JPH0648702B2 - 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 printed circuit pattern group is
The surface of the semiconductor wafer is a square or rectangular shape that fits within the circular wafer, and the surface of the semiconductor wafer other than the portion where the circuit pattern is printed remains as a mirror surface with high reflectance. The semiconductor wafer on which the circuit pattern group has been baked is diced into a matrix and then braked to be 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 manufactured in this manner are mounted on a substrate such as a lead frame by a pellet bonding apparatus, so that chips such as IC and LSI 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. Not only that, while the surface is a reflective surface having a high reflectance, a defective pellet having a defective mark displayed on the surface and a circuit pattern are formed on the surface, and the surface is 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. these,
Distinguish good pellets from defective and good pellets,
In order to perform the pellet bonding operation only on the non-defective pellets, a non-defective pellet discriminating device has been conventionally used.

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. A defective pellet 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 is provided. That is, the defective pellet detecting means of this device is displayed 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. Therefore, when the reflectance of the pellet surface is high, such as a defective pellet having no circuit pattern formed on the surface, the amount of reflected light measured by the defective pellet detection means is correspondingly large, and the defective In the pellet, it has been difficult to discriminate a defective mark due to a decrease in the amount of reflected light.

From the above, the defective mark is displayed by the mark display device only on the defective pellets having a low surface reflectance having the circuit pattern formed on the surface, and the defective pellets and the circuit patterns having different surface reflectances are formed. It has been desired to develop a non-defective pellet discriminating apparatus capable of surely discriminating only non-defective pellets from among the formed defective pellets and the defective pellets having no circuit pattern.

An object of the present invention is to reliably determine a good pellet from a defective pellet even when the surface reflectance differs depending on whether or not a circuit pattern is formed.

[0009]

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. A non-defective pellet discriminating apparatus capable of discriminating non-defective pellets from each of a pellet and a defective pellet in which a circuit pattern is not formed on the surface and the surface is a reflective surface having high reflectance. For each surface of good and bad pellets aligned in
An inspection light source capable of irradiating the inspection light and a reference reflected light amount equivalent value capable of detecting a defective pellet are predetermined, the reflected light amount of the inspection light is measured, and the measured reflected light amount equivalent value and the reference reflected light amount equivalent value are determined. Comparing the defective pellet detection means, the reference reflected light amount equivalent value of the defective pellet detection means, for the defective mark of the defective pellet having a circuit pattern formed on the surface, the reflected light amount equivalent value of the inspection light is the reference The level is lower than the reflected light amount equivalent value, and for defective pellets having no circuit pattern formed on the surface and non-defective pellets, the reflected light amount equivalent value of the inspection light is higher than the reference reflected light amount equivalent value. The reference reflected light quantity equivalent value and the defective quantity of the circuit pattern formed on the surface and the good quality pellet are the reflected light quantity equivalent values of the inspection light. A level lower than this value, and for a defective pellet having no circuit pattern formed on the surface, a value equivalent to the reflected light amount of the inspection light is a level higher than the value equivalent to the reference reflected light amount. And a means for changing settings.

[0010]

In the state where the reference reflected light amount equivalent value is set to the first reference reflected light amount equivalent value, the reflected light amount of the inspection light is obtained only when the defective mark detecting means detects a defective mark in a defective pellet having a circuit pattern. It is detected that the corresponding value is lower than the reference reflected light amount corresponding value, and the defective mark existing on the surface can be surely detected.

Under the condition that the reference reflected light quantity equivalent value is set to the second reference reflected light quantity equivalent value, the reflected light quantity equivalent value of the inspection light is obtained only when the defective mark detecting means detects a defective pellet having no circuit pattern. Is detected to be a level higher than the reference reflected light amount equivalent value, and the defective pellet is surely fixed despite the fact that the reflected light amount on the surface is generally large due to having no circuit pattern. Detectable.

According to the above, even when the reflectance of the surface is different depending on whether or not the circuit pattern is formed, it is possible to surely discriminate the good pellet from the defective pellet.

[0013]

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 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).

The semiconductor wafer 10 that has been subjected to the circuit characteristic test is crushed into individual pellets in the non-defective pellet discriminating apparatus 16 as shown in FIG. Is discriminated.

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. By heating the adhesive sheet 23 in this state and further stretching the sheet 23 in the circumferential direction of the semiconductor wafer 10, pellets at a constant interval are aligned in the upper surface XY direction of the adhesive sheet 23. The peripheral portion of the adhesive sheet 23 has the support ring 1
9 is chucked via a rubber ring 25 in a groove 24 formed in the side portion of 9. As a result, as shown in FIG.
The circuit pattern 12 is formed on the surface of the table 18, the surface is made 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 surface The defective pellet 27 in which the circuit pattern 12 is not formed on the surface and the surface is a reflective surface having a high reflectance, and the circuit pattern 12 is formed on the surface and the surface is a reflective surface having a low reflectance. 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 aligned in the XY direction at regular intervals.

An inspection light source 29 and a sensing portion 31 of a sensor 30 as defective pellet detecting means are arranged above the XY table 18. The inspection light source 29 is capable of irradiating the non-defective pellets 28 and the defective pellets 26 and 27 arranged on the adhesive sheet 23 with the inspection light 32. 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 detects the presence or absence of the defective mark 14 on the surface of the pellet, and discriminates the defective pellets 26 and 27 from the amount of reflected light of the inspection light 32. Non-defective pellet 28 capable of storing the coordinate position of the pellet 28
Discriminating circuit 33 is connected. The discriminating circuit 33 for the non-defective pellet 28 includes a voltage converting section 34, a comparing section 35, a reference reflected light amount equivalent value setting section 36, a non-defective pellet discriminating section 37, and a storage section 38. The voltage conversion unit 34 includes the sensing unit 3
The change in the reflected light amount sensed at 1 is converted into a change in the output voltage V1, and 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 of the pellets 26, 27, and 28 based on the movement of the XY table 18 shown in FIG. 5 causes the comparison unit 35 and the reference reflected light amount equivalent value setting unit 36 to generate the voltage V1.
Will be transmitted as. At this time, the voltage V1 changes to be high when the amount of reflected light of each pellet 26, 27, 28 is large, and to be low when the amount of reflected light is small. Therefore, the voltage V1 has a lower value than the output voltage V1 based on the normal reflected light amount in the defective pellet 26 in the region B where the defective mark 14 in the defective pellet 26 is sensed. In addition, the output voltage V1 is higher in the reflectance of the defective pellet 27 in which the circuit pattern 12 is not formed than in the defective pellet 26 and the non-defective pellet 28 in which the circuit pattern 12 is formed on the surface. It shows a high value as a whole.

The comparison unit 35 compares the measured voltage V1 with a reference voltage level based on a preset reference reflected light amount, and determines the voltage V1 which is lowered when the defective mark 14 of the defective pellet 26 is detected. Change and defective pellet 2
A change in the output voltage V1 that rises when 7 is detected can be detected.

The setting unit 36 is capable of variably setting the reference voltage level based on the reference reflected light amount, 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 L1 is lower than the output voltage V1 based on the amount of reflected light from the defective pellet 27 and the non-defective pellet 28.

The reference voltage level L2 is the voltage V1 output from the voltage conversion unit 34 to the comparison unit 35 in the sensing area C when the defective pellet 27 having no circuit pattern is sensed by the sensing unit 31. It is set to a value higher than the voltage level L2. still,
The reference voltage level L2 is set to a value higher than the output voltage V1 based on the amount of reflected light from the defective pellet 26 and the non-defective pellet 28.

Therefore, in the setting unit 36, the reference voltage level is normally set to L1 and the comparing unit 35 detects the decrease in the output voltage V1 when the sensing unit 31 senses the defective mark 14 in the defective pellet 26. In some cases, the defective pellet 26 is detected.

When the comparing section 35 does not detect the defective pellet 26 under the above-mentioned normal setting state,
The pellet is a defective pellet 27 or a good pellet 28.
Based on the estimation that it is, the reference voltage level is set to L2. In this way, when the comparison unit 35 detects that the output voltage V1 based on the amount of reflected light from the pellets is still higher than the reference voltage level L2 while the setting unit 36 sets the reference voltage level to L2. , Defective pellets 27 are detected.

As a result, in the comparison unit 35, when the voltage change due to the detection of the region B is measured by comparison with the reference voltage level L1, and when it is detected that the output voltage V1 is equal to or higher than the reference voltage level L2. , 0 indicating that the defective pellet 26 or 27 is discriminated, as shown in FIG.
It becomes possible to output the discrimination pulse P of No. 2 to the non-defective pellet discriminating unit 37. On the other hand, in other cases, the discrimination pulse P of 1 indicating that the pellet is the non-defective pellet 28 can be output to the non-defective pellet discriminating section 37.

The non-defective pellet discriminating unit 37, based on the discriminating pulse P input from the comparing unit 35, each pellet 26 with respect to an arbitrary coordinate origin on the non-defective pellet discriminating device 16.
The positions of 27 and 28 are analyzed. 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. The memory in the memory 38 is a floppy disk,
A storage medium such as a magnetic tape is used. 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, when the reference voltage level is changed to L2 in the setting unit 36 and the output voltage V1 is still higher than the reference voltage level L2, the pellet is defective pellet 2.
Therefore, the non-defective pellet 28 can be finally 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 is linear, but the defective pellet 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 if the surface reflectance differs depending on whether or not a circuit pattern is formed, it is possible to reliably determine a good pellet from a defective pellet.

[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. A non-defective pellet discriminating apparatus capable of discriminating non-defective pellets for each of defective pellets which are not formed and whose surface is a reflective surface having high reflectance, and non-defective pellets and defective pellets aligned on a table. For each surface of, the inspection light source capable of irradiating the inspection light, the reference reflected light amount equivalent value capable of detecting the defective pellet is predetermined, and the reflected light amount of the inspection light is measured,
A defective pellet detection unit that compares the measured reflected light amount equivalent value with the reference reflected light amount equivalent value, and the reference reflected light amount equivalent value of the defective pellet detection unit to a defective mark of a defective pellet having a circuit pattern formed on its surface. On the other hand, the reflected light amount equivalent value of the inspection light is lower than the reference reflected light amount equivalent value, and the reflected light amount equivalent value of the inspection light is concerned for defective pellets on which no circuit pattern is formed on the surface and good pellets. The first reference reflected light amount equivalent value, which has a higher level than the reference reflected light amount equivalent value, and the defective light pellet having a circuit pattern formed on the surface and the non-defective pellet are the reflected light amount equivalent value of the inspection light. For a defective pellet without a circuit pattern formed on the surface, the level equivalent to the amount of reflected light of the inspection light is the reference Good pellet discriminating apparatus comprising a means for changing setting to the second reference reflected light amount equivalent value becomes higher than the amount equivalent value level.