JPH01133703A - Semiconductor wafer and semiconductor device using the same - Google Patents

Abstract

PURPOSE:To prevent a defect to be generated on a scribe line from entering into a circuit forming region in a dicing process, by a method wherein the title wafer is made into one whose width of a scribe line is varied according to the size of its cleavability of a direction of crystallographic axis. CONSTITUTION:A wafer 1 comprised of gallium/arsenic single crystal is sliced so that its face (100) becomes a crystal face and a scribe line 2 running parallel with a crystallographic axis [0-1-1] and a scribe line 3 running parallel with a crystallographic axis [01-1] meeting at right angles with the scribe line 2 are formed in a state of a lattice. Cleavability of the gallium/arsenic single crystal varies with a direction of the crystallographic axis and when, for example, a width of the scribe line 2 is 110mum, that of the scribe line 3 becomes 90mum. Deep grooves 2a, 3a are formed along the center lines of the scribe lines 2, 3 each by using a dicing blade in about 30mum width to separate the wafer into pellets. A defect of the circumference of the deep groove 2a is prevented from entering into a circuit forming region by setting the width of the scribe line wide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a technique particularly effective when applied to a wafer made of a compound semiconductor and a semiconductor device using the same.

[Conventional technology]

The technique for dividing semiconductor wafers (hereinafter referred to as wafers) is described, for example, in "Electronic Materials / Separate Volume", pp. 67-68, published by Kogyo Kenkyukai Co., Ltd., November 15, 1980.

By the way, semiconductor pellets (hereinafter referred to as pellets), which serve as integrated circuit boards for semiconductor devices, are produced by dividing the surface of a wafer made of a semiconductor single crystal into a large number of lattice-like blocks, and forming a predetermined integrated circuit in each block. After undergoing circuit measurement tests, it is separated into blocks, which are then mounted on tabs and sealed in a package made of synthetic resin or ceramic.

In order to separate the wafer into pellets after the above-mentioned integrated circuits have been formed, it is customary to form deep grooves with a ding blade along grid-like scribe lines formed on the wafer surface.

[Problem that the invention seeks to solve]

The inventors of the present invention have discovered that the following problems occur in the wafer wisping process.

That is, in the dicing process of forming deep grooves along the scribe lines, consideration is given to removing the oxide film on the surface of the scribe lines in advance so as not to damage the circuit forming area.

However, since wafers have different cleavage properties depending on the direction of their crystal axes, when dicing a wafer with the surface exposed as described above, the cleavage properties of wafers around the deep grooves of the scribe line parallel to the crystal axis direction, where cleavage properties are large, are Defects such as cracks and chips are more likely to occur around deep grooves formed in the direction perpendicular to the deep grooves.

In particular, compound semiconductor single crystals such as gallium arsenide (Ga-As) have a larger difference in cleavage depending on the crystal axis direction than non-containing single crystals, so the scribe line is the same regardless of the crystal axis direction as in the past. In wafers formed with a wide width, defects generated around the deep grooves of scribe lines parallel to the crystal axis direction, which have a high cleavability, tend to enter the circuit forming area, which reduces the pellet acquisition rate and affects the circuit characteristics of semiconductor devices. This was the cause of the decline.

The present invention has been made focusing on the above problems,
The purpose is to provide a technique that can effectively prevent defects from entering a circuit forming area during a dicing process.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the wafer has a wafer in which the width of the scribe line formed along the crystal axis direction is increased or decreased depending on the degree of cleavage in the crystal axis direction.

Further, the present invention provides a semiconductor device in which pellets are separated from the wafer so that the width of the entire area surrounding the circuit forming area is different in one direction and in a direction perpendicular to the one direction, and the pellets are attached to a tab.

[Effect]

According to the above-mentioned means, by forming the width of the scribe line parallel to the crystal axis direction with high cleavage property to be wider than the width of the scribe line parallel to the crystal axis direction with low cleavage property, the scribe line is formed in the dicing process. The resulting defects can be effectively prevented from entering the circuit forming area.

〔Example〕

FIG. 1 is a schematic plan view of a wafer according to an embodiment of the present invention, FIG. 2 is a partially enlarged plan view of this wafer in a dicing process, and FIG. 3 is a schematic plan view of a wafer separated from this wafer. FIG. 2 is a perspective view of a main part of a semiconductor device in which a pellet is attached to a tab.

The wafer 1 of this example made of gallium arsenide (Ga.ΔS) single crystal is sliced so that its (100) plane becomes the crystal plane, and the crystal axis f: A scribe line 2 parallel to the scribe line 2, and a scribe line 3 parallel to the Co11) direction of the crystal axis orthogonal to this.
A predetermined integrated circuit (not shown) is formed in a rectangular circuit formation area 4 which is formed in a grid pattern and separated from each other by each scribe line 2, 3.

Gallium arsenide (Ga.As') single crystal has different cleavage properties depending on the direction of the crystal axis, and in particular, the cleavage property in the [01] direction of the crystal axis is large.
In this case, the width of the scribe line 2 parallel to the [OT] direction is wider than the width of the scribe line 3 in the 0111 direction perpendicular thereto, for example, if the width of the scribe line 2 is 110 μm, , scribe line 3
The width of is 90 μm.

To separate this wafer 1 into pellets, for example, a width of 3
Using a dicing blade of approximately 0 μm, deep grooves 2a and 3a are formed along the center line of each scribe line 2 and 3 (FIG. 2).

At this time, there are more defects such as cracks and chips around the deep groove 2a formed in the scribe line 2 in the OT direction, which has a high cleavability, than around the deep groove 3a formed in the scribe line 3. However, by forming the width of the scribe line 2 wider, it is possible to prevent defects generated around the deep groove 2a from entering the inside of the circuit forming region 4.

As shown in FIG. 3, in the semiconductor device in which the pellet 5 separated in this way is attached to the tab 6, the entire area 7a surrounding the circuit forming area 4 is formed.

The width of 7b is different between the first direction and the direction perpendicular to this direction, and specifically, the width a of the entire region 7a parallel to the direction with high cleavage is the entire region in the direction perpendicular to this direction. It is wider than the width of 7b.

As described above, according to this embodiment, the following effects can be obtained.

(1), scribe line 3 perpendicular to the width of scribe line 2 parallel to the [01st direction] direction where W opening is large
By forming the width wider than the width of the circuit forming area 4, defects such as cranks and chips that occur around the deep grooves 2a and 3a of the scribe lines 2 and 3 during the die song process can be avoided.
This can effectively prevent the intrusion into the inside of the device.

(2) According to (1) above, a highly reliable semiconductor device can be obtained.

(3) According to (1) above, the number of pellets of the same size that can be obtained from a wafer of the same diameter (pellet acquisition rate) is increased, and as a result, the cost of semiconductor devices is reduced.

As above, the invention made by the present inventor has been specifically explained based on the examples.
a-As) It goes without saying that the present invention is not limited to wafers made of single crystals, but can also be applied to wafers made of other semiconductor single crystals whose cleavage properties differ depending on the direction of the crystal axis.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly explained below.

In other words, by creating a wafer in which the width of the scribe line formed along the crystal axis direction is increased or decreased depending on the degree of cleavage in the crystal axis direction, defects that occur in the scribe line during the dicing process are prevented from occurring within the circuit formation area. This can effectively prevent the intrusion into the pellets and improve the pellet acquisition rate.

In addition, reliability can be improved by separating pellets from the wafer so that the width of the entire area surrounding the circuit formation area is different in one direction and in a direction perpendicular to this, and attaching the pellets to a tab to form a semiconductor device. A high quality semiconductor device can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view of a wafer that is an embodiment of the present invention, Fig. 2 is a partially enlarged plan view of this wafer in the dicing process, and Fig. 3 is a semiconductor with pellets separated from this wafer attached to a tab. FIG. 2 is a perspective view of the main parts of the device. DESCRIPTION OF SYMBOLS 1... Semiconductor wafer, 2, 3... Scribe line, 2a, 3a... Deep groove, 4... Circuit formation area, 5...
...Pellet, 6...Tab, 7a, 7b...All areas. 2.3...Scribe lines 2a, 3a...Deep grooves 4...Circuit forming area 5...Pellet 7a, 7b...All areas Fig. 3 a>b -18=

Claims (1)

Claims: 1. A semiconductor wafer, characterized in that the width of a scribe line formed along the crystal axis direction is increased or decreased depending on the magnitude of cleavage in the crystal axis direction. 2. The semiconductor wafer according to claim 1, which is made of a single crystal of a compound semiconductor. 3. The crystal plane is the (100) plane, and the crystal axis [0
A patent characterized in that the width of the scribe line parallel to the @1@@1@] direction is wider than the width of the scribe line parallel to the [01@1@] direction perpendicular to this. A semiconductor wafer according to claim 1 or 2. 4. A semiconductor device characterized in that a semiconductor pellet is attached to a tab in which the width of the extra area surrounding the circuit forming area differs in one direction and in the direction perpendicular to this. 5. The semiconductor device according to claim 4, wherein the semiconductor pellet is made of a single crystal of a compound semiconductor. 6. The crystal plane is the (100) plane, and the crystal axis [0
The width of the extra region parallel to the @1@@1@] direction is wider than the width of the extra region parallel to the [01@1@] direction perpendicular to this. A semiconductor device according to claim 4 or 5.