Method for flatly fixing small crystal grains of wafer

Abstract

The invention discloses a method for flatly fixing small crystal grains of a wafer. The method comprises the following steps: S1, dripping an adhesive at the center of the top end of a carrier; s2, placing the crystal grains on an adhesive, and adhering the crystal grains to the top end of a carrier; s3, tiling a piece of diamond paper for covering the crystal grains above the carrier; s4, pressing the rhombic paper by using a plane tool to keep the top ends of the small crystal grains of the wafer flat; and S5, taking down the rhombic paper, and detecting the flatness of the top end of the crystal grain through a detection device. According to the method, the diamond paper and the plane tool are used in a combined mode, the top ends of the small crystal grains of the wafer can be effectively flattened, initial flattening of the crystal grains is achieved before the plane tool presses the crystal grains, the crystal grains are further flattened through follow-up pressing of the round pressing block, and finally the crystal grains are flattened by means of uniform resilience force of the rubber cushion. The flatness of the top end of the crystal grain is ensured, and then the detection accuracy of the cut crystal grain is ensured.

Description

Technical Field

[0001] The patent of this invention relates to the field of chip detection technology, specifically a method for flattening and fixing small crystal grains on a wafer. Background Art

[0002] A grain is a small piece cut from a wafer (commonly known as a wafer grain). As the basic material for semiconductor manufacturing, the wafer will be cut into multiple such small grains after a series of processing steps. Each grain contains a designed complete circuit and is the basic functional unit in electronic equipment.

[0003] Currently, the detection of crystal grains (volume [micrometers]: 60*60*500 high) involves a variety of tests that require cutting the crystal grains to obtain the cross-section surface, such as grain size detection, metallographic inspection, material performance research and failure analysis. Before the test, the crystal grains are usually glued to a specific carrier with an adhesive. However, due to the small size of the crystal grains, it is difficult to ensure that the top of the crystal grain is flat after the gluing is completed, which can easily cause inaccurate cross-sectioning and reduce the accuracy of subsequent tests.

[0004] Invention patent content

[0005] The purpose of the present invention is to provide a method for flattening and fixing small crystal grains on a wafer to solve the problems raised in the above-mentioned background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for flattening and fixing small wafer grains, comprising the following steps:

[0007] S1: Apply adhesive to the center of the top of the carrier;

[0008] S2: placing the die on the adhesive and bonding it to the top of the carrier;

[0009] S3: Lay a piece of diamond-patterned paper on the carrier to cover the grains;

[0010] S4: Use a flat tool to press the diamond paper to keep the top of the small grains on the wafer flat;

[0011] The plane tool is a circular pressing block with a rubber pad bonded to the bottom, a connecting rod is fixedly connected to the top of the circular pressing block, and a hydraulic device is connected to the far end of the connection;

[0012] S41: moving the carrier carrying the crystal grains and the diamond-patterned paper to below the circular pressing block, and aligning the raised portion of the diamond-patterned paper with the center of the circular pressing block;

[0013] S43: starting the hydraulic device to drive the circular pressing block to slowly press down until the rubber pad at the bottom of the circular pressing block fits with the protrusion at the top of the diamond-shaped paper;

[0014] S44: The circular pressing block continues to press downward until the rubber pad fits against the top of the carrier, and the pressing state is maintained until the adhesive is cured;

[0015] S5: remove the diamond-shaped paper and detect the flatness of the top of the grain through a detection device;

[0016] The detection device is an OM optical microscope;

[0017] S51: Remove the diamond pattern paper;

[0018] S52: moving the carrier together with the crystal to the stage of the OM optical microscope, and aligning the crystal with the objective lens;

[0019] S53: Observe through the eyepiece whether the top of the grain is flat.

[0020] In step S52, the stage of the OM optical microscope is in a horizontal state.

[0021] The flatness in step S53 means that the top of the grain has no reflection.

[0022] The beneficial effects achieved by the present invention are:

[0023] 1. By combining the use of diamond paper with flat tools (circular pressing blocks and rubber pads), the top of the small grains on the wafer can be effectively flattened. This method not only achieves the initial flattening of the grains before being pressed by the flat tool, but also further flattens the grains through the subsequent pressure of the circular pressing blocks. Finally, the uniform rebound force of the rubber pad is relied on to ensure the flatness of the top of the grains, thereby ensuring the accuracy of detection after grain cutting.

[0024] 2. By using OM optical microscope for inspection, the flatness of the top of the grain can be accurately observed to ensure product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a control method for a method for flattening and fixing small crystal grains on a wafer in Embodiment 1;

[0026] Figure 2 It is a structural schematic diagram of the leveling tool in the first embodiment;

[0027] Figure 3 This is a diagram showing the resilience of the rubber pad in Example 1. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings.

[0029] Embodiment 1

[0030] like Figure 1-3As shown, the present invention discloses a method for flattening and fixing small crystal grains on a wafer, comprising the following steps:

[0031] S1: Apply adhesive to the center of the top of the carrier;

[0032] S2: placing the die on the adhesive and bonding it to the top of the carrier;

[0033] S3: Lay a piece of diamond-patterned paper on the carrier to cover the grains;

[0034] S4: Use a flat tool to press the diamond paper to keep the top of the small grains on the wafer flat;

[0035] The plane tool is a circular pressing block with a rubber pad bonded to the bottom, a connecting rod is fixedly connected to the top of the circular pressing block, and a hydraulic device is connected to the far end of the connection;

[0036] S41: Pressing two symmetrical ends of the diamond-shaped paper with both hands, and then stretching the two ends of the diamond-shaped paper while keeping the two symmetrical ends of the diamond-shaped paper pressed, so that a bulge is formed at the top of the diamond-shaped paper;

[0037] Specifically, during the stretching process of both ends of the diamond paper, the contact surface between the diamond paper and the crystal grain is stretched to generate downward pressure. After the crystal grain is pressed, the pressure is transmitted to the adhesive. After the adhesive is pressed, it diffuses to the surroundings, and the bottom end of the crystal grain approaches the top end of the carrier, thereby achieving preliminary flattening.

[0038] At the same time, the crystal grains exert a reaction force on the diamond-shaped paper, and the top of the crystal grains is embedded in the diamond-shaped paper, causing the diamond-shaped paper to deform and form a bulge.

[0039] During the stretching process of the two ends of the diamond paper, a downward force is generated, which presses the top of the grain, and the grain moves downward under pressure, with the bottom of the grain close to the top of the carrier;

[0040] S42: moving the carrier carrying the crystal grains and the diamond-patterned paper to below the circular pressing block, and aligning the raised portion of the diamond-patterned paper with the center of the circular pressing block;

[0041] S43: starting the hydraulic device to drive the circular pressing block to slowly press down until the rubber pad at the bottom of the circular pressing block fits with the protrusion at the top of the diamond-shaped paper;

[0042] S44: The circular pressing block continues to press downward until the rubber pad fits against the top of the carrier, and the pressing state is maintained until the adhesive is cured;

[0043] Specifically, in the process of pressing the circular pressing block, the pressure exerted on the circular pressing block acts on the rubber cushion, the diamond-shaped paper, the top of the die and the adhesive in sequence until the bottom of the die is attached to the top of the carrier;

[0044] During this process, the crystal grain generates a reaction force on the rubber pad, the force-bearing surface of the rubber pad is sunken, and the rubber pad around the crystal grain wraps the crystal grain. Based on the elasticity of the rubber material itself, when the rubber pad is sunken, the non-sunken part of the rubber pad will exert a uniform rebound force on the sunken part, thereby uniformly exerting a downward pulling force on the top of the crystal grain, thereby achieving the flatness of the top of the crystal grain.

[0045] S5: remove the diamond-shaped paper and detect the flatness of the top of the grain through a detection device;

[0046] The detection device is an OM optical microscope;

[0047] S51: Remove the diamond pattern paper;

[0048] S52: moving the carrier together with the crystal to the stage of the OM optical microscope, and aligning the crystal with the objective lens;

[0049] S53: Observe through the eyepiece whether the top of the grain is flat.

[0050] In step S52, the stage of the OM optical microscope is in a horizontal state.

[0051] The flatness in step S53 means that the top of the grain has no reflection.

[0052] The patent of the present invention can effectively flatten the top of the small grain on the wafer by combining the use of diamond-shaped paper with flat tools (circular pressing blocks and rubber pads). This method not only achieves the initial flattening of the grain before the flat tool is pressed, but also further flattens the grain through the subsequent pressure of the circular pressing blocks. Finally, the uniform rebound force of the rubber pad is relied on to ensure the flatness of the top of the grain, thereby ensuring the accuracy of the detection after the grain is cut. At the same time, by using an OM optical microscope for detection, the flatness of the top of the grain can be accurately observed to ensure product quality.

[0053] The above are only preferred specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and invention concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for flattening and fixing small crystal grains on a wafer, characterized in that: The steps include: S1: Apply adhesive to the center of the top of the carrier; S2: placing the die on the adhesive and bonding it to the top of the carrier; S3: Lay a piece of diamond-patterned paper on the carrier to cover the grains; S4: Use a flat tool to press the diamond paper to keep the top of the small grains on the wafer flat; S5: Remove the rhombus paper and detect the flatness of the top of the grain using a detection device.

2. The control method for a method for flattening and fixing small wafer grains according to claim 1, characterized in that: The plane tool in step S4 is a circular pressing block with a rubber pad bonded to the bottom, a connecting rod is fixedly connected to the top of the circular pressing block, and a hydraulic device is connected to the distal end of the connection.

3. The method for flattening and fixing small wafer grains according to claim 2, characterized in that: The step S4 includes the following sub-steps: S41: Pressing two symmetrical ends of the diamond-shaped paper with both hands, and then stretching the two ends of the diamond-shaped paper while keeping the two symmetrical ends of the diamond-shaped paper pressed, so that a bulge is formed at the top of the diamond-shaped paper; S42: moving the carrier carrying the crystal grains and the diamond-patterned paper to below the circular pressing block, and aligning the raised portion of the diamond-patterned paper with the center of the circular pressing block; S43: starting the hydraulic device to drive the circular pressing block to slowly press down until the rubber pad at the bottom of the circular pressing block fits with the protrusion at the top of the diamond-shaped paper; S44: The circular pressing block continues to press downward until the rubber pad fits against the top of the carrier, and the pressing state is maintained until the adhesive is cured.

4. The method for flattening and fixing small wafer grains according to claim 1, characterized in that: The detection device in step S5 is an OM optical microscope.

5. The method for flattening and fixing small wafer grains according to claim 4, characterized in that: The step S5 includes the following sub-steps: S51: Remove the diamond pattern paper; S52: moving the carrier together with the crystal to the stage of the OM optical microscope, and aligning the crystal with the objective lens; S53: Observe through the eyepiece whether the top of the grain is flat.

6. The method for flattening and fixing small wafer grains according to claim 5, characterized in that: In step S52, the stage of the OM optical microscope is in a horizontal state.

7. The method for flattening and fixing small wafer grains according to claim 5, characterized in that: The flatness in step S53 means that the top of the grain has no reflection.

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