KR100249793B1 - Fabrication method of backside via-hole using sapphire wafer - Google Patents

Abstract

An object of the present invention is to provide a method for fabricating a wafer polishing sample for backside via-holes with good uniformity and controllability. According to the present invention, a sapphire wafer is attached to a glass substrate using low temperature wax at the time of polishing the back side, and a wafer having a process completed using high temperature wax is attached thereto. After polishing from 50 microns to 100 microns, the glass substrate is removed at low temperature and subjected to back via-hole lithography. After the lithography is completed, the via-hole is etched and the backside is plated by electroplating to complete the via-hole process, and the wafer is removed from the sapphire transparent support at high temperature and cleaned. Therefore, via holes can be used as mask alignment and dry etching wafer holders for etch masks using sapphire transparent supports, and high temperature and low temperature waxes are used for the protection of samples. During the etching process, it is possible to stabilize the etching rate which changes rapidly according to the substrate temperature. Thus, this process is a way to obtain uniform, reproducible backside via-holes in the wafer.

Description

How to make back via-holes using sapphire clear support

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process and a fabrication method for forming a highly polished, highly reproducible back ground sample that can be used for high frequency and high speed devices and integrated circuits. The present invention relates to a method of fabricating a back via-hole using a sapphire transparent support that can be used as a mask alignment for a mask and a dry etching wafer support, and is easily removed after use by using high and low temperature wax for protecting a sample.

In order to increase device integration and facilitate heat dissipation, backside polishing and backside via-hole processing of the wafer must be precisely controlled.

A conventional polishing process for backside via-holes is shown in FIG.

As shown in FIG. 1, the already fabricated device and the integrated circuit board 1 are placed on a glass substrate 5 coated with a low temperature wax 4, heated and pasted, and then the back side 6 is wrapped. ) Method.

In this conventional manufacturing method, a wafer (substrate) 1 is attached to the glass substrate 5 by using a low temperature wax 4 when polishing the back side. After polishing the substrate 1, the back side via-hole lithography process is performed. At this time, when using the alignment device, the use of the device due to the use of a thick support, and the horizontal adjustment is difficult, there is a limit in reducing the error of alignment even during alignment.

In addition, if the support is thick in the process of etching the via-hole after the lithography is completed, it is difficult to load into the etching apparatus and heat is difficult to be released during the etching process, resulting in an increase of the wafer temperature and deformation of the mask. For this reason, in order to fabricate a high performance backside via-hole type device, it is necessary to introduce a better polishing sample preparation process and to develop additional processes.

Therefore, the present invention solves alignment and exposure problems by using a transparent sapphire substrate, which is easy to dissipate heat, and improves the etching uniformity by dissipating heat generated during via-hole etching. Because of its thickness, it can be safely loaded into the etch apparatus.

And sapphire substrate has better thermal conductivity than glass substrate, stabilizes back surface polishing and via-hole process, and provides uniform and reproducible manufacturing process in wafer.

1 is a cross-sectional view showing a conventional method for manufacturing a back via-hole.

Figure 2 is a cross-sectional view showing a method for manufacturing a back via-hole using a sapphire transparent support according to the present invention.

Figure 3 (a) to (i) is a process chart showing a method of manufacturing the back via-hole using the sapphire transparent support according to the present invention.

<Description of the code | symbol about the principal part of drawing>

1: substrate 2: high temperature wax

3: sapphire transparent support 4: low temperature wax

5: glass substrate 6: polished back part

7: photosensitive film 8: via-hole

9: plating layer

Figure 2 is a cross-sectional view showing a method for manufacturing the back via-hole using the sapphire transparent support according to the present invention, Figure 3 (a) to (i) is a manufacturing process of the back via-hole using the sapphire transparent support according to the present invention.

FIG. 3 (a) shows a sapphire substrate (support) of about 500 microns thick, which is a transparent support for the already fabricated device and the integrated circuit board 1 by coating a photoresist film as a surface protection film, and as shown in FIG. 3 (b). 3) After applying the high temperature wax (2) to the surface of the substrate (1) facing the support (3), heated to a high temperature of about 160 ℃ in a hot-plate (Hot-Plate) to prevent air To ensure uniform contact in vacuo.

Subsequently, as shown in (c) of FIG. 3, this was placed on a glass substrate 5 having a thickness of 3 millimeters, and the low temperature wax 4 was applied at about 60 ° C., followed by using a hot plate. The sample produced in (b) of FIG. 3 is attached to the glass substrate 5 in a vacuum so as not to generate bubbles by heating at a low temperature (about 80 ° C. or lower). Using this, as shown in Fig. 3 (d), the back side 6 of the substrate is wrapped and polished with an abrasive using a lapping method to a suitable thickness (about 50 to 100 microns). .

As shown in (e) of Figure 3, using a hot-plate (Hot Plate) heated to about 80 ℃, the glass substrate (5) attached with a low temperature wax is removed and washed with an organic solvent.

As shown in FIG. 3F, a via-hole mask is formed on the rear surface of the substrate 1 using the photosensitive film 7. Thereafter, as shown in FIG. 3 (g), the back via-hole 8 is etched by a dry etching method. At this time, since the loading of the substrate 1 is free and the heat generated during etching is easily released to the electrode part of the dry etching equipment through the sapphire support 3, the etching uniformity is increased and the etching mask is not deformed.

As shown in FIG. 3H, the photoresist layer and Ni, which are mask layers, are removed by a wet etching method, and the base metal is deposited by an electron beam deposition apparatus. In addition, the gold (9) is electroplated by the electroplating method to form a stable ground electrode. After the plating process is completed, as shown in FIG. 3 (i), the transparent support 3 is removed from the substrate 1 by heating to about 160 ° C. using a heat-plate, and then desorbed by cleaning the substrate 1. To remove.

Therefore, according to the present invention, it is possible to precisely and easily align the mask for forming the etch mask and the substrate, to facilitate the heat dissipation by using the wafer support during dry etching, and to provide high and low temperature wax for protecting the sample. It is easy to remove after use. Thus, this process is a way to obtain uniform, reproducible backside via-holes in the wafer.

The present invention is a method for precisely controlling the backside polishing and post processing of a wafer. The present invention relates to a process and a method for forming a highly reliable, reproducible backside polishing sample, wherein a transparent support such as sapphire is used to facilitate alignment during lithography and etching processes and to facilitate wafer loading and heat release into the etching apparatus. This has the advantage.

When polishing the back side, the sapphire wafer is attached to the glass substrate using low temperature wax, and the process of attaching the completed wafer using the high temperature wax thereon is advantageous in that the substrate is easily detached. After polishing the substrate, the glass substrate is removed at low temperature, and the back via-hole lithography process is performed. At this time, even in the use of the alignment device can reduce the trouble of using the device due to the use of a thick support and can minimize the error of alignment during alignment.

When the support is thick in the process of etching via-holes after the lithography is completed, it is difficult to load into the etching apparatus and heat is difficult during the etching process, causing the wafer temperature to rise and the mask to be deformed. Therefore, using a sapphire substrate that is easy to dissipate heat solves this problem, improves the etching uniformity, and when loading the substrate can be loaded safely because the same thickness as the normal sample.

Therefore, this process stabilizes the back side of the substrate and makes the via-hole process, and it is a uniform and reproducible manufacturing process in the wafer.

Claims (4)

Coating a photoresist film, which is a surface protective film, on the fabricated device and the integrated circuit board 1 by about 2 microns; Attaching the transparent support (3) for use as a support on the substrate (1) in a vacuum so as to be in uniform contact by heating to a high temperature in a hot-plate; Attaching the sample having the transparent support 3 attached to the glass substrate 5 in a vacuum by heating to a low temperature using a hot plate; Lapping and polishing a back side portion on which the photoresist film of the substrate 1 is formed; Heating the sample to about 80 ° C. using a heat-plate, and then removing the glass substrate 5; Forming a via-hole mask on the rear surface of the substrate 1; Etching the back via-holes by dry etching; Removing the mask layer and depositing the base metal; Electroplating gold by electroplating method, Heating and removing the transparent support 3 from the substrate 1 by heating the substrate to about 160 ° C. using a hot plate, Method for manufacturing a back via-hole using a sapphire transparent support, characterized in that to perform a process for cleaning the substrate. The method of claim 1, wherein the transparent support is A method of fabricating a back via-hole using a sapphire transparent support, characterized in that the transparent sapphire substrate is used as a transparent support to facilitate alignment in lithography and etching processes and to facilitate wafer loading and heat release into the etching apparatus. The substrate (1) and the transparent support (3) are attached using a high temperature wax (2), and the glass substrate (5) and the transparent support (3) are made using a low temperature wax (4). Method for making a back via-hole using a sapphire transparent support, characterized in that the paste. The method of claim 1, wherein the back surface of the substrate (1) is polished from 50 microns to 100 microns, and then the glass substrate is peeled off at a low temperature.

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