JPH0548622B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a device for determining non-defective pellets.

[Prior Art] A semiconductor wafer is formed by printing circuit patterns on the surface layer of a circular wafer made of a material such as silicon and having a mirror surface with high reflectivity.
The circuit pattern group consists of multiple circuit patterns
It is arranged and configured in the direction. The shape of the circuit pattern group to be printed is a square or rectangle that fits within the circular wafer, and the surface of the semiconductor wafer other than the part where the circuit pattern is printed is
It remains a highly reflective mirror surface. The semiconductor wafer on which the circuit patterns have been printed is diced into matrix shapes, and further broken into pellets. Dicing is performed by carving dicing lines in the XY directions on the surface of the semiconductor wafer using a diamond grindstone, a laser, or the like. Thereby, by breaking the semiconductor wafer along the dicing line and separating it, pellets having a circuit pattern on the surface can be manufactured. The pellets produced in this way are processed using pellet bonding equipment.
Mounted on a board such as a lead frame,
This allows us to manufacture chips such as ICs and LSIs.

Incidentally, a group of circuit patterns to be printed on a circular wafer is broken into pellets in advance, and a circuit characteristic test is conducted for each circuit pattern before being separated. The circuit characteristic test is carried out using a characteristic testing machine, and the probe of the testing machine is brought into contact with the surface electrode of the printed circuit pattern, thereby making it possible to inspect whether the circuit pattern is good or bad. As a result of the circuit characteristic test, a defective mark is displayed in red or other ink on the surface of the circuit pattern corresponding to a defective pellet determined to be defective by a mark surface device. Furthermore, a mark display device is used to display a defective mark in red or other ink at a position corresponding to the surface of the defective pellet on which the circuit pattern is not printed.

The semiconductor wafer undergoes the defect marking operation as described above, and is then broken into pellets and separated. As a result, a circuit pattern is formed on the surface, and the surface becomes a reflective surface with low reflectance.As a result of the above circuit characteristic test, a defective pellet with a defect mark displayed on the surface and a circuit pattern are formed on the surface. A defective pellet with a defective mark displayed on the surface, a circuit pattern formed on the surface, and the surface being a reflective surface with a low reflectance, and a defective pellet with a defect mark displayed on the surface. As a result of the above circuit characteristic test, good pellets with no defect marks displayed on their surfaces were formed. In order to distinguish good pellets from these defective and non-defective pellets and perform pellet bonding work only on the good pellets,
A device was used to identify good pellets.

The device for identifying non-defective pellets includes an inspection light source that can irradiate inspection light onto the surface of the pellet, a reference reflected light amount equivalent value that allows determining the presence or absence of a defective mark on each pellet, and a A defective pellet detection means is provided for measuring the amount of light and comparing the measured value equivalent to the amount of reflected light and the value equivalent to the reference amount of reflected light. That is, the defective pellet detection means of this device detects a defective pellet on the surface of the pellet based on the fact that the value equivalent to the amount of reflected light on the pellet surface of the inspection light irradiated to the defective mark is lower than the level of the reference amount of reflected light. This makes it possible to determine the presence or absence of defective marks. As a result, it becomes possible to recognize and discriminate pellets for which no defect mark has been detected as good pellets, and pellet bonding work is performed only on pellets that are judged to be good pellets.

[Problems to be Solved by the Invention] However, in the conventional non-defective pellet discriminating device described above, although pellets with different surface reflectances coexist, the standard for discriminating defective marks is usually not met. The only value corresponding to the amount of reflected light was set that matched the reflectance of the pellet with a circuit pattern formed on its surface. Therefore, if the reflectance of the pellet surface is high, such as a defective pellet without a circuit pattern formed on its surface, the amount of reflected light measured by the defective pellet detection means will be correspondingly large as a whole, and therefore the In defective pellets, it has been difficult to distinguish defective marks due to a decrease in the amount of reflected light.

Based on the above, the defective mark is displayed by the mark display device only on defective pellets with a circuit pattern formed on the surface and low surface reflectance, and the defective pellets have circuit patterns formed with different surface reflectances from the good pellets. Defective pellets and defective pellets with no circuit pattern formed,
It has been desired to develop a device for discriminating good pellets that can reliably distinguish only good pellets from among pellets.

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

[Means for Solving the Problems] The present invention has a circuit pattern formed on a surface, the surface is a reflective surface with low reflectance, and as a result of a circuit characteristic test, a defect mark is displayed on the surface. A good pellet discriminating device is capable of discriminating good pellets from pellets and defective pellets on which a circuit pattern is not formed on the surface and whose surface has a high reflectance.
An inspection light source that can irradiate the inspection light onto the surfaces of each of the non-defective and defective pellets arranged on the table, and a reference reflected light amount equivalent value that makes it possible to detect defective pellets are determined in advance, and the reflected light amount of the detection light is determined in advance. a defective pellet detection means for measuring the measured reflected light amount equivalent value and the reference reflected light amount equivalent value;
When the inspection light intensity of the inspection light source is adjusted to a defect mark of a defective pellet with a circuit pattern formed on the surface, the reflected light intensity equivalent value of the inspection light is lower than the reference reflected light intensity equivalent value, and a circuit pattern is formed on the surface. For defective pellets that have not been tested, and for good pellets, a reference light amount value is set such that the reflected light amount equivalent value of the inspection light is higher than the reference reflected light amount equivalent value, and for defective pellets that have a circuit pattern formed on the surface, For non-defective pellets, the value equivalent to the reflected light amount of the inspection light is lower than the reference reflected light amount equivalent value, and for defective pellets with no circuit pattern formed on the surface, the value equivalent to the reflected light amount of the inspection light is lower than the reference reflected light amount equivalent value. The correction light amount value is set to a higher level than the reflected light amount equivalent value.

[Function] When the inspection light amount is set to the reference light amount value, the reflected light amount equivalent value of the inspection light becomes smaller than the reference reflected light amount equivalent value only when the defective mark detection means detects a defective mark on a defective pellet having a circuit pattern. To detect a low level and to reliably detect a defective mark existing on the surface.

Under the condition where the inspection light amount is set to the corrected light amount value, the reflected light amount equivalent value of the inspection light becomes a higher level than the reference reflected light amount equivalent value only when the defective mark detection means detects a defective pellet that does not have a circuit pattern. By detecting this, the defective pellet can be reliably detected even though the amount of reflected light on the surface is large overall due to the absence of a circuit pattern.

According to the above, even if the reflectance of the surface differs depending on whether a circuit pattern is formed or not, it is possible to reliably distinguish good pellets from defective pellets.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a partially cutaway front view showing a non-defective pellet discriminating device according to an embodiment of the present invention, FIG. 2 is a plan view showing a semiconductor wafer before it is broken into pellets and separated, and FIG. The figure is a plan view showing good and defective pellets arranged on an XY table, Figure 4 is a plan view showing an enlarged part of Figure 3, and Figure 5 shows the variable setting state of the inspection light intensity of the inspection light source. FIG.

The semiconductor wafer 10 shown in FIG. 2 has a circuit pattern group 11 on the surface layer of a circular wafer made of silicon or the like and having a mirror surface with high reflectance.
Burned from. The outline of this circuit pattern group 11 is a rectangular shape that fits within a circular wafer, and is composed of a plurality of circuit patterns 12 arranged in the XY directions. As a result, the surface of the semiconductor wafer 10 other than the portion where the circuit pattern 12 is printed remains as a mirror surface with high reflectance. Semiconductor wafer 1 on which circuit pattern group 11 is printed
0 is diced along matrix-like dicing lines 13 and further braked.
As a result, by breaking and separating the semiconductor wafer 10 along the dicing line 13, it is possible to obtain a plurality of pellets having the circuit pattern 12 on the surface.

The semiconductor wafer 10 has a printed circuit pattern 1 before being broken into pellets and separated.
Circuit characteristic tests were conducted for each of 2.
The test is conducted using a characteristic testing machine (not shown). That is, the circuit characteristic test is carried out by bringing the probe of the characteristic testing machine into contact with the surface electrode of the printed circuit pattern 12, thereby making it possible to inspect whether each circuit pattern 12 is good or bad. As a result of the circuit characteristic test, a defective mark 14 is displayed in red or other ink on the surface of the circuit pattern 12 determined to be defective by a mark display device (not shown).

Semiconductor wafer 1 subjected to the above circuit characteristic test
0, after the above-mentioned defect mark display operation, a good pellet discriminating device 41 as shown in FIG.
Each pellet is broken and separated, and then a process is performed to determine which pellets are good.

The non-defective pellet discriminating device 41 includes an XY table 18 that is movable in the XY directions with respect to a pedestal 17, and a support ring 19 that supports the semiconductor wafer 10 can be attached to the XY table 18. . The support ring 19 is attached to the support part 21 of the support frame 20, and the support frame 20 is
It is fixed to the upper surface of the XY table 18 by bolts 22. The semiconductor wafer 10 supported by the support ring 19 is broken onto the upper surface of the adhesive sheet 23.
That is, the semiconductor wafer 10 that has been subjected to the circuit characteristic test is broken onto the adhesive sheet 23 and then broken along the dicing line 13 and 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 are arranged at regular intervals in the XY direction on the upper surface of the adhesive sheet 23. The peripheral edge of the adhesive sheet 23 is stuck to a groove 24 formed on the side of the support ring 19 via a rubber ring 25. As a result, as shown in FIG. 3, a circuit pattern 12 is formed on the surface of the XY table 18, and the surface becomes a reflective surface with low reflectance. Defective pellet 26 with mark 14 displayed
and a defective pellet 2 on which the circuit pattern 12 is not formed and whose surface is a reflective surface with high reflectance.
7 and a good pellet 28 on which a circuit pattern 12 is formed and the surface is a reflective surface with low reflectance, and where no defective mark 14 is displayed on the surface as a result of the circuit characteristic test. They will be aligned in the direction.

An inspection light source 2 is located above the XY table 18.
9 and a sensing section 31 of a sensor 30 as means for detecting defective pellets are provided. The inspection light source 29 is
Good pellets 28 arranged on adhesive sheet 23
and for each of the defective pellets 26 and 27,
The inspection light 32 can be irradiated. Further, the sensing portion 31 of the sensor 30 is capable of sensing changes in the amount of reflected light of the inspection light 32 reflected from the good 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 determined by the width W of each pellet 26, 27, 28, as shown in FIG.
It is linear with a width W2 somewhat larger than 1,
To sense the amount of reflected light on each pellet 26, 27, 28, the XY table 18 is moved in the X direction or the Y direction.
Each pellet 26, 27, 2 aligned in the XY direction
I try to do this by moving 8. As a result, as shown in FIG.
The pellets 26, 27, 2 are arranged as if
8, scanning is performed in the direction of arrow A, and the magnitude of the amount of reflected light on each pellet 26, 27, 28 is sensed by the sensing section 31.

The sensor 30 detects defect mark 1 on the pellet surface.
In addition to detecting the presence or absence of pellets 4, the defective pellets 26 and 27 are determined based on the amount of reflected light of the inspection light 32.
A non-defective pellet 28 discriminating circuit 42 is provided which is capable of storing the coordinate position of each non-defective pellet 28 with respect to an arbitrary coordinate origin of the non-defective pellet discriminating device 41. The judgment circuit 42 for determining the good pellet 28 includes a voltage conversion section 43, a comparison section 44, an inspection light amount setting section 45,
It is composed of a reference reflected light amount equivalent value setting section 46, a non-defective pellet discriminating section 47, and a storage section 48. The voltage conversion unit 43 converts the change in the amount of reflected light detected by the sensing unit 31 into a change in the output voltage V1, and the output voltage V1 is sent to the comparison unit 44 and the inspection light amount setting unit 45.
are output respectively. The result is shown in Figure 5.
Each pellet 2 based on the movement of the XY table 18
Changes in the amounts of reflected light from the surfaces of the test tubes 6, 27, and 28 are transmitted as a voltage V1 to the comparison section 44 and the inspection light amount setting section 45. At this time, the voltage V1 changes to be high when the amount of reflected light from each pellet 26, 27, and 28 is large, and becomes low when the amount of reflected light is small. Therefore, the voltage V1 in the region B where the defective mark 14 on the defective pellet 26 is detected,
This shows a lower value than the output voltage V1 based on the normal amount of reflected light from the defective pellet 26.
In addition, the output voltage V1 is determined by the circuit pattern 12 on the surface.
Compared to the defective pellet 26 on which the circuit pattern 12 is formed and the good pellet 28, the defective pellet 27 on which the circuit pattern 12 is not formed exhibits a higher overall value due to the higher reflectance of the surface.

The comparison unit 44 determines a reference voltage level L based on the transmitted voltage V1 and a preset reference amount of reflected light.
3, it is possible to detect the change in the voltage V1 that decreases when the defective mark 14 is detected and the change in the voltage V1 when the defective pellet 27 is detected. Setting of the reference voltage level L3 is performed by the setting section 46, so that a constant reference voltage level L3 can be output to the comparison section 44.

On the other hand, the inspection light amount setting section 45 controls the inspection light source 29
The amount of inspection light emitted by the sensor can be variably set. That is, in this embodiment, the test light amount setting unit 45 sets the test light amount emitted by the test light source 29 to a reference light amount value D1 and a corrected light amount value D2 indicating a light amount value lower than this reference light amount value D1. It is now possible to change settings.

Here, the reference light amount value D1 means that when the detected light amount is set to this reference light amount value D1, the sensing unit 31 detects the defective mark 14 of the defective pellet 26 on which the circuit pattern is formed, as shown in FIG. When sensing, the voltage V1 outputted from the voltage converter 43 to the comparator 44 in the sensing region B is set to a value that is locally lower than the reference voltage level L3. Note that, under this reference light amount value D1, the output voltage V1 based on the amount of light reflected from the defective pellet 27 on which no circuit pattern is formed and the good pellet 28 is set to a level higher than the reference voltage level L3. Ru.

Further, the corrected light amount value D2 is the reference light amount value D for the defective pellet 27 on which no circuit pattern is formed.
Output voltage V1 when a test light amount of 1 is irradiated
The change E can be reduced to the change F by irradiation with the inspection light set to this corrected light amount value D2, and under the inspection light amount of this corrected light amount value D2,
When the sensing section 31 senses the defective pellet 27, the voltage V1 outputted from the voltage converting section 43 to the comparing section 44 in the sensing region C is set to a value that is still higher than the reference voltage level L3. . Note that under this corrected light amount value D2, the defective pellets 26 and the good pellets 28
The output voltage V1 based on the amount of reflected light from the reference voltage level L3 is set to be equal to or lower than the reference voltage level L3.

Therefore, the setting section 45 sets the normal inspection light amount to the reference light amount value D1, and the comparison section 44 detects a decrease in the output voltage V1 when the sensing section 31 senses the defective mark 14 on the defective pellet 26. Sometimes, a defective pellet 26 is detected.

Then, under the above-mentioned normal setting state, when the comparing unit 44 does not detect a defective pellet 26, the setting unit 45 corrects the inspection light amount on the assumption that the pellet is a defective pellet 27 or a non-defective pellet 28. Change the setting to light amount value D2. In this way, the comparing unit 44 detects that the output voltage V1 based on the amount of reflected light from the pellet is still higher than the reference voltage level L3 under the condition that the setting unit 45 sets the inspection light level to the corrected light level value D2. When this happens, the pellet 27 is detected to be defective.

As a result, in the comparator 44, when the voltage change due to the detection of region B is measured by comparison with the reference voltage level L3, and the output voltage V1 at the light amount values D1 and D2 is both at the reference voltage level L3.
If the above is detected, as shown in FIG.
It becomes possible to output on 7. On the other hand, in other cases, one discrimination pulse P indicating that the pellet is a non-defective pellet 28 can be output to the non-defective pellet discriminating section 47.

The good pellet discriminating section 47 uses the defective mark discriminating pulses P sequentially inputted from the comparing section 44 to
The position of each pellet 26, 27, 28 with respect to an arbitrary coordinate origin on the non-defective pellet discriminating device 41 is analyzed. As a result, good pellets 2 out of the arranged pellets 26, 27, 28
The coordinate position of the pellet 8 is analyzed, and the coordinate position of the good pellet 28 is stored in the storage section 48. The storage in the storage unit 48 is performed by a storage medium such as a copy disk or a magnetic tape. In this way, each pellet 26, 2 whose coordinate position of the good pellet 28 has been determined
7 and 28, sorting work is performed by a good pellet sorting section of the pellet bonding device, and the sorting work is performed based on data regarding the coordinate position of the good pellets 28 stored in the storage medium. ing.

Good pellet discrimination device 41 according to the above embodiment
According to the above, when a defective mark 14 is detected by comparing the output voltage V1 based on the amount of reflected light from the pellet with the reference voltage level L3 under the condition that the inspection light amount is set to the reference light amount value D1, the pellet It can be seen that this is a defective pellet 26. On the other hand, when the defective mark 14 is not detected under this condition, the pellet is classified as a good pellet 28 from the defective pellet 27. Therefore, when the inspection light intensity is set to the corrected light intensity value D2 in the inspection light intensity setting section 45, if the output voltage V1 is still higher than the reference voltage level L3, the pellet is detected as a defective pellet 27, and is ultimately a non-defective pellet. This allows the pellet 28 to be reliably identified.

According to the device 41 for identifying good pellets according to the above embodiment, it is possible to discriminate good pellets 28 by variable setting of the light intensity values D1 and D2 of the inspection light intensity, but the reference voltage level L3 can also be variably set. As such, the sensor 30 may be provided with a circuit 42 for determining good pellets.

Further, in the above embodiment, the sensor 30 is a line sensor, and the sensing area Q is linear, but in the defective mark detection means of the present invention, the sensing area is a surface that can sense the entire surface of each pellet. It can also be used as a sensor.

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably distinguish good pellets from defective pellets even when the reflectance of the surface differs depending on whether a circuit pattern is formed or not.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing a non-defective pellet discriminating device according to an embodiment of the present invention, FIG. 2 is a plan view showing a semiconductor wafer before it is broken into pellets and separated, and FIG. The figure is a plan view showing good and defective pellets arranged on an XY table, Figure 4 is a plan view showing an enlarged part of Figure 3, and Figure 5 shows the variable setting state of the inspection light intensity of the detection light source. FIG. 12... Circuit pattern, 14... Defective mark,
18...XY table, 26, 27...defective pellet, 28...good pellet, 29...inspection light source, 30...sensor, 32...inspection light, 41...
Good pellet discrimination device, 42... Good pellet discrimination circuit, 45... Inspection light amount setting unit, 46...
... Reference reflected light amount equivalent value setting section, 47 ... Good pellet discrimination section, L3 ... Reference voltage level, D1 ...
...Reference light amount value, D2...Corrected light amount value.

Claims (1)

[Claims] 1 A defective pellet has a circuit pattern formed on its surface, and the surface is a reflective surface with low reflectance, and a defect mark is displayed on the surface as a result of a circuit characteristic test, and a defective pellet has no circuit pattern formed on its surface. A device for discriminating good pellets from each of defective pellets whose surface is a reflective surface with a high reflectance, the device being capable of discriminating good pellets from each other, the surface of each of the good pellets and the defective pellets being arranged on a table. An inspection light source that can irradiate the inspection light and a reference reflected light amount equivalent value that can detect defective pellets are determined in advance, the reflected light amount of the inspection light is measured, and the measured reflected light amount equivalent value and the reference reflected light amount are determined in advance. A defective pellet detection means that compares the light intensity equivalent value and the inspection light intensity of the inspection light source, and for a defective mark of a defective pellet with a circuit pattern formed on the surface, the reflected light intensity equivalent value of the inspection light is equivalent to the reference reflected light intensity. a reference light amount value at which the reflected light amount equivalent value of the inspection light is higher than the reference reflected light amount equivalent value for defective pellets with no circuit pattern formed on the surface and good pellets;
For defective pellets with a circuit pattern formed on the surface and good pellets, the reflected light amount equivalent value of the inspection light is lower than the reference reflected light amount equivalent value, which indicates that the defective pellet has no circuit pattern formed on the surface. and means for changing the setting of the reflected light amount equivalent value of the inspection light to a corrected light amount value that makes the reflected light amount equivalent value higher than the reference reflected light amount equivalent value.