JPH03159153A - Division of semiconductor substrate - Google Patents

Abstract

PURPOSE:To obtain a method of division facilitating high-yield cutting and division without decrease in strength at the edges of an attached film such as a metallic film and without imperfect division by making a wider groove than a scribe region in the rear before the attached film is formed. CONSTITUTION:In using a method of dividing a semiconductor substrate by which a semiconductor substrate 4 having a film 5 attached to the rear is divided by cutting at a scribe region, a wider groove G than the scribe region is made in the rear before the attached film 5 is formed. For example, the wider groove G than the scribe region is made along the scribe region with a dicing blade. The metallic film 5 is formed on the rear of the semiconductor substrate 4 by the vacuum deposition method or other methods. An adhesive sheet 6 is adhered to the rear of the semiconductor substrate 4, which is cut at the scribe region with the dicing blade 7. In cutting, the dicing blade 7 must reach the bottom of the groove G made in the rear but must not be in contact with the adhesive sheet 6.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a semiconductor substrate with an adhesive film formed on the back surface.
The present invention relates to a method for dividing a semiconductor substrate by cutting along a scribe region.

[Conventional technology]

When semiconductor elements are fabricated on a semiconductor wafer through processes such as diffusion and etching, a large number of elements are regularly arranged within one wafer. These elements are
It is divided into unit sections and incorporated into a package or the like as a chip. Chips are often bonded to a metal surface of a package or the like using eutectic solder, and in this case, a metal adhesion film is previously formed on the back surface of the wafer by a method such as vapor deposition. In this case, in order to increase the number of chips that hit the sea urchin, it is necessary that there be no splitting defects. Furthermore, since the reliability of bonding adhesion is greatly influenced by the adhesion strength of the film attached to the back surface of the wafer, it is necessary that the adhesion strength after chip division be high.

In general, methods for dividing a semiconductor wafer into unit sections include: (1) full-cut dicing method, (2) half-cut dicing method with combined braking, and (2) scribing method with combined braking. Here, since breaking is a technique that utilizes the cleavability of a single crystal, its application conditions such as the division direction are limited, but the full-cut dicing method is characterized by its wide range of application and simplicity.

The outline of the full-cut dicing method will be explained below. First, a wafer with a metal film deposited on the back side is attached to an expandable adhesive sheet, and cut from the front surface with a blade along the unit division boundary area (hereinafter referred to as "scribe area"). In this case, only the wafer and metal film are cut, but the adhesive sheet is not cut. Next, the chip is divided into unit sections by expanding the adhesive sheet.

[Problem to be solved by the invention]

However, the conventional dividing method has the disadvantage that the adhesion strength of the metal film formed on the back surface of the chip deteriorates at the edges. In addition, advanced technology is required to perform cutting and division at a high yield without causing division defects.

FIG. 4 shows an example of cutting a wafer using the conventional dividing method. A metal film 2 is deposited on the back surface of the wafer 1, and an adhesive sheet 3 is attached to the metal film 2. Cutting examples A and B are defective examples in which not only the wafer 1 and metal film 2 but also the adhesive sheet 3 are cut, which causes problems when expanding the adhesive sheet 3. Cutting example C is good because only the wafer 1 and metal film 2 are cut.

Cutting examples and E are bad examples in which the adhesive sheet 3 cannot be expanded because the metal film 2 is not completely cut.

FIG. 5 is a process diagram showing the drawbacks of the prior art, and shows the process of expanding the adhesive sheet 3 using the aforementioned defective example (cutting example or cutting example E). In this case, since the metal film 2 is not completely cut, the wafer 1 is divided by forced "tearing" by pulling the metal film 2 from the lateral direction. Therefore, peeling occurs at the edges of the metal film 2, and the adhesion strength of the metal film deteriorates at the edges.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dividing method that facilitates high-yield cutting and division without deteriorating the strength of an attached film such as a metal film at the edges and without causing division defects.

[Means to solve the problem]

In order to achieve the above object, in the present invention, in a method for dividing a semiconductor substrate in which a semiconductor substrate with an attached film formed on the back side is cut along a scribe area, the width of the scribe area is cut before forming the attached film. It is characterized by a wide groove formed on the back surface.

[Effect]

Since the present invention is configured as described above, it becomes easy to cut only the semiconductor substrate and the attached film using the groove formed on the back surface.

〔Example〕

Hereinafter, a method for dividing a semiconductor substrate according to the present invention will be explained based on the accompanying drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description will be omitted.

FIG. 1 is a process diagram showing a method for dividing a semiconductor substrate according to an embodiment of the present invention. In this embodiment, a metal film is used as the deposited film. A large number of semiconductor elements are formed on the surface of the semiconductor substrate 4, and each unit element is divided by a scribe area. In addition, including the scope of claims,
The "scribe area" mentioned in the present invention does not necessarily mean a partition pattern drawn on the surface of the substrate, but is an area to be cut with a dicing blade, etc., and does not require the alignment accuracy of the blade or the kerf loss during cutting. Refers to the virtual partition area width, which is considered as a margin. By dividing the semiconductor substrate within this scribe area (see FIG. 12(a)), each unit element is made into a chip. First, a groove G wider than the width of the scribe area is formed along the scribe area using a dicing blade (FIG. 2(b)). As a method of forming this groove portion G, a rotary grinder having a wider cutting width than a dicing blade may be used.

As shown in FIG. 2, for example, the width of the scribe area is W(
For example, 100 μm), the 2XW (for example, 200 μm)
A groove G having a width of is formed. In this case, the depth of the groove is set individually taking into account variations in the positional accuracy of the dicing blade, but it is
One guideline is around 1/0. For example, if the total thickness of the semiconductor device is 100 μm, the thickness can be approximately 10 μm. Next, a metal film 5 is formed on the back surface of the semiconductor substrate 4 by vacuum evaporation or the like (FIG. 1(C)). The metal film 5 is also formed inside the groove G. After that, the semiconductor substrate 4
The adhesive sheet 6 is pasted on the back side of the board, and the dicing blade 7 is used to cut it along the scribe area (see (d) in the same figure).
)).

In this case, the dicing blade 7 reaches the bottom of the groove G formed on the back surface, but has a cutting depth that does not contact the adhesive sheet 6.

FIG. 3 shows a dividing method according to another embodiment of the invention. The difference from the above embodiment is that there is a metal film 5 in the groove G.
is not formed. In this case, this is an example in which the metal film 5 is prevented from being deposited inside the groove G by masking the groove G.

This embodiment is useful, for example, when the adhered film is very hard and difficult to cut, or conversely, when the adhered film is soft and highly malleable and difficult to cut sharply.

According to the above-mentioned embodiment, by forming the groove in advance before depositing the metal film, it is possible to alleviate the critical condition of having to cut exactly to the interface of the adhesive sheet, allowing dicing with a large margin. Cutting can be performed reliably during the process.

Furthermore, since the number of cutting defects is reduced, the number of defective splits that lead to deterioration of the adhesion strength of the attached film during expansion and splitting is also reduced, and the reliability of chip fixation is increased when the chip is bonded to the package.

Furthermore, as a side effect, when die-bonding a divided chip onto another board, the edges on the bottom of the chip are chamfered, so the adhesive that protrudes (e.g. eutectic solder) wraps around and strengthens the bond. increases.

Note that this invention is not limited to the above embodiments. For example, in the above embodiments, a metal film is used as the deposited film, but it is not limited to a metal film. An insulating film such as an oxide film or a nitride film may be used.

Further, the attached film is not limited to a single layer film, but may be a film having an appropriately selected multilayer structure.

Furthermore, although the above embodiment describes a dividing method in which the substrate is cut in a direction perpendicular to the front and back surfaces of the substrate, it is also applicable to a dividing method in which the substrate is cut diagonally, for example. In this case, a "groove wider than the width of the scribe area" is created based on the intersection line between the cutting surface of the blade and the back surface of the semiconductor substrate.
is set.

〔Effect of the invention〕

Since this invention is configured as explained above,
The grooves formed on the back surface can reduce defective cutting and defective splitting, and prevent the strength of the deposited film from deteriorating at the edges.

[Brief explanation of the drawing]

Fig. 1' is a process diagram showing a method for dividing a semiconductor substrate according to an embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing an example of the structure of a groove part applicable to the present invention, and Fig. 3 is a process diagram showing a method of dividing a semiconductor substrate according to an embodiment of the present invention. A vertical cross-sectional view for explaining a semiconductor substrate dividing method according to another embodiment, FIG. 4 is a vertical cross-sectional view showing an example of cutting a wafer cut with a blade, and FIG. This is a process diagram. DESCRIPTION OF SYMBOLS 1... Wafer 2.5... Metal film, 3.6... Adhesive sheet, 4...' semiconductor substrate, 7... Dicing blade, F... Groove part.

Claims (1)

[Scope of Claims] A method for dividing a semiconductor substrate in which a semiconductor substrate having an attached film formed on the back surface is cut along a scribe region, the method comprising: cutting a groove wider than the width of the scribe region before forming the attached film; A method for dividing a semiconductor substrate, characterized in that: is formed on the back surface.