Ultra-thin wafer conveying device and method

Abstract

The present invention provides a conveying device for ultra-thin wafers, comprising: two parallel slides, baffles are provided at both ends of the slides, the baffles are used to be fixed to a wafer grinder, each slide is respectively sleeved with a connecting tube, at least one handle is respectively fixed to the outside of the connecting tube, a carrier is fixed to the inside of the connecting tube, the horizontal position of the carrier is lower than the horizontal position of the connecting tube, and the carrier has a detachable function. The method for conveying ultra-thin wafers is to use a carrier to receive the wafers floated by the water flow, and to take the wafers out through the conveying device for ultra-thin wafers. The present invention effectively solves the problem that the wafer cannot be safely taken out after the wafer grinder completes the significant back thinning, and can realize the safe removal of a single wafer with a thickness of less than 50μm. At the same time, the carrier has a detachable function, and the carrier with the thinned wafer can be directly placed in a wafer bonding machine to be directly bonded with other wafers as a bottom wafer.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor processing and manufacturing, and specifically provides a device and method for conveying ultra-thin wafers. Background Art

[0002] With the rapid development of integrated circuit technology, the integration of devices is getting higher and higher, and semiconductor processing technology is becoming more and more complex and precise. When the chip size design reaches the limit in the horizontal direction, people begin to study the vertical direction of the chip. The thinning of the back of the wafer not only improves the heat dissipation performance of the chip, reduces resistance and power consumption, but also provides better conditions for the chip stacking process, so that a device can realize multiple functions. Therefore, the thickness of the wafer is an important factor in realizing the high integration of devices. Wafer grinding machine (grinding) is the most commonly used wafer thinning equipment at present. According to the thinning order, it is divided into three thinning areas Z1, Z2 and Z3 and Z4 pure polishing area. Among them, Z1 area performs rough thinning of the wafer. At this time, the removal amount is relatively large, and the real-time thickness of the wafer is detected by contact measurement; Z2 area performs fine polishing of the wafer, and the removal amount is small. The wafer thickness is monitored in real time by non-contact measurement; finally, Z3 uses chemical grinding liquid mixed with deionized water to participate in the thinning work in this area, and similar to the chemical mechanical polisher, it also has a certain polishing effect, and the removal amount is very small, basically maintained at about 3μm; Z4 area has no removal amount. Whether it is back thinning for wafers with or without logic circuits on the surface, when thinning to about 100μm, the wafer itself is too thin, resulting in the transmission system of the grinding equipment being unable to accurately identify the wafer. Wafers of different thicknesses also have different degrees of hardness and softness, and the manipulator used for wafer transmission cannot make appropriate adjustments to wafers of different thicknesses, resulting in a very high probability of wafer fragmentation. Therefore, the wafer can only be taken out manually after the Z4 part of the wafer surface is polished, but at this time the wafer is very soft and manual operation is very difficult, which can easily cause the wafer to be greatly deformed or even fragmented, affecting the subsequent process, causing certain economic losses and delaying the progress of the overall process. Therefore, it is a very critical step to ensure that the wafer can be safely and smoothly taken out of the equipment after thinning.

[0003] Therefore, there is an urgent need for a device and method for safely transferring ultra-thin wafers. Summary of the invention

[0004] The ultra-thin wafer conveying device provided by the present invention comprises: a slideway, a handle, a baffle, a connecting tube and a slide;

[0005] There are two slideways, which are arranged in parallel. Baffles are arranged at both ends of the slideways, and the baffles are used to fix with the wafer grinding machine;

[0006] Each slideway is respectively provided with a connecting tube, at least one handle is respectively fixed on the outside of the connecting tube, a specimen slide is fixed on the inside of the connecting tube, the horizontal position of the specimen slide is lower than that of the connecting tube, and the specimen slide is detachable.

[0007] Preferably, the slide is a ring provided with vertical cross plates.

[0008] A method for conveying an ultra-thin wafer comprises the following steps:

[0009] S1. Affix a UV protective film to the non-thinning surface of the wafer to be thinned, and place the wafer in a wafer grinder to complete wafer thinning and polishing;

[0010] S2. Adjust the vacuum adsorption capacity of the wafer grinder to ensure that the wafer can float under the action of buoyancy;

[0011] S3, fixing the ultra-thin wafer conveying device on the wafer grinding machine;

[0012] S4, start the water spraying program to make the wafer float, and move the specimen slide under the wafer through the handle;

[0013] S5, turn off the water spraying program, and take out the wafer through the carrier;

[0014] S6. Use UV lamp to debond and remove the UV protective film, and complete the transfer of the thinned wafer.

[0015] Preferably, in S1, wafer polishing is completed in a manual mode of the wafer grinder.

[0016] Preferably, after the wafer polishing is completed, the process further includes raising the polishing head of the wafer grinder to an initial position.

[0017] Preferably, the method further includes: S7, removing the carrier sheet with the thinned wafer and loading it into a wafer box.

[0018] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0019] The present invention effectively solves the problem that the wafer cannot be safely removed after the wafer grinding machine has completed the significant back thinning. When the grinding device performs back thinning, the wafer with a single thickness of less than 50 μm can be safely removed. At the same time, the carrier of the device of the present invention has a detachable function, and the carrier with the thinned wafer can be directly placed in the wafer bonding machine to be directly bonded with other wafers as the bottom wafer, which provides a powerful condition for the development of 3D stacking process in semiconductors, especially in the field of preparing metal oxide semiconductor (CMOS) and complementary field effect transistor (CFET) devices, and provides safety guarantee for preparing semiconductor devices with excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a top view of an ultra-thin wafer conveying device provided according to an embodiment of the present invention;

[0021] Figure 2 is a side view of an ultra-thin wafer conveying device provided according to an embodiment of the present invention;

[0022] Figure 3 is a front view of an ultra-thin wafer conveying device provided according to an embodiment of the present invention;

[0023] Figure 4 The figure is a flow chart of a method for transferring ultra-thin wafers according to an embodiment of the present invention.

[0024] Reference numerals include:

[0025] Slide 1, handle 2, baffle 3, connecting tube 4, slide 5. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0028] Figure 1 The top view structure of the ultra-thin wafer conveying device provided according to an embodiment of the present invention is shown.

[0029] Figure 2 A side view structure of an ultra-thin wafer conveying device provided according to an embodiment of the present invention is shown.

[0030] Figure 3 The front view structure of the ultra-thin wafer conveying device provided according to an embodiment of the present invention is shown.

[0031] like Figure 1 , Figure 2 and Figure 3 As shown, the ultra-thin wafer conveying device provided in the embodiment of the present invention is used to protect the ultra-thin wafer from being taken out safely, and mainly comprises: two slideways 1, two handles 2, two baffles 3, two connecting tubes 4 and a specimen slide 5, wherein:

[0032] The two slides 1 are arranged in parallel, and baffles 3 are arranged at both ends of the slide 1. The shape surrounded by the slide 1 and the baffle 3 is a rectangle. The baffle 3 is used to be fixed to the wafer grinder. A connecting tube 4 is sleeved on each slide 1, and a handle 2 is arranged on the outside of each connecting tube 4. The handle 2 is convenient for moving the connecting tube 4. A downward extending connecting rod is arranged on the inner side of the connecting tube 4. A carrier plate 5 is fixed at the end of the connecting rod. The carrier plate 5 is in a circular ring shape with a mutually perpendicular cross plate in the middle. Other circular plates or square plates with hollows can also be selected. It is necessary to ensure that the horizontal position of the carrier plate 5 is lower than the horizontal position of the connecting tube 4, and the carrier plate 5 has a detachable function and is fixed by a snap-on structure.

[0033] Figure 4 The flowchart of the ultra-thin wafer transfer method provided according to an embodiment of the present invention is shown.

[0034] like Figure 4 As shown, the present invention also provides a method for conveying ultra-thin wafers. This embodiment will describe the use of an ultra-thin wafer conveying device to take out a wafer that has been thinned on the back by a wafer grinder (grinding). The specific process is as follows:

[0035] S1. Whether the wafer to be thinned has logic circuits or not, before thinning, a UV protective film is applied to the non-thinning surface (front side) of the wafer to be thinned, which can effectively avoid damage to the front side of the wafer during the thinning process. The processed wafer is automatically transferred to the grinding equipment and passes through the three zones Z1, Z2 and Z3 to complete the thinning work.

[0036] After thinning is completed, the grinding equipment is switched to manual mode to ensure that the vacuum at the contact position between the wafer and the carrier of the grinding equipment remains unchanged. The purpose of the vacuum is to adsorb the wafer to prevent the wafer from shifting during processing.

[0037] The polishing head of polishing area Z4 is moved to the top of the wafer to polish the back of the wafer. After polishing is completed, the polishing head of Z4 is raised and moved to the initial position of the polishing head.

[0038] S2. Adjust the vacuum adsorption capacity of the wafer carrier of the wafer grinder to ensure that the wafer can float under the action of buoyancy. At this time, the wafer will not move on the carrier due to external factors such as equipment vibration. Actual experiments have shown that when the wafer thickness is less than 50μm, the vacuum adsorption can be completely closed.

[0039] S3. Fix the ultra-thin wafer conveying device on the grinding device through two baffles 3 to ensure that the ultra-thin wafer conveying device will not deviate significantly due to small vibrations.

[0040] S4, start the water spraying program of the grinding equipment. At this time, the water on the surface of the carrier will gently lift the thinned wafer to a certain height under the action of buoyancy. At this time, the carrier sheet 5 is slid to the bottom of the wafer through the handle 2.

[0041] S5, turn off the water spraying program, and the wafer will slowly fall onto the specimen carrier 5 as the water level drops, and then the ultra-thin wafer conveyor is taken out of the grinding equipment.

[0042] S6. Use UV lamp to irradiate the UV protective film on the front of the wafer to debond and remove it. Using UV lamp to remove the UV protective film is convenient and simple and will not damage the wafer surface.

[0043] S7, dismantle the carrier sheet 5 with the thinned wafer and put it into a wafer box to complete the wafer thinning work. Subsequently, the carrier sheet with the thinned wafer can be directly put into a wafer bonding machine to be directly bonded with other wafers as a bottom wafer.

[0044] Experimental verification shows that at present, when the wafer is thinned to below 50μm, the success rate of wafer removal is low. However, the current equipment and method can safely transfer and remove wafers thinned to about 100μm to 35μm, which can fully meet the current needs of semiconductor processing.

[0045] In addition, the ultra-thin wafer conveying device is expected to be designed as an electronically controlled device. The structure of the slideway 1 and the connecting tube 4 can be designed as an electronically controlled slide, and the power supply and specific working conditions can be controlled through an external interface. The ultra-thin wafer conveying device can also be integrated into the grinding equipment.

[0046] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0047] The above specific implementations of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for conveying ultra-thin wafers, applied to a wafer grinding machine for thinning a wafer, characterized in that: The following steps are involved: S1. Affix a UV protective film to the non-thinning surface of the wafer to be thinned, and place the wafer in a wafer grinder to complete wafer thinning and polishing; S2. Adjust the vacuum adsorption capacity of the wafer grinder to ensure that the wafer can float under the action of buoyancy; S3, fixing the ultra-thin wafer conveying device on the wafer grinding machine, the ultra-thin wafer conveying device comprising: a slide, a handle, a baffle, a connecting tube and a carrier; There are two slideways, which are arranged in parallel. The baffles are arranged at both ends of the slideways, and the baffles are used to be fixed to the wafer grinding machine; The connecting tube is respectively sleeved on each of the slideways, at least one of the handles is respectively fixed on the outside of the connecting tubes, the specimen slide is fixed on the inside of the connecting tubes, the horizontal position of the specimen slide is lower than the horizontal position of the connecting tubes, and the specimen slide has a detachable function; S4, start the water spraying program to make the wafer float, and move the specimen slide under the wafer through the handle; S5, turn off the water spraying program, and take out the wafer through the carrier; S6. Using a UV lamp to debond and remove the UV protective film, completing the transfer of the thinned wafer.

2. The method for transferring ultra-thin wafers according to claim 1, wherein: In S1, wafer polishing is completed in the manual mode of the wafer grinder.

3. The method for transferring ultra-thin wafers according to claim 2, wherein: After the wafer polishing is completed, it also includes raising the polishing head of the wafer grinder to the initial position.

4. The method for transferring ultra-thin wafers according to claim 1, wherein: Also includes: S7. Remove the carrier sheet with the thinned wafer and place it into a wafer box.

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