KR100428945B1 - Semiconductor wafer sawing machine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer sawing apparatus, wherein a vacuum chuck in which a wafer having a plurality of scribe lines formed to be parallel to each other in a direction perpendicular to one direction and defining an area in which an element is formed is mounted and rotated along a θ axis. A first conveying means comprising: and moving the wafer along an X axis; Cutting means for sawing the wafer separately into chips as unit elements by using a blade to which the coolant is supplied while moving the wafer along the scribe line in one direction or the other direction; The monitoring means displayed on the monitor by imaging the wafer and the blades by initializing the wafer and removing the remaining coolant by spraying high pressure air to the cut portion of the wafer, and the cutting means and the monitoring means are mounted. A second transfer means for moving the blade along the Y axis to be aligned with the next scribe line in the one direction after the scribe line in the one direction is cut, and the second transfer means is fixed to one side and the blade And a third transfer means configured to move up and down along the Z axis to be in contact with or separated from the wafer. Therefore, if a defect occurs during sawing, the process is stopped after removing the defect and the process is progressed to improve the yield. Also, since the defect inspection can be simultaneously performed during the sawing process, a separate inspection process is not required after the sawing process. Will not.

Description

Semiconductor wafer sawing machine {Semiconductor wafer sawing machine}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer sawing apparatus, and more particularly, to a semiconductor wafer sawing apparatus capable of visually inspecting the state of a sawed portion of a wafer while performing a sawing process of separating the semiconductor wafer into individual chips. will be.

In the manufacture of a semiconductor device, a device consisting of an electrical circuit is formed on a wafer, and the wafer is separated into individual chips as unit devices. Then, the separated chips are mounted in a lead frame, wire bonding and molding, and the lead frame is cut and bent to complete packaging.

In the above, separating the wafer into individual chips, which are unit devices, is called a sawing or dicing process.

After the sawing process completes the manufacturing process of the device on the wafer, first, each chip in the wafer state is electrically inspected to sort out defective products. Then, the adhesive tape is adhered to the back surface where the elements of the wafer are not formed so that the chips are not dispersed during the sawing, and separated into individual chips.

In the above, chip separation is accomplished by using a semiconductor wafer sawing device to saw along a plurality of scribe lines rather than the chip region of the wafer. The plurality of scribe lines are formed in a matrix shape in which a plurality of parallel lines are parallel in one direction and a plurality of parallel lines in another direction perpendicular to the one direction.

In the semiconductor wafer sawing apparatus according to the prior art, a vacuum chuck is installed on a frame conveyed in the X-axis direction, and a wafer to be processed with an adhesive tape adhered to the back is mounted on the vacuum chuck.

Then, a disk-shaped blade coated with diamond is installed to saw the wafer by rotation. The blade is movable in the Y-axis and Z-axis directions. That is, when the blade is sawed, it descends along the Z axis to be in contact with the scribe line to be sawed of the wafer, and is also raised along the Z axis after the sawing. Then, while moving the wafer-mounted vacuum chuck in the X-axis direction, the blade is sawed along the scribe line in one direction, and then raised along the Z-axis to saw along the next parallel scribe line, then moved in the Y-axis direction. Let's do it.

Before sawing the wafer, the vacuum chuck must be aligned along the X and θ axes, and the blade finely moved along the Y axis to align the initial position. In the initial position alignment, the light source may be aligned with the camera by imaging the camera while irradiating light to the initial position of the wafer.

Then, the initially aligned wafer is sawed along a scribe line in one direction while moving the vacuum chuck on the X axis. After the wafer is sequentially sawed along a plurality of scribe lines in one direction, the vacuum chuck is rotated 90 ° along the θ axis to sequentially saw again along the plurality of non-sawed scribe lines in another direction to complete the sawing process.

In the sawing process, the blade rotates at a high speed of about tens of thousands of revolutions per minute (RPM), for example, 30,000 to 60,000 RPM, so that a lot of heat is generated to carbonize the coated diamond. In addition, silicon particles generated as the wafer is sawn are scattered and contaminate the equipment. Therefore, during sawing to separate the wafer into chips, cooling water is supplied through the cooling water supply nozzle to cool the blades to prevent carbonization of the diamond as well as to prevent the scattering of silicon particles generated by the sawing of the wafer.

However, in the semiconductor wafer sawing apparatus according to the prior art, the coolant supplied through the nozzle during the wafer sawing is left on the surface of the wafer so that the light irradiated from the light source is reflected and refracted by the water. Therefore, the focus of the camera does not focus on the wafer surface at the time of imaging, and therefore the state of the portion to be shot is not captured by the camera, so that inspection by the monitor cannot be performed. Thus, when a misalignment occurs when the sawing is not aligned, the defect cannot be solved, and the yield is lowered, and a separate process of inspecting the defect after the sawing has been required.

Accordingly, an object of the present invention is to provide a semiconductor wafer sawing apparatus capable of eliminating defects and improving yield even when defects occur during wafer sawing.

Another object of the present invention is to provide a semiconductor wafer sawing apparatus capable of simultaneously performing defect inspection during wafer sawing.

A semiconductor wafer sawing apparatus according to the present invention for achieving the above objects is a wafer having a plurality of scribe lines formed to be parallel to each other in the direction perpendicular to one direction to define the region in which the element is formed is mounted and rotated along the θ axis First conveying means including a vacuum chuck and moving said wafer along an X axis; Cutting means for sawing the wafer separately into chips as unit elements by using a blade to which the coolant is supplied while moving the wafer along the scribe line in one direction or the other direction; The monitoring means displayed on the monitor by imaging the wafer and the blades by initializing the wafer and removing the remaining coolant by spraying high pressure air to the cut portion of the wafer, and the cutting means and the monitoring means are mounted. A second transfer means for moving the blade along the Y axis to be aligned with the next scribe line in the one direction after the scribe line in the one direction is cut, and the second transfer means is fixed to one side and the blade And a third transfer means configured to move up and down along the Z axis to be in contact with or separated from the wafer.

The monitoring means preferably comprises a camera for imaging the wafer, an illuminator used as a light source of the camera, and an air nozzle for supplying high pressure air.

1 is a schematic perspective view of a semiconductor wafer sawing apparatus according to the present invention;

2 is an enlarged cross-sectional view of the cutting means shown in FIG.

3 is an enlarged cross-sectional view of the monitoring means shown in FIG.

4 is a cross-sectional view showing a sawing state using a semiconductor wafer sawing apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

11: wafer 13: vacuum chuck

15: first transfer means 17: first transfer table

19: first motor 21: first feed shaft

23: first guide rail 25: second conveying means

27: 2nd conveyance table 29: 2nd motor

31: second feed shaft 33: second guide rail

35: third transfer means 37: third transfer table

39: third motor 41: third feed shaft

43: fourth guide rail 45: cutting means

47: blade 49: coolant supply nozzle

51: imaging means 53: camera

55 lighting device 57 air nozzle

59: monitor

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic perspective view of a semiconductor wafer sawing apparatus, FIG. 2 is an enlarged cross-sectional view of the cutting means shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of the monitoring means shown in FIG.

The semiconductor wafer sawing apparatus according to the present invention includes first, second and third transfer means 15, 25, 35, cutting means 45 and monitoring means 51.

The first transfer means 15 is a vacuum chuck 13 on which a first transfer table 17 moving along an X axis, an adhesive tape (not shown) is adhered to the rear surface, and a wafer 11 to be sawed is mounted thereon, It consists of a 1st motor 19, the 1st feed shaft 21, and the 1st guide rail 23. As shown in FIG.

As the first transfer table 17 moves along the first transfer shaft 21 along the X axis, the vacuum chuck 13 on which the wafer 11 is mounted is also moved in the same manner. In addition, the vacuum chuck 13 is rotated 90 degrees to the left or right with respect to the X axis along the θ axis with respect to the first conveyance table 17.

In the above, the first feed shaft 21 is composed of a screw rod (long) extending in the X-axis direction is screwed with the lower portion of the first feed table 17, the first guide rail 23 is a first feed It extends in parallel with the shaft 21 therebetween and is axially coupled with the lower part of the 1st conveyance 17.

The first motor 19 rotates the first feed shaft 21, whereby the first feed table 17 slides along the first guide rail 23 and moves along the X axis.

The second conveying means 25 is composed of a second conveying table 27, a second motor 29, a second conveying shaft 31 and a second guide rail 33.

In the above, the second transfer table 27 is mounted with cutting means 45 for sawing the wafer 11 and imaging means 51 for picking up the wafer 11 to show the alignment state of the wafer 11.

The second feed shaft 31 is composed of a screw rod extending in the Y-axis direction and screwed with the lower portion of the second feed table 27, the second guide rail 33 between the second feed shaft 31 It extends in parallel to the axis and is coupled to the lower portion of the second carriage 27.

The second motor 29 rotates the second feed shaft 31, whereby the second feed table 27 is moved along the Y axis while sliding the second feed table 27 along the second guide rail 33. Therefore, the cutting means 45 and the imaging means 51 mounted on the second transfer table 27 are also moved along the Y axis.

The third transfer means 35 is composed of a third transfer table 37, a third motor 39, a third transfer shaft 41, and a third guide rail 43.

In the above, the third transfer table 37 is moved up and down along the Z axis so that the second transfer means 25 is fixed to one side.

The third feed shaft 41 is composed of a screw rod extending vertically in the Z-axis direction and is screwed with the other side of the third feed table 37, the third guide rail 43 is the third feed shaft 41 ) Extends in parallel with each other and is axially coupled to the other side of the third transfer table 37.

The third motor 39 rotates the third feed shaft 41, whereby the third feed table 37 is moved while sliding up and down along the Z axis along the third guide rail 43. Therefore, the second conveying means 25 fixedly installed on one side of the third conveying table 37 is also moved up and down along the Z axis, whereby the cutting means 45 mounted on the second conveying table 27. ) And the imaging means 51 are also moved up and down along the Z axis.

As shown in FIG. 2, the cutting means 45 includes a disk-shaped blade 47 coated with diamonds on its surface, and a plurality of cooling water supply nozzles 49 for supplying cooling water to the blade 47 when sawing the wafer 11. It is composed of In addition, the cutting means 45 further includes a rotating motor (not shown) for rotating the blade 47 when sawing the wafer 11.

As described above, the blade 47 saw the wafer 11 while rotating at a high speed of about 30,000 to 60,000 RPM (Revolutions Per Minute) by a rotating motor, whereby a lot of heat is generated to increase the temperature of the blade 47. do.

Therefore, the diamond coated on the surface of the blade 47 is carbonized and the hardness becomes low. Therefore, the heat generated in the blade 47 is cooled by the coolant supplied through the plurality of coolant supply nozzles 49 when the wafer 11 is sawed, thereby preventing the diamond coated on the surface from being carbonized. In addition, the cooling water prevents the scattering of the silicon particles generated when the wafer 11 is sawed. The plurality of cooling water supply nozzles 49 are installed to supply cooling water to both side surfaces of the blade 47 and to corners of the cutting portion.

The monitoring means 51 comprises a camera 53, an illuminator 55, an air nozzle 57 and a monitor 59 as shown in FIG. 3.

In the above, the camera 53 captures an alignment state and a sawing state of the wafer 11 mounted on the vacuum chuck 13, the illuminator 55 is used as a light source when the wafer 11 is captured, and the monitor 59 is a wafer. The picked-up part of (11) is enlarged and displayed on a screen so that the alignment state and the sawing state of the wafer 11 can be confirmed. In addition, the air nozzle 57 supplies high pressure air for removing the coolant on the portion to be sawn when sawing the wafer 11.

4 is a cross-sectional view showing a sawing state using a semiconductor wafer sawing apparatus according to the present invention.

In the above, the blade 47 is rotated at a high speed to saw the wafer 11 mounted on the vacuum chuck 13. At this time, the cooling water is supplied to the blade 47 through the plurality of cooling water supply nozzles 49 to prevent the diamond coated on the surface from being carbonized by heat. In addition, the cooling water prevents the scattering of the silicon particles generated when the wafer 11 is sawed.

In addition, when the wafer 11 is sawed, the high-pressure air is supplied to the portion to be sawed through the air nozzle 57 to remove the coolant remaining in the portion to be sawed, and the image is captured by the camera 55 and monitored through the monitor 59. . Since the coolant is not in the portion to be sawed of the wafer 11 in the above, the phenomenon that the camera is out of focus is prevented. Therefore, the situation in which the wafer 11 is sawed is clearly captured by the camera 53 and displayed on the screen by the monitor 59. Therefore, the sawing state can be confirmed when sawing the wafer 11.

The operation of the semiconductor wafer sawing apparatus of the above-described configuration will be described.

The wafer 11 is mounted on the vacuum chuck 13. Then, the initial position of the wafer 11 and the position of the blade 47 are captured by the camera 53 and monitored by the monitor 59. At this time, if the initial position of the wafer 11 and the position of the blade 47 are misaligned, the first carriage 17 and the vacuum chuck 15 are finely moved along the X axis and the θ axis, respectively. 2 Move the carriage 27 finely along the Y axis to align it.

The third carriage 37 is moved downward along the Z axis to bring the blade 47 into contact with the wafer 11. Then, the wafer 11 is sawed along the scribe line in one direction with the blade 47 while the first transfer table 17 is moved along the X axis. That is, the first feed shaft 21 is rotated by the driving of the first motor 19 to move the first feed table 17 along the first guide rail 23 while moving in the X-axis direction. A rotating motor (not shown) in the cutting means 47 is driven to rotate the blade 47 at a high speed of about 30,000 to 60,000 RPM to saw the wafer 11.

At this time, the cooling water is supplied to the blade 47 through the cooling water supply nozzle 57 to prevent the diamond coated on the surface from being carbonized by heat. In addition, the cooling water prevents the scattering of the silicon particles generated when the wafer 11 is sawed.

In addition, while supplying high-pressure air through the air nozzle 57 to the portion to be sawed when the wafer 11 is sawed, this portion is captured by the camera 53 and monitored through the monitor 59. At this time, the cooling water remaining in the portion to be sawed of the wafer 11 is moved to another portion by the high pressure air supplied through the air nozzle 57. Therefore, since the camera focuses because there is no cooling water in the portion to be sawed of the wafer 11, the image is captured clearly, thereby clearly displaying the situation in which the monitor 59 is sawed by the wafer 11.

Therefore, when a defect such as sawing a chip region other than a scribe line occurs when the wafer 11 is sawed, the process may be stopped and aligned, and the process may be performed again, thereby improving yield. In addition, since the defect inspection can be performed at the same time during the sawing process, there is no need for a separate inspection process after the sawing process.

After the wafer 11 is sawed along a scribe line in one direction, the third carrier 37 is moved upward along the Z axis to space the blade 47 from the wafer 11. Then, the second carriage 27 is moved along the Y axis so that the blade 47 coincides with the next scribe line of the wafer 11. Then, the third transfer table 37 is lowered along the Z axis to bring the blade 47 into contact with the wafer 11, and then sawing is continued.

As such, the wafer 11 is sequentially sawed along a scribe line in one direction, and the vacuum chuck 13 is rotated 90 ° along the θ axis to the left or the right about the X axis, and then the plurality of non-sawed holes in different directions are vertical. Saw again sequentially along the scribe line to complete the sawing process. That is, the third carriage 37 is moved upward along the Z axis to separate the blade 47 from the wafer 11, and then the vacuum chuck 13 is rotated 90 ° left or right with respect to the X axis along the θ axis. Then, the third transfer table 37 is lowered along the Z-axis to bring the blade 47 into contact with the wafer 11 and to perform sawing.

As described above, the semiconductor wafer sawing apparatus according to the present invention mounts a wafer on a vacuum chuck and aligns the initial position of the wafer and the position of the blade with a camera and monitors it through a monitor. Then, the blade is used for sawing the wafer, and the portion to be sawed of the wafer is cameraed while supplying cooling water to prevent carbonization caused by heat of diamond coated on the blade surface and scattering of silicon particles caused by wafer sawing. Is focused and sharply captured so that the monitor can clearly see the sawing state by supplying high-pressure air to move the remaining coolant to another part.

Therefore, the semiconductor wafer sawing apparatus according to the present invention can improve the yield by stopping the process and removing the defects when the failure occurs during the sawing process, and can also improve the yield during the sawing process at the same time, so after the sawing process The advantage is that no separate inspection process is required.

Claims (2)

A wafer having a plurality of scribe lines mounted to be parallel to each other in a direction perpendicular to one direction and defining a region in which an element is formed, and including a vacuum chuck which is rotated along the θ axis and moves the wafer along the X axis; Transfer means; Cutting means for sawing the wafer separately into chips as unit elements by using a blade to which the coolant is supplied while moving the wafer along the scribe line in one direction or the other direction; Monitoring means for imaging an initial alignment state of the wafer and the blade, and imaging the wafer while removing the remaining coolant by injecting a high-pressure air to the cut portion of the wafer and displaying it on a monitor; Second conveying means mounted with the cutting means and the monitoring means and moving the blade along the Y axis to coincide with the next scribe line in the one direction after the scribe line in the one direction of the wafer is cut; And a third transfer means fixed to one side of the second transfer means to move the blade up and down along the Z axis so as to contact or separate the blade. The semiconductor wafer sawing apparatus of claim 1, wherein the monitoring unit comprises a camera for photographing the wafer, an illuminator used as a light source of the camera, and an air nozzle for supplying the high pressure air.