TWI652751B - Point measuring method for surface-emitting laser crystal grains of vertical resonance cavity - Google Patents

Abstract

A method for spot measurement of vertical resonant cavity surface-emitting laser die, the steps of which include: providing a wafer with a plurality of VCSEL die, the operating current of each die is greater than or equal to 1 ampere, the die K regions in a matrix arranged in I columns and J rows, each region has R positions in a matrix arranged in M columns and N rows, M and N are greater than or equal to 3, and at least one location of each region is provided with a die; Spot the grains at a specific position among the R positions in these areas until the grains located at the specific positions in these areas are all spotted; repeat the previous step with each of the R positions as a specific position until each The grain points in this area are measured. This spot measurement method can avoid the thermal energy generated by the spot measurement of the high-power VCSEL die from affecting the detection results of neighboring die, thereby improving the accuracy of the detection results.

Description

Point measuring method for surface-emitting laser crystal grains of vertical resonance cavity

The invention relates to a spot measuring method used for laser crystal grain testing, in particular to a spot measuring method for a vertical resonant cavity surface laser (Vertical-Cavity Surface-Emitting Laser; VCSEL for short) .

VCSEL is a laser diode made by semiconductor process. Its beam is emitted from the front instead of the traditional side, so it is called a surface-emitting laser (Surface-Emitting Laser). The general side-emitting laser (Edge-Emitting Laser) test is that after the wafer is made and the whole piece is cut into a large number of die, the die is touched by a one-point measuring machine and detected from its side Optical characteristics. The VCSEL adopts front light emission, and the optical characteristics can be detected before the die is cut.

Further, the VCSEL die adopts the form of upper and lower electrodes, that is, the positive and negative electrodes are located on the front (upper surface) and back (lower surface), respectively. In addition, the VCSEL die adopts the form of a common cathode on the back, that is, the whole The lower electrode (or back electrode) of the wafer is the same conductor layer, and this conductor layer serves as the negative electrode (common cathode) of all the die of the wafer, so the VCSEL die must be spot-tested before being cut. .

In detail, the point measuring machine uses a probe to touch the upper electrode (ie, anode and positive electrode) of the VCSEL die that has not been cut to provide power to the VCSEL die, so that the VCSEL die emits light positively, and then is located at the VCSEL The integrating sphere above the front of the die receives light to analyze the optical characteristics of the VCSEL die. For the spot testing sequence of the die of the same wafer, the current spot testing method adopts the spot testing process of continuous testing of adjacent die, that is, one or more spot testing is completed (depending on the number of probes of the spot testing machine) Immediately after the die, another or more die adjacent to the one or more die are spotted. Such a spotting process can minimize the moving distance of the probe, thereby obtaining the highest detection efficiency.

For the detection of high-power VCSEL die, the spot tester can also use multiple parallel probes to touch the electrodes on the same VCSEL die at the same time to provide high current pulses to the VCSEL die to detect the presence of the VCSEL die. Optical characteristics at higher operating currents. However, during the inspection of high-power VCSEL die, due to the interconnection between the die and the die, the thermal energy generated by the die tested with high current is easily conducted to the die around it. In the case where the adjacent die is subsequently tested, the thermal energy generated by the former die will affect the optical properties of the latter die, so that the test data of each die may come from the optical properties of the die itself and other die The impact of the heat energy generated during the test reduces the accuracy of the test results.

In order to quickly inspect a large number of dies on the same wafer, the current inspection method for any type of dies adopts the point test process of continuous testing of adjacent dies as mentioned above to achieve the highest inspection efficiency, but it is ignored The importance of detection accuracy has affected the performance of various subsequent products using the die.

In view of the above deficiencies, the main purpose of the present invention is to provide a spot measurement method for VCSEL die, which can avoid the thermal energy generated by the spot measurement of high-power VCSEL die from affecting the detection results of neighboring die, thereby improving the accuracy of the detection results Sex.

In order to achieve the above-mentioned object, the method for spot measuring laser crystal grains of a vertical resonator provided by the present invention includes the following steps:

a) Provide a wafer with a plurality of crystal grains for the vertical cavity cavity surface emitting laser, and the working current of each crystal grain is greater than or equal to 1 ampere (preferably, but not limited to , Less than or equal to 20 amps), the die position of the wafer corresponds to the third number of regions arranged in a matrix with a first number of columns and a second number of rows, each of which has a matrix arranged in a fourth number of columns and The sixth quantity position of the five quantity rows, the fourth quantity and the fifth quantity are greater than or equal to 3, at least one of the positions of each region is provided with the die;

b) Spot the grains at a specific position among the sixth number of positions in the areas until the grains located at the specific positions in the areas are all spotted, wherein the specific positions in the areas are Correspond to each other; and

c) Repeat the step b) taking the sixth number of positions as the specific position one by one until the grain points in each of the areas are measured.

Since each area will have a sixth number of positions arranged in a matrix, and the sixth number is greater than or equal to 9, and the flow of this spot measurement method does not continuously spot the grains in the same area, therefore, consecutive spots The measured grains will be separated by a distance, and the distance is greater than the width of the two grains. In this way, even if each of the grains has a higher operating current, it will generate higher thermal energy during the detection and affect the surrounding grains. The optical properties of the optical fiber will not affect the optical properties of the next tested grain. Moreover, the same wafer usually has thousands or even more dies, so the number of regions (that is, the third number) is quite large, and only after all the dies at specific locations in all regions are measured. It may be possible to measure the other grains in the overlapping area again. In this way, even if the spotting speed is quite fast, when the spotting process returns to the area where the grains that have been spotted belong, the grains to be tested previously It has been recovered by the thermal energy of the spot-checked grains, so the test results will not be affected. In this way, the spot testing method of the present invention can avoid the thermal energy generated by the spot testing of the high-power VCSEL die from affecting the test results of neighboring die, thereby improving the accuracy of the test results.

Furthermore, although the fourth quantity and the fifth quantity are set to be greater than or equal to 3, the grains in continuous spot measurement can be separated by a sufficient distance to avoid the thermal energy of spot measurement affecting the detection result. However, in order to take into account both good detection accuracy and detection efficiency, the fourth number and the fifth number are preferably set to less than or equal to 5, whereby by this, each area will only have a minimum of nine and a maximum of twenty-five Positions, that is, the sixth quantity is less than or equal to 25, so as to avoid repeating the step b) too many times in the step c) (less than or equal to twenty-five times), and then in a good detection accuracy On the premise of improving detection efficiency.

In order to take into account both good detection accuracy and detection efficiency, this step b) may (but not limited to) continuously spot the grains at the specific location in the adjacent area, that is, one or more spots have been spotted (depending on spot measurement) The number of probes in the machine) the die at a specific position in the area, and then immediately spot the die at a specific position in another area or areas adjacent to the area or areas. In other words, in step b), the order of the spot measurement regions can be set in such a manner that the spot measurement probe is displaced by the minimum distance, thereby improving the detection efficiency under the premise of good detection accuracy.

Similarly, the sequence of the sixth number of positions as the specific position in step c) can also improve the detection efficiency under the premise of good detection accuracy through a better setting method. For example, in the case where the positions of the regions are arranged in a three-by-three matrix (that is, the fourth quantity is 3, the fifth quantity is 3, and the sixth quantity is 9), this step c) may be (but not limited to) continuous The adjacent position among the nine positions is repeated as the specific position, and the step b) is repeated nine times, that is, the nine positions are set as the first position to the ninth position in the order of consecutive neighbors, and in order This step b) is repeated nine times with the first position to the ninth position as the specific position. The step c) may also (but not limited to) sequentially perform the step b) on the three rows, and sequentially perform the step b) on the three positions of the same row, and then sequentially on the three positions of the next row Performing this step b) means that after the three positions of the first row are respectively used as the specific positions, the three positions of the second row are respectively used as the specific positions, and so on. Alternatively, the step c) may also (but not limited to) perform the step b) on the three rows in sequence, and perform the step b) on the three positions in the same row in sequence, and then on the three positions in the next row The step b) is performed in order, that is, after the three positions in the first row are respectively used as the specific positions, the three positions in the second row are respectively used as the specific positions, and so on.

The point measuring method of the present invention is mainly used for high-power VCSEL die, and its operating current is set at 1-20 amps. Further, the die size (usually refers to the side length of square die) is greater than or equal to 1000 Under the application of micrometers (the larger the grain size, the larger the number of emitters and the greater the operating current), the spot measurement method of the present invention has a more significant effect of improving the detection accuracy than the conventional spot measurement method.

The detailed structure, characteristics, assembling or using method of the spot measurement method for the surface-resonant laser crystal grains provided by the present invention will be described in the detailed description of the subsequent embodiments. However, those of ordinary knowledge in the field of the present invention should be able to understand that these detailed descriptions and specific embodiments listed for implementing the present invention are only used to illustrate the present invention, and are not intended to limit the scope of the patent application of the present invention.

Please refer to FIG. 1, a method for spot measuring laser crystal grains of a vertical resonator provided by a preferred embodiment of the present invention includes the following steps:

a) A wafer 10 is provided. The wafer 10 has a plurality of dies 20 for a vertical cavity cavity surface-emitting laser. The operating current of each die 20 is greater than or equal to 1 ampere. Preferably, the operating current of each die 20 may be (but not limited to) less than or equal to 20 amperes. In other words, each die 20 belongs to a high-power VCSEL die. In this step a), a complete wafer 20 distribution map can be obtained by performing wafer scanning.

The actual wafer 10 has thousands or even more tiny dies 20, and the dies 20 are not cut and connected to each other. However, in order to simplify the diagram and facilitate the description, the diagram of the present invention The formula is not drawn according to the actual scale, but the die 20 is drawn so that the wafer 10 has only about two hundred dies 20, and not all of the dies 20 are drawn. In detail, in the first flow P1 of FIG. 1, the wafer 10 is shown in a circle without drawing the dies 20. In the second flow P2 and the third flow P3 of FIG. 1 In the middle, some of the crystal grains 20 are shown by a plurality of squares, but not all of the crystal grains 20 are drawn.

In addition, as shown in the first flow P1 of FIG. 1, the position of the die 20 of the wafer 10 corresponds to the first row of the matrix arranged in a first number (hereinafter referred to as I) column and a second number (hereinafter referred to as J) row Three quantity (hereinafter referred to as K) regions 30, as shown in FIG. 2, each region 30 has a sixth quantity arranged in a matrix into a fourth quantity (hereinafter referred to as M) column and a fifth quantity (hereinafter referred to as N) row ( Hereafter referred to as R) positions 32, M and N are greater than or equal to 3, and at least one position 32 of each region 30 is provided with a die 20. The area 30 and the location 32 described in this step a) can be planned by the tester during the test, or can be preset in the test machine by the machine supplier.

As shown in FIG. 1, in this embodiment, the position of the die 20 of the wafer 10 corresponds to the area 30 of five rows and five columns, that is, I and J are both equal to 5, and the number K of the area 30 is equal to 25 . As shown in FIG. 2, in this embodiment, the positions 32 of each area 30 are arranged in three rows and three columns, that is, M and N are both equal to 3, then the number R of positions 32 of each area 30 is equal to 9 .

As mentioned before, the pattern of the present invention draws the size of the die 20 larger and the number of the die 20 smaller, so the twenty-five areas 30 shown in the first figure are more than the actual area 30 The number is much smaller, and this is also to simplify the diagram and facilitate the explanation. In addition, the dies 20 of the actual wafer 10 are not cut and connected to each other. However, in order to clearly show the area 30, the position 32, and the dies 20, the dies 20 in the diagram of the present invention are mutually connected. Separation, thereby clearly distinguishing the position 32 and the die 20.

Since the wafer 10 is circular, and the region 30 in this embodiment is (but not limited to) a square shape, not all of the positions 32 are provided with a die 20 respectively. In this embodiment, each of the nine locations 32 of the nine central regions 30 is provided with a die 20, as shown in FIG. 2; and among the sixteen peripheral regions 30, the nine locations 32 of each region 30 have only One to seven locations 32 are provided with dies 20.

b) Spotting the die 20 at a specific position among the R positions 32 of the regions 30 until the die 20 at the specific position of the regions 30 are all spotted. The specific positions correspond to each other. The so-called spot measurement here involves using an integrating sphere to receive the light generated by the crystal grain 20 to perform the photoelectric characteristic analysis test.

In this embodiment, each area 30 has nine positions 32. In step b), one of the nine positions 32 is selected as the specific position, and the specific position of each area 30 corresponds to each other. For example, In other words, the second flow P2 of FIG. 1 selects the position of the upper left corner as the specific position, which means that the specific position is the position 32 shown in FIG. 2 and located in the first column and the first row. Then, a spot measuring machine (not shown) is used to spot the die 20 at the specific positions of the regions 30. In the second process P2 of FIG. 1, there are only the specific positions of the sixteen regions 30 (Upper left corner) There are die 20, so only the sixteen die 20 are spotted. The spot tester may first spot one or more of the sixteen die 20 (depending on the spot tester's Number of probes) die 20, after spotting, then another or more of the sixteen die 20 are spotted, until all sixteen die 20 are spotted, this step is completed b).

c) Repeat the step b) using the R positions 32 as the specific positions one by one until the grain 20 in each of the regions 30 is measured.

In this embodiment, the number R of the positions 32 of each region 30 is equal to 9, so the step b) needs to be performed nine times before the entire die 20 can be measured. For example, the second process P2 of FIG. 1 selects the position of the upper left corner as the specific position and finishes measuring all the sixteen die 20, that is, the first step b) is completed, and then, the second step b) It can be carried out as shown in the third flow P3 of FIG. 1 by selecting the upper middle position as the specific position, which means that the specific position is the position 32 shown in FIG. 2 in the second column and the first row 32 In the third process P3 of FIG. 1, only the fourteen areas 30 are provided with the die 20 at the specific position (upper middle), so the second step b) only spot the fourteen die 20. Then select the remaining seven positions 32 of the nine positions 32 one by one as the specific position, and perform the third to ninth step b in the same way as the first and second steps b) ), You can complete the step c) by measuring all the 20 grains.

In this way, the spot measuring method of the present invention does not continuously spot the die 20 in the same area 30. Therefore, the die 20 continuously spotted will be separated by a distance, and the segment distance is at least greater than two die 20 In this way, even if each die 20 will generate higher thermal energy during detection due to the higher operating current and thus affect the optical characteristics of the surrounding die 20, it will not affect the next tested die 20 optical properties. Moreover, the wafer 10 actually has a relatively large number of dies 20, so the number of regions K is actually quite large, and it is only possible to measure again after the dies 20 at all specific locations of the regions 30 have been measured To the other die 20 in the overlapping area, even if the spotting speed is quite fast, when the spotting process returns to the area 30 to which the die 20 has been spotted, the die 20 to be tested It has been recovered by the thermal energy of the spot-checked die 20, so the detection result will not be affected. Therefore, the spot testing method of the present invention can avoid the thermal energy generated by the spot testing of the high-power VCSEL die 20 from affecting the test results of the neighboring die 20, thereby improving the accuracy of the test results.

Further, although M and N are set to be greater than or equal to 3, the grains 20 in continuous spot measurement can be separated by a sufficient distance to avoid the thermal energy of spot measurement affecting the detection result. However, in order to balance good detection accuracy and detection efficiency, M and N are preferably set to less than or equal to 5, so that each area 30 will only have a minimum of nine and a maximum of twenty-five positions 32, and That is, R is less than or equal to 25, so that step b) can be avoided from repeating step b) too many times (less than or equal to twenty-five times), and the detection efficiency can be improved under the premise of good detection accuracy.

In order to take into account both good detection accuracy and detection efficiency, the aforementioned step b) may (but not limited to) continuously spot test the die 20 at the specific position of the adjacent region 30. Taking the second process P2 in FIG. 1 as an example, the spot testing machine spot-tests one or more dies 20 of the sixteen dies 20, and then spot-tests the neighbor of the one or more dies 20 The other one or more grains 20 in the area until all the sixteen grains 20 are measured. In other words, in step b), the order of the area 30 for spot measurement can be set in such a manner that the probe of the spot measuring machine is displaced by the minimum distance, thereby improving the detection efficiency under the premise of good detection accuracy.

Similarly, in order to balance good detection accuracy and detection efficiency, the foregoing step c) may (but is not limited to) continuously repeat the step b) R times using adjacent positions of the R positions as the specific position. That is to say, in this embodiment, the nine positions 32 of each area 30 are set as the first position to the ninth position in the consecutive adjacent order, for example, the position 32 of the first row and the first column is the first position , The position 32 of the first row and the second column is the second position, the position 32 of the first row and the third column is the third position, the position 32 of the second row and the third column is the fourth position, the second row and The position in the second row is the fifth position, and so on. Then, the step b) is repeated nine times in order from the first position to the ninth position as the specific position. The step c) may also (but not limited to) perform the step b) on the three rows in sequence, and perform the step b) on the three positions 32 on the same row in sequence, and then on the three positions 32 on the next row Perform step b) in sequence, that is, as in the previous example, the three positions 32 of the first row are set to the first to third positions, and the three positions 32 of the second row are then set to the fourth to sixth positions , And so on. Alternatively, the step c) may also (but not limited to) perform the step b) on the three rows in sequence, and perform the step b) on the three positions 32 of the same row in sequence, and then perform the next three Position 32 performs this step b) in sequence, which means that the three positions 32 in the first row are set to the first to third positions, and the three positions 32 in the second row are then set to the fourth to sixth positions to And so on.

As mentioned above, the point measurement method of the present invention is mainly used for high-power VCSEL die, and its operating current is set at 1-20 amps. Further, at the size of die 20 (usually refers to the edge of a square die (Long) greater than or equal to 1000 microns (the larger the grain size, the greater the number of emitters, the greater the operating current), the spot measurement method of the present invention is more effective than conventional spot measurement methods in improving detection accuracy Notable.

Finally, it must be explained again that the constituent elements disclosed in the foregoing embodiments of the present invention are only examples and are not intended to limit the scope of the case. The substitution or change of other equivalent elements should also be the scope of the patent application of the case Covered.

10‧‧‧ Wafer

20‧‧‧ grain

30‧‧‧Region

32‧‧‧Location

P1‧‧‧ First process

P2‧‧‧ Second process

P3‧‧‧ Third process

I‧‧‧Number

J‧‧‧ second quantity

M‧‧‧ fourth quantity

N‧‧‧ fifth quantity

FIG. 1 is a schematic diagram of a spot measurement method for a surface resonator type laser die of a vertical resonator provided by a preferred embodiment of the present invention; and FIG. 2 is a view provided by the preferred embodiment of the present invention. A schematic diagram of an area in the point measurement method of the surface-emitting laser crystal grains of the vertical resonator.

Claims (8)

A method for spot measurement of a laser beam of a vertical resonant cavity surface type includes the following steps: a) Providing a wafer (10) with a plurality of wafers for the surface cavity type of a vertical resonant cavity type Laser die (20), the operating current of each die is greater than or equal to 1 ampere, the die position of the wafer corresponds to the matrix arranged in a first number (I) row and a second number (J) The third quantity of rows, each of which has a matrix arranged into a fourth quantity (M) of columns and a fifth quantity (N) of a sixth quantity of rows, a fourth quantity (M) and a fifth quantity (N) All are greater than or equal to 3, at least one of the positions of each of the regions is provided with the grain; b) Spot the grains at a specific position among the sixth number of positions in the areas until the position is located in the areas All the grains at a specific position are measured, wherein the specific positions of the areas correspond to each other; and c) the step b) is repeated with the sixth number of positions as the specific position one by one until each of the areas The grain point measurement is completed. As described in item 1 of the scope of the patent application, a point measurement method for a vertical resonant cavity surface-emitting laser die, wherein the fourth quantity (M) and the fifth quantity (N) are both less than or equal to 5. As described in item 1 of the scope of the patent application, a point measurement method for a surface resonator type laser crystal grain of a vertical resonator, in which the side length of each crystal grain is greater than or equal to 1000 microns. As described in item 1 of the scope of the patent application, a method for spot measurement of surface-emitting laser crystal grains of a vertical resonator, wherein step b) is to continuously spot the grains at the specific position in the adjacent area. As described in item 1 of the scope of the patent application, a point measurement method for a surface resonator type laser grain of a vertical resonator, wherein the step c) is to continuously use the adjacent position in the sixth number of positions as the specific Step b) is repeated for each position. The method for spot measurement of surface-emitting laser crystal grains of a vertical resonator as described in item 1 or 5 of the patent application scope, wherein the step c) is to perform the steps in sequence for the fifth number (N) rows b), and the step b) is sequentially performed on the fourth number (M) of the positions in the same row after the step b) is sequentially performed. As described in item 1 or 5 of the patent application scope, a method for spot measurement of surface-emitting laser crystal grains in a vertical resonator, wherein the step c) is to sequentially perform the step for the fourth number (M) row b), and perform the step b) sequentially on the fifth number (N) of the positions in the same row, and then sequentially perform the step b) on the fifth number (N) of the positions in the next row. As described in item 1 of the scope of the patent application, the point measurement method for surface-emitting laser crystal grains of a vertical resonator, in which the working current of each crystal grain is less than or equal to 20 amperes.