Integrated chip flip-chip leveling method, system and chip

Abstract

A method, system, and chip for leveling an integrated chip flip-chip solder joint, comprising the following steps: Step 100: placing curved mirrors at multiple chip illumination points on the chip and multiple substrate illumination points on the substrate; Step 200: outputting detection beams to the chip and substrate, respectively, and adjusting the substrate position based on the reflectivity of the detection beams on each curved mirror, so that each substrate illumination point is aligned with its corresponding chip illumination point; Step 300: obtaining the alignment distance value between each chip illumination point and its corresponding substrate illumination point; Step 400: moving the substrate to an initial position so that the chip illumination point corresponding to the maximum alignment distance value approaches its corresponding substrate illumination point, and then skipping to Step 200 until all alignment distance values ​​simultaneously meet a preset leveling condition. The present invention achieves chip-substrate leveling without increasing the laser emission intensity or the absorption area of ​​the reflected light detector, thereby reducing the complexity and manufacturing cost of the equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated chip packaging, and specifically relates to an integrated chip flip-chip leveling method, an integrated chip flip-chip leveling system for implementing the leveling method, and an integrated chip manufactured using the flip-chip leveling method. Background Art

[0002] Flip-chip bonding is a packaging technology widely used in integrated chip production. Through layout design, corresponding bumps are formed on the surfaces of the chip and substrate, respectively. Through alignment and lamination, ultra-high-density pinouts are achieved. This technology boasts superior electrical properties with high frequency, low latency, and low crosstalk, making it suitable for applications in compound optoelectronics, microLEDs, infrared, and ultraviolet focal plane devices. Leveling is a critical step in existing flip-chip bonding processes. This is primarily accomplished using optical modules such as a coaxial microscope and a laser rangefinder built into the equipment. The coaxial microscope provides the operator with a field of view, while the laser rangefinder transmits and receives reflected light from the chip and substrate, measuring the distance between them and adjusting their relative position based on feedback. Repeated feedback adjustments ensure that the lamination surfaces of the substrate and chip are perfectly parallel, completing the leveling process. In practice, the complex microstructures on the chip and substrate surfaces cause diffuse reflections from the detection beam emitted by the laser rangefinder. Therefore, conventional methods typically increase the intensity of the reflected light by increasing the laser emission intensity or by increasing the absorption area of ​​the reflected light detector. Both of these solutions increase the complexity and manufacturing cost of the equipment. Therefore, how to develop a new flip-chip bonding method to overcome the above-mentioned defects of the prior art is a research direction for those skilled in the art. Summary of the Invention

[0003] The first object of the present invention is to provide an integrated chip flip-chip bonding method for reducing the complexity and preparation cost of the equipment while achieving leveling of the chip and the substrate.

[0004] A second object of the present invention is to provide an integrated chip flip-chip leveling system for implementing the above flip-chip leveling method.

[0005] The third object of the present invention is to provide an integrated chip, which is manufactured using the above-mentioned flip-chip leveling method.

[0006] The first technical solution provided by the present invention is a method for leveling an integrated chip flip-chip.

[0007] It comprises the following steps:

[0008] Step 100: Setting a first curved mirror at a plurality of chip irradiation points on a first surface of the chip and a second curved mirror at a plurality of substrate irradiation points on a second surface of the substrate, respectively, so that the chip irradiation points correspond one-to-one with the substrate irradiation points, and moving the chip and substrate to their initial positions respectively;

[0009] Step 200: Outputting a detection beam to the first surface of the chip and the second surface of the substrate, respectively, and adjusting the relative position of the substrate to the chip based on the reflectivity of the detection beam on each of the first curved mirror and the second curved mirror, so that each substrate illumination point is sequentially moved to a position where its corresponding chip illumination point is considered aligned;

[0010] Step 300: Obtaining alignment distance values ​​between each chip irradiation point and its corresponding substrate irradiation point;

[0011] Step 400: moving the substrate to an initial position, and adjusting the relative position of the chip to the substrate based on the alignment distance values ​​so that the irradiation point of the chip with the largest alignment distance value is closer to the corresponding irradiation point of the substrate;

[0012] Step 500: Repeat steps 200 to 400 until all alignment distance values ​​simultaneously meet the preset leveling conditions.

[0013] Preferably, step 100 includes:

[0014] Step 110: setting a plurality of non-collinear chip illumination points on the first surface of the chip, and setting a plurality of substrate illumination points at corresponding positions on the second surface of the substrate, so that the substrate illumination points correspond one-to-one with the chip illumination points;

[0015] Step 120: Obtain a first theoretical distance value between the laser source and the irradiation point of the chip and a second theoretical distance value between the laser source and the irradiation point of the substrate;

[0016] Step 130: placing a first curved mirror having a curvature radius consistent with a first theoretical spacing value at the chip irradiation point, and placing a second curved mirror having a curvature radius consistent with a second theoretical spacing value at the substrate irradiation point;

[0017] Step 140 : placing the substrate on a horizontal plane so that the first surface of the chip is opposite to the second surface of the substrate.

[0018] Preferably, step 200 includes:

[0019] Step 210: Disposing a laser source for outputting an uplink light beam and a downlink light beam between the first surface and the second surface;

[0020] Step 220: Select a chip irradiation point and a corresponding substrate irradiation point, and move the laser source until the reflectivity of the first curved mirror of the uplink beam of the laser source at the selected chip irradiation point reaches a preset first threshold;

[0021] Step 230: Horizontally rotate the substrate until the reflectivity of the second curved mirror of the downstream beam of the laser source at the selected substrate irradiation point reaches a preset first threshold, that is, the selected substrate irradiation point is considered to be moved to a position where it is aligned with the corresponding chip irradiation point.

[0022] Step 240: Repeat steps 220 to 230 until each substrate irradiation point is sequentially moved to a position where the corresponding chip irradiation point is aligned;

[0023] Preferably, step 300 includes: step 310, obtaining the alignment distance value between each chip irradiation point and its corresponding substrate irradiation point based on a laser range finder.

[0024] Preferably, step 400 includes:

[0025] Step 410: Obtain the pairwise differences between the alignment distance values;

[0026] Step 420: Compare the pairwise differences obtained in step 410 with a preset second threshold value. When at least one of the pairwise differences is greater than the second threshold value, jump to step 430; otherwise, it is considered that the chip and the substrate have been leveled.

[0027] Step 430: Obtain the chip irradiation point corresponding to the maximum value of the alignment distance values ​​and the corresponding substrate irradiation point;

[0028] Step 440: Move the substrate to an initial position, and adjust the relative position of the chip and the substrate so that the chip irradiation point selected in step 430 is close to the corresponding substrate irradiation point.

[0029] Preferably, step 440 includes rotating the chip in the z-axis direction with the geometric center point of the chip as the center of the circle and the line connecting the geometric center of the chip and the chip irradiation point as the spiral arm so that the z-axis coordinate of the chip irradiation point in step 430 decreases.

[0030] Preferably, step 420 further includes: when each of the pairwise differences is less than the second threshold, removing each first curved mirror from the chip irradiation point, and removing each second curved mirror from the substrate irradiation point.

[0031] Preferably, the mirror body surface of the first curved mirror and the mirror body surface of the second curved mirror are respectively coated with a reflective coating.

[0032] The second technical solution provided by the present invention is an integrated chip flip-chip leveling system for implementing the above-mentioned flip-chip leveling method, which comprises:

[0033] a pre-processing module, the pre-processing module being configured to respectively set a first curved mirror at a plurality of chip irradiation points on a first surface of the chip and a second curved mirror at a plurality of substrate irradiation points on a second surface of the substrate, so that the chip irradiation points correspond one-to-one with the substrate irradiation points, and move the chip and the substrate to their initial positions;

[0034] an alignment module, the alignment module being configured to move the chip and the substrate to initial positions, output a detection beam to the first surface of the chip and the second surface of the substrate, respectively, and adjust the relative position of the substrate to the chip based on the reflectivity of the detection beam on each of the first curved mirror and the second curved mirror, so that each substrate illumination point is sequentially moved to a position where its corresponding chip illumination point is considered aligned;

[0035] a calculation module, the calculation module being used to respectively obtain an alignment distance value between each chip irradiation point and its corresponding substrate irradiation point;

[0036] A leveling module is used to return the substrate to its initial position and adjust the relative position of the chip to the substrate based on each alignment distance value, so that the chip irradiation point corresponding to the largest alignment distance value approaches the corresponding substrate irradiation point, and restart the alignment module and the operation module until each alignment distance value simultaneously meets the preset leveling conditions.

[0037] The third technical solution provided by the present invention is an integrated chip, which is manufactured using the above-mentioned flip-chip leveling method.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] First, the present invention can achieve leveling of the chip and the substrate without increasing the laser emission intensity or the absorption area of ​​the reflected light detector, thereby reducing the complexity and preparation cost of the equipment.

[0040] Secondly, the present invention avoids the adverse effects of the curved mirrors on the surfaces of the chip and substrate on subsequent processes by efficiently removing the curved mirrors.

[0041] Finally, the device of the present invention has a simple structure, convenient operation steps, and is easy to implement in mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1a The figure is a flow chart of the integrated chip flip-chip leveling method;

[0043] Figure 1b The specific working flow diagram of Example 1

[0044] Figure 2 This is a functional module diagram of Example 2;

[0045] Figure 3 This is a schematic diagram of the working state of Example 2, in which the loading platform and the manipulator holding the laser source are omitted;

[0046] Figure 4 for Figure 3 Enlarged view of area A in the middle;

[0047] Figure 5 for Figure 3 Magnified view of area B.

[0048] In the figures, the component names corresponding to the reference numerals are as follows:

[0049] 100. Pre-processing module; 200. Alignment module; 300. Operation module; 400. Leveling module; 1. Chip; 2. Substrate; 3. Laser source; 4. Upward beam; 5. Downward beam; 6. Chip irradiation point; 7. First curved mirror; 8. Substrate irradiation point; 9. Second curved mirror. DETAILED DESCRIPTION

[0050] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and functions of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the present invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0051] It should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0052] Example 1, please refer to Figure 1:

[0053] A method for leveling an integrated chip flip-chip, comprising the following steps:

[0054] Step 110: Set a plurality of non-collinear chip irradiation points 6 on the first surface of the chip 1, and set a plurality of substrate irradiation points 8 at corresponding positions on the second surface of the substrate 2, and make the substrate irradiation points 8 and the chip irradiation points 6 satisfy a one-to-one correspondence; in practice, based on the principle that three non-collinear points can determine a plane, the number of the chip irradiation points 6 and the substrate irradiation points 8 is set to 3-5.

[0055] Step 120: Based on the preset heights of the chip 1, substrate 2, and laser source 3 during the leveling process, respectively obtain a first theoretical spacing value between the laser source 3 and the chip irradiation point 6 and a second theoretical spacing value between the laser source 3 and the substrate irradiation point 8;

[0056] Step 130: A first curved mirror 7 having a curvature radius consistent with the first theoretical spacing value is disposed at each of the chip irradiation points 6, and a second curved mirror 9 having a curvature radius consistent with the second theoretical spacing value is disposed at each of the substrate irradiation points 8. Preferably, a reflective coating may be further applied to the mirror body surface of the first curved mirror 7 and the mirror body surface of the second curved mirror 9. The reflective coating may be a highly reflective metal layer.

[0057] Step 140: Place the plate body of the substrate 2 on a horizontal plane, and place the first surface of the chip 1 opposite to the second surface of the substrate 2; in this example: fix the substrate 2 and the chip 1 on the upper and lower loading platforms respectively, and place the second surface of the substrate 2 below the first surface of the chip 1.

[0058] Step 210: a laser source 3 for outputting an uplink beam and a downlink beam is provided between the first surface and the second surface. In this example, a laser rangefinder is integrated on the laser source 3 to achieve synchronous execution of alignment and distance measurement.

[0059] Step 220: Select a chip irradiation point 6 and a corresponding substrate irradiation point 8, and move the laser source 3 until the reflectivity of the first curved mirror 7 of the upward beam of the laser source 3 on the selected chip irradiation point 6 reaches a preset first threshold;

[0060] Step 230: Horizontally rotating the substrate 2 until the reflectivity of the downlink beam of the laser source 3 on the second curved mirror 9 at the selected substrate irradiation point 8 reaches a preset first threshold value, that is, the selected substrate irradiation point 8 is considered to be moved to a position where it is aligned with the corresponding chip irradiation point 6;

[0061] Step 240: Repeat steps 220 to 230, so that each substrate irradiation point 8 moves in turn to a position where it is aligned with its corresponding chip irradiation point 6; it should be noted here that: during the execution of this step, since the substrate 2 needs to be rotated multiple times, when a certain substrate irradiation point 8 is aligned with its corresponding chip irradiation point 6, if other substrate irradiation points 8 have already been aligned with their corresponding chip irradiation points 6, the relative positions of the previously aligned substrate irradiation points 8 and chip irradiation points 6 will change.

[0062] Step 310: Obtaining alignment distance values ​​between each chip irradiation point 6 and its corresponding substrate irradiation point 8 using a laser rangefinder;

[0063] Step 410: Obtain the pairwise differences between the alignment distance values;

[0064] Step 420: Compare the pairwise differences obtained in step 410 with a preset second threshold value. When at least one of the pairwise differences is greater than the second threshold value, jump to step 430. When the pairwise differences are all less than the second threshold value, it is considered that the chip 1 and the substrate 2 have been leveled. In order to avoid the curved mirrors set on the surface of the chip 1 and the substrate 2 affecting the subsequent process, each first curved mirror 7 is removed from the chip irradiation point 6, and each second curved mirror 9 is removed from the substrate irradiation point 8. In practice, in order to facilitate the removal of the curved mirror and prevent the removal process from interfering with the leveling result, ultraviolet photosensitive adhesive is selected to fix the curved mirror to the surface of the chip 1 and the substrate 2, and UV lamp irradiation and air blowing are used to complete the removal of the curved mirror from the surface of the chip 1 and the substrate 2.

[0065] Step 430: Obtain the chip irradiation point 6 corresponding to the maximum value of the alignment distance values ​​and the corresponding substrate irradiation point 8;

[0066] Step 440: Move substrate 2 to its initial position, then adjust the relative positions of chip 1 and substrate 2 so that chip illumination point 6, corresponding to the maximum of the alignment distance values, approaches its corresponding substrate illumination point 8. Specifically, with chip 1's geometric center as the center of a circle and the line connecting the chip's geometric center and chip illumination point 6 as the arm, rotate chip 1 in the z-axis direction so that the z-axis coordinate of chip illumination point 6 in step 430 decreases.

[0067] Example 2, please refer to Figure 2-5 :

[0068] A flip-chip leveling system for implementing the flip-chip leveling method of embodiment 1 includes: a pre-processing module 001, an alignment module 002, a calculation module 003 and a leveling module 004.

[0069] The preprocessing module 001 is used to set a first curved mirror 7 at several chip irradiation points 6 on the first surface of the chip 1, and to set a second curved mirror 9 at several substrate irradiation points 8 on the second surface of the substrate 2, so that the chip irradiation points 6 correspond to the substrate irradiation points 8 one by one, and move the chip 1 and the substrate 2 to the initial positions respectively; in practice, the preprocessing module 001 may further include an operation unit for calculating the first theoretical spacing value and the second theoretical spacing value, a curved mirror processing device for producing the first curved mirror 7 and the second curved mirror 9, and a curved mirror mounting device for setting the first curved mirror 7 and the second curved mirror 9 on the surfaces of the chip 1 and the substrate 2 respectively; the chip 1 and the substrate 2 are respectively fixed on two movable loading platforms.

[0070] The alignment module 002 is used to move the chip 1 and substrate 2 to their initial positions, output detection beams to the first surface of the chip 1 and the second surface of the substrate 2, respectively, and adjust the relative position of the substrate 2 to the chip 1 based on the reflectivity of the detection beams on the first curved mirror 7 and the second curved mirror 9, so that each substrate illumination point 8 is sequentially moved to a position that is considered aligned with its corresponding chip illumination point 6. In practice, a robot is used to move the laser source 3 used to output the detection beam. The laser source 3 is also integrated with a laser rangefinder for real-time distance measurement.

[0071] The calculation module 003 is used to respectively obtain the alignment distance value between each chip irradiation point 6 and its corresponding substrate irradiation point 8; the calculation module 003 is implemented by a data processing unit having data processing capabilities. The calculation module 003 can further display its calculation results by transmitting data to a display unit having display capabilities.

[0072] The leveling module 004 is used to return the substrate 2 to its initial position and adjust the relative position of the chip 1 to the substrate 2 based on the alignment distance values, so that the chip illumination point 6 corresponding to the largest alignment distance value approaches the corresponding substrate illumination point 8. The alignment module 002 and the calculation module 003 are then restarted until all alignment distance values ​​simultaneously meet the preset leveling conditions. The leveling module 004 includes a drive device for driving the two loading platforms and a control device for controlling the operation of the drive device.

[0073] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A method for leveling an integrated chip flip-chip, characterized in that: The steps include: Step 100: Setting a first curved mirror at a plurality of chip irradiation points on a first surface of the chip and a second curved mirror at a plurality of substrate irradiation points on a second surface of the substrate, respectively, so that the chip irradiation points correspond one-to-one with the substrate irradiation points, and moving the chip and substrate to their initial positions respectively; Step 200: Outputting a detection beam to the first surface of the chip and the second surface of the substrate, respectively, and adjusting the relative position of the substrate to the chip based on the reflectivity of the detection beam on each of the first curved mirror and the second curved mirror, so that each substrate illumination point is sequentially moved to a position where its corresponding chip illumination point is considered aligned; Step 300: Obtaining alignment distance values ​​between each chip irradiation point and its corresponding substrate irradiation point; Step 400: moving the substrate to an initial position, and adjusting the relative position of the chip to the substrate based on the alignment distance values ​​so that the irradiation point of the chip with the largest alignment distance value is closer to the corresponding irradiation point of the substrate; Repeat steps 200 to 400 until all alignment distance values ​​simultaneously meet the preset leveling conditions; Wherein, step 100 includes: Step 110: setting a plurality of non-collinear chip illumination points on the first surface of the chip, and setting a plurality of substrate illumination points at corresponding positions on the second surface of the substrate, so that the substrate illumination points correspond one-to-one with the chip illumination points; Step 120: Obtain a first theoretical distance value between the laser source and the irradiation point of the chip and a second theoretical distance value between the laser source and the irradiation point of the substrate; Step 130: placing a first curved mirror having a curvature radius consistent with a first theoretical spacing value at the chip irradiation point, and placing a second curved mirror having a curvature radius consistent with a second theoretical spacing value at the substrate irradiation point; Step 140 : placing the substrate on a horizontal plane so that the first surface of the chip is opposite to the second surface of the substrate.

2. The flip chip leveling method according to claim 1, wherein: Step 200 includes: Step 210: Disposing a laser source for outputting an uplink light beam and a downlink light beam between the first surface and the second surface; Step 220: Select a chip irradiation point and a corresponding substrate irradiation point, and move the laser source until the reflectivity of the first curved mirror of the uplink beam of the laser source at the selected chip irradiation point reaches a preset first threshold; Step 230: Horizontally rotating the substrate until the reflectivity of the second curved mirror at the selected substrate illumination point of the downlink beam of the laser source reaches a preset first threshold, i.e., the selected substrate illumination point is considered to be moved to a position where it is aligned with the corresponding chip illumination point; Step 240: Repeat steps 220 to 230, and move each substrate irradiation point in sequence to a position where the corresponding chip irradiation point is considered to be aligned.

3. The flip chip leveling method according to claim 1, wherein: Step 300 includes: obtaining alignment distance values ​​between each chip irradiation point and its corresponding substrate irradiation point based on a laser range finder.

4. The flip chip leveling method according to claim 1, wherein: Step 400 includes: Step 410: Obtain the pairwise differences between the alignment distance values; Step 420: Compare the pairwise differences obtained in step 410 with a preset second threshold value. When at least one of the pairwise differences is greater than the second threshold value, jump to step 430; otherwise, it is considered that the chip and the substrate have been leveled. Step 430: Selecting the chip irradiation point corresponding to the maximum value of the alignment distance values ​​and the corresponding substrate irradiation point; Step 440: Move the substrate to an initial position, and adjust the relative position of the chip and the substrate so that the chip irradiation point selected in step 430 is close to the corresponding substrate irradiation point.

5. The flip chip leveling method according to claim 4, wherein: Step 440 includes rotating the chip in the z-axis direction with the geometric center of the chip as the center of the circle and the line connecting the geometric center of the chip and the chip irradiation point as the arm to reduce the z-axis coordinate of the chip irradiation point in step 430.

6. The flip chip leveling method according to claim 4, wherein: Step 420 further includes: when each of the pairwise differences is less than the second threshold, removing each first curved mirror from the chip irradiation point, and removing each second curved mirror from the substrate irradiation point.

7. The flip chip leveling method according to claim 1, wherein: The mirror body surface of the first curved mirror and the mirror body surface of the second curved mirror are respectively coated with a reflective coating.

8. An integrated chip flip chip leveling system for implementing the flip chip leveling method according to any one of claims 1 to 7, characterized in that: include: a pre-processing module, the pre-processing module being configured to respectively set a first curved mirror at a plurality of chip irradiation points on a first surface of the chip and a second curved mirror at a plurality of substrate irradiation points on a second surface of the substrate, so that the chip irradiation points correspond one-to-one with the substrate irradiation points, and move the chip and the substrate to their initial positions; an alignment module, the alignment module being configured to output a detection beam to the first surface of the chip and the second surface of the substrate, respectively, and to adjust the relative position of the substrate to the chip based on the reflectivity of the detection beam on each of the first curved mirror and the second curved mirror, so that each substrate illumination point is sequentially moved to a position where its corresponding chip illumination point is considered aligned; a calculation module, the calculation module being used to respectively obtain an alignment distance value between each chip irradiation point and its corresponding substrate irradiation point; A leveling module is used to return the substrate to its initial position and adjust the relative position of the chip to the substrate based on each alignment distance value, so that the chip irradiation point corresponding to the largest alignment distance value approaches the corresponding substrate irradiation point, and restart the alignment module and the operation module until each alignment distance value simultaneously meets the preset leveling conditions.

9. An integrated chip, characterized in that: The device is manufactured by the flip-chip leveling method according to any one of claims 1 to 7.

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