JPH0648701B2 - Non-defective pellet discriminating device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-defective pellet discriminating apparatus.

[0002]

2. Description of the Related Art A semiconductor wafer is made of a material such as silicon, and is formed by baking a circuit pattern group on a surface layer of a circular wafer whose surface is a mirror surface having a high reflectance. The circuit pattern is arranged in the XY directions. The shape of the group of circuit patterns to be printed is a square or rectangular shape that fits within the circular wafer, and the surface of the semiconductor wafer other than the part of the circuit pattern to be printed is left as a mirror surface with high reflectance. It The semiconductor wafer with the printed circuit pattern group is
It is diced into a matrix and then braked and separated into pellets. The dicing is performed by engraving a dicing line in the XY directions on the surface of the semiconductor wafer using a diamond grindstone or a laser. Thus, the semiconductor wafer is broken along the dicing line and separated to manufacture a pellet having a circuit pattern on the surface. The pellets produced in this way are
It is mounted on a substrate such as a lead frame, so that chips such as ICs and LSIs are manufactured.

By the way, a circuit pattern group printed on a circular wafer is broken into pellets in advance, and a circuit characteristic test is performed for each circuit pattern before separation. The circuit characteristic test is performed by a characteristic tester, and the probe of the tester is brought into contact with the surface electrode of the printed circuit pattern so that each circuit pattern can be inspected for good or bad. As a result of the circuit characteristic test, on the surface of the circuit pattern corresponding to the defective pellet determined to be defective, a defective mark is displayed by ink such as red by the mark display device. Further, the mark display device is used to display the defective mark with red ink or the like at a position corresponding to the surface of the defective pellet on which the circuit pattern is not printed.

The semiconductor wafer is broken into individual pellets through the defective mark displaying operation as described above and separated. As a result, a circuit pattern is formed on the surface, and the surface becomes a reflective surface having a low reflectance, and as a result of the circuit characteristic test, a defective pellet having a defective mark displayed on the surface and a circuit pattern formed on the surface. In addition, the surface is made a reflective surface having a high reflectance, defective pellets having a defective mark displayed on the surface and a circuit pattern are formed on the surface, and the surface is made a reflective surface having a low reflectance. As a result of the circuit characteristic test, each of the good pellets having no defective mark on the surface is formed. Conventionally, a non-defective pellet discriminating apparatus has been used to discriminate non-defective pellets from these defective and non-defective pellets and perform the pellet bonding operation only on the non-defective pellets.

The non-defective pellet discriminating apparatus predetermines an inspection light source capable of irradiating the surface of the pellet with inspection light and a reference reflected light amount equivalent value capable of discriminating the presence or absence of a defective mark in each pellet. It is provided with a defective mark detecting means for measuring the reflected light amount of light and comparing the measured reflected light amount equivalent value with the reference reflected light amount equivalent value. That is, the defective mark detecting means of this device displays on the surface of the pellet based on the fact that the reflected light amount equivalent value of the inspection light irradiated on the defective mark on the pellet surface is lower than the level of the reference reflected light amount equivalent value. It is possible to determine the presence or absence of a defective mark. As a result, it is possible to identify and discriminate a pellet in which the defective mark is not detected as a non-defective pellet, and perform the pellet bonding operation only for the pellet discriminated as a non-defective pellet.

[0006]

However, in the above conventional non-defective pellet discriminating apparatus, the standard for discriminating a defective mark is normally used even though pellets having different surface reflectances are mixed. The only value corresponding to the amount of reflected light was set according to the reflectance of the pellet having the circuit pattern formed on the surface. For this reason, when the pellet surface has a high reflectance, such as a defective pellet having no circuit pattern formed on the surface, the amount of reflected light measured by the defective mark detection means is correspondingly large, and therefore the defective portion is defective. In the pellet, it has been difficult to discriminate a defective mark due to a decrease in the amount of reflected light.

The present invention makes it possible to reliably detect a defective mark existing on the surface of a pellet even when the reflectance of the surface of the pellet differs depending on whether or not a circuit pattern is formed, thereby discriminating a good pellet. The purpose is to ensure the work.

[0008]

According to the present invention, a circuit pattern is formed on the surface, and the surface is a reflecting surface having a low reflectance, and as a result of a circuit characteristic test, a defective mark is displayed on the surface. For each of the pellet and the defective pellet in which the circuit pattern is not formed on the surface and the surface is a reflective surface having high reflectance, and the defective mark is displayed on the surface, a good pellet in which the defective mark is not displayed It is a device for discriminating non-defective pellets, which discriminates the surface of non-defective and defective pellets arranged on the table from the inspection light source capable of irradiating inspection light and the presence or absence of defective marks in each pellet. A possible reference reflected light amount equivalent value is predetermined, the reflected light amount of the inspection light is measured, and the measured reflected light amount equivalent value is compared with the reference reflected light amount equivalent value. The level of the reference reflected light amount equivalent value of the defective detection means and the defective mark detection device is lower than the reference reflected light amount equivalent value of the inspection light with respect to the defective mark of the defective pellet having the circuit pattern formed on the surface. The first reference reflected light amount equivalent value and the second reference value in which the reflected light amount equivalent value of the inspection light with respect to the defective mark of the defective pellet having no circuit pattern formed on its surface is lower than the reference reflected light amount equivalent value. And a means for changing the setting to a reflected light amount equivalent value.

[0009]

In the state where the reference reflected light amount equivalent value is set to the first reference reflected light amount equivalent value, the defective mark detection means corresponds to the reflected light amount of the inspection light when the defective mark on the defective pellet having the circuit pattern is detected. Detecting that the value is lower than the reference equivalent amount of reflected light,
The defective mark existing on the surface can be surely detected.

Under the condition that the reference reflected light amount equivalent value is set to the second reference reflected light amount equivalent value, the reflected light amount of the inspection light when the defective mark detecting means detects a defective mark in a defective pellet having no circuit pattern. Detects that the equivalent value is at a level lower than the reference reflected light amount equivalent value, and is present on the surface even though the reflected light amount on the surface is generally large due to not having a circuit pattern. It is possible to reliably detect defective marks.

According to the above, even when the reflectance of the pellet surface differs depending on the presence or absence of the circuit pattern formation, it is possible to reliably detect the defective mark existing on the surface, thereby discriminating the good pellet. Work can be ensured.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a partially cutaway front view showing a non-defective pellet discriminating apparatus according to an embodiment of the present invention, FIG. 2 is a plan view showing a semiconductor wafer before being broken into individual pellets and separated, and FIG. 3 is XY. FIG. 4 is a plan view showing good and defective pellets arranged on a table, FIG. 4 is an enlarged plan view showing a part of FIG. 3, and FIG. 5 shows a variable setting state of a reference reflected light amount equivalent value with respect to a measured reflected light amount equivalent value. It is a diagram showing.

The semiconductor wafer 10 shown in FIG. 2 is printed with the circuit pattern group 11 on the surface layer of a circular wafer which is formed of silicon or the like and whose surface is a mirror surface having a high reflectance. The outline of the circuit pattern group 11 is a rectangular shape that fits within a circular wafer.
2 are arranged in the XY directions. As a result, the semiconductor wafer 1 other than the portion of the circuit pattern 12 to be printed is printed.
The surface of 0 is left as a mirror surface with high reflectance.
Semiconductor wafer 10 on which circuit pattern group 11 is printed
Are diced along the matrix-shaped dicing lines 13 and further braked. As a result, by breaking the semiconductor wafer 10 along the dicing line 13 and separating it, a plurality of pellets having the circuit pattern 12 on the surface can be obtained.

The semiconductor wafer 10 is broken into pellets and printed on the circuit pattern 1 before being separated.
A circuit characteristic test is performed for each of the two, and the test is performed by a characteristic tester (not shown). That is, the circuit characteristic test is performed by bringing the probe of the characteristic tester into contact with the surface electrode of the printed circuit pattern 12, and it is possible to inspect whether each circuit pattern 12 is good or bad. As a result of the circuit characteristic test, on the surface of the circuit pattern 12 which is determined to be defective, a defective mark 14 is displayed with red ink or the like by a mark display device (not shown). Further, the mark display device also displays the defective mark 14 with ink such as red on the portion 15 of the circuit pattern 12 on the surface of the semiconductor wafer 10 which is not baked and corresponds to the defective pellet.

The semiconductor wafer 10 that has been subjected to the circuit characteristic test is separated into each pellet by the defective pellet discriminating apparatus 16 as shown in FIG. Done.

The non-defective pellet discriminating device 16 includes a pedestal 17
On the other hand, it has an XY table 18 movable in the XY directions, and a support ring 19 for supporting the semiconductor wafer 10 can be attached to the XY table 18. The support ring 19 is attached to the support portion 21 of the support frame base 20, and the support frame base 20 is fixed to the upper surface of the XY table 18 with bolts 22. The semiconductor wafer 10 supported by the support ring 19 is attached to the upper surface of the adhesive sheet 23. That is, the semiconductor wafer 10 subjected to the circuit characteristic test is attached to the adhesive sheet 23, and then broken along the dicing line 13 to be separated. In this state, the adhesive sheet 23 is heated, and further, the sheet 23 is stretched in the circumferential direction of the semiconductor wafer 10.
The pellets at a constant interval are aligned in the XY direction on the upper surface of the No. 3 sheet. The peripheral portion of the adhesive sheet 23 has a support ring 19
It is chucked via a rubber ring 25 in a groove 24 formed in the side portion of. As a result, as shown in FIG. 3, the circuit pattern 12 is formed on the surface of the XY table 18.
The surface is a reflective surface having a low reflectance, and as a result of the circuit characteristic test, the defective pellet 26 having the defective mark 14 on the surface and the circuit pattern 12 not formed on the surface, and the surface has a high reflectance. With a high reflective surface,
Defective pellet 27 with defective mark 14 displayed on the surface
Then, the circuit pattern 12 is formed on the surface, and the surface is made a reflecting surface having a low reflectance, and as a result of the circuit characteristic test, each of the non-defective pellets 28 on which the defective mark 14 is not displayed is XY at regular intervals. Will be aligned in the direction.

An inspection light source 29 and a sensing portion 31 of a sensor 30 as a defective mark detecting means are arranged above the XY table 18. The inspection light source 29 includes the non-defective pellets 28 and the defective pellets 2 aligned on the adhesive sheet 23.
The inspection light 32 can be emitted to each of 6 and 27. Further, the sensing section 31 of the sensor 30 is capable of sensing a change in the amount of reflected light of the inspection light 32 reflected from the non-defective pellet 28 or the defective pellet 26 or 27. The sensing area Q of the amount of reflected light by the sensing unit 31 is a linear shape having a width W2 somewhat larger than the width W1 of each pellet 26, 27, 28 as shown in FIG.
Sensing the amount of reflected light at 6, 27 and 28 moves the XY table 18 in the X direction or the Y direction.
Each pellet 2 aligned in the XY direction with respect to the sensing unit 31
6, 27 and 28 are moved. As a result, as shown in FIG. 5, for each of the pellets 26, 27 and 28 in which the sensing area Q of the sensing unit 31 is aligned,
Scanning in the direction of arrow A, the pellets 26, 2
The magnitude of the reflected light amount at 7 and 28 is sensed by the sensing unit 31.

The sensor 30 is connected to a non-defective pellet 28 discriminating circuit 33 which detects the presence or absence of the defective mark 14 on the pellet surface and can store the coordinate position of the non-defective pellet 28. 34, comparison unit 35, setting unit 36 of reference reflected light amount equivalent value, non-defective product pellet determination unit 3
7 and a storage unit 38. The voltage conversion unit 34
The change in the reflected light amount sensed by the sensing unit 31 is output voltage V
The output voltage V1 is output to the comparison unit 35 and the reference reflected light amount equivalent value setting unit 36, respectively.
As a result, the change in the amount of reflected light on the surface of each pellet 26, 27, 28 based on the movement of the XY table 18 shown in FIG. 5 is transmitted to the comparison unit 35 and the reference reflected light amount equivalent value setting unit 36 as the voltage V1. It will be.

At this time, the voltage V1 is equal to that of the pellets 26, 2
When the amount of reflected light of Nos. 7 and 28 is large, it is high, and when the amount of reflected light is small, it is low. Therefore, the voltage V1 is applied to the defective pellets 26 and 27 of the defective pellet 26 in the region B where the defective mark 14 is detected and the defective pellet 27 of the region C where the defective mark 14 is detected.
The value is lower than the voltage V1 based on the normal amount of reflected light on the surface. In addition, the voltage V1 is higher in the defective pellets 27 in which the circuit pattern 12 is not formed than in the defective pellets 26 and the non-defective pellets 28 in which the circuit pattern 12 is formed on the surface because of the high reflectance of the surface. Will show a high value.

The comparator 35 compares the measured voltage V1 with a reference voltage level based on a preset reference reflected light amount, and lowers the voltage V when the defective mark 14 is sensed.
A change of 1 can be detected.

The setting unit 36 can variably set the reference voltage level based on the reference reflected light quantity, and outputs the set reference voltage level to the comparison unit 35. That is, in the present embodiment, the setting unit 36 sets the reference voltage level L1 based on the first reference reflected light amount and the reference voltage level L2 based on the second reference reflected light amount higher than the reference voltage level L1. The settings can be changed.

Here, as shown in FIG. 5, when the sensing unit 31 senses the defective mark 14 of the defective pellet 26 having the circuit pattern, the reference voltage level L1 is the voltage conversion unit in the sensing region B. The voltage V1 output from 34 to the comparison unit 35 is set to a value that is locally lower than the reference voltage level L1.

The reference voltage level L2 is a voltage output from the voltage conversion unit 34 to the comparison unit 35 in the sensing area C when the sensing unit 31 senses the defective mark 14 of the defective pellet 27 in which the circuit pattern is not formed. V1 is
It is set to a value that locally becomes lower than the reference voltage level L2. At this time, non-defective pellets 28
Since the output voltage V1 based on the amount of reflected light from the whole is below the reference voltage level L2, the defective pellet 27 and the non-defective pellet 28 can be discriminated.

Therefore, the setting unit 36 normally sets the reference voltage level to L1, and the sensing unit 31 causes the defective pellet 2
When the comparison unit 35 detects a decrease in the output voltage V1 when the defective mark 14 in 6 is detected, the defective pellet 26 is detected.

Then, under the above-mentioned normal setting state, the setting unit 36, when the comparison unit 35 does not detect the defective pellet 26, the setting unit 36 presumes that the pellet is the defective pellet 27 or the non-defective pellet 28, and then the standard is set. Change the voltage level to L2. When the comparison unit 35 detects a decrease in the output voltage V1 when the sensing unit 31 senses the defective mark 14 on the defective pellet 27 under the condition that the reference voltage level is set to L2 by the setting unit 36 in this way. , Defective pellets 27 are detected. As a result, in the comparison unit 35, when the local voltage change in each of the areas B and C is measured by comparison with the reference voltage level L1 or L2, the defective mark 14 is determined as shown in FIG. It is possible to output the determination pulse P of 0 indicating that it has been performed to the non-defective pellet determining unit 37. On the other hand, other than that,
That is, when the local voltage drop is not measured in comparison with either of the reference voltage levels L1 and L2, the determination pulse P of 1 indicating that the pellet is the non-defective pellet 28 is sent to the non-defective pellet determining section 35. Output becomes possible.

The non-defective pellet discriminating section 37 analyzes the position of each pellet 26, 27, 28 with respect to an arbitrary coordinate origin on the non-defective pellet discriminating apparatus 16 based on the discrimination pulse P sequentially input from the comparing section 35. I am trying to do it.
As a result, the coordinate position of the non-defective pellet 28 among the aligned pellets 26, 27, 28 is analyzed, and the coordinate position of the non-defective pellet 28 is stored in the storage unit 38. Storage in the storage unit 38 is performed by a storage medium such as a floppy disk or a magnetic tape. In this way, each of the pellets 26, 27, and 28 for which the coordinate position of the non-defective pellet 28 has been determined is selected by the non-defective pellet selection unit of the pellet bonding apparatus, and the selection operation is stored in the storage medium. This is performed based on the data regarding the coordinate position of the non-defective pellet 28.

Next, the operation of the above embodiment will be described. According to the non-defective pellet discriminating apparatus 16 according to the above embodiment, when the defective mark 14 is detected when the output voltage V1 based on the amount of reflected light from the pellet is compared with the reference voltage level L1, the pellet is a defective pellet 26. It can be seen that it is. On the contrary, when the defective mark 14 is not detected at the reference voltage level L1, the pellet is the defective pellet 27 or the good pellet 28. Therefore, if the defective mark 14 is detected when the reference voltage level is changed to L2 in the setting unit 36, the pellet is detected as the defective pellet 27, and finally the good pellet 28 can be surely discriminated. Of.

According to the non-defective pellet discriminating apparatus 41 according to the above-mentioned embodiment, the output voltage V1 and the reference voltage level L3 based on the reflected light quantity from the pellet are set under the condition that the inspection light quantity is set to the reference light quantity value D1. Bad mark 14 by comparison of
Is detected, it means that the pellet is a defective pellet 26. On the contrary, under this condition, the defective mark 1
When 4 is not detected, the pellet is a defective pellet 27 or a good pellet 28. Therefore, the inspection light amount is set to the reference light amount value D2 in the inspection light amount setting unit 45.
If the defective mark 14 is detected when the setting is changed to, the pellet is detected as the defective pellet 27, and finally the non-defective pellet 28 can be surely discriminated.

According to the non-defective pellet discriminating apparatus 16 according to the above embodiment, the non-defective pellet 28 can be discriminated by variably setting the reference voltage levels L1 and L2, but the inspection light quantity can also be variably set. So that the sensor 30
It is also possible to provide a non-defective pellet discriminating circuit 33.

Also, in the above embodiment, the sensor 30
Is used as a line sensor, and the sensing area Q thereof is linear, but the defective mark detecting means of the present invention may be a surface sensor capable of sensing the entire surface of each pellet.

[0031]

As described above, according to the present invention, even when the reflectance of the pellet surface differs depending on the presence or absence of the circuit pattern formation, it is possible to reliably detect the defective mark existing on the surface. As a result, it is possible to ensure the work of discriminating the non-defective pellets.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a non-defective pellet discriminating apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a semiconductor wafer before being broken into pellets and separated.

FIG. 3 is a plan view showing non-defective products and defective pellets aligned on an XY table.

FIG. 4 is a plan view showing a part of FIG. 3 in an enlarged manner.

FIG. 5 is a diagram showing a variable setting state of a reference reflected light amount equivalent value with respect to a measured reflected light amount equivalent value.

[Explanation of symbols]

 12 Circuit Pattern 14 Bad Mark 16 Good Pellet Discriminating Device 18 XY Table 26, 27 Bad Pellet 28 Good Pellet 29 Inspection Light Source 30 Sensor 32 Inspection Light 33 Good Pellet Discrimination Circuit 36 Reference Reflected Light Equivalent Value Setting Section 37 Good Pellet Discrimination unit L1, L2 Reference voltage level

Claims (1)

[Claims] 1. A circuit pattern is formed on the surface, the surface is made a reflective surface having a low reflectance, and a defective pellet having a defective mark displayed on the surface as a result of a circuit characteristic test and a circuit pattern on the surface. Distinction of non-defective pellets capable of discriminating non-defective pellets in which the defective mark is not displayed for each of the defective pellets in which the surface is formed as a reflective surface having high reflectance and the defective mark is displayed on the surface The device is an inspection light source that can irradiate inspection light to each surface of good and defective pellets that are aligned on the table, and a reference reflected light amount equivalent value that can determine the presence or absence of a defective mark on each pellet. A defective mark detecting means for measuring the reflected light amount of the inspection light and comparing the measured reflected light amount equivalent value with the reference reflected light amount equivalent value; The reference reflection light amount equivalent value of the detection means is a first reference reflection at which the reflection light amount equivalent value of the inspection light with respect to the defective mark of the defective pellet having the circuit pattern formed on the surface becomes a level lower than the reference reflection light amount equivalent value. Set to a light amount equivalent value and a second reference reflected light amount equivalent value at which the reflected light amount equivalent value of the inspection light with respect to the defective mark of the defective pellet having no circuit pattern formed on the surface becomes a level lower than the reference reflected light amount equivalent value. An apparatus for discriminating non-defective pellets, which comprises a replacement means.