Wafer warping correction mechanism and correction method

Abstract

The application discloses a wafer warping correction mechanism and a correction method, which comprise a lower vacuum cavity plate, a lower heating plate, a lower suction disc, an upper porous negative pressure suction disc, an upper heating plate, a product debonding accommodation area, a concentric circular groove, a connecting groove and a negative pressure source connecting hole, the lower surface of the lower vacuum cavity plate is provided with the lower heating plate, the upper surface of the lower vacuum cavity plate is provided with the lower suction disc, the upper surface of the upper porous negative pressure suction disc is provided with the upper heating plate, and the upper porous negative pressure suction disc is arranged above the lower suction disc in a position concentric with the lower suction disc to form the product debonding accommodation area. Through the above mode, the wafer warping correction mechanism and the correction method are provided, one-time warping correction is implemented on the upper porous negative pressure suction disc, second-time warping correction is implemented on the lower suction disc, and the wafer is protected from being scratched in the whole debonding operation process, so that the yield is greatly improved, and the production cost is effectively saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wafer debonding, in particular to a wafer warping correction mechanism and a correction method. BACKGROUND

[0002] The bonded wafer product has warping due to the difference in expansion coefficient of different materials or the difference in structure of the two sides of the same material. The traditional debonding equipment directly places the wafer on the silicon carbide chuck surface. During the placement process, the placement process itself has scratches due to horizontal friction. The warped wafer cannot completely adhere to the chuck surface of the silicon carbide chuck. When the silicon carbide chuck is loaded with negative pressure, the wafer is distorted and adheres to the chuck surface under the action of negative pressure. The wafer and the chuck surface are damaged and scrapped due to scratching during the distortion process. SUMMARY

[0003] The technical problem solved by the present application is to provide a wafer warping correction mechanism and a correction method. The product to be debonded is placed with the carrier facing up and the wafer facing down. The wafer is fixed to the product to be debonded by the carrier and the upper multi-hole negative pressure chuck, avoiding the first scratch during wafer placement. The first warping correction is performed on the upper multi-hole negative pressure chuck, avoiding the second scratch when the warped product is forced to be parallel. The second warping correction is performed on the lower silicon carbide chuck, avoiding the third scratch. The wafer is protected from scratches during the entire debonding operation, greatly improving the yield and effectively saving production costs.

[0004] To solve the above technical problems, one technical solution adopted by the present application is to provide a wafer warping correction mechanism, comprising a lower vacuum cavity plate, a lower heating plate, a lower chuck, an upper multi-hole negative pressure chuck, an upper heating plate, a product debonding containing area, a concentric circular groove, a connecting groove, and a negative pressure source connecting hole. The lower surface of the lower vacuum cavity plate is equipped with a lower heating plate. The upper surface of the lower vacuum cavity plate is placed with a lower chuck. The upper surface of the upper multi-hole negative pressure chuck is equipped with an upper heating plate. The upper multi-hole negative pressure chuck is arranged vertically above the lower chuck and concentrically matched to form a product debonding containing area. The lower surface of the upper multi-hole negative pressure chuck is parallel and opposite to the lower chuck. The upper surface of the lower vacuum cavity plate is provided with a plurality of concentric circular grooves. The connecting grooves are arranged between every two adjacent concentric circular grooves along the radial direction. Each concentric circular groove connected by the connecting grooves is provided with a negative pressure source connecting hole. The negative pressure source connecting hole vertically penetrates the lower vacuum cavity plate and independently connects a negative pressure gas source.

[0005] In a preferred embodiment of the present application, the negative pressure source connecting hole is provided with at least 3.

[0006] In a preferred embodiment of the present application, the lower surface of the lower chuck completely covers the concentric circular grooves.

[0007] A wafer warping correction method is also provided, comprising the following steps:

[0008] Step one, preparing wafer raw material warped and bonded on a slide;

[0009] Step two, establishing a first correction plane of high-temperature negative pressure on the upper porous negative pressure chuck;

[0010] Step three, traceless adsorbing the slide by the first correction plane, taking the first correction plane as the deformation basis, making the slide soften and flatten under the action of high-temperature negative pressure to form intermediate raw material;

[0011] Step four, establishing a second correction plane of high-temperature negative pressure on the lower chuck;

[0012] Step five, traceless adsorbing the wafer on the intermediate raw material by the second correction plane, performing regular debonding to obtain the debonded wafer;

[0013] Step six, progressively releasing the negative pressure of the second correction plane on the debonded wafer from outside to inside along the radial direction of the debonded wafer;

[0014] Step seven, completing the warping correction, and discharging the debonded wafer.

[0015] The wafer warping correction mechanism and method provided by the application can avoid the first scratch of the wafer when the wafer is placed, the second scratch when the warped product is forced to be parallel, and the third scratch when the wafer is debonded, and can protect the wafer from being scratched during the whole debonding process, greatly improve the yield, and effectively save the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor.

[0017] Figure 1 is a structure diagram of a preferred embodiment of the wafer warping correction mechanism and method of the application;

[0018] Figure 2 is a structure diagram of a preferred embodiment of the wafer warping correction mechanism and method of the application;

[0019] Figure 3is a structural diagram of a preferred embodiment of a wafer warping correction mechanism and correction method of the present application;

[0020] Figure 4 is a structural diagram of a preferred embodiment of a wafer warping correction mechanism and correction method of the present application;

[0021] Figure 5 is a structural diagram of a preferred embodiment of a wafer warping correction mechanism and correction method of the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0023] As shown in Figures 1-5 the present application comprises:

[0024] A wafer warping correction mechanism comprises a lower vacuum cavity plate 1, a lower heating plate 2, a lower chuck 3, an upper porous negative pressure chuck 4, an upper heating plate 5, a product debonding accommodation area 6, concentric circular grooves 7, connecting grooves 8, and negative pressure source connecting holes 9. The lower surface of the lower vacuum cavity plate 1 is equipped with the lower heating plate 2. The upper surface of the lower vacuum cavity plate 1 is placed with the lower chuck 3. The upper surface of the upper porous negative pressure chuck 4 is equipped with the upper heating plate 5. The upper porous negative pressure chuck 4 is arranged in the position directly above the lower chuck 3 and is concentrically matched with each other to form the product debonding accommodation area 6. The lower surface of the upper porous negative pressure chuck 4 is parallel to and directly opposite to the lower chuck 3. The upper surface of the lower vacuum cavity plate 1 is provided with a plurality of concentric circular grooves 7. Connecting grooves 8 are provided between every two adjacent concentric circular grooves 7 along the radial direction. Each concentric circular groove 7 connected in series by the connecting groove 8 is provided with one negative pressure source connecting hole 9. The negative pressure source connecting hole 9 vertically penetrates the lower vacuum cavity plate 1 and independently circumscribes a negative pressure gas source.

[0025] The lower chuck is a silicon carbide chuck or a porous ceramic chuck with similar functions, a porous sapphire chuck, etc.

[0026] The negative pressure source connecting hole 9 is provided with at least three.

[0027] Further, the lower surface of the lower chuck 3 completely covers the concentric circular grooves 7.

[0028] A wafer warping correction method comprises the following steps:

[0029] Step one, prepare a wafer raw material warped and bonded on a slide;

[0030] Step two, establish a high temperature negative pressure of the first correction plane, in this embodiment, the first correction plane is the upper porous negative pressure suction disc 4, the disc surface of the upper porous negative pressure suction disc 4 is uniformly distributed with a large number of vacuum round holes, the upper surface of the upper porous negative pressure suction disc 4 is sealed and assembled with the lower surface of the heating plate to form an upper vacuum cavity, the heating plate provides a high temperature environment, and the upper vacuum cavity is circumscribed by a negative pressure pump source to provide a negative pressure environment; the disc surface of the porous suction disc is pure flat, which provides an absolute plane required for correction;

[0031] Step three, the wafer is non-marksly adsorbed on the first correction plane, and the wafer is softened under the action of high temperature and negative pressure until it is flattened to form an intermediate material; in this embodiment, the wafer is non-marksly loaded on the first correction plane (i.e. the upper porous negative pressure suction disc 4) by using a non-mark concentric mechanism, wherein one side of the wafer is attached to the porous suction disc; different from the prior art, the flattening operation in this embodiment is transferred to the upper suction disc, so that the unavoidable friction occurs between the wafer and the porous upper suction disc 4, thereby protecting the wafer. Under the action of vacuum and high temperature, the wafer is softened and slowly flattened on the correction plane.

[0032] Step four, establish a high temperature negative pressure of the second correction plane; the second correction plane is the lower suction disc 3 in this embodiment, which is used not only for debonding but also for secondary warping correction of the wafer after debonding operation, and the steps are as follows.

[0033] Step five, the wafer on the intermediate material is non-marksly adsorbed on the second correction plane to perform conventional debonding to obtain a debonded wafer; the lower suction disc 3 realizes the effects of scratch prevention and debonding in this step. Since the wafer is softened and flattened in step three, the intermediate material is completely parallel to the second correction plane, thereby achieving the process condition required for debonding. Due to the complete parallelism, the process of adsorbing and fixing the wafer by the second correction plane (the lower suction disc 3) only has z-axis adsorption displacement, completely avoiding the x-axis and y-axis displacement caused by warping, thereby effectively avoiding the scratch problem of the wafer.

[0034] Step six, the negative pressure pressure of the second correction plane acting on the debonded wafer is progressively released along the radial direction of the debonded wafer from the outside to the center of the circle; the lower suction disc 3 realizes the effect of secondary warping correction in this step. The negative pressure of the lower suction disc 3 is provided by the lower vacuum cavity plate 1, as shown in Figure 4 、 5As shown, the lower vacuum cavity plate 1 is divided into three independent cavities: a primary cavity 21, a secondary cavity 22, and a tertiary cavity 23. Depending on the wafer size, debonding of 4-inch wafers uses the primary and secondary cavities 22 for vacuum adsorption, while debonding of 6-inch wafers uses the primary, secondary, and tertiary cavities 23 for vacuum adsorption. After debonding is complete, to prevent wafer warping recurrence under stress, the negative pressure within the cavities needs to be released in stages from the outside in. First, the negative pressure in the tertiary cavity 23 is released, then the negative pressure in the secondary cavity 22 is released, and finally the negative pressure in the primary cavity 21 is released.

[0035] Step 7: Warp correction completed, unbonded wafers discharged.

[0036] In summary, this invention provides a wafer warpage correction mechanism and method. With the wafer to be debonded facing upwards and the product facing downwards, the wafer is first fixed to the product by the carrier and an upper multi-hole negative pressure chuck, preventing primary scratches during wafer placement. First, warpage correction is performed on the upper multi-hole chuck, preventing secondary scratches when the warped product is forced parallel. Second, warpage correction is performed on the lower silicon carbide chuck, preventing tertiary scratches. This provides scratch protection for the wafer throughout the entire debonding process, significantly improving yield and effectively saving production costs.

[0037] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A wafer warpage correction method, characterized by, The method comprises the following steps: Step one, prepare wafer raw materials warped and bonded on a slide; step two, establish a first correction plane of high-temperature negative pressure on the upper porous negative pressure chuck; step three, non-markedly adsorb the slide from the first correction plane, take the first correction plane as the deformation basis, make the slide soften under the action of high-temperature negative pressure until it is flattened, and form an intermediate raw material; step four, establish a second correction plane of high-temperature negative pressure on the lower chuck, and the intermediate raw material is completely parallel to the second correction plane; step five, non-markedly adsorb the wafer on the intermediate raw material from the second correction plane, perform regular unbonding, and obtain an unbonded wafer; step six, the negative pressure of the second correction plane acting on the unbonded wafer is progressively released from outside to inside along the radial direction of the unbonded wafer; step seven, the warping correction is completed, and the unbonded wafer is discharged.

2. A wafer warping correction mechanism for use in the wafer warping correction method of claim 1, characterized by, The device comprises a lower vacuum cavity plate, a lower heating plate, a lower chuck, an upper porous negative pressure chuck, an upper heating plate, a product unbonding containing area, concentric circular grooves, connecting grooves, and negative pressure source connecting holes. The lower surface of the lower vacuum cavity plate is assembled with the lower heating plate. The upper surface of the lower vacuum cavity plate is placed with the lower chuck. The upper surface of the upper porous negative pressure chuck is assembled with the upper heating plate. The upper porous negative pressure chuck is arranged in the position directly above the lower chuck and is concentrically matched to form the product unbonding containing area. The lower surface of the upper porous negative pressure chuck is parallel and opposite to the lower chuck. The upper surface of the lower vacuum cavity plate is provided with a plurality of concentric circular grooves. The connecting grooves are arranged between every two adjacent concentric circular grooves along the radial direction. Each concentric circular groove connected by the connecting grooves is provided with one negative pressure source connecting hole. The negative pressure source connecting hole vertically penetrates the lower vacuum cavity plate and independently connects the negative pressure gas source. There are at least three negative pressure source connecting holes. The lower disc surface of the lower chuck completely covers the concentric circular grooves.

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