Method for taking out a ring from a taiko thinned wafer

Abstract

The application discloses a kind of taiko thinning wafer's ring taking method, comprising: step one, to taiko thinning wafer is cut out;Step two, carries out double alignment process, comprising: the outer side edge of the intermediate portion after cutting out is detected to realize first double alignment;The outer side edge of the support ring after cutting out is detected to realize second double alignment;Step three, carries out ring taking process and removes the support ring;In ring taking process, the position of intermediate portion is determined using first double alignment, and the action position of ring taking blade is determined using second double alignment.The application can improve the accuracy of alignment process after cutting out is completed and before ring taking, increase the ring taking window, reduce the crack rate, and finally improve the ring taking stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a semiconductor integrated circuit manufacturing method, in particular to a ring taking method of a Taiko thinned wafer. BACKGROUND

[0002] The Taiko ring, i.e. a support ring, of a 12-inch wafer prepared by a Taiko thinning process can provide support force for the wafer and reduce wafer warpage.

[0003] The Taiko ring needs to be removed before wafer dicing and packaging, while maintaining the wafer edge integrity.

[0004] When removing the Taiko ring, the Taiko wafer, i.e. a Taiko thinned wafer, after ring cutting needs to be aligned. The accuracy of the alignment will not only affect the position of the wafer on the chuck and cause edge cracks, but also affect the action position of the ring taking blade and cause ring taking failure or even cracks.

[0005] Therefore, improving the accuracy of the alignment of the Taiko wafer after ring cutting is one of the main methods to improve the stability of ring taking.

[0006] As shown in FIG. 1, it is a schematic diagram of the alignment process in the ring taking method of the Taiko thinned wafer 102 of the embodiment of the present application; the ring taking method of the Taiko thinned wafer 102 of the embodiment of the present application comprises the following steps: Figure 1

[0007] Step one, providing a Taiko thinned wafer 102, the Taiko thinned wafer 102 comprising a support ring 102b and an intermediate portion 102a inside the support ring 102b; ring cutting the Taiko thinned wafer 102 to form a groove between the support ring 102b and the intermediate portion 102a, the groove separating the support ring 102b and the intermediate portion 102a.

[0008] The Taiko thinned wafer 102 is thinned by Taiko, the intermediate portion 102a of the Taiko thinned wafer 102 is thinned to the required thickness, and the edge portion of the wafer is not thinned to form the support ring 102b.

[0009] The thickness of the intermediate portion 102a of the Taiko thinned wafer 102 is 10 microns to 250 microns.

[0010] The front surface of the Taiko thinned wafer 102 is pasted on a cutting tape 103 and fixedly placed on a chuck 101.

[0011] ​The cutting tape 103 includes a UV irradiation tape or a heat-sensitive tape.

[0012] The first step and the subsequent second and third steps are all implemented on the same ring cutting apparatus.

[0013] The second step is to perform an alignment process, including:

[0014] The outer side edge 105 of the ring-cut support ring 102b is detected by the alignment unit 104 to achieve alignment.

[0015] The third step is to perform a ring removal process to remove the support ring 102b.

[0016] In the ring removal process, the alignment process is used to determine the position of the intermediate portion 102a and the action position of the ring removal blade at the same time. This can easily make the position of the intermediate portion 102a and the action position of the ring removal blade not very accurate. When the position of the intermediate portion 102a is offset, a crack is easily formed. When the action position of the ring removal blade is abnormal, ring removal failure and cracks are easily caused. SUMMARY

[0017] The technical problem to be solved by the present application is to provide a method for removing a support ring from a taiko thinned wafer, which can improve the accuracy of the alignment process after ring cutting and before ring removal, increase the ring removal window, reduce the crack rate, and finally improve the stability of ring removal.

[0018] To solve the above technical problem, the present application provides a method for removing a support ring from a taiko thinned wafer, which includes the following steps:

[0019] The first step is to provide a taiko thinned wafer, which includes a support ring and an intermediate portion inside the support ring. The taiko thinned wafer is ring cut to form a groove between the support ring and the intermediate portion, which separates the support ring and the intermediate portion.

[0020] The second step is to perform a double alignment process, including:

[0021] The outer side edge of the ring-cut intermediate portion is detected to achieve the first alignment.

[0022] The outer side edge of the ring-cut support ring is detected to achieve the second alignment.

[0023] The third step is to perform a ring removal process to remove the support ring.

[0024] In the ring removal process, the position of the intermediate portion is determined by the first alignment, thereby preventing the position of the intermediate portion from being offset and eliminating the crack formed by the position of the intermediate portion being offset.

[0025] The second alignment is used to determine the action position of the ring taking blade, so as to prevent the action position of the ring taking blade from being abnormal and eliminate the ring taking failure and cracks caused by the abnormal action position of the ring taking blade.

[0026] Further improvement is that in step one, the taiko thinned wafer is thinned by taiko thinning, and the middle part of the taiko thinned wafer is thinned to the required thickness, and the edge part of the wafer is not thinned to form the support ring.

[0027] Further improvement is that the thickness of the middle part of the taiko thinned wafer is 20 microns to 250 microns.

[0028] Further improvement is that in step one, the front surface of the taiko thinned wafer is pasted on the cutting tape and fixedly placed on the adsorption platform.

[0029] Further improvement is that in step two, the double alignment process is realized by using the same alignment unit.

[0030] Further improvement is that after one of the first alignment and the second alignment is completed, the alignment unit is moved and then the other of the first alignment and the second alignment is completed.

[0031] Further improvement is that the first alignment is to detect the whole circle of the outer side edge of the middle part and calculate the position of the middle part according to the logical operation result of the whole circle detection.

[0032] Further improvement is that the second alignment is to detect the whole circle of the outer side edge of the support ring and calculate the action position of the ring taking blade according to the logical operation result of the whole circle detection.

[0033] Further improvement is that in the first alignment process, the alignment unit moves along the diameter direction of the taiko thinned wafer and the moving distance is between -5 microns and 20 microns.

[0034] Further improvement is that in the second alignment process, the alignment unit moves along the diameter direction of the taiko thinned wafer and the moving distance is between -5 microns and 20 microns.

[0035] Further improvement is that steps one to three are realized on the same ring cutting device.

[0036] Further improvement is that the cutting tape includes ultraviolet irradiation tape or heat sensitive tape.

[0037] The present application is different from the prior art in that the position of the middle part of the drum thin wafer and the action position of the ring taking blade are determined simultaneously by a single alignment process, the alignment process of the present application is a double alignment process, and the first alignment is achieved by detecting the outer side edge of the middle part, and the second alignment is achieved by detecting the outer side edge of the support ring, so that the position of the middle part can be determined by the first alignment, and the action position of the ring taking blade can be determined by the second alignment, thereby simultaneously achieving the position of the middle part and the action position of the ring taking blade, accurate positioning of the position of the middle part can prevent the position of the middle part from deviating and eliminate the cracks caused by the deviation of the position of the middle part, and accurate positioning of the action position of the ring taking blade can prevent the action position of the ring taking blade from being abnormal and eliminate the cracks caused by the abnormal action position of the ring taking blade, such as too deep or too shallow entry depth, so that the ring taking fails, therefore, the present application can improve the accuracy of the alignment process after ring cutting is completed and before the ring is taken, increase the ring taking window, reduce the crack rate, and finally improve the stability of the ring taking. BRIEF DESCRIPTION OF DRAWINGS

[0038] The present application will be further described in detail below in combination with the drawings and specific embodiments:

[0039] Figure 1 is a schematic diagram of the alignment process in the prior art ring taking method of the drum thin wafer;

[0040] Figure 2 is a flowchart of the ring taking method of the drum thin wafer of the embodiment of the present application;

[0041] Figure 3 is a schematic diagram of the alignment process in the ring taking method of the drum thin wafer of the embodiment of the present application. DETAILED DESCRIPTION

[0042] As shown in Figure 2 , it is a flowchart of the ring taking method of the drum thin wafer 202 of the embodiment of the present application; as shown in Figure 3 , it is a schematic diagram of the alignment process in the ring taking method of the drum thin wafer 202 of the embodiment of the present application; the ring taking method of the drum thin wafer 202 of the embodiment of the present application comprises the following steps:

[0043] Step one, providing a drum thin wafer 202, the drum thin wafer 202 comprising a support ring 202b and a middle part 202a located inside the support ring 202b; ring cutting is performed on the drum thin wafer 202 to form a groove between the support ring 202b and the middle part 202a, the groove separates the support ring 202b and the middle part 202a.

[0044] In the embodiment of the present application, the taiko thinned wafer 202 is thinned by taiko thinning, and the middle part 202a of the taiko thinned wafer 202 is thinned to a required thickness, and the edge part of the wafer is not thinned to form the support ring 202b.

[0045] The thickness of the middle part 202a of the taiko thinned wafer 202 is 20 microns to 250 microns.

[0046] The front surface of the taiko thinned wafer 202 is pasted on the cutting adhesive tape 203 and fixedly placed on the adsorption platform 201.

[0047] The cutting adhesive tape 203 includes ultraviolet irradiation adhesive tape or heat-sensitive adhesive tape.

[0048] The step one and the subsequent steps two and three are implemented on the same ring cutting device.

[0049] The step two is to perform a double alignment process, including:

[0050] The outer side edge 206 of the middle part 202a after the ring cutting is detected to implement the first re-alignment.

[0051] The outer side edge 205 of the support ring 202b after the ring cutting is detected to implement the second re-alignment.

[0052] In the embodiment of the present application, the same alignment unit 204 is used to implement the double alignment process.

[0053] After one of the first re-alignment and the second re-alignment is completed, the alignment unit 204 is moved and then the other of the first re-alignment and the second re-alignment is completed. Figure 2 In the embodiment, the process of first performing the first re-alignment and then performing the second re-alignment is shown; wherein the alignment unit 204 during the first re-alignment is represented by a solid line, and the position to which the alignment unit 204 is to be moved after the first re-alignment is completed is represented by a dashed line 204a.

[0054] The first re-alignment is to detect the entire circle of the outer side edge 206 of the middle part 202a and calculate the position of the middle part 202a according to the result of the entire circle detection. In some embodiments, during the first re-alignment, the alignment unit 204 moves along the diameter direction of the taiko thinned wafer 202 and the moving distance is between -5 microns and 20 microns.

[0055] The second re-alignment is to detect the whole circle of the outer side edge 205 of the support ring 202b and to calculate the action position of the ring taking blade according to the result of the whole circle detection. In some embodiments, in the second re-alignment process, the alignment unit 204 moves along the diameter direction of the drum thinning wafer 202 and the moving distance is between -5 microns and 20 microns.

[0056] Step three, the ring taking process is performed to remove the support ring 202b.

[0057] In the ring taking process, the position of the middle part 202a is determined by the first re-alignment, so as to prevent the position of the middle part 202a from deviating and eliminate the cracks caused by the deviation of the position of the middle part 202a.

[0058] The action position of the ring taking blade is determined by the second re-alignment, so as to prevent the action position of the ring taking blade from being abnormal and eliminate the ring taking failure and cracks caused by the abnormality of the action position of the ring taking blade.

[0059] Different from the prior art in which the position of the middle part 202a of the drum thinning wafer 202 and the action position of the ring taking blade are determined simultaneously by one alignment process, the alignment process of the embodiments of the present application is a double re-alignment process, and the first re-alignment is achieved by detecting the outer side edge 206 of the middle part 202a, and the second re-alignment is achieved by detecting the outer side edge of the support ring 202b. Thus, the position of the middle part 202a can be determined by the first re-alignment, and the action position of the ring taking blade can be determined by the second re-alignment, so as to simultaneously determine the position of the middle part 202a and the action position of the ring taking blade. The accurate positioning of the position of the middle part 202a can prevent the position of the middle part 202a from deviating and eliminate the cracks caused by the deviation of the position of the middle part 202a. The accurate positioning of the action position of the ring taking blade can prevent the action position of the ring taking blade from being abnormal and eliminate the ring taking failure and cracks caused by the abnormality of the action position of the ring taking blade, such as too deep or too shallow entering depth. Therefore, the embodiments of the present application can improve the accuracy of the alignment process after the ring cutting is completed and before the ring taking, increase the ring taking window, reduce the crack rate, and finally improve the ring taking stability.

[0060] The present application is described in detail through specific embodiments above, but these do not constitute a limitation on the present application. Those skilled in the art can also make many modifications and improvements without departing from the principles of the present application, and these should also be considered as falling within the protection scope of the present application.

Claims

1. A method of ring taking of a taiko thinned wafer, characterized by, The method comprises the following steps: Step 1: providing a drum-thinned wafer, the drum-thinned wafer comprising a support ring and a middle portion inside the support ring; ring cutting the drum-thinned wafer to form a groove between the support ring and the middle portion, the groove separating the support ring and the middle portion; Step 2: performing a double alignment process, comprising: detecting the outer edge of the ring-cut middle portion to achieve a first re-alignment; detecting the outer edge of the ring-cut support ring to achieve a second re-alignment; Step 3: performing a ring removal process to remove the support ring; In the ring removal process, the position of the middle portion is determined by the first re-alignment, thereby preventing the position of the middle portion from deviating and eliminating cracks caused by the deviation of the position of the middle portion; The action position of the ring removal blade is determined by the second re-alignment, thereby preventing the action position of the ring removal blade from being abnormal and eliminating ring removal failure and cracks caused by the abnormality of the action position of the ring removal blade.

2. The method of claim 1, wherein: In Step 1, the drum-thinned wafer is drum-thinned, the middle portion of the drum-thinned wafer is thinned to the required thickness, and the edge portion of the wafer is not thinned to form the support ring.

3. The method of claim 2, wherein: The thickness of the middle portion of the drum-thinned wafer is 20-250 microns.

4. The method of claim 1, wherein: In Step 1, the front surface of the drum-thinned wafer is pasted on a cutting tape and fixedly placed on a suction platform.

5. The method of claim 4, wherein: In Step 2, the double alignment process is achieved by using the same alignment unit.

6. The method of claim 5, wherein: After completing one of the first re-alignment and the second re-alignment, the alignment unit is moved and then the other one of the first re-alignment and the second re-alignment is completed.

7. The method of claim 6, wherein: The first re-alignment is detecting the entire circumference of the outer edge of the middle portion and calculating the position of the middle portion by logical operation according to the detection result.

8. The method of claim 6, wherein: The second re-alignment is detecting the entire circumference of the outer edge of the support ring and calculating the action position of the ring removal blade by logical operation according to the detection result.

9. The method of claim 7, wherein: In the first re-alignment process, the alignment unit moves along the diameter direction of the drum-thinned wafer by a distance of-5-20 microns.

10. The method of claim 8, wherein: In the second re-alignment process, the alignment unit moves along the diameter direction of the drum-thinned wafer by a distance of-5-20 microns.

11. The method of claim 5, wherein: Steps 1-3 are all achieved on the same ring cutting device.

12. The method of claim 4, wherein: The cutting tape comprises an ultraviolet irradiation tape or a heat-sensitive tape.

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