CN111446165A - A wafer heat treatment process and a wafer double-sided electroplating process - Google Patents

Abstract

The invention discloses a wafer heat treatment process and a wafer double-sided electroplating process, belonging to the field of wafer processing. A wafer heat treatment process, comprising the following steps: bonding one end face of the wafer with a glass carrier plate; grinding the other end face of the wafer to make the wafer thin; etching the wafer In the middle, the shape of the wafer is thin in the center and thick at the edge; yellow light and ion implantation processes are sequentially performed on the other end face of the wafer; the glass carrier plate is debonded by laser or resistance heating or ultraviolet light irradiation , cleaning to remove the bonding agent; heat treatment process to form the ohmic contact resistance of the alloy. Compared with the prior art, the wafer double-sided electroplating and heat treatment process of the present application can effectively avoid the bending deformation of the wafer during the heat treatment process or the double-sided electroplating process.

Description

A wafer heat treatment process and a wafer double-sided electroplating process

technical field

The invention relates to the field of wafer processing, in particular to a wafer heat treatment process and a wafer double-sided electroplating process.

Background technique

At present, in the wafer production process of MOSFET and IGBT power devices and 3-D devices, in order to produce ultra-thin wafers, it is necessary to bond the wafers with the glass carrier, and mount the wafer on the glass carrier. , so as to facilitate the processing and transfer of the wafer; or use the Taico Wafer to thin the wafer, and perform photolithography patterning, etching, ion implantation, annealing, annealing, etc. Processes such as metal deposition are performed.

In the process of bonding the glass carrier, the glass carrier can be thinned, but the double-sided electroplating process cannot be continuously performed, and the heat treatment process cannot be performed because the glass carrier is not resistant to high temperature.

In the Taiko process, the wafer does not need to be bonded to a glass carrier, but after the wafer is thinned, in the heat treatment process, the wafer is easily deformed, bent and broken by heat. Therefore, after the Taiko Taiko process is completed, it is often necessary to Removes the curved edge of the wafer, causing material loss. On the other hand, when performing metal deposition (evaporation/sputtering/electroplating/electroless plating), the wafer also requires special fixtures and carriers. Especially in the current chemical bath type of electroplating equipment, batch multi-piece fixture design, because thin wafers are easily shaken or even broken due to the plating solution in the bath, in order to homogenize the metal ion density of the plating solution, a specific circulating flow field is required.

SUMMARY OF THE INVENTION

In view of the deficiencies of the prior art, the present invention proposes a wafer heat treatment process and a wafer double-sided electroplating process, which can perform double-sided electroplating and avoid edge deformation during the heat treatment process.

The object of the present invention can be realized through the following technical solutions:

A wafer heat treatment process, comprising the following steps:

bonding one end face of the wafer with the glass carrier;

grinding the other end face of the wafer to thin the wafer;

Etching the middle of the wafer, so that the shape of the wafer is thin in the center and thick at the edge;

performing yellow light and ion implantation processes on the other end face of the wafer in sequence;

Debonding the glass carrier by laser or resistance heating or ultraviolet light irradiation, cleaning and removing the bonding agent;

A heat treatment process is performed to form the ohmic contact resistance of the alloy.

Further, after etching, the shape of the wafer is stepped or sloped.

Further, after etching, the thickness of the thinnest part of the wafer is 20-100 microns.

Further, in the heat treatment process, the wafer is placed in a furnace tube device, and heated after nitrogen is introduced.

Further, the thickness of the glass carrier plate is 400-700 microns.

Further, after the wafer is ground, the thickness of the thickest part is 200-400 microns.

A wafer double-sided electroplating process, comprising the following steps:

bonding one end face of the wafer with the glass carrier;

grinding the other end face of the wafer to thin the wafer;

Etching the middle of the wafer, so that the shape of the wafer is thin in the center and thick at the edge;

performing yellow light and ion implantation processes on the other end face of the wafer in sequence;

Debonding the glass carrier by laser or resistance heating or ultraviolet light irradiation, cleaning and removing the bonding agent;

Double-sided electroplating process.

Beneficial effects of the present invention:

In the wafer double-sided electroplating process of the present invention, a wafer with a thin center and thick edges is obtained first, and after debonding, the wafer can be directly removed from the glass carrier for double-sided electroplating and heat treatment. , the deformation resistance of the wafer is enhanced to avoid bending deformation during heat treatment.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

1 is a schematic structural diagram of a bonded glass carrier and a wafer according to the present application;

FIG. 2 is a schematic diagram of a heating method of a wafer in an embodiment of the present application;

3 is a schematic diagram of a heating method of a wafer in another embodiment of the present application;

4 is a schematic diagram of a heating method of a wafer in another embodiment of the present application;

Fig. 5 is the schematic diagram of electroless plating in the application;

FIG. 6 is a schematic diagram of electroplating in the application.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "around", etc. Indicates the orientation or positional relationship, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, are constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention .

As shown in FIG. 1, a heat treatment process for a wafer 1 includes the following steps:

One end face of the wafer 1 is bonded to the glass carrier plate 2, wherein the thickness of the glass carrier plate 2 is 400-700 microns. The other end face of the wafer 1 is ground to make the wafer 1 thin, and after thinning, the thickness of the thickest part of the wafer 1 is 200-400 microns. Then, the wafer 1 is etched, so that the shape of the wafer 1 is thin in the center and thick at the edges, wherein the specific shape of the wafer 1 can be but not limited to a step shape or a slope shape, and the thickness of the thinnest part of the wafer 1 is 20 ~100 microns. Then, yellow light and ion implantation processes are sequentially performed on the other end face of the wafer 1 .

The glass carrier plate 2 is debonded by laser or resistance heating or ultraviolet light irradiation, and the bonding agent is cleaned and removed; finally, a heat treatment process is performed to form the ohmic contact resistance of the alloy.

Through the above process, firstly, a wafer 1 with a thin center and a thick edge is obtained by grinding and etching. After debonding, the wafer 1 can be directly put into the thermal processing equipment. Because the edge is thick and the thickness is kept at 200-400, the wafer 1 has good deformation resistance. Therefore, after heat treatment, the deformation of the wafer 1 is small to avoid bending deformation after heat treatment.

For thermal processing, the wafer can be heated by thermal conduction, thermal radiation, and thermal convection. Specifically, it may be a heating process using furnace tube equipment, RTP (Rapid Thermal Process, rapid heat treatment process) or a resistance heating process. More specifically, as shown in FIG. 2 , in one embodiment of the present invention, the wafer 1 is placed on the support 3 of the furnace tube equipment, and the wafer 1 is subjected to the operation by clamping or supporting the edge portion of the wafer 1 . fixed. Then, a high-heat gas is introduced into the equipment to form convection in the equipment to heat the wafer 1 . And this high-heat gas does not chemically react with the wafer 1 , such as nitrogen gas.

As shown in FIG. 3 , in another embodiment of the present invention, a clamp is used to fasten and fix the wafer 1 , and a protective cover 4 made of transparent material is used to seal the wafer 1 , and then the protective cover 4 is introduced into the protective cover 4 that does not interact with the wafer 1 . The gas for the circular reaction is, for example, nitrogen. Then, the wafer 1 is irradiated with ultraviolet light to heat the wafer 1 by thermal radiation.

As shown in FIG. 4 , in another embodiment of the present invention, a clamp is also used to clamp the wafer 1 , the wafer 1 is placed on the resistance wire 5 , the protective cover 4 is used to encircle and seal the wafer 1 , and then the protection cover 4 is used to seal the wafer 1 . A gas that does not react with the wafer 1 is introduced into the cover 4 , such as nitrogen gas. Then, the heating resistance wire 5 contacts the wafer 1 and heats the wafer 1 .

In addition, the present invention also provides a wafer double-sided electroplating process, and the specific steps are as follows.

First, one end surface of the wafer 1 is bonded to the glass carrier plate 2, wherein the thickness of the glass carrier plate 2 is 400-700 microns. The other end face of the wafer 1 is ground to make the wafer 1 thin, and after thinning, the thickness of the thickest part of the wafer 1 is 200-400 microns. Then, the wafer 1 is etched, so that the shape of the wafer 1 is thin in the center and thick at the edges, wherein the specific shape of the wafer 1 can be but not limited to a step shape or a slope shape, and the thickness of the thinnest part of the wafer 1 is 20 ~100 microns. Then, yellow light and ion implantation processes are sequentially performed on the other end face of the wafer 1 .

The glass carrier plate 2 is debonded by laser or resistance heating or ultraviolet light irradiation, and the bonding agent is removed by cleaning.

Finally, the double-sided metal plating process is performed. More specifically, the wafer 1 can be put into the process tank of the electroplating equipment first, and the metal plating process is performed on both sides of the wafer 1. The specific method can be either electroplating or electroplating. Electroless plating. In the process of electroless plating, as shown in Figure 5, it is necessary to use the clamp 3 to clamp the thicker part of the edge and put it into the electroless plating solution. The metal ions are deposited on the metal layer of the wafer 1, so that the electroless plating of the wafer 1 is performed.

During the electroplating process, as shown in FIG. 6 , the clamp 3 provided with the electrode 7 clamps the thicker part of the edge of the wafer 1, and the electrolyte 6 is added. The seed layer is ion-exchanged, so that the anode target 8 is ion-plated on the seed layer, so that the wafer 1 is electroplated.

In the process of electroless plating and electroplating, the advantage of this process is that since the wafer 1 has a thicker edge and better rigidity, double-sided electroless plating and electroplating can be performed. No matter in the process of clamping and transfer, or in the specific circulating flow field of the electroplating solution 6, the wafer 1 will not be easily broken, and the glass carrier plate 2 does not need to be bonded, which can effectively reduce the number of wafers 1 during electroplating. Risk of breakage.

In the description of this specification, description with reference to the terms "one embodiment," "example," "specific example," etc. means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one aspect of the present invention. in one embodiment or example. In this specification, schematic representations of the above terms 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 has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention.

Claims (7)

1. a wafer heat treatment process, is characterized in that, comprises the following steps: bonding one end face of the wafer with the glass carrier; grinding the other end face of the wafer to thin the wafer; Etching the middle of the wafer, so that the shape of the wafer is thin in the center and thick at the edge; performing yellow light and ion implantation processes on the other end face of the wafer in sequence; Debonding the glass carrier by laser or resistance heating or ultraviolet light irradiation, cleaning and removing the bonding agent; A heat treatment process is performed to form the ohmic contact resistance of the alloy. 2 . The wafer heat treatment process according to claim 1 , wherein after etching, the shape of the wafer is stepped or sloped. 3 . 3 . The wafer heat treatment process according to claim 1 , wherein, after etching, the thickness of the thinnest part of the wafer is 20-100 μm. 4 . 4 . The wafer heat treatment process according to claim 1 , wherein, in the heat treatment process, the wafer is put into a furnace tube equipment, and then heated after nitrogen is introduced. 5 . 5 . The wafer heat treatment process according to claim 1 , wherein the thickness of the glass carrier plate is 400-700 μm. 6 . 6 . The wafer heat treatment process according to claim 1 , wherein after the wafer is ground, the thickness of the thickest part is 200-400 μm. 7 . 7. a wafer double-sided electroplating process, is characterized in that, comprises the following steps: bonding one end face of the wafer with the glass carrier; grinding the other end face of the wafer to thin the wafer; Etching the middle of the wafer, so that the shape of the wafer is thin in the center and thick at the edge; performing yellow light and ion implantation processes on the other end face of the wafer in sequence; Debonding the glass carrier by laser or resistance heating or ultraviolet light irradiation, cleaning and removing the bonding agent; Carry out double-sided electroplating or electroless plating process.

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