JPH0456149A - Semiconductor substrate - Google Patents

Abstract

PURPOSE:To prevent chipping by excellent cutting of a substrate itself by providing dicing lines for dividing a plurality of chips on the substrate, and covering a rear surface with metal except dicing line existing positions. CONSTITUTION:Dicing lines 4,... for dividing a plurality of chips 3,... are formed on a substrate 2 in a semiconductor substrate 1. The rear surface of the substrate 2 are covered with metals 5,... to be described in detail later except existing positions of the lines 4,.... When it is cut by a dicing blade to be divided into chips (separated into chips), the blade can cut without touching the metals 5,....

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a semiconductor substrate on which a plurality of chips separated by dicing lines are arranged on the front surface and metal is deposited on the back surface.

(Prior Art) Conventional semiconductor substrates are manufactured to a predetermined chip thickness (approximately 130 μm to 150 μm
).

Then, a brazing metal for chip die bonding is applied to the entire back surface of the substrate by electron beam and resistance heating vapor deposition.
T i : 1000 people/A u G e : 100
0 people/A u S n: 30,000 people/Au: 50
The metal was formed by vapor deposition, and then heat treatment was performed to improve the adhesion between the substrate and the back metal.

Thereafter, in a dicing process, the semiconductor substrate is cut into chips (chip separation) by cutting using a diamond dicing blade.

(Problems to be Solved by the Invention) However, the above-mentioned conventional technology has the following problems.

That is, in the dicing process, approximately 130μ to 150μ
A GaAs substrate with a thickness of
．． At the same time, a diamond dicing blade was used to cut the back metal with a thickness of 2 μm to form chips (chip separation).

At this time, the dicing blade is G a A s at the top.
While cutting the board, the bottom part has a thickness of approximately 3.2μ OA.
The U-type back metal will be canted.

For this reason, a diamond dicing blade for cutting GaAs substrates has to be used to cut the Au-based metal, which results in clogging, poor cutting of the GaAs substrate itself, and chipping (chips). There was a problem that it often caused cracks and chips.

There is also a problem in that the usage limit of the dicing blade is 1/10 or less compared to when cutting only a GaAs substrate.

Note that there are no existing dicing blades that can cut metals at the same time, and all of them cut non-metallic materials.

An object of the present invention is to solve the above-mentioned conventional problems.

That is, metal is deposited on the back surface of the substrate except for the area where the dicing line is present. Therefore, there is no metal in the cut portion for forming the chip. Therefore, only the board can be canted without cutting the metal. As a result, clogging does not occur, the substrate itself is sharply cut, and chipping (chip cracking or chipping) can be prevented from occurring.

Furthermore, it is an object of the present invention to provide a semiconductor substrate that allows a dicing blade to last a long time.

(Means for Solving the Problem) In order to solve the above problem, the present invention provides a dicing line for dividing a plurality of chips on the front surface of a substrate, and a portion where the dicing line exists on the back surface of the substrate. It is assumed that metal is coated except for the following.

(Function) In this way, metal is coated on the back side of the substrate except for the area where the dicing line exists, so when cutting it into chips with a dicing blade (chip separation),
It is possible to cut without the dicing blade touching the metal.

(Example) Hereinafter, an example of a semiconductor substrate according to the present invention will be described based on the drawings.

FIG. 1 is an enlarged plan view of a semiconductor substrate according to the present invention, and FIG.
The figure is an enlarged rear view of the same, FIG. 3 is an explanatory view showing the dimensions of the vapor deposition mask and the chip dimensions on the back surface of the semiconductor substrate, and FIG. 4 is a plan view of the substrate covered with the vapor deposition mask.

The semiconductor substrate 1 of the present invention is provided with dicing lines 4 on the surface of the substrate 2 for dividing a plurality of chips 3 .

Then, on the back side of this substrate 2, a dicing line 4...
As will be explained in detail later, metal 5... is deposited except for the area where .

The semiconductor substrate 1 has a pattern arrangement in which dicing lines 4 with a width of 100 μ are provided on a substrate 2 made of a 2-inch GaAS wafer so that the chips 3 have a size of 400 μ×450 μ. (See Figure 1).

The metal 5 on the back surface of the substrate 2 is formed as described below.

That is, a substrate 2 made of a GaAS wafer that has been shaved to about 130 μm to 150 μm in a lapping process is subjected to a pre-evaporation treatment, and then a dicing line 4 on the back side of the substrate 2 is formed.
. . . is selectively vapor-deposited except for the areas where . . . exists (see Fig. 2).

For this vapor deposition, a mesh-like vapor deposition mask 6 having a punched pattern of 300 μ x 350 μ as shown in FIG. 4 is used.

That is, the substrate 2 is fixed to the mesh-like vapor deposition mask 6 so that the mesh is aligned with the area where the dicing lines 4 are present on the back surface of the substrate 2 made of a GaAS wafer.

The alignment of this mesh-like vapor deposition mask 6 is performed using GaAS.
Alignment pins (not shown) are installed at two points on the origny joint flat portion 21 and one other point on the substrate 2 made of a wafer.
is provided to align the dicing lines 4 and the mesh of the mesh-like vapor deposition mask 6.

After that, G fixed to the mesh-like vapor deposition mask 6
Ti: 1000/AuGe was deposited on the back surface of the substrate 2 made of an aAS wafer by electron beam and resistance heating vapor deposition.
: 1000 people/AuSn: 30000 people/Au: 5
00 metals are sequentially deposited to form metal 5...

Thereafter, the substrate 2 made of a GaAS wafer is removed from the mesh vapor deposition mask 6 and subjected to heat treatment.

400μ×450 formed on the surface of the substrate 20 with a thickness of about 3.2
The dimensional difference between the μ size a1, a2 chip 3, etc. and the 300 μ×350 μ size b1, b2 metal 5… deposited on the back surface of the substrate 2 is an alignment margin which is the lower limit value that can be bonded.

However, if the size aLa2 of the chips 3 .

In addition, as another implementation method, metal 5 is provided on the entire back surface of the substrate 2.
After vapor-depositing, it is also possible to form a metal 5 separated from the back surface of the substrate 2 except for the portion where the dicing line 4 exists of the metal 5 by etching after forming a pattern using a photo process. .

As mentioned above, the metal 5... is adhered to the back side of the substrate 2 except for the area where the dicing line exists, so when cutting it with a dicing blade to form chips (chip separation), the dicing The blade is metal 5.
It is possible to cut without touching...

In this way, in order to be able to cut stably,
The dicing speed is more than twice that of conventional methods (10 to 20
/sec). Also, chipping (chips, chips, etc.) is reduced.

Furthermore, the usable limit of the dicing blade used for cutting has become more than 10 times that of the conventional one, and now corresponds to the original usable limit of a diamond blade for GaAs.

(Effects of the Invention) As explained above, in the present invention, a dicing line is provided on the front surface of a substrate to separate a plurality of chips, and metal is deposited on the back surface of the substrate except for the area where the dicing line is present. Therefore, the following effects can be achieved.

That is, by depositing metal on the back surface of the substrate except for the portion where the dicing line is present, no metal is present in the cut portion for forming chips.

Therefore, only the substrate can be cut without cutting the metal.

This prevents clogging, the board itself is sharp, and there is no chance of chipping (chips or cracks).
can be prevented from occurring.

Furthermore, the dicing blade can last longer.

[Brief explanation of drawings]

FIG. 1 is an enlarged plan view of an embodiment of a semiconductor substrate according to the present invention, FIG. 2 is an enlarged back view thereof, and FIG. 3 is an explanatory diagram showing the dimensions of a deposition mask and the dimensions of a chip on the back surface of the semiconductor substrate. , FIG. 4 is a plan view of the substrate covered with an evaporation mask. 3...Chip 4...Dicing line 5...Metal

Claims (1)

[Claims] 1) A semiconductor substrate characterized in that a dicing line for dividing a plurality of chips is provided on the front surface of the substrate, and metal is deposited on the back surface of the substrate except for the area where the dicing line is present.