disc, 3-back metal layer, 4-aluminum metal layer, 5-metal ring, 6-noble metal layer; 7-carrier, 8-sucker, 9-mould frame, 10-through hole, 11-photoresistor and 101-crystal grain.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, fig. 2 and fig. 3, a wafer 1 processing process includes the following steps:

finishing a back metal process on the back of the wafer 1, namely forming a back metal layer 3 on the back of the wafer 1, and bonding the back of the wafer 1 on the carrying disc 2;

coating an aluminum metal layer 4 on the front surface of the wafer 1 and the upper end surface of the carrying disc 2, coating a photoresist 11 on the aluminum metal layer 4, and exposing the aluminum metal layer 4 above a reserved cutting channel of the wafer 1;

etching the aluminum metal layer 4 exposed out of the photoresist 11 and forming a metal ring 5 at the joint of the wafer 1 and the carrier plate 2;

invisible cutting is carried out on the wafer 1 at the position with preset cutting lines,

heating the wafer 1 to form an ohmic alloy;

and performing chemical plating on the aluminum metal layer 4 to form a noble metal layer 6. The material of the noble metal layer 6 may be, but is not limited to, nickel, palladium, or gold.

Cutting off and removing the metal ring 5, and cutting the part of the wafer 1, which is preset with a cutting channel, to form a cutting channel;

the film is expanded and cracked to form crystal grains 101.

The carrier disc 2 is made of transparent materials, in the step of cutting the part of the wafer 1 with the cutting channels preset to form the cutting channels, the bottom surface of the carrier disc 2 faces upwards, the front surface of the wafer 1 faces downwards and is placed on a transparent carrier 7, a device for positioning the part with the cutting channels preset is arranged on the carrier 7, and laser is projected above the carrier disc 2 to penetrate through the transparent carrier disc 2 to cut the metal layer to be surface-deposited and the wafer 1 to form the cutting channels.

The boat 2 may be a glass boat 2. Since the carrier 7 needs to transmit laser light, it may be made of glass.

In some embodiments of the present invention, the through holes 10 may be formed on both the carrier plate 2 and the carrier 7, so that when the wafer 1 is transferred from the carrier plate 2 to the carrier 7 and then to the mold frame 9, the wafer 1 can be safely transferred by performing negative pressure suction through the backside adhesive chuck 8.

In some embodiments of the present invention, before the electroless plating, the region where aluminum plating is not desired needs to be protected, and specifically, the portion of the upper end surface of the wafer 1 where noble metal plating is not desired may be covered with a protective layer, such as the photoresist 11. Then, the part to be plated with the noble metal, i.e. the upper part of the aluminum metal layer 4, is exposed by photolithography. And after the steps are finished, carrying out chemical plating.

In addition, in the chemical plating process, the metal ring 5 can also serve as a partition, so that unnecessary waste caused by the fact that the chemical plating solution carrying precious metal permeates to the back of the wafer 1 is avoided.

As shown in fig. 2 and 3, in the present embodiment, the metal ring 5 for fixing and sealing the wafer 1 is cut off and removed, and then the wafer 1 and the carrier 2 are transferred to the carrier 7 by the suction cup 8 and the like, and cut to form a scribe line.

In the description herein, references to the description of "one embodiment," "an example," "a specific example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.

Claims

1. A wafer processing process, comprising the steps of:

depositing an aluminum metal layer on the front surface of the wafer and the upper end surface of the carrying disc, coating a photoresist on the aluminum metal layer, and exposing the aluminum metal layer above the cutting channel reserved on the wafer;

heating the wafer to form an ohmic alloy;

and transferring to a mold frame, and performing film expansion and splitting to form crystal grains.

2. The wafer processing technology as claimed in claim 1, wherein the material of the noble metal layer is one or more of nickel, palladium and gold.

3. The wafer processing technology as claimed in claim 1, wherein the carrier is made of transparent material, the pre-set scribe line is located, and in the step of forming the scribe line by cutting the metal at the scribe line portion on the back surface of the wafer, the bottom surface of the carrier is upward, the front surface of the wafer is downward placed on a transparent carrier, a device for locating the portion of the pre-set scribe line is disposed on the carrier, and the laser is projected above the carrier to cut the back metal layer through the transparent carrier to form the scribe line.

4. The wafer processing process of claim 3, wherein the carrier disk is a glass carrier disk.

5. The wafer processing technology as claimed in claim 1, wherein during the electroless plating, the part of the upper end face of the wafer, which is not expected to be plated with the noble metal, is covered by photolithography, so that the aluminum metal layer is exposed.