JP2013045885A - Semiconductor wafer manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor wafer manufacturing method which enables transferring of a semiconductor wafer having been subject to patterning to a next process after grinding a rear face side of the semiconductor wafer with preventing warp and breakage of the semiconductor wafer.SOLUTION: A semiconductor wafer manufacturing method comprises: attaching a pattern surface on a surface side of a semiconductor wafer 1 having been subject to patterning to a carrier plate 2; grinding a rear face 1b side of the semiconductor wafer 1 to a thickness of 50-120 μm; subsequently vacuum suctioning the rear face 1b side to detach the semiconductor wafer 1 from the carrier plate 2; attaching a surface protection sheet 6 to the pattern surface on the surface 1a side; subsequently, releasing vacuum suction on the rear face 1b side to invert the semiconductor wafer 1; and attaching a rear face protection sheet 7 to the rear face 1b side.

Description

  The present invention relates to a method for manufacturing a semiconductor wafer used for an LED or the like.

  In recent years, with the power saving, LEDs are frequently used for backlights of liquid crystal displays for liquid crystal televisions and personal computers. Further, from the viewpoint of energy saving and power saving, LEDs have been used in general lighting. For this reason, demand for LEDs is expected more and more in the future, which is one of the growing industries.

  By the way, many single crystal sapphire substrates are used for this semiconductor wafer for LED. Conventionally, this single crystal sapphire has been used only for some applications that take advantage of properties such as mechanical and thermal characteristics, chemical reaction characteristics, and light transmittance. This is because single crystal sapphire itself is expensive, and there are few applications that are used in large quantities, so technology that satisfies productivity and crystal quality has not been developed, and there has been no dramatic spread. is there.

  However, this single crystal sapphire has become inexpensive and can be stably mass-produced with recent technological advances, and has come to be widely used as an industrial material. Among them, in particular, it has been used in large quantities as a substrate for growing GaN (gallium nitride) for manufacturing blue and white LEDs and as a polarizer holding substrate essential for improving the brightness of liquid crystal projectors. It can be said that it has spurred the establishment of mass production technology.

  In this method of manufacturing a sapphire wafer using single crystal sapphire, first, a photoresist pattern is masked on a sapphire substrate to form a dot pattern called PSS having a size of about 3 μm. Then, a compound semiconductor is deposited by MOCVD, a transparent conductive film is attached to the top, a part is etched into a mesa shape, an electrode is attached, a protective sheet is attached to the surface, and then dicing with leather, Package.

  Note that the compound semiconductor is manufactured by combining two or more elements, and by changing the combination, many types of semiconductors can be manufactured. Examples of the compound semiconductor include gallium arsenide (GaAs) having a high electron mobility and gallium nitride (GaN) having a large band gap.

  In the manufacture of the sapphire wafer, the thickness dimension of the grinding finish of the semiconductor wafer has been reduced with the miniaturization of the mounting package. Therefore, as shown in FIG. 2, the patterned surface on the front surface 10a side of the patterned semiconductor wafer 10 is attached to the carrier plate 20, and the back surface 10b side of the semiconductor wafer 10 is ground to a predetermined thickness by the grinding means 90. After grinding to the dimensions, the carrier plate 20 was placed on the hot plate 80, the adhesive was melted by heat at 110 ° C., and the worker removed the semiconductor wafer 10 from the hot plate 80 by hand.

  However, when the semiconductor wafer 10 is manually removed from the carrier plate 20 while being heated on the hot plate 80, an excessive force or impact is applied to the semiconductor wafer 10, and the semiconductor wafer 10 is warped to maintain flatness. In the worst case, the semiconductor wafer 10 itself is damaged. For this reason, there is a problem that improvement in quality and productivity cannot be expected.

  In addition, when the front surface 10a and the rear surface 10b of the semiconductor wafer 10 are cleaned in the cleaning tank 40 after being removed from the carrier plate 20, the semiconductor wafer 10 is warped, and the surface protection sheet 60 is moved to the front surface 10a after cleaning. There is also a problem that the semiconductor wafer 10 is damaged when the back surface protective sheet 70 is stuck to the back surface 10b.

  The present invention has been made in view of such circumstances, and after grinding the back surface side of a patterned semiconductor wafer, the semiconductor wafer can be conveyed to the next process by preventing warpage and breakage of the semiconductor wafer. It is an object to propose a manufacturing method.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a pattern surface on the front surface side of a patterned semiconductor wafer is attached to a carrier plate, and the back surface side of the semiconductor wafer is ground to obtain a thickness dimension. After the thickness of 50 to 120 μm, the back surface side is vacuum-sucked, the semiconductor wafer is peeled off from the carrier plate, a surface protection sheet is attached to the surface side pattern surface, and then the back side suction is removed. The semiconductor wafer is inverted, and a back surface protection sheet is attached to the back surface side.

  According to a second aspect of the present invention, in the first aspect of the invention, the back surface side of the semiconductor wafer is vacuum-sucked and the semiconductor wafer is separated from the carrier plate, and then the pattern surface is washed. The surface protective sheet is attached to the pattern surface, and then the semiconductor wafer is reversed after removing the adsorption on the back side, and the pattern surface to which the surface protective sheet is attached is vacuum-adsorbed, The back surface side is washed, and the back surface protection sheet is adhered to the back surface side.

  The invention described in claim 3 is the invention described in claim 1 or 2, wherein the semiconductor wafer is a sapphire wafer.

  According to invention of Claims 1-3, after sticking the pattern side of the surface side of a semiconductor wafer on a carrier plate and grinding the back side of the semiconductor wafer, the back side is vacuum-adsorbed, In order to peel the semiconductor wafer from the carrier plate, the semiconductor wafer having a thickness reduced by grinding the back surface side can be peeled without excessive force or impact, and the semiconductor The wafer does not warp. Thereby, even if it is a sapphire wafer with which the said semiconductor wafer is easy to be damaged, while being able to peel efficiently, the yield of the said semiconductor wafer for which flatness is calculated | required can be improved, and it can lead to quality improvement.

  In addition, since the surface protection sheet is attached to the surface side pattern surface before reversing the semiconductor wafer, the surface side pattern surface can be vacuum-sucked after reversing the semiconductor wafer. . As a result, handling properties when cleaning and moving the semiconductor wafer can be improved.

  According to the second aspect of the present invention, the back surface side of the semiconductor wafer is vacuum-sucked, and after the semiconductor wafer is peeled off from the carrier plate, the back-surface side is vacuum-sucked and the front surface side is left. The surface protective sheet is adhered to the front surface, and then the back surface side is removed, and then the semiconductor wafer is reversed and the surface on which the surface protective sheet is adhered is vacuum adsorbed. In order to clean the back surface and paste the back surface protection sheet on the back surface side, the back surface side is ground and the semiconductor wafer having a reduced thickness is used in the cleaning tank. When cleaning the back side, the semiconductor wafer does not warp, and the semiconductor wafer can be prevented from being damaged when the protective sheet is adhered.

It is process drawing which simulated the series of processes of the manufacturing method of the semiconductor wafer of this invention. It is process drawing which simulated the series of processes of the manufacturing method of the conventional semiconductor wafer.

  As shown in FIG. 1, an apparatus used in an embodiment of a method for producing a semiconductor wafer 1 according to the present invention includes a carrier plate 2 for attaching a patterned surface on the surface 1a side of a patterned semiconductor wafer 1, and a semiconductor wafer. 1, a grinding means 9 for grinding the back surface 1 b side, a robot hand 3 that vacuum-sucks the front surface 1 a side and the back surface 1 b side of the semiconductor wafer 1, and the adhesive of the semiconductor wafer 1 adhered to the carrier plate 2. A hot plate 8, a pattern surface on the front surface 1 a side of the semiconductor wafer 1, a cleaning tank 4 that cleans the back surface 1 b side of the semiconductor wafer 1, and a reversing machine 5 that reverses the semiconductor wafer 1 are roughly configured.

Here, the semiconductor wafer 1 is a sapphire wafer 1 using single crystal sapphire. The single crystal sapphire used in the sapphire wafer 1 has excellent properties such as mechanical and thermal properties, chemical stability, and light transmittance. Crystalline sapphire is used. The single crystal sapphire is an alumina (Al ₂ O ₂ ) crystal.

  The carrier plate 2 is formed of a heat resistant material such as ceramics. An adhesive for fixing the sapphire wafer is applied to the upper surface of the carrier plate 2. As this adhesive, an adhesive that melts when heated is used.

  And the grinding means 9 uses the surface grinder which grinds the back surface 1b of the sapphire wafer 1, for example, when a grindstone rotates. The surface grinding machine is preferably capable of high flatness grinding and low damage grinding.

  Furthermore, the hot plate 8 includes a heating wire that can be heated to 110 ° C. or more by energizing the inside of the plate having heat resistance. The robot hand 3 that vacuum-sucks the sapphire wafer 1 is provided with a vacuum suction pad that can suck the front surface 1 a and the back surface 1 b of the sapphire wafer 1. In this vacuum suction pad, a plurality of small holes are formed, and the entire surface 1a and back surface 1b of the sapphire wafer 1 is formed in a size capable of being vacuum-sucked.

  The cleaning tank 4 for cleaning the front surface 1a and the back surface 1b of the sapphire wafer 1 includes, for example, ammonia hydrogen peroxide water, hydrochloric acid peroxide to remove particles, metal impurities, and organic impurities attached to the sapphire wafer 1. A chemical solution made of hydrogen water, dilute hydrofluoric acid or the like is injected.

  And the inversion machine 5 is provided with the table 5a provided rotatably. The table 5a is provided with holding means capable of holding the sapphire wafer 1 and releasing the hold of the sapphire wafer 1 after the table 5a is rotated and the sapphire wafer 1 is reversed.

  In order to manufacture the sapphire wafer 1 using the semiconductor wafer 1 manufacturing apparatus having the above-described configuration, first, the patterned surface on the surface 1a side of the patterned sapphire wafer 1 is turned downward, and the upper surface of the carrier plate 2 is formed. Place. At this time, since the adhesive is applied to the upper surface of the carrier plate 2, the sapphire wafer 1 is attached to the carrier plate 2.

  Subsequently, the thickness of the sapphire wafer 1 is 50 to 120 μm, preferably 50 μm, using a surface grinder capable of grinding the back surface 1b side of the sapphire wafer 1 by, for example, rotation of a grindstone. Grind to thickness dimension. Then, the ground back surface 1 b side of the sapphire wafer 1 is vacuum-sucked using the robot hand 3 and moved to the hot plate 8 together with the carrier plate 2.

  The carrier plate 2 is placed on the hot plate 8 while the sapphire wafer 1 is attracted to the robot hand 3, the switch of the hot plate 8 is turned on, the heating wire is energized, and the carrier plate 2 is heated. To do. At this time, the hot plate 8 is heated to 110 ° C. By this heating, the adhesive bonding the carrier plate 2 and the sapphire wafer 1 is melted. Then, the robot hand 3 adsorbing the sapphire wafer 1 is shifted to the side to peel the sapphire wafer 1 from the carrier plate 2. At this time, since the vacuum suction pad of the robot hand 3 sucks the entire surface of the back surface 1b of the sapphire wafer 1, it can be peeled while maintaining the flatness of the sapphire wafer 1.

  Further, the sapphire wafer 1 peeled off from the carrier plate 2 is moved to the cleaning tank 4 containing the chemical solution while being adsorbed by the robot hand 3, and the surface 1a side of the sapphire wafer 1 is cleaned. By this cleaning, particles, metal impurities, and organic impurities attached to the sapphire wafer 1 are removed. At this time, the sapphire wafer 1 is not warped because the sapphire wafer 1 is attracted to the vacuum suction pad of the robot hand 3 while maintaining flatness.

  Next, the sapphire wafer 1 is taken out from the cleaning tank 4 while being adsorbed to the robot hand 3 and dried. Then, the sapphire wafer 1 is moved to the reversing machine 5 while being adsorbed to the robot hand 3, and is placed on a table 5 a provided so as to be rotatable. A surface protective sheet 6 is adhered to the pattern surface. Since this surface protective sheet 6 is preliminarily coated with an adhesive, it can be easily attached.

  Then, the robot hand 3 sucking the back surface 1b side of the sapphire wafer 1 is removed, the sapphire wafer 1 is held on the table 5a of the reversing machine 5 by the holding means, and the table 5a is rotated. By this rotation, the sapphire wafer 1 held on the table 5a is reversed with the back surface 1b side positioned on the lower side, the holding means is released, and the surface 1a of the inverted sapphire wafer 1 is moved to the robot hand 3 Adsorbed by a vacuum suction pad.

  Furthermore, the sapphire wafer 1 adsorbed by the robot hand 3 is moved to the cleaning tank 4 containing the chemical solution, and the back surface 1b side of the sapphire wafer 1 is cleaned. By this cleaning, particles, metal impurities, and organic impurities attached to the sapphire wafer 1 are removed. At this time, since the sapphire wafer 1 is attracted to the vacuum suction pad of the robot hand 3 while maintaining the flatness, the sapphire wafer 1 does not warp.

  Next, the sapphire wafer 1 is taken out from the cleaning tank 4 while being adsorbed to the robot hand 3 and dried. And after drying, the back surface protection sheet 7 is stuck on the back surface 1b of the sapphire wafer 1 with the sapphire wafer 1 adsorbed to the robot hand 3. Since this back surface protective sheet 7 is previously coated with an adhesive, it can be easily attached.

  The sapphire wafer 1 having the surface protective sheet 6 on the front surface 1a and the back surface protective sheet 7 attached to the back surface 1b is conveyed to a downstream process, diced with leather, and packaged.

  According to the method for manufacturing a semiconductor wafer according to the above-described embodiment, the pattern surface on the front surface 1a side of the sapphire wafer 1 is attached to the carrier plate 2 and the back surface 1b side of the sapphire wafer 1 is ground, and then the back surface 1b. In order to peel the sapphire wafer 1 from the carrier plate 2 by vacuum suction, the sapphire wafer 1 that has been reduced in thickness by grinding the back surface 1b side is peeled without applying excessive force or impact. In addition, the sapphire wafer 1 does not warp. Thereby, even if it is the sapphire wafer 1 which is easy to break, while being able to peel efficiently, the yield of the said semiconductor wafer for which flatness is calculated | required can be improved, and it can lead to the improvement of quality.

  Moreover, since the surface protection sheet 6 is stuck on the pattern surface on the surface 1a side before the sapphire wafer 1 is inverted, the pattern surface on the surface 1a side can be vacuum-sucked after the sapphire wafer 1 is inverted. . As a result, it is possible to improve handling when the sapphire wafer 1 is cleaned and moved.

  And after vacuum-sucking the back surface 1b side of the sapphire wafer 1 and peeling the sapphire wafer 1 from the carrier plate 2, the front surface 1a side is cleaned while the back surface 1b side is vacuum-sucked to the surface 1a. After adhering the surface protection sheet 6 and then removing the adsorption on the back surface 1b side, the sapphire wafer 1 is inverted, the surface 1a to which the surface protection sheet 6 is adhered is vacuum-adsorbed, and the back surface 1b side is washed. In order to attach the back surface protection sheet 7 to the back surface 1b side, the back surface 1b side is ground to clean the sapphire wafer 1 having a reduced thickness in the cleaning tank 4, and the front surface 1a side and the back surface 1b side are cleaned. In doing so, the sapphire wafer 1 is not warped, and damage to the sapphire wafer 1 when the front surface protective sheet 6 and the rear surface protective sheet 7 are stuck can be prevented.

  In the above embodiment, the semiconductor wafer 1 has been described only in the case of the sapphire wafer 1 using single crystal sapphire. However, the present invention is not limited to this. For example, single crystal SiC (single crystal silicon carbide) is used. Even SiC wafers can be handled.

  It can utilize when manufacturing the sapphire wafer for LED.

1 Sapphire wafer (semiconductor wafer)
1a Front surface 1b Back surface 2 Carrier plate 3 Robot hand 4 Cleaning tank
5 reversing machine
6 Surface protection sheet
7 Back protection sheet
8 Hot plate 9 Grinding means

Claims (3)

  The pattern surface on the front side of the patterned semiconductor wafer is attached to a carrier plate, the back side of the semiconductor wafer is ground to a thickness of 50 to 120 μm, and then the back side is vacuum-sucked to form the semiconductor The wafer is peeled off from the carrier plate, a surface protection sheet is attached to the pattern surface on the front side, the suction on the back side is removed, the semiconductor wafer is inverted, and a back protection sheet is attached to the back side. A method of manufacturing a semiconductor wafer, comprising:   After vacuum-sucking the back side of the semiconductor wafer and peeling the semiconductor wafer from the carrier plate, the pattern surface is cleaned and the surface protective sheet is adhered to the pattern surface, and then the back side suction is performed. The semiconductor wafer is reversed after removing the vacuum, the pattern surface on which the surface protective sheet is adhered is vacuum-sucked, the back surface is washed, and the back protective sheet is adhered to the back surface. The method of manufacturing a semiconductor wafer according to claim 1, wherein   The method for producing a semiconductor wafer according to claim 1, wherein the semiconductor wafer is a sapphire wafer.

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