JPH05283382A - Rear processing method of semiconductor wafer and surface side structure of semiconductor wafer at the time of rear processing - Google Patents

Abstract

PURPOSE:To provide a rear processing method of a semiconductor allowing execution while securing a parallel state to a wafer support of a semiconductor wafer and the surface side structure of the semiconductor wafer time of rear processing. CONSTITUTION:A rear processing method of a semiconductor wafer 1 includes a process of overall covering the surface side of the semiconductor wafer to be subjected to rear processing by a film body 10, a process of forming a plurality of groove parts 11 opening while being taken out up to an outer end edge of the semiconductor wafer 1 on the prescribed spots of the film body 10 respectively and a process of putting on the surface side of the semiconductor wafer 1 covered by the film body 10 on the wafer support 2 through wax 3 for junction followed by press. Further, as to the surface side structure of the semiconductor wafer 1, its surface side is overall covered by the film body 10, a plurality of groove parts 11 opening while being taken out up to an outer end edge of the semiconductor wafer 1 are formed on the prescribed sports of this film body 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a back surface of a semiconductor wafer and a front surface side structure of the semiconductor wafer at the time of processing the back surface.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a semiconductor element, in order to enhance a heat dissipation function at the time of mounting the semiconductor element, the substrate thickness is thinned to about 100 μm or less at a semiconductor wafer stage. Therefore, in order to reduce the thickness of the substrate, it is general to employ a method of gradually scraping the semiconductor wafer from the back surface side. Then, in carrying out such back surface processing, a support structure as illustrated in FIG. 3, that is, a semiconductor wafer 1 to be back processed and a wafer support 2 supporting the front surface side of the semiconductor wafer 1 are bonded together. A supporting structure formed by laminating via a wax 3 is used, and the semiconductor wafer 1 is processed on the back surface according to the following procedure.

First, a glass disk, which faces the semiconductor wafer 1 to be processed on the back surface and supports the entire surface, is prepared as a wafer support 2, and a bonding wax 3 is applied to one surface thereof. Melt. Next, by pressing the processed surface of the semiconductor wafer 1 against the bonding wax 3 in the molten state, the semiconductor wafer 1 and the wafer support 2 are attached to each other via the bonding wax 3. To match. Then, after solidifying the bonding wax 3 to integrate the semiconductor wafer 1 and the wafer support 2, the other surface of the wafer support 2, that is, the semiconductor wafer 1
The back surface of the semiconductor wafer 1 (upper side surface in the figure) while using the surface not bonded (lower side surface in the figure) as a processing reference.
By polishing or grinding, the substrate is thinly processed until it has a predetermined thickness.

[0004]

By the way, the back surface processing of the semiconductor wafer 1 as described above is performed by this semiconductor wafer 1.
Since the wafer support 2 for supporting the wafer is used as a processing reference, whether or not the parallel state between the semiconductor wafer 1 and the wafer support 2 is ensured is an important factor during the back surface processing. Whether or not the parallel state between these two is ensured is whether or not the thickness of the bonding wax 3 interposed between the semiconductor wafer 1 and the wafer support 2 is uniform at any position between them. It will be decided based on whether or not.

However, when the semiconductor wafer 1 and the wafer support 2 are bonded together using the bonding wax 3, the bonding wax 3 does not always have a uniform thickness therebetween. Instead, as shown in FIG.
Excessive amount of the bonding wax 3 remains between the semiconductor wafer 1 and the wafer support 2, and the thickness of the bonding wax 3 becomes non-uniform. It may happen that the attached semiconductor wafer 1 is integrated with the wafer support 2 in an inclined posture. Then, in such a case, the back surface processing of the semiconductor wafer 1 is performed in an inclined state, and as a result of the substrate thickness becoming nonuniform, the obtained semiconductor elements have different thicknesses. It causes inconvenience.

The present invention was devised in view of such inconveniences, and can be carried out while ensuring the parallel state of the semiconductor wafer with respect to the wafer support. In order to provide a front surface side structure of a semiconductor wafer in.

[0007]

A method of processing a back surface of a semiconductor wafer according to the present invention comprises a step of entirely covering a front surface side of a semiconductor wafer to be processed by a film body with a film body and an outer edge of the semiconductor wafer. A step of forming a plurality of groove portions that are pulled out and opened at predetermined positions of the film body,
And a step of placing the front surface side of the semiconductor wafer covered with the film body on a wafer support through a bonding wax and pressing the wafer support. Also, the structure of the front surface side of the semiconductor wafer during back surface processing is
The surface side of the semiconductor wafer supported by the wafer support is entirely covered with a film body, and a plurality of groove portions that are drawn out to the outer edge of the semiconductor wafer and open at predetermined positions of the film body. Are formed.

[0008]

According to the above method, when the front surface side of the semiconductor wafer covered with the film is placed on the wafer support and then pressed, the excess amount of the bonding wax is transmitted through the groove formed in the film. However, it is quickly extruded to the outer edge of the semiconductor wafer. Therefore, the extra bonding wax does not exist between the film body covering the front surface side of the semiconductor wafer and the wafer support, and the thickness of the bonding wax between both of them is made uniform. The state will be secured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing the front surface side structure of a semiconductor wafer and its supporting structure at the time of processing the back surface.
FIG. 2 is a side sectional view showing a bonded state. In these figures, parts and portions which are the same as or correspond to those in FIG. 3 showing the conventional example are denoted by the same reference numerals, and detailed description thereof is omitted here.

In the support structure according to the present embodiment, a semiconductor wafer 1 to be processed on the back surface and a wafer support 2 which entirely supports the front surface side of the semiconductor wafer 1 are bonded together via a bonding wax 3. On the other hand, as a front surface side structure of the semiconductor wafer 1, the front surface side of the semiconductor wafer 1 is entirely covered with a film body 10 having a predetermined thickness, and the semiconductor wafer 1 is provided at each predetermined position of the film body 10. A structure in which a plurality of groove portions 11 that are drawn out and open to the outer edge of is formed is adopted. That is, a resist film, which is the film body 10 having a thickness of several μm, is formed on the already processed surface of the semiconductor wafer 1 through a protective film (not shown), and A plurality of groove portions 11 are formed in this resist film along the vertical and horizontal directions. The film body 10 is not limited to the resist film, and it goes without saying that it may be an insulating resin sheet or the like. As the wafer support 2 that faces the semiconductor wafer 1 and supports it, a glass disk is used as in the conventional example.

Next, a method of processing the back surface of the semiconductor wafer 1 having such a support structure and a front surface side structure will be described according to the procedure.

First, by forming and patterning a resist film on the front surface side of the semiconductor wafer 1, a resist film as a film body 10 covering the front surface side of the semiconductor wafer 1 and a plurality of groove portions 11 are formed. .. At this time, if each of the groove portions 11 is formed along a scribe line (not shown) of the semiconductor wafer 1, the width of the scribe line is about 40 μm, whereas the width of the groove portion 11 has an alignment margin. About 20 μm, which can be sufficiently secured, is sufficient. Next, a glass disk is prepared as the wafer support 2, and one surface thereof is coated with a bonding wax 3 such as sky wax (trade name) and then melted.

Thereafter, the semiconductor wafer 1 is pressed against the bonding wax 3 in the molten state, that is, the semiconductor wafer 1 is pressed toward the bonding wax 3 from the film body 10 covering the surface thereof. The semiconductor wafer 1 and the wafer support 2 are bonded to each other with the wax 3 in between. Furthermore, after such bonding is performed, when the semiconductor wafer 1 and the wafer support 2 bonded together are pressed along the bonding direction, the excess amount of the bonding wax 3 covers the surface of the semiconductor wafer 1. While being transmitted through the groove portion 11 formed in the film body 10, it is pushed out to the outer edge of the semiconductor wafer 1. Therefore, the extra bonding wax 3 does not exist between the semiconductor wafer 1 and the wafer support 2 bonded to each other, and the thickness of the bonding wax 3 between them is made uniform. ..

Subsequently, the semiconductor wafer 1 and the wafer support 2 are integrated by solidifying the bonding wax 3, and the other surface of the wafer support 2, that is, the semiconductor wafer 1 is integrated.
The back surface of the semiconductor wafer 1 (upper side surface in the figure) while using the surface not bonded (lower side surface in the figure) as a processing reference.
By polishing or grinding, the substrate is thinly processed until it has a predetermined thickness. Then, when the back surface processing of the semiconductor wafer 1 is completed, the semiconductor wafer 1 is peeled from the wafer support 2 by using a peeling solvent capable of dissolving the bonding wax 3. At this time, since the stripping solvent penetrates through the groove 11 formed in the film body 10 covering the surface of the semiconductor wafer 1, the time required for the stripping work can be shortened, and at the same time, the film body 10 There is an advantage that the element surface is protected by the resist film.

Further, the semiconductor wafer 1 separated from the wafer support 2 is dipped in a solvent such as acetone, the resist film is removed from the surface, and then the semiconductor wafer 1 is scribed in the next step. A semiconductor element divided into two is obtained.

[0017]

As described above, according to the method of processing the back surface of the semiconductor wafer and the structure of the front surface side of the semiconductor wafer during the back surface processing according to the present invention, the front surface side of the semiconductor wafer covered by the film body and the wafer support. No extra bonding wax is present between the body and the thickness of the bonding wax between these two is made uniform,
The parallel state of the semiconductor wafer with respect to the wafer support is ensured. Therefore, it is possible to obtain an effect that the substrate thickness of the semiconductor wafer whose back surface is processed with the wafer support as a processing reference and the semiconductor element obtained from each of the wafers are uniform without variation.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a structure on a front surface side of a semiconductor wafer and a supporting structure thereof when a back surface is processed.

FIG. 2 is a side sectional view showing the pasted state.

FIG. 3 is a side sectional view showing a bonded state of a support structure for a semiconductor wafer during backside processing according to a conventional example.

[Explanation of symbols]

 1 Semiconductor Wafer 2 Wafer Support 3 Wax for Bonding 10 Membrane 11 Groove

Claims (2)

[Claims] 1. A step of entirely covering a front surface side of a semiconductor wafer (1) to be processed on the back surface with a film body (10), and a plurality of pieces which are pulled out and opened to an outer edge of the semiconductor wafer (1). Forming a groove part (11) at a predetermined position of the film body (10), and a front surface side of the semiconductor wafer (1) covered with the film body (10) with a bonding wax (3) interposed. And then pressing the wafer support (2) on the wafer support (2). 2. The surface side of a semiconductor wafer (1) supported by a wafer support (2) is entirely covered with a film body (10), and each of the predetermined portions of the film body (10) has the above-mentioned structure. A front surface side structure of a semiconductor wafer at the time of backside processing, characterized in that a plurality of groove portions (11) that are drawn out and opened to the outer edge of the semiconductor wafer (1) are formed.