TW202124172A - Method for removing adhesive after wafer thinning process in which a cleaned wafer is put, together with a porous silicon carbide disc located below the wafer, into a wafer frame for storage for use in subsequent processes - Google Patents

Abstract

A method for removing an adhesive after a wafer thinning process includes: (a) separating: separating a wafer from a carrier after heating, and then, matching with a porous silicon carbide disc as a supporting base for the wafer after separation; (b) central positioning: subjecting the wafer to central positioning in order to obtain a central point of the wafer; (c) cleaning: making the wafer rotating, and flushing the wafer with an organic solvent to remove a residual adhesive on the wafer by spinning by virtue of a centrifugal force generated during rotation, and then, spraying nitrogen gas to the wafer to avoid oxidizing so as to be beneficial for storage; and (d) storage: putting the wafer so cleaned, together with the porous silicon carbide disc located below the wafer, into a wafer frame so as to be stored for use in subsequent processes. Therefore, after the wafer thinning process, the wafer may be separated from the carrier, and the residual adhesive on the wafer may be effectively removed so as to be beneficial to the subsequent processes.

Description

Adhesive removal method after wafer thinning process

The present invention is a method for separating the wafer from the carrier after the wafer thinning process and cleaning and removing the adhesive remaining on the wafer after the separation.

At present, in the global semiconductor IC wafer manufacturing process, in order to facilitate the smooth progress of the wafer cutting and packaging process in the later process, the thickness of the entire wafer is required to be thinner, which makes the "wafer thinning process" method of importance and Visibility is improving day by day. The "wafer thinning process" is also known as the Wafer Backside Grinding process, which helps to reduce the size of IC chips, reduce current on-resistance, speed up current flow, reduce unnecessary electrical waste heat generation, and extend semiconductor life. In the "wafer thinning process", in order to protect the wafer from damage due to the thinning of the thickness during the polishing process, an adhesive (such as wax) is usually used to temporarily bond the front surface of the wafer together before polishing. On the carrier, the carrier is used as a base for supporting the wafer during polishing. Therefore, after the "wafer thinning process" is completed, it is necessary to separate the wafer from the carrier and remove the adhesive to enable the wafer to undergo subsequent processes such as dicing and packaging.

The main purpose of the present invention is to separate the wafer from the carrier after the wafer thinning process, and then clean and remove the adhesive remaining on the separated wafer, so that the wafer can be subjected to subsequent processes such as cutting and packaging.

The adhesive removal method after the wafer thinning process of the present invention includes the steps of (a) separating, (b) centering, (c) cleaning, and (d) storage. Among them, the separation step (a) refers to heating to melt the adhesive used to bond the wafer and the carrier in the wafer assembly after the wafer thinning process, and then to separate the wafer from the carrier, and then match a porosity The silicon carbide disk serves as a support base for the separated wafer. The (b) centering step refers to centering the wafer on the porous silicon carbide disk to obtain the center point of the wafer. The (c) cleaning step refers to rotating the center-calibrated wafer and the porous silicon carbide disk below it, and using organic solvent to rinse the remaining adhesive on the wafer to be removed by the centrifugal force during rotation. Then spray nitrogen gas on the wafer to prevent oxidation and help preservation. The (d) storage step refers to sending the cleaned wafers together with the porous silicon carbide disks underneath them to a wafer rack for storage for subsequent processing.

The adhesive removal method after the wafer thinning process provided by the present invention can use the porous silicon carbide disk provided in the separation step as a pedestal for supporting the wafer in the subsequent cleaning process to prevent the cleaning process When the wafer is broken. In particular, in the cleaning process, organic solvents can be used to rinse the remaining adhesive on the wafer and the adhesive is thrown off by the centrifugal force of rotation to achieve the purpose of effectively removing the adhesive. Finally, nitrogen is sprayed on the wafer. Prevents the wafer from oxidizing and contributes to preservation.

10‧‧‧Wafer combination

11‧‧‧wafer

12‧‧‧Carrier

13‧‧‧Adhesive

20‧‧‧Porous Silicon Carbide Disk

30‧‧‧Lower suction module

31‧‧‧Upper suction module

40‧‧‧Positioning turntable

41‧‧‧First nozzle

42‧‧‧Second nozzle

43‧‧‧Nitrogen nozzle

Figure 1 is a block diagram of the flow of the present invention.

Figure 2 is a block diagram of the separation process of the present invention.

Figure 3 is a schematic diagram of the separation operation of the present invention.

Figure 4 is a block diagram of the cleaning process of the present invention.

Figure 5 is a schematic diagram of the cleaning action of the present invention.

Please refer to Figure 1, which shows that the adhesive removal method after the wafer thinning process of the present invention includes (a) separation, (b) centering, (c) cleaning, and (d) storage. in:

(a) Separation: Use a robotic arm to send the wafer assembly 10 after the wafer thinning process to a separation device, cooperate with a porous silicon carbide disk 20 for adsorption, and then heat the wafer assembly 10 After the adhesive for bonding the wafer 11 and the carrier 12 is melted, the carrier 12 is sucked away to separate the wafer 11 and the carrier 12.

(b) Center positioning: the porous silicon carbide disk 20 and the wafer 11 on it are transported to a center positioning device to perform the center positioning of the wafer 11 by using a mechanical arm.

(c) Cleaning: Use a robotic arm to transport the center-positioned wafer 11 together with the porous silicon carbide disk 20 below it to a cleaning device, and use a first organic solvent (such as acetone) to rinse the remaining adhesive on the wafer 11 Then use the centrifugal force of rotation to shake off the adhesive 13, and then use a second organic solvent (such as ethanol) to wash away the first organic solvent on the wafer 11, and finally spray nitrogen to the wafer 11 to prevent oxidation. Yu save.

(d) Storage: Use a robotic arm to transport the cleaned wafer 11 together with the porous silicon carbide disk 20 below it to a wafer rack for storage for subsequent production 程用。 Process used.

Please refer to Figures 2 and 3, which point out the implementation steps of (a) separation are as follows:

(a1) Preparation of porous silicon carbide disk 20: using a mechanical arm to place the porous silicon carbide disk 20 on the separation device;

(a2) Placement: Place the wafer assembly 10 on the porous silicon carbide disk 20 with a robotic arm, so that the back side of the wafer 11 (different from the side of the adhesive 13) is attached to the porous The upper side of the silicon carbide disk 20;

(a3) Adsorption: the lower adsorption module 30 of one of the separation devices is used to adsorb the wafer 11 through the porous characteristics of the porous silicon carbide disk 20 from below;

(a4) Heating: Use the heating module of the separating device to heat the wafer assembly 10 to melt the adhesive 13 at a heating temperature of 110~150°C for 15~30 seconds; and

(a5) Remove: Use the upper adsorption module 31 of the separation device to adsorb the upper part of the carrier 12 and drag a distance to achieve the purpose of separating the carrier 12 from the wafer 11, and then facilitate the use of the porosity The silicon carbide disk 20 is used as a susceptor for supporting the wafer 11 in the subsequent cleaning process.

Please refer to Figures 4 and 5, which point out the implementation steps of (c) cleaning are as follows:

(c1) Adsorption and positioning: using a robotic arm to send the center-positioned wafer 11 and the porous silicon carbide disk 20 below it to a positioning turntable 40 of the cleaning device, and the positioning turntable 40 penetrates the porous silicon carbide Porous characteristics of disc 20 Adsorb the wafer 11;

(c2) Rotation: the positioning turntable 40 drives the porous silicon carbide disk 20 and the wafer 11 on it to rotate at a speed of 1000 to 10000 revolutions per minute;

(c3) First organic solvent flushing: use a first nozzle 41 of the cleaning device to spray a first organic solvent (such as acetone) from 5 to 20 cm above the wafer 11 to the top surface of the wafer 11 at 0.3 pounds of water pressure For about 15 seconds, rinse and shake off the remaining adhesive 13 on the wafer 11 by rotating centrifugal force;

(c4) Remove the first organic solvent: use a second nozzle 42 of the cleaning device to spray a second organic solvent (such as ethanol) from 5 to 20 cm above the wafer 11 to the top surface of the wafer 11 at 0.3 pounds of water pressure About 15 seconds to remove the first organic solvent remaining on the wafer 11, and then the second nozzle 42 sucks the second organic solvent back to avoid the second organic solvent in the second nozzle 42 from dripping and contaminating the wafer 11. While the second nozzle 42 sprays and sucks back the second organic solvent, the first nozzle 41 also sucks back the first organic solvent to prevent the first organic solvent in the first nozzle 41 from dripping and contaminating the wafer 11 ;as well as

(c5) Nitrogen spray: Use at least one nitrogen spray pipe 43 of the cleaning device to spray nitrogen from the top of the wafer 11 at a pressure of 3 kg at a pressure of 3 kg from 5 to 20 cm above the wafer 11 for about 15 to 20 seconds to prevent the wafer 11. It is oxidized to help preservation, and then the positioning turntable 40 stops rotating, so that the cleaning process is completed.

The adhesive removal method after the wafer thinning process provided by the present invention can use the porous silicon carbide disk 20 provided in the separation step as a base for supporting the wafer 11 in the subsequent cleaning process to prevent The wafer is broken during the cleaning process. In particular, the first organic solvent (such as acetone) can be used for rinsing during the cleaning process Remove the remaining adhesive 13 on the wafer 11, and shake off the adhesive 13 by the centrifugal force of rotation, and then use a second organic solvent (such as ethanol) to wash away the first organic solvent on the wafer 11 to achieve effective The purpose of removing the adhesive 13 and finally spraying nitrogen gas on the wafer can prevent the wafer 11 from being oxidized and help storage.

To sum up, because the present invention has the above advantages and practical value, and no similar products have been published in similar products, it has met the requirements of an invention patent application, and an application is filed in accordance with the law.

Claims (9)

A method for removing adhesive after wafer thinning process includes: (a) Separation: After heating to melt the adhesive used to bond the wafer and the carrier in the wafer assembly after the wafer thinning process, the wafer and the carrier are separated, and then a porous silicon carbide disk is used for separation Support base for the subsequent wafer; (b) Center positioning: center the wafer on the porous silicon carbide disk to obtain the center point of the wafer; (c) Cleaning: Rotate the center-calibrated wafer and the porous silicon carbide disk below it, and use organic solvent to rinse the remaining adhesive on the wafer to be removed by the centrifugal force during rotation, and then move towards The wafers are sprayed with nitrogen gas to prevent oxidation and facilitate preservation; and (d) Storage: Send the cleaned wafers together with the porous silicon carbide disk below it to a wafer rack for storage for subsequent processing. The adhesive removal method after the wafer thinning process of claim 1, wherein a robotic arm is used to perform corresponding process materials between a separating device, a centering device, a cleaning device, and the wafer rack Transportation, in order to achieve the automatic operation of one of the above-mentioned separation, center calibration, cleaning and storage processes in order. The adhesive removal method after the wafer thinning process of claim 2, wherein the (a) separation step includes: (a1) Preparation of porous silicon carbide disc: using a mechanical arm to place the porous silicon carbide disc on the separation device; (a2) Placement: Place the wafer assembly on the porous silicon carbide disk with a robotic arm, so that the side of the wafer different from the adhesive is attached to the porosity The upper side of the silicon carbide disc; (a3) Adsorption: using one of the lower adsorption modules of the separation device to adsorb the wafer through the porous characteristics of the porous silicon carbide disk from below; (a4) Heating: using the heating module of the separating device to heat the wafer assembly to melt the adhesive; and (a5) Remove: Use one of the upper adsorption modules of the separation device to adsorb the upper part of the carrier and drag it for a distance, so as to achieve the purpose of separating the carrier from the wafer. The method for removing the adhesive after the wafer thinning process according to claim 3, wherein the heating temperature of the (a4) heating step is 110 to 150° C., and the time is 15 to 30 seconds. The method for removing the adhesive after the wafer thinning process according to claim 2, wherein the (c) cleaning step includes: (c1) Adsorption and positioning: use the robotic arm to send the center-positioned wafer and the porous silicon carbide disk below it to a positioning turntable of the cleaning device, and the positioning turntable absorbs the wafer through the porous silicon carbide disk. Wafer (c2) Rotation: the positioning turntable drives the porous silicon carbide disk and the wafers on it to rotate; (c3) First organic solvent flushing: use one of the first nozzles of the cleaning device to spray the first organic solvent toward the top surface of the wafer for flushing, and spin off the remaining adhesive on the wafer by rotating centrifugal force; (c4) Remove the first organic solvent: use one of the second nozzles of the cleaning device to spray the second organic solvent toward the top surface of the wafer to remove the first organic solvent remaining on the wafer Agent (c5) Nitrogen spray: Use at least one nitrogen nozzle of the cleaning device to spray nitrogen toward the top surface of the wafer, and then position the turntable to stop rotating, thus completing the cleaning process. The adhesive removal method after the wafer thinning process according to claim 5, wherein the first organic solvent is acetone, and the second organic solvent is ethanol The method for removing the adhesive after the wafer thinning process according to claim 5, wherein the rotation speed of the (c2) rotating step is 1,000 to 10,000 revolutions per minute. The method for removing the adhesive after the wafer thinning process according to claim 5, wherein the (c3) first organic solvent rinsing step and the (c4) first organic solvent removal step are both from the upper side of the wafer 5~ Spray the corresponding solvent on the top surface of the wafer with 0.3 lbs of water pressure at 20 cm for 15 seconds. The (c5) nitrogen spraying step is to spray nitrogen on the top surface of the wafer at a pressure of 3 kg from 5 to 20 cm above the wafer. 15~20 seconds. The method for removing the adhesive after the wafer thinning process according to claim 8, wherein the first nozzle immediately sucks back the first organic solvent after a predetermined time to avoid dripping of the first organic solvent in the first nozzle Contaminate the wafer, the second nozzle will suck back the second organic solvent immediately after a predetermined time to avoid the second organic solvent in the second nozzle from dripping and contaminating the wafer.

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