JPH1116965A - Characteristics inspection method of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of crack of a water, when a semiconductor wafer is handled. SOLUTION: A p-n junction separation trench 2 separating a p-n junction 4 from a bonding pad electrode 3 side of a wafer 1 is formed. A diebond side electrode 5 is mounted on a tape 9 having adhesive agent on which a gold wire 10 is stuck, and the wafer 1 is stuck on the diebond side electrode 5. Since the tape 9 becomes a retaining member, crackings of the wafer is hardly generated, when the p-n junction separation trench 2 is formed deep. The diebond side electrode 5 is electrically led out via the gold wire 10, so that the characteristics of the respective chips on a semiconductor wafer can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting characteristics of a semiconductor wafer, and more particularly to an inspection method capable of reducing cracks in a wafer.

[0002]

2. Description of the Related Art A conventional process for forming a chip such as an LED will be described with reference to FIG. A bonding pad electrode 3 based on wire bonding is provided on one side of a wafer 1 having a thickness of about 300 μm (one surface is p-type and the other surface is n-type) having a two-layer structure of a p-type semiconductor and an n-type semiconductor. On the other hand, the electrode 5 is formed on the premise that it is bonded (die-bonded) to a lamp housing or the like with a silver paste.

The bonding pad electrode 3 is a dot electrode having a size suitable for wire bonding, and the die bonding side electrode 5
In general, a combination of a mesh electrode and a dot electrode, which are connected to the entire surface of the wafer 1 and have eyes smaller than the chip size, are generally used even in the case of a whole electrode covering the entire surface of the wafer 1 or a partial electrode.

In order to measure the electrical and optical characteristics of the individual chips formed on the wafer 1, p / n is mechanically diced from the bonding pad forming surface side of the wafer 1 to a size corresponding to the chip size. After the junction 4 is separated, it is necessary to prepare a state in which chemical etching is performed to remove processing strain.

The depth of the p / n junction separation groove 2 is the p / n of the wafer 1
The distance must be greater than the distance from the surface on the side where the bond 4 is separated to the p / n bond 4. On the other hand, in order to handle the bonded and separated wafer 1 alone, it is necessary to leave at least about 100 μm as the remaining margin. .

In order to inspect the characteristics of the wafer 1, FIG.
As shown in (1), the wafer 1 is handled independently, the electrode 5 on the side surface of the die bond is brought into contact with the metal plate (test stage 7) to secure electrical contact, and the probe needle 6 is brought into contact with the electrode 3 on the side surface of the bonding pad. In this way, the electrical connection is ensured, so that the electrical and optical characteristics of each chip are measured and pass / fail judgment is made. This is repeated with the total number of chips formed on the wafer 1 or with a predetermined extraction frequency. Thereafter, in order to divide the chips into individual chips, scribing is formed along the p / n junction separation groove 2 from the surface on the die bond side, and processing is performed using a scribing method of mechanically dividing.

[0007]

In the prior art, in the step of dividing into individual chips by such a scribe method, when the cleavage direction of the p / n junction separation groove 2 and the wafer 1 do not match, the size of the remaining margin is increased. However, there is a disadvantage that the chip shape is deteriorated in proportion to (the crack is broken at another position without breaking at the designed position).

On the other hand, if the remaining margin is made thinner, the mechanical strength of the wafer 1 is reduced, and the wafer is cracked during wafer handling, resulting in a significant decrease in work efficiency. The present invention provides a method of inspecting the electrical and optical characteristics of a wafer 1 in which the remaining portion of the p / n junction separation groove 2 is reduced in order to stabilize the chip shape and which can reduce the crack of the wafer. To provide.

[0009]

According to the method for inspecting the characteristics of a semiconductor wafer according to the present invention, a bonding pad electrode,
A die-bonding electrode is formed on the other surface, a groove is formed from the one surface so as to be divided at a size corresponding to a chip size, and a characteristic inspection of a semiconductor wafer is left on the other surface. In the method, an electrically conductive metal wire is attached to a tape coated with an adhesive material, and the tape is attached to the other surface of the semiconductor wafer, thereby making electrical contact of the electrode on the other surface side to the conductive metal wire. What to take in. As described above, by attaching the tape to the wafer, the mechanical strength is increased as compared with the case of the wafer alone.

In addition, by irradiating the adhesive with ultraviolet light, the adhesive is changed in a direction in which the adhesive strength is weakened, so that after the characteristic measurement, ultraviolet light is applied to the tape adhesive so that an unnecessary force is not applied to the wafer. Irradiation reduces the adhesive strength and allows the wafer to be removed from the tape. Further, by attaching the tape to the donut-shaped metal frame, the handling itself is facilitated, and the electrical extraction is also facilitated.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in FIG.
For wafer 1 having a thickness of about 300 μm, the remaining allowance is 20 to
The p / n junction separation groove 2 is formed deeply to have a thickness of 50 μm. On the other hand, as shown in FIG. 2, a gold wire 10 is used as a conductive metal wire, and a material whose adhesiveness changes in a direction in which the adhesiveness is weakened by irradiating ultraviolet rays is used as an adhesive. A gold wire 10 is attached to the tape 9. The tape 9 to which the gold wire 10 has been attached is attached to the hollow donut-shaped metal frame 8 without loosening.

The wafer 1 is placed on the adhesive material of the tape 9 in this state, and is adhered on the side surface of the die bond. The wafer 1 on which the tape 9 is stuck in this manner is placed on the test stage 7, one electrode of the prober device is attached to the metal frame 8, and the other electrode is attached to the probe needle 6 of the prober device. Is brought into contact with the bonding pad electrode 3 so that the + side (or-side) of the device power supply-the probe needle 6-the bonding pad electrode 3-the tip p / n junction 4-the die bonding side electrode 5-the gold wire 10-the metal frame 8 A current flow on the minus side (or plus side) of the device power supply is made, and the electrical and optical characteristics of the chips on the wafer 1 are measured to make a pass / fail decision. Bad marks are attached to defective chips. This is repeated for all bonding pads on the wafer 1 or at a predetermined extraction frequency.

After the measurement of the characteristics, the tape 1 is removed from the tape 9 by irradiating the tape adhesive with ultraviolet rays to reduce the adhesive force so that unnecessary force is not applied to the wafer 1. Then, p / n
A scratch was made (scribed) using a diamond tool from the side of the die bond along the bonding separation groove 2.
Thereafter, pressure is applied to divide the individual chips starting from the scribed scratches.

The above is a basic embodiment of the present invention. The following is a more detailed description. The tape 9 is sufficiently larger than the test stage 7 and has an allowable size due to the structure of the prober device. There are no special restrictions on the material, thickness, etc., of the tape base material.

The conductive metal wire is preferably a gold wire 10 because it is highly malleable because it is processed to be thin, and the conductivity is not deteriorated by corrosion or rust. The gold wire 10 is sufficiently thinner than the chip size, and has a thickness of 20 μm or less so that the height of the adhesive material does not greatly change when sandwiched between the wafer 1 and the adhesive material to cause a crack in the wafer 1. . At least one gold wire 10 or a plurality of gold wires 10 if necessary, in a range sufficiently larger than the size of the tape-adhesive wafer 1 and sufficiently in the metal frame 8 so that the gold wires 10 do not cross each other. Paste to reach.

The tape 9 to which the gold wire 10 is attached is not loosened and is attached to the hollow donut-shaped metal frame 8 so that the handling becomes easy, and the metal frame 8 and the attached gold are attached. The electric potential of the wire 10 is the same as that of the wire 10, so that electrical withdrawal becomes easy.

By attaching the wafer 1 to the above-mentioned tape 9, the entire surface or the mesh-shaped die-bonding electrode 5 comes into contact with the gold wire 10, and the die-bonding electrode 5 has the same potential as the gold wire 10 and the metal frame 8. .

[0018]

According to the method of the present invention in which the tape 9 is adhered to the wafer 1 for handling, the tape 9 serves as a holding material so that the wafer 1 is less likely to be broken as compared with the conventional method. Since the positional relationship between the wafer piece and the other wafer piece maintains the original positional relationship in the original shape, any of the wafers is connected to the die bonding electrode 5 by the gold wire 10.
As long as the contact can be ensured, the measurement of the electrical and optical characteristics can be continued as one wafer, and the working efficiency is improved.

Since the remaining margin of the p / n junction separation groove 2 of the wafer 1 is formed thinner, the chip shape is more stable than the conventional method in which the remaining margin is made thicker. Since the electrical contact of the electrode 5 on the die bond side of the wafer 1 is made with a conductive metal wire, there is no restriction that the test stage 7 be made of a conductive material.

[Brief description of the drawings]

FIG. 1 is an overall view of the present invention.

FIG. 2 is a diagram illustrating the operation of the present invention.

FIG. 3 is a diagram illustrating a conventional technique.

FIG. 4 is an overall view of the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... p / n junction separation groove, 3 ... Bonding pad electrode, 4 ... p / n junction, 5 ... Die bond side electrode, 6 ...
Probe needle, 7 ... test stage, 8 ... metal frame,
9 Tape with adhesive material 10 Gold wire

Claims (3)

[Claims] 1. A bonding pad electrode is formed on one surface, a die-bonding electrode is formed on the other surface, a groove is formed from the one surface in a size corresponding to a chip size, and a groove is formed on the other surface side. In the method for inspecting characteristics of a semiconductor wafer in which the remaining margin is left, a conductive metal wire is attached to a tape coated with an adhesive, and the tape is attached to the other surface of the semiconductor wafer, so that the other surface is formed. A method for inspecting characteristics of a semiconductor wafer, wherein an electrical contact of a side electrode is made with the conductive metal wire. 2. The semiconductor wafer characteristic inspection method according to claim 1, wherein the adhesive changes in a direction in which the adhesiveness decreases when the adhesive is irradiated with ultraviolet rays. 3. The method according to claim 1, wherein the tape is attached to a donut-shaped metal frame.