CN104362111A - Silicon wafer edge breakage automatic detection method - Google Patents

Abstract

The invention relates to a silicon wafer edge breakage automatic detection method and belongs to the field of silicon wafer production. The method includes the steps that firstly, a silicon wafer is drawn out from a basket and horizontally placed on a moving conveyor belt, the conveyor belt drives to the silicon wafer to move until the silicon wafer is conveyed to a silicon wafer stopping position opposite to a camera, a conveying device stops, the camera is automatically focused, the focal distance is automatically adjusted, a picture is shot, a control unit calculates an RGBdiff numerical value of the side face of the whole silicon wafer according to the acquired picture, if the RGBdiff numerical value of a measurement unit exceeds a set threshold value, it is judged that edge breakage is likely to happen in the position, if the RGBdiff numerical value of the measurement unit does not exceed the set threshold value, it is judged that edge breakage is not likely to happen in the position, the control unit controls the conveying device to operate, and a detection system enters a next detection period. The detection system is high in work efficiency, a short pause exists in the working process, the camera is automatically focused, the picture with the high definition is obtained, and detection accuracy is greatly improved.

Description

A kind of silicon chip collapses the automatic testing method on limit

Technical field

The invention belongs to field of silicon chip production, particularly a kind of silicon chip collapses the automatic testing method on limit.

Background technology

Along with the fast development of semiconductor and photovoltaic industry, the quality requirement of equipment to silicon chip is more and more higher, and collapsing limit is then one of topmost mass defect of silicon chip.

Traditional limit detection method that collapses adopts artificial naked eyes recognition detection, the go-on-go collapsing limit is also existed to the judgement of perception.Due to the quantity of silicon chip product very huge (quantity can reach hundreds thousand of/days) in actual production, to carry out manual measurement sorting to each silicon chip, then the labour intensity brought is excessive, and operating cost also can be too high.

Engendered Automatic Measurement Technique afterwards, principle is use fixed-focus camera to take pictures to the silicon chip being in travel position, and carries out primaries value RGB and analyze.

The problem brought like this is, in conventional detection system, use belt conveyance silicon chip, the silicon chip instability be in dynamic environment has tiny vibrations, rocks, and causes image blur when finding a view;

Fixed-focus camera is used to take pictures to the silicon chip being in travel position, focusing image camera requires very harsh to image position, focal length and physical location etc., the tiny mechanical shock of detection system also can aggravate image blur, and the rotation of silicon chip also can cause local tomography distortion, causes flase drop.

Summary of the invention

The technical problem solved

In order to solve in existing silicon chip detection method, easy flase drop, undetected and propose a kind of method that automatic detection silicon chip collapses limit, to realize detection system high accuracy, closed-loop system high-intelligentization.

For to solve the problem and the technical scheme provided is:

A kind of automatic detection silicon chip collapses the method on limit, it is characterized in that: realize by means of silicon chip transportation and detection apparatus, described silicon wafer conveying device comprises conveyer belt, drive motors, transducer, autozoom camera and computer control system for driving conveyer belt to operate, autozoom camera is provided with above the side of the output of conveyer belt, be provided with the transducer passed through for detecting silicon chip at the picture-taking position place of autozoom camera, described drive motors, transducer, autozoom camera are all connected with computer control system; Specifically comprise the following steps:

Step one: silicon wafer horizontal to be detected is placed on the conveyer belt be kept in motion, conveyer belt drives silicon chip to move, and when silicon chip is by sensing station, the silicon chip detected is sent to computer control system by information by transducer; (object of this step one is, secondary damage when level is taken out to avoid silicon chip extracting also ensures that detection system can efficiently work, and silicon chip is delivered to the precise degrees that fixed position ensures detection, and unconventional " sweep and cross ")

Step 2: computer control system controls drive motors and stops operating and photographing instruction is sent to autozoom camera, autozoom camera automatic focus adjustable is also taken pictures, (this step 2 object is afterwards photo to be sent to computer control system, hold transport ring, open lower ring, automatic focusing camera automatic focus adjustable aims at silicon chip side to ensure under static state, accessed silicon chip image can have resolution large as far as possible, ensure that follow-up accurate calculation)

Step 3: computer control system controls drive motors on the one hand and restarts, and taking a picture to autozoom camera on the other hand calculates and detect:

Go out the Red Green Blue value RGB of whole silicon chip side according to the photo detection computations obtained, and be designated as average RGBavg; Again silicon chip side is divided into several measuring units, and the rgb value of each detecting unit of detection computations, and be designated as RGBs; The misalignment rate value of each detecting unit is;

$\mathrm{RGBdiff}=\frac{\left(\right|\mathrm{RGBs}-\mathrm{RGBavg}\left|\right)}{\mathrm{RGBavg}}\×100$

Wherein, RGBdiff is the misalignment rate value of each detecting unit;

(this step 3 object is, try to achieve the deviate of each unit color value and average and try to achieve several deviation ratio magnitude, the position deviation value that more can be tending towards damage trend is thus larger, be tending towards full location deviate less, there are some unit can obtain thus collapsing position, limit owing to dividing, if coordinate corresponding instrument also directly can measure the degree of crumbling)

Step 4: the misalignment rate of each detecting unit step 3 obtained and the silicon chip misalignment rate value of setting compare one by one, if there is the misalignment rate value of some detecting units to be greater than the silicon chip misalignment rate value of setting, then thinks that this silicon chip to be detected exists and collapse limit; Otherwise this silicon chip to be detected does not exist and collapses limit;

Complete the automatic detection that silicon chip collapses limit.

(this step 4 object is, coordinate outside corresponding warning facility to warn the existence of this block silicon chip and collapse limit possibility, to carry out sorting or other process, computer survey calculation conclusion numerical value is several milliseconds can enters next sense cycle at once, and high-efficiency operation improves the detection efficiency of detection system)

Compared with prior art, acquired beneficial effect is in the present invention:

(1) transducer fixing duration different from the past stops dynamic formula equipment, the discrimination capabilities of transducer is accurate, sense that silicon chip arrives at signal back computer control system, it is all just right with automatic focusing camera that silicon wafer conveying device stops each silicon chip position of rest, inactive state ensures to find a view validity, improves accuracy of detection.

(2) conveyer belt continuative transport different from the past, the streamline that camera is taken pictures continuously is galloped along on horseback and is seen lamp-based detection mode, because automatic focusing camera focusing needs necessarily not often, but the photo of shooting is relative to solid burnt formula camera, advantage is clear for finding a view, the distortion factor is little, improves accuracy of detection further.

(3) above-mentioned automatic focusing camera, transducer, silicon wafer conveying device and the computer control system mentioned forms a closed loop detect system; and unconventional open loop checkout gear; transducer detects in long-time and to arrive at without silicon chip; whole system meeting autostop; could open after ensureing safety by testing staff's detection failure, therefore coefficient of safety is higher.

(4) after using this checkout gear, tristimulus values RGB detection method resolution is higher, the phenomenon of photo None-identified before there will not be, more there will not be flase drop, detection leakage phenomenon, if it is undetected to make field silicon chip at high precision silicon slice, after silicon chip inferior is applied to electronic instrument and equipment or large-sized solar panel devices, once break down, whole electronic instrument can be caused to paralyse, if generation catastrophe failure also can be exploded, bring out fire can cause hardly imaginable serious consequence, therefore making field at high precision silicon slice, Si wafer quality is the most important thing.

Accompanying drawing explanation

Fig. 1 is conveying arrangement structural representation

Fig. 2 is RGBdiff bit map/bitmap

There is the silicon chip side view collapsing limit defect in Fig. 3

Embodiment

Described conveying arrangement comprise transducer 1, autozoom camera 2, with computer control system 3.

Below, the present invention will be further described for composition graphs 1 to Fig. 3 and specific embodiment.

A kind of automatic detection silicon chip collapses the method on limit, realize by means of silicon chip transportation and detection apparatus, described silicon chip transportation and detection apparatus comprises conveyer belt, the drive motors operated for driving conveyer belt, transducer 1, autozoom camera and computer control system 3, autozoom camera is provided with above the side of the output of conveyer belt, autozoom camera can carry out auto-focusing, the transducer 1 passed through for detecting silicon chip is provided with at the picture-taking position place of autozoom camera, described drive motors, transducer 1, autozoom camera 2 is all connected with computer control system 3,

Described autozoom camera 2 also can carry out the angle change of 10-60 degree.

Specifically comprise the following steps:

Step one: silicon wafer horizontal to be detected is placed on the conveyer belt be kept in motion, conveyer belt drives silicon chip to move, and when silicon chip is by transducer 1 position, the silicon chip detected is arrived at information and is sent to computer control system 3 by transducer 1;

Described drive motors is connected with conveyer belt, when silicon chip to be detected is extracted out from the gaily decorated basket and level is placed on conveyer belt, computer control system 3 controls drive motors and rotates, conveyer belt carries silicon chip and moves, when silicon chip arrives transducer 1 present position just, transducer 1 senses that silicon chip arrives at, and will arrive at information feed back and return computer control system 3.

Step 2: computer control system controls drive motors and stops operating and photographing instruction is sent to autozoom camera, and autozoom camera automatic focus adjustable is also taken pictures, and afterwards photo is sent to computer control system;

Photographing instruction is sent to autozoom camera 2 by computer control system 3, autozoom camera 2 automatic focus adjustable, the timer countdown that simultaneous computer control system 3 comprises 1 second, while timer timing in 1 second is complete, automatic focusing camera 2 has been taken pictures, and returns photo feedback to computer control system 3.

Step 3: computer control system 3 one aspect controls drive motors and restarts, taking a picture to autozoom camera on the other hand calculates and detects:

Go out the Red Green Blue value RGB of whole silicon chip side according to the photo detection computations obtained, and be designated as average RGBavg; Again silicon chip side is divided into several measuring units, and the rgb value of each detecting unit of detection computations, and be designated as RGBs; The misalignment rate value of each detecting unit is;

$\mathrm{RGBdiff}=\frac{\left(\right|\mathrm{RGBs}-\mathrm{RGBavg}\left|\right)}{\mathrm{RGBavg}}\×100$

Wherein, RGBdiff is the misalignment rate value of each detecting unit;

Computer control system 3 controls drive motors and starts, and simultaneous computer is detected silicon chip by the computational methods of above-mentioned RGBdiff, and electric motor starting has detected simultaneously just.

Step 4: the misalignment rate of each detecting unit step 3 obtained and the silicon chip misalignment rate value of setting compare one by one, if there is the misalignment rate value of some detecting units to be greater than the silicon chip misalignment rate value of setting, then thinks that this silicon chip to be detected exists and collapse limit; Otherwise this silicon chip to be detected does not exist and collapses limit;

External staff inputs certain numerical value as reservation threshold, RGBs and RGBavg compares by computer, if this measuring unit misalignment ratio has exceeded setting threshold, then judge that there is the possibility existing and collapse limit this position, this measuring unit misalignment ratio is without exceeding setting threshold, then judge that the possibility collapsing limit is got rid of in this position, next sense cycle is entered after judgement, prepare to detect next silicon chip, by corresponding outside alarming device, testing result is fed back to external environment condition after judging simultaneously, manipulation personnel obtain warning doing respective record and obtaining to be judged as to be existed the silicon chip collapsing limit and carries out respective handling,

Described transducer 1 also can be arranged in the middle part of conveyer belt, when transducer 1 is arranged in the middle part of conveyer belt, silicon chip is transferred in way and is namely detected, silicon chip is understood computer control system 3 by signal feedback by transducer 1, computer control system 3 controls timer 0.5 second reciprocal, namely on a timeline with 0.5 second for spacing arranges multiple silicon chip position of rest, the complete control unit of 0.5 reciprocal sec controls silicon chip transportation and detection apparatus to be stopped, now silicon chip is in silicon chip position of rest just, then performs above-mentioned steps two, three, four step successively.

Composition graphs 2,3 is described, and wherein the concrete numerical value of Fig. 2 is as shown in the table:

Meas-unit	RGB-avg	RGB-diff	RGB-s
				1～7	182.25	2％	185
8	182.25	27％	185
				9	182.25	33％	232
10	182.25	29％	242
				11	182.25	20％	236
12	182.25	15％	220
				13	182.25	9％	210

14	182.25	15％	200
				15	182.25	1％	210

By showing in above-mentioned table that a little 1 ~ 7RGBdiff (misalignment ratio) value is less, then represent with everywhere that rgb value is equal herein, get rid of the possibility existing and collapse limit herein, 8-14 point position RGBdiff (misalignment ratio) value is larger, there are several unit to there is shade in corresponding diagram 3, then represent the possibility existing and collapse limit herein.

Claims (1)

1. one kind is detected the method that silicon chip collapses limit automatically, it is characterized in that: this method realizes by means of silicon chip transportation and detection apparatus, described silicon wafer conveying device comprises conveyer belt, drive motors, transducer, autozoom camera and computer control system for driving conveyer belt to operate, autozoom camera is provided with above the side of the output of conveyer belt, the picture-taking position place of autozoom camera is provided with the transducer for detecting silicon chip, and described drive motors, transducer, autozoom camera are all connected with computer control system; Specifically comprise the following steps:

Step one: silicon wafer horizontal to be detected is placed on the conveyer belt be kept in motion, conveyer belt drives silicon chip to move, and when silicon chip is by sensing station, the silicon chip detected is arrived at information and is sent to computer control system by transducer;

Step 2: computer control system controls drive motors and stops operating and photographing instruction is sent to autozoom camera, and autozoom camera automatic focus adjustable is also taken pictures, and afterwards photo is sent to computer control system;

Step 3: computer control system controls drive motors on the one hand and restarts, and taking a picture to autozoom camera on the other hand calculates and detect:

Go out the tristimulus values RGB of whole silicon chip side according to the photo detection computations obtained, and be designated as average RGBavg; Again silicon chip side is divided into several measuring units, and the rgb value of each detecting unit of detection computations, and be designated as RGBs; The misalignment rate value of each detecting unit is;

$\mathrm{RGBdiff}=\frac{\left(\right|\mathrm{RGBs}-\mathrm{RGBavg}\left|\right)}{\mathrm{RGBavg}}\×100$

Wherein, RGBdiff is the misalignment rate value of each detecting unit;

Step 4: the misalignment rate of each detecting unit step 3 obtained and the silicon chip misalignment rate value of setting compare one by one, if there is the misalignment rate value of some detecting units to be greater than the silicon chip misalignment rate value of setting, then thinks that this silicon chip to be detected exists and collapse limit; Otherwise this silicon chip to be detected does not exist and collapses limit;

Complete the automatic detection that silicon chip collapses limit.