A tray for wafer thinning and a wafer thinning method

Abstract

The present invention provides a tray for wafer thinning and a wafer thinning method, belonging to the technical field of wafer thinning. The tray for wafer thinning includes a disc body, which is circular in shape and has a first surface and a second surface arranged opposite to each other. The first surface is used for adhering the wafer to be processed, and a liquid inlet groove is arranged on the first surface, and the liquid inlet groove communicates with the edge of the disc body. The wafer thinning method includes the following steps: Step 1, adhering the wafer to the first surface of the tray; Step 2, placing the tray in a thinning device to thin the wafer; Step 3, separating the wafer from the tray by using a wax removal process. For the tray for wafer thinning provided by the present invention, the arrangement of the liquid inlet groove enables the wax removal liquid to quickly diffuse into the wafer surface through the liquid inlet groove when the wafer is unloaded, with a fast dissolution speed, making it easier to separate the wafer and the tray. The wafer unloading process can be completed in about 3 minutes, saving a lot of time.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer thinning, and particularly relates to a tray for wafer thinning and a wafer thinning method. Background Art

[0002] With the popularity of smaller and thinner packages for portable and handheld products, the demand for thinner semiconductor devices has increased, so wafer thinning technology has become more important. Currently, the mature mechanical back grinding and polishing technology is used for thinning wafers. When performing mechanical back grinding and polishing, the wafer needs to be temporarily attached to a fixed disk and unloaded after the thinning and polishing are completed.

[0003] Currently, the wafer is attached to the fixed disk, and the wax layer is removed by soaking in a dewaxing solution after the thinning is completed. However, since the existing fixed disk has a smooth surface design and is completely attached to the wafer pattern surface without gaps during wafer attachment, during the unloading stage, the dewaxing solution cannot enter the gap between the wafer and the fixed disk in time to react with the wax, resulting in the unloading step usually taking about 60 minutes to complete, consuming a large amount of man-hours. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the fixed disk for wafer thinning in the prior art has a smooth surface design, resulting in a large amount of man-hours consumed during the unloading process, so as to provide a tray for wafer thinning and a wafer thinning method.

[0005] To solve the above technical problem, the present invention provides a tray for wafer thinning, including:

[0006] A disk body, which is circular in shape and has a first surface and a second surface arranged opposite to each other. The first surface is used for attaching the wafer to be processed, and a liquid inlet groove is arranged on the first surface, and the liquid inlet groove communicates with the edge of the disk body.

[0007] Optionally, the first surface has a central area located at the center and a slotted area located outside the central area, and the liquid inlet groove is arranged in the slotted area.

[0008] Optionally, the liquid inlet groove is located on a straight line radiating from the center of the disk body.

[0009] Optionally, the length of the straight line radiating from the center of the disk body in the central area is A, and the length in the slotted area is B, and A / B = 20%.

[0010] Optionally, there are multiple liquid inlet grooves, and the multiple liquid inlet grooves are evenly arranged along the circumferential direction of the disk body.

[0011] Optionally, there are four liquid inlet grooves.

[0012] Optionally, the length of the liquid inlet groove is 3.5 cm, the width of the liquid inlet groove is 600 um, and the depth of the liquid inlet groove is 90 um.

[0013] Optionally, the material of the disk body is glass or ceramic.

[0014] The present invention also provides a wafer thinning method, which uses the wafer thinning tray described in any one of the above, and includes the following steps:

[0015] Step 1, adhering the wafer to the first surface of the tray;

[0016] Step 2, placing the tray in a thinning device to thin the wafer;

[0017] Step 3, separating the wafer from the tray using a wax removal process.

[0018] Optionally, in Step 1, the following steps are included:

[0019] Heating the heating table to a specified temperature T1;

[0020] Placing the tray on the heating table to preheat for a specified time t1;

[0021] Placing white wax on the first surface of the tray, and placing the front surface of the wafer on the first surface coated with white wax;

[0022] Placing the tray on a cooling table for cooling, and performing tablet pressing after the white wax cools and solidifies;

[0023] And / or, in Step 3, the following steps are included:

[0024] Heating the heating table to a specified temperature T2;

[0025] Pouring the wax removal liquid into a petri dish, and placing the petri dish on the heating table to heat for a specified time t2;

[0026] Placing the thinned tray on the heating table to preheat for a specified time t3;

[0027] Inverting the tray over the petri dish to perform wafer unloading.

[0028] The technical solution of the present invention has the following advantages:

[0029] 1. The wafer thinning tray provided by the present invention includes a disk body in the form of an original sheet, having a first surface and a second surface arranged opposite to each other. The first surface is used to adhere the wafer to be processed, and a liquid inlet groove is provided on the first surface. The liquid inlet groove communicates with the edge of the disk body. The setting of the liquid inlet groove enables the wax removal liquid to quickly diffuse into the wafer surface through the liquid inlet groove when unloading the wafer, with a fast dissolution speed, making it easier to separate the wafer and the tray. The wafer unloading process can be completed in about 3 minutes, saving a lot of time.

[0030] 2. The tray for wafer thinning provided by the present invention has a central area located at the center on the first side and a slotted area located outside the central area. The liquid inlet groove is arranged in the slotted area, and the liquid inlet groove is only arranged in the slotted area without slotting in the central area, ensuring the stability of the tray during the wafer pressing process and avoiding cracking of the tray due to stress problems of the slotted tray. After the wax in the slotted area is removed, the wafer completely falls off under the action of gravity.

[0031] 3. The tray for wafer thinning provided by the present invention has the liquid inlet groove on a straight line radiating from the center of the tray body. The straight line processing is relatively simple, and it is arranged along the straight line radiating from the center, facilitating the falling off of the wafer.

[0032] 4. The tray for wafer thinning provided by the present invention has a length A of the straight line radiating from the center of the tray body in the central area and a length B in the slotted area, and A / B = 20%. The setting of the ratio makes it easy to drive the wafer in the central area to fall off under the action of gravity after falling off in the slotted area. If the proportion of the slotted area is relatively large, the tray is likely to be damaged during wafer pressing. If the proportion of the slotted area is relatively small, less wax liquid is removed, and the wafer cannot all fall off.

[0033] 5. The tray for wafer thinning provided by the present invention has a plurality of liquid inlet grooves, and the plurality of liquid inlet grooves are evenly distributed along the circumferential direction of the tray body, so that wax is evenly applied around the wafer, facilitating the falling off of the complete wafer and improving the wafer unloading efficiency.

[0034] 6. The tray for wafer thinning provided by the present invention has four liquid inlet grooves, which are in a cross-shaped structure, that is, it improves the wafer unloading efficiency and also ensures the stability of the tray.

[0035] 7. The wafer thinning method provided by the present invention uses the tray for wafer thinning. During the waxing process, the arrangement of the liquid inlet groove facilitates the rapid diffusion of the wax-removing liquid into the wafer surface, with a fast dissolution speed, making it easier to separate the wafer from the tray. The wafer unloading process can be completed in about 3 minutes, saving a lot of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 It is a schematic structural diagram of the tray for wafer thinning provided in the embodiment of the present invention;

[0038] Figure 2 isFigure 1 Top view structural schematic diagram.

[0039] Explanation of reference numerals:

[0040] 1. Disk body; 2. First surface; 3. Second surface; 4. Liquid inlet groove; 5. Central area; 6. Grooved area. Specific implementation manner

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] The tray for wafer thinning provided in this embodiment is used in the wafer thinning process, and the use of this tray greatly improves the efficiency of wafer unloading during thinning.

[0046] As Figure 1 and Figure 2 shown, a specific implementation manner of the tray for wafer thinning provided in this embodiment includes a disk body 1, which is circular in shape and has a first surface 2 and a second surface 3 arranged opposite to each other. The first surface 2 is used to adhere to the wafer to be processed, and a liquid inlet groove 4 is provided on the first surface 2, and the liquid inlet groove 4 communicates with the edge of the disk body 1.

[0047] The setting of the liquid inlet groove 4 enables the dewaxing liquid to quickly diffuse into the wafer surface when the wafer is unloaded, with a fast dissolution rate, making it easier to separate the wafer from the tray. The unloading process can be completed in about 3 minutes, saving a lot of time. Among them, the diameter size of the tray body 1 is the same as that of the wafer to be processed.

[0048] As Figure 2 shown, for the tray for wafer thinning provided in this embodiment, the first surface 2 has a central area 5 located at the center and a slotted area 6 located outside the central area 5, and the liquid inlet groove 4 is arranged in the slotted area 6. The liquid inlet groove is only arranged in the slotted area 6, and there is no slot in the central area 5, ensuring the stability of the tray during the wafer pressing process and avoiding cracking of the tray due to stress problems of the slotted tray. After the wax in the slotted area is removed, the wafer completely falls off under the action of gravity.

[0049] Specifically, the central area 5 is a circular structure, and the slotted area 6 is an annular structure, facilitating the uniform and rapid unloading of the wafer. The length of the liquid inlet groove 4 is the same as the ring width size of the slotted area 6. Additionally, as an alternative implementation, the central area 5 can also be square.

[0050] As Figure 1 shown, for the tray for wafer thinning provided in this embodiment, the liquid inlet groove 4 is located on a straight line radiating from the center of the tray body 1. The straight line processing is relatively simple, and setting it along the straight line radiating from the center facilitates the falling off of the wafer. Additionally, as an alternative implementation, the liquid inlet groove 4 may not be along the straight line radiating from the center, and it can also be perpendicular to this straight line.

[0051] As Figure 2 shown, for the tray for wafer thinning provided in this embodiment, the length of the straight line radiating from the center of the tray body 1 located in the central area 5 is A, and the length located in the slotted area 6 is B, and A / B = 20%. The setting of the ratio makes it easy to drive the wafer in the central area 5 to fall off under the action of gravity after falling off in the slotted area 6. If the proportion of the slotted area 6 is relatively large, it is easy to damage the tray during wafer pressing. If the proportion of the slotted area 6 is relatively small, less wax liquid is removed, and the wafer cannot all fall off.

[0052] As Figure 1 shown, for the tray for wafer thinning provided in this embodiment, there are multiple liquid inlet grooves 4, and the multiple liquid inlet grooves 4 are evenly arranged along the circumferential direction of the tray body 1. The wax on the wafer is evenly removed around the circumference, facilitating the falling off of the complete wafer and improving the unloading efficiency.

[0053] As Figure 1As shown in the figure, the tray for wafer thinning provided in this embodiment has four liquid inlet grooves, which are in a cross-shaped structure, improving the wafer unloading efficiency and ensuring the stability of the tray. Additionally, as an alternative embodiment, the liquid inlet grooves 4 can also be in a cross of crosses shape.

[0054] In one specific embodiment, the length of the liquid inlet groove 4 is 3.5 cm, the width of the liquid inlet groove 4 is 600 μm, and the depth of the liquid inlet groove 4 is 90 μm.

[0055] For the tray for wafer thinning provided in this embodiment, the material of the tray body 1 is glass or ceramic.

[0056] This embodiment also provides a wafer thinning method, which uses the tray for wafer thinning described in any one of the above embodiments, and includes the following steps:

[0057] Step 1, adhering the wafer to the first surface of the tray;

[0058] Step 2, placing the tray in the thinning equipment and thinning the wafer;

[0059] Step 3, separating the wafer from the tray using the wax removal process.

[0060] Using the tray for wafer thinning, during the wax removal process, the setting of the liquid inlet groove facilitates the rapid diffusion of the wax removal liquid into the wafer surface, with a fast dissolution rate, making it easier to separate the wafer and the tray. The wafer unloading process can be completed in about 3 minutes, saving a lot of time. Specifically, the thinning equipment can be a grinding equipment. The thickness of the wafer is measured before thinning and measured again after thinning. If it does not meet the requirements, the thinning is continued.

[0061] For the wafer thinning method provided in this embodiment, in the step 1, it includes the following steps:

[0062] Heating the heating table to the specified temperature T1;

[0063] Placing the tray on the heating table and preheating for the specified time t1;

[0064] Placing the white wax on the first surface 2 of the tray, and placing the front surface of the wafer on the first surface 2 coated with the white wax;

[0065] Placing the tray on the cooling table for cooling, and pressing the wafer after the white wax cools and solidifies.

[0066] In one specific embodiment, it includes the following steps:

[0067] Set the heating stage to 100°C. When the temperature reaches the set value, place the tray on the heating stage and preheat it for 3 minutes. Use tweezers to pick up white wax and place it on the already heated tray. Start smearing in a circular motion from the center of the tray. The amount of white wax used for a three-inch wafer is 6 pieces. Place the wafer face up on the tray that has been smeared with white wax. Then place the tray on the cooling stage for cooling. After the white wax cools and solidifies, send it to the mounter for pressing.

[0068] The steps in the mounter include the following:

[0069] Open the protective door, take out the central glass disk of the chamber and place it on the table; take out the metal baffle and place it in the center of the chamber, and check whether the edges are aligned; then place the trays with wafers attached at four corresponding positions of the baffle (the wafers are facing up). If the number of wafers is not enough, empty trays can be used instead; then neatly place 2 pieces of filter paper on the surface of the empty tray, with the filter paper completely covering the tray, and place 1 piece of filter paper on the surface of the wafer bonding tray (the filter paper completely covers the tray); finally, close the protective door;

[0070] After parameter setting, the equipment starts automatic wafer bonding;

[0071] Two minutes after the wafer bonding is completed, open the protective door, first take out the metal baffle, then remove the filter paper, and finally take out the tray, and blow the surface of the wafer with a nitrogen gun;

[0072] Place the tray with the bonded wafer on the quartz stage of the thickness gauge, measure the thickness at five marked positions and record it;

[0073] Put the glass disk back to the center of the chamber, cover it with filter paper, and close the protective door to complete the wafer bonding.

[0074] In the third step, the following steps are included:

[0075] Heat the heating stage to the specified temperature T2;

[0076] Pour the wax-removing liquid into a petri dish, and place the petri dish on the heating stage and heat it for the specified time t2;

[0077] Place the thinned tray on the heating stage and preheat it for the specified time t3;

[0078] Invert the tray over the petri dish to unload the wafer.

[0079] One specific implementation method includes the following steps:

[0080] Set the heating stage to 101°C, pour the dewaxing liquid into a petri dish, and place the petri dish on the heating stage that has been heated to 101°C for 30 minutes. Place the surface of the wafer tray after thinning on the heating stage for preheating for 3 minutes, then invert the preheated tray in the middle of the waxing fixture, and place the waxing fixture in the heated petri dish for wafer placement. A conventional fixture can be used for the waxing fixture;

[0081] When the wafer completely detaches from the tray, take the waxing fixture out of the petri dish and soak the wafer in the dewaxing liquid for 10 minutes; preheat trichloroethylene on a hot plate at 101°C for 30 minutes, keep heating, and blow dry after heating ends.

[0082] In the wafer thinning method provided in this embodiment, after the wafer is separated from the tray, wait for the tray to cool to room temperature, wipe the tray with a lint-free cloth and acetone, and clean the wax marks on the tray.

[0083] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation methods. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all implementation methods here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A tray for wafer thinning, characterized in that, Comprising: A disk body (1), in a circular sheet shape, having a first surface (2) and a second surface (3) arranged opposite to each other, the first surface (2) being used to adhere the wafer to be processed, a liquid inlet groove (4) being arranged on the first surface (2), and the liquid inlet groove (4) communicating with the edge of the disk body (1); The first surface (2) has a central area (5) at the center and a grooved area (6) outside the central area (5), and the liquid inlet groove (4) is arranged in the grooved area (6); The liquid inlet groove (4) is located on a straight line radiating from the center of the disk body (1); The length of the straight line radiating from the center of the disk body (1) in the central area (5) is A, and the length in the grooved area (6) is B, and A / B = 20%; 2. The tray for wafer thinning according to claim 1, characterized in that, There are a plurality of the liquid inlet grooves (4), and the plurality of liquid inlet grooves (4) are evenly arranged along the circumferential direction of the disk body (1).

3. The tray for wafer thinning according to claim 2, wherein There are four of the liquid inlet grooves (4).

4. The tray for wafer thinning according to claim 1, characterized in that, The length of the liquid inlet groove (4) is 3.5 cm, the width of the liquid inlet groove (4) is 600 μm, and the depth of the liquid inlet groove (4) is 90 μm.

5. The tray for wafer thinning according to any one of claims 1-4, characterized in that, The material of the disk body (1) is glass or ceramic.

6. A wafer thinning method, characterized in that: Using the tray for wafer thinning according to any one of claims 1-5, comprising the following steps: Step 1, adhering the wafer to the first surface of the tray; Step 2, placing the tray in a thinning device to thin the wafer; Step 3, separating the wafer from the tray using a wax removal process.

7. The wafer thinning method according to claim 6, wherein In step 1, it includes the following steps: Heating the heating table to a specified temperature T1; Placing the tray on the heating table to preheat for a specified time t1; Placing white wax on the first surface (2) of the tray, and placing the front surface of the wafer on the first surface (2) coated with white wax; Placing the tray on a cooling table for cooling, and performing pressing after the white wax cools and solidifies; And / or, in step 3, it includes the following steps: Heating the heating table to a specified temperature T2; Pouring the wax removal liquid into a culture dish, and placing the culture dish on the heating table to heat for a specified time t2; Placing the tray after thinning on the heating table to preheat for a specified time t3; Placing the tray upside down in the culture dish for wafer unloading.

Images