KR100493990B1 - Identification equipment of semiconductor wafer and method - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

Identifier stamping device for semiconductor wafer and its stamping method

2. The technical problem to be solved by the invention

To make the depth of the identifier constant after the mirror finish of the sliced wafer

3. Summary of Solution to Invention

The table 5 for supporting and moving the semiconductor wafer 2a, the thickness measuring device 3 for measuring the thickness of the semiconductor wafer 2a, and the semiconductor wafer 2a using laser light to imprint an identifier An identifier stamping device to a semiconductor wafer 2a having a laser head 4 and a control device 7 for controlling the stamping by the laser head 4 in accordance with the value measured by the thickness gauge 3 ( 10).

4. Important uses of the invention

Used for quality control of semiconductor wafers in device process.

Description

Identifier stamping device for semiconductor wafer and its stamping method

The present invention provides a laser on the surface of a wafer in a semiconductor wafer manufacturing process for quality control of the semiconductor wafer in a device process (a process subsequent to a semiconductor wafer manufacturing process, for example, a pattern printing process, a chip bonding process, and the like). A marking apparatus for a semiconductor wafer identifier for marking an identifier with light and a marking method thereof.

Generally, a semiconductor wafer is manufactured by the following process.

① After cutting the ingot to obtain a sliced wafer, it is cleaned.

(2) After lapping the slice wafer, it is cleaned.

(3) After etching the wrapped wafer, it is cleaned.

(4) Mirror and etch the etched wafer.

⑤ Dry the cleaned wafers.

Further, a step of imprinting an identifier consisting of a character, a barcode or the like for identifying the type of semiconductor wafer using a laser beam on the wafer surface, and a step of inspecting the imprinted identifier may be appropriately added. This is to read the engraved identifier in the device process and to confirm the semiconductor wafer suitable for each device process.

By the way, in order to ensure reading in a device process, this identifier must satisfy | fill the specification of the depth of 70 +/- 20micrometer, for example, and must make constant the depth in finishing of a semiconductor wafer manufacturing process. Therefore, if the imprinting of this identifier is performed after the mirror surface polishing process, since the stamping cause causes particle generation, it is preferable to carry out before etching or lapping.

By the way, when this identifier is imprinted on the wrapped wafer, the defect which may be stained by the imprinting edge which generate | occur | produces by the imprinting of an identifier may arise with the etching liquid used for the subsequent etching. In addition, if the identifier is engraved before the lapping process with a large cutting value, it is difficult to make the depth of the identifier constant at the finish of the mirror polishing, not only to comply with the standard required by the device process, but also the identifier itself disappears. Make.

As a method for resolving such defects, slice wafers are classified into a plurality of groups according to the thickness measurement values of the centers of slice wafers conventionally measured for the purpose of making the thickness after wrapping constant. There is an engraving of the identifier to a depth in consideration of the cutting value. According to this method, the stamping column generated by the stamping of the identifier is removed by washing after lapping, so that staining does not occur in etching.

On the other hand, the inspection of the imprinted identifier is also important for ensuring that the identifier can be read in the device process. Therefore, the detection of a defect such as the positional shift, the skewness, the bending of the character, etc. of the imprinted identifier is performed by the operator, after imprinting the identifier by the imprinter, for example, the worker extracts the wafer and extracts the imprinted portion of the identifier in the extracted wafer. The monitor is magnified and the characters and barcodes of the identifier are examined by the operator's eyes.

First, in the conventional stamping process, even if the slice wafers are classified according to their thickness, the number of classification groups is limited, and even if the slice wafers classified in the same group have a large thickness imbalance, they satisfy the specifications required by the device process. There is a problem that an identifier cannot be imprinted. In addition, since the sorting step must be provided at all the steps of the stamping step, the wafers sliced in slices cannot be processed in addition to increasing the sorting step, which is inefficient.

On the other hand, in the inspection step of the identifier, as the inspection for identifying the image displayed on the monitor with the operator's eyes after the identifier is imprinted, the inspection error of the operator occurs, and it is difficult to carry out an accurate inspection. In addition, for the reason of the production efficiency, since the extraction frequency can be performed only about one sheet per 100 sheets of semiconductor wafers, there is a problem that it is difficult to inspect all the manufactured semiconductor wafers by this method.

According to the present invention, the depth of the identifier after the mirror finish is made constant so that the identification of the identifier in the device process can be reliably read and the stamping process is efficiently performed on the wafers sliced in the sliced order. This can be done. An object of the present invention is to provide a device for imprinting an identifier on a semiconductor wafer and a method of stamping the same.

In addition, the present invention makes it possible to easily inspect the identifiers imprinted on the semiconductor wafer, and moreover, all the identifiers, thereby preventing the imprinted semiconductor wafer of the defective identifiers from being distributed to the market. As a result, an object of the present invention is to ensure reading of an identifier in a device process, and to provide an identifier marking device and a method of marking the same on a semiconductor wafer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is an enlarged side cross-sectional view of a semiconductor wafer manufactured by Example 1 of the present invention, and FIG. 2 is a schematic diagram showing a stamping apparatus of Example 1 of the present invention.

The stamping step in the present embodiment is provided after the step of cutting the ingot corresponding to 1 to obtain a slice wafer as the manufacturing step of the semiconductor wafer already described in the prior art.

First, the marking device will be described with reference to FIG. As shown in FIG. 2 (a), the engraving device 10 includes a turntable 5 for holding the bottom surface of the sliced wafer 2 and rotating it in a horizontal direction. A reflective thickness meter 3 for measuring thickness, for example, and a laser head 4 which stamps an identifier on the slice wafer 2 by laser light. In addition, it is preferable that the thickness measuring device 3 measures the thickness of the marking (predetermined) position of the identifier in the sliced wafer 2 or the position close to the marking position. In this embodiment, the thickness of an arbitrary point of the circumferential edge of the sliced wafer 2 held on the turntable 5 can be measured. In addition, the value measured by the thickness measuring device 3 can be output to the control device 7, so that the control device 7 receives the laser head from the laser oscillator 6 in accordance with the measurement signal output from the thickness measuring device 3. The number of pulses of the laser beam irradiated toward the sliced wafer 2 is controlled by interposing (4) therebetween to control the engraving depth.

The stamping operation by this stamping apparatus 10 is performed as follows. First, the sliced wafer 2 cut out from the ingot is placed on the turntable 5 and held, and then the turntable 5 is rotated so that the stamping position 11 is below the thickness gauge 3. Here, the thickness measuring device 3 measures the thickness of the stamping position 11 in the slice wafer 2 and outputs a measurement signal to the control device 7.

Next, as shown in FIG. 2 (b), the turntable 5 is rotated such that the marking position 11 of the sliced wafer 2 is positioned under the laser head 4 of the marking apparatus 10. From the laser head 4, laser light is irradiated toward the engraving position of the slice wafer 2 rather than the laser oscillator 6, and is imprinted. At this time, the control apparatus 7 controls the pulse number of the laser beam irradiated through the laser head 4 as follows based on the measurement signal from the thickness measuring device 3.

As shown in FIG. 1 (a), when the value measured by the thickness measuring device 3 is set to the thickness T1 of the stamping position 11, the thickness T2 after the mirror surface finish is known in advance and until the mirror surface finish is obtained. The cutting value T3 of is calculated. In addition, the stamping depth D1 has already been input to the control device 7 after finishing to the standard required by the device process, and the cutting value is added to the identifier 1 to be imprinted on the sliced wafer 2. The machining engraving depth D2 can be obtained. By the way, the correspondence relationship between the pulse number of the laser beam to irradiate and the depth of processing engraving can be calculated | required previously by experiment etc. Therefore, in the control apparatus 7, the laser oscillator 6 is controlled by selecting the pulse number of the laser beam corresponding to this depth D2 from the predetermined correspondence based on the depth D2 which was calculated | required as mentioned above.

In this way, the sliced wafer 2 in which the identifier 1 is engraved is processed after that until the mirror surface finish is processed, as shown in FIG. 1 (b), and the cutting value T3 becomes It becomes the removed semiconductor wafer 2a, and the stamped depth D1 of the identifier 1 is always a fixed value.

According to this embodiment, the depth of the identifier 1 after mirror finishing can be made constant, and thereby, the identifier 1 can be reliably read in the device process.

In addition, since the engraving work can be performed on the slice wafers 2 in the sliced order, there is no need to provide a whole process for classifying each thickness as in the prior art, and the process can be shortened, thereby increasing the work efficiency. It can also be processed and shipped in the sliced order.

Next, Example 2 of the present invention will be described.

3 is a schematic block diagram showing a marking device according to a second embodiment of the present invention, and FIG. 4 is a flowchart showing a marking method according to the second embodiment of the present invention.

In addition, the stamping process in this embodiment is also provided with the position following the process of cut | disconnecting the ingot corresponding to (1) and obtaining a slice wafer as a manufacturing process of the semiconductor wafer demonstrated by the prior art like Example 1.

First, the marking device of this embodiment will be described.

As shown in FIG. 3, the marking device 20 holds the bottom surface of the sliced slice wafer 21 and inscribes an identifier to the turntable 22 rotating in the horizontal direction and the slice wafer 21. A marking device body 24 to which a laser head 23 is connected, and a reading device body 26 to which a reading camera 25 for reading a stamped identifier is connected, and a marking device body 24 and a reading device. The main body 26 is connected and comprised by the information processing apparatus 27 which comprises a control apparatus.

The imprinting information of the identifier to be imprinted by the keyboard 24a, the mouse (not shown), etc. is input to the imprinting device main body 24, and the inputted imprinting information can be confirmed on the screen 24b. It is also sent to the information processing apparatus 27. The laser head 23 connected to the marking device main body 24 is disposed above the laser head 23 so as to face the marking position of the slice wafer 21. In addition, the read-out camera 25 is also disposed thereon so as to face the sliced wafer 21, and when the identifier imprinted on the sliced wafer 21 as described below is located thereunder, the identifier thereof The image of will be input. The image of the identifier input by the reading camera 25 is input to the reading device main body 26. The image input by the reading camera 25 is projected onto the screen 26a of the reading device main body 26, and is image-processed by the reading device main body 26 to read the identifier. The read information is sent to the information processing apparatus 27.

The marking operation by this marking apparatus 20 is performed by the procedure which followed the flow shown in FIG.

(1) The thickness of the slice wafer is measured and the thickness information is input to the marking device main body 24 (S1). In addition, this thickness is good also if it installs the thickness measuring device 3 demonstrated in Example 1 also in FIG. 3, and may measure it automatically, and you may input separately by measuring separately.

(2) Input engraving information such as a character or a barcode which is an identifier to be imprinted into the marking device main body 24 (S2).

(3) In the marking device main body 24, the marking depth is determined according to the shape (size or position) of the identifier based on the input thickness information and the marking information of the identifier (S3). This rotates the turntable 22, opposes the engraving position of the sliced wafer 21 held on the turntable 22 to the laser head 23, and slices the laser beam from the laser head 23 in this state. The identifier is imprinted upon irradiation with the completed wafer 21.

(4) The imprinted identifier is read by the reading device main body 26 (S4). This rotates the turntable 22 to position the carved identifier of the slice wafer 21 held on the turntable 22 under the reading camera 25. The image input by the reading camera 25 is displayed on the screen 26a, and is image-processed by the reading device main body 26 to read the identifier, and the read information is sent to the information processing device 27. Lose.

(5) The information read from the reading device main body 26 and the marking information from the marking device main body 24 are collated with the information processing apparatus 27 (S5).

(6) In the information processing apparatus 27, if the matching result is within a predetermined allowable value, the lapping process transfer instruction is sent (S6), and at the same time, the error is obtained and the error information for imprinting correction is input to the imprinting apparatus main body 24. (S7). This error information is used, for example, for correction of laser intensity or the like that can be placed during the stamping operation on the next sliced wafer 21.

(7) When the collation result is outside the predetermined allowable value, the transfer to the wrapping process is stopped (S8) and the stamping operation is stopped (S9).

As described above, according to the second embodiment, the identifier stamped on the wafer 21 sliced by laser irradiation is given a position at a position opposite to the reading camera 25 in the subsequent rotation of the turntable 22. When the read information based on the image information received by the reading camera 25 is compared with the imprinting information, the inspection of the imprinted identifier, that is, the good or the bad, is determined. For this reason, the inspection of the imprinted identifier can be performed correctly, without going through an operator's hand. In addition, since the identifier is inspected every time it is carved by the laser beam, all of the identifiers can be easily inspected. In short, according to the present embodiment, it is possible to prevent the semiconductor wafer imprinted with the defective identifier from being distributed to the market and, as a result, to ensure the reading of the identifier in the device process.

In this embodiment, the stamping process and the inspection process of the identifier are performed on the sliced wafer before the lapping process. This means that if a defect is found in the inspection process, for example, after the etching process or after the end of the final manufacturing process, if the cause of the defect is on the side of the stamping device of the identifier, a large quantity of defective products will be produced. Or there is a problem that the time and cost to the end of the final manufacturing process is wasted. In this embodiment, however, the inspection is performed almost simultaneously with the stamping. When the defect is detected further, the lapping process transfer is stopped and the stamping operation is stopped. Therefore, the occurrence of defective products can be extremely prevented.

In Example 2, the stamping step and the inspection step were performed following the step of cutting the ingot to obtain the slice wafer, thereby achieving the effect of extremely preventing the occurrence of defective products. As for the effect that the identifier can be inspected precisely, and all the identifiers can be easily examined, this effect can be obtained even if the inspection process is between different processes.

Further, in the above two embodiments, the tables 5 and 22 are rotated in the horizontal plane, but, for example, are rotated in the vertical plane, so that the thickness measurement, engraving, and identifier of the wafers arranged vertically. Image congestion may be performed. In addition, it may be parallel movement instead of rotation.

In the present invention, since the depth of the identifier after the mirror finish can be made constant, it is possible to ensure reading of the identifier in the device process, and also to stamp the wafer sliced efficiently in the slice order. Work can be done.

In addition, according to the present invention, since the identifiers imprinted on the semiconductor wafer can be inspected accurately and moreover, all the identifiers can be easily inspected, thereby preventing the imprinted semiconductor wafer of the defective identifiers from being distributed to the market, and consequently, Reading of the identifier in the device process can be assured.

1 is an enlarged side cross-sectional view of a semiconductor wafer manufactured in Example 1 of the present invention.

2 is a schematic diagram showing a stamping device of Embodiment 1 of the present invention.

3 is a schematic block diagram showing a marking device according to a second embodiment of the present invention.

4 is a flowchart showing a stamping method according to the second embodiment of the present invention.

`` Explanation of symbols for main parts of drawings ''

1: identifier 2: sliced wafer

2a: semiconductor wafer 3: thickness meter

4 laser head 5 turntable

6 laser oscillator 7 control device

10: stamping device 11: stamping position

20: engraving device 21: slice wafer

22 turntable 23 laser head

24: imprinting device body 24a: keyboard

24b: screen 25: camera

26: reading device 26a: screen

27: information processing device D1: depth stamping finish

D2: engraving depth T1: thickness

T2: Finishing thickness T3: Mounting

Claims (14)

A table for supporting and moving the semiconductor wafer; A thickness meter for measuring the thickness of the semiconductor wafer; A laser oscillator for irradiating laser light onto the semiconductor wafer; A laser head for imprinting an identifier on the semiconductor wafer using laser light; It has a control device for controlling the stamping by the laser head based on the value measured by the thickness meter, And the semiconductor wafer is sequentially positioned at the thickness measurement position by a thickness gauge and the marking position by the laser head by the movement control of the table. 2. The apparatus of claim 1, wherein the thickness meter measures the thickness of the periphery of the semiconductor wafer. 2. The apparatus of claim 1, wherein the thickness measuring device measures the thickness of the stamping position in the semiconductor wafer or a position near the stamping position. 2. The apparatus of claim 1, wherein the control device controls the number of pulses of the irradiated laser light from the laser head based on the value measured by the thickness measuring device. A table for supporting and moving the semiconductor wafer; A marking device main body into which the marking information of the identifier is input; A laser head for imprinting an identifier on the semiconductor wafer using laser light; A camera for inputting an image of an identifier imprinted on the semiconductor wafer by the laser head; A reading device which processes an image input by the camera and reads out the identifier engraved on the semiconductor wafer, and And a control device which checks the read information of the identifier by the reading device and the marking information, and controls the marking by the laser head based on a matching result. The device of claim 1, wherein the table is a rotating table rotating in a horizontal plane. 6. The apparatus of claim 5, wherein the controller checks the shape of the identifier. In the method of stamping an identifier of a semiconductor wafer, which stamps the identifier using a laser beam on the semiconductor wafer, Measuring the thickness of the semiconductor wafer; A process for obtaining the required processing depth of the identifier in consideration of the measured thickness of the semiconductor wafer, a predetermined engraving depth, and the thickness of the semiconductor wafer after the thickness measuring process of the semiconductor wafer, up to the final manufacturing process; and And imprinting the identifier having the processing depth obtained in the step onto the semiconductor wafer using a laser beam. In the method of stamping an identifier of a semiconductor wafer, which stamps the identifier using a laser beam on the semiconductor wafer, Stamping the identifier on the semiconductor wafer using laser light; Inputting an image of the imprinted identifier into the camera, and reading out the imprinted identifier from the input image; and And a step of controlling the stamping by the laser light on the basis of the matching result by matching the read-out information with preset stamping information. In the method of stamping an identifier of a semiconductor wafer, which stamps the identifier using a laser beam on the semiconductor wafer, Measuring the thickness of the semiconductor wafer; Obtaining a processing depth requiring an identifier using the measured thickness of the semiconductor wafer and preset stamping information; Stamping an identifier having a calculated processing depth on the semiconductor wafer using a laser beam, Inputting an image of the imprinted identifier into the camera, and reading out the imprinted identifier from the input image; and And a step of controlling the stamping by the laser light on the basis of the matching result by matching the read-out information with the marking information. The method according to claim 9 or 10, wherein the identification of the identifier is carried out with respect to the shape of the identifier. A table for supporting and moving the semiconductor wafer; A thickness meter for measuring the thickness of the semiconductor wafer; A laser head for imprinting an identifier on the semiconductor wafer using laser light; An identifier stamping apparatus for a semiconductor wafer having a control device for controlling the marking by the laser head based on a value measured by the thickness measuring device, And the thickness measuring device measures the thickness of the periphery of the semiconductor wafer. 13. The apparatus of claim 12, wherein the thickness measuring device measures the thickness of the stamping position on or near the stamping position on the semiconductor wafer. The device of claim 12, wherein the controller controls the number of pulses of the irradiated laser light from the laser head based on the value measured by the thickness measuring device.

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