Chip packaging and bonding equipment

Abstract

The invention relates to the technical field of chip packaging, and particularly discloses chip packaging bonding equipment which comprises a feeding assembly, a bonding head assembly and a bonding platform. The feeding assembly comprises a chip adsorption head and an XYZ three-axis sliding table; the bonding head assembly comprises a 6-DoF piezoelectric platform, a micropore array suction cup and a machine vision positioning module. The bonding platform is a leveling hot plate platform with a telescopic structure; a hot plate and an infrared laser array are arranged on the leveling hot plate platform, and 128 independent temperature control units are arranged on the hot plate in a partitioned manner; the 6-DoF piezoelectric platform, the micropore array suction cup, the machine vision positioning module, the hot plate and the infrared laser array are all electrically connected with a photon AI processing system. The technical problems that in the prior art, when the chip is curled in the bonding process, mechanical correction of mechanical hard pressing and rigid limiting is mainly adopted, so that the stress of the bonded chip remains, and microcracks are caused are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip packaging, in particular to a chip packaging bonding device. BACKGROUND

[0002] Chip bonding device, also known as bonder or die bonder, is the most critical and core device in the chip mounting link of semiconductor post-process packaging and testing. The bonder is mainly used for mounting bare chips or micro electronic components, and is used to install the chips on lead frames, heat sinks, substrates or directly on PCBs, so as to realize the electrical connection between the chips and the outside. The chip bonding not only requires that the packaged chip product can withstand the physical pressure of subsequent assembly and dissipate the heat generated during the operation of the chip, but also requires that it must maintain constant conductivity and achieve high level of insulation.

[0003] In the traditional technology, the bonding of the chip is mainly wire bonding, which is an interconnection technology connecting the chip pad and the packaging substrate through micron-level metal wires. However, due to the connection between the chip and the substrate by metal wires, the high-frequency performance is relatively poor, so the flip bonding process appears in the industry. Flip bonding is an advanced packaging technology that directly bonds the integrated circuit chip active surface downward to the substrate. Compared with traditional wire bonding, flip bonding directly uses the functional surface (including I / O pads) of the chip to align the substrate downward, and realizes electrical connection through micron-level solder bumps or copper columns. Therefore, it omits the interconnection line of traditional wire bonding, greatly reduces the capacitance and inductance of interconnection, especially meets the needs of high-frequency and high-speed electronic products. At the same time, the area occupied by the substrate can significantly improve the chip mounting density. However, the bonding process is carried out by hot pressing, and due to the difference in thermal expansion coefficient between the chip and the substrate and other materials, deformation occurs when the temperature changes. For example, the difference between the silicon chip (CTE≈3.5ppm / °C) and the packaging substrate (such as epoxy resin CTE≈15-20ppm / °C) will cause thermal stress concentration, causing the chip to curl, which will exacerbate the stress concentration when the temperature changes, leading to solder fatigue, and eventually causing solder cracking or device failure. Therefore, how to avoid or reduce the curling of the chip during flip bonding is an inevitable technical difficulty in flip bonding production.

[0004] In the prior art, to solve the problem of curling of the chip, a metal or ceramic tray is usually used to fix the substrate and the chip to ensure the flatness of the substrate during high-temperature processing. Double-layer clamps are usually used for clamping, and uniform pressure is applied to ensure consistent stress on the bonding interface and maintain structural stability. However, this method only uses mechanical correction by mechanical hard pressure and rigid limiting, which cannot eliminate the stress concentration between the chip and the substrate during the bonding process, although it can temporarily flatten the chip, but the stress remains after cooling, causing micro-cracks. SUMMARY

[0005] The chip packaging bonding device aims to solve the technical problem that the existing technology mainly adopts mechanical correction of mechanical hard pressing and rigid limiting to correct the chip curling problem in the bonding process, so that the stress of the bonded chip remains and micro cracks are caused.

[0006] In order to solve the above problems, the technical scheme adopted by the present application is as follows: a chip packaging bonding device, comprising a feeding assembly, a bonding head assembly and a bonding platform; the feeding assembly comprises a chip suction head for rotating the chip to form an inverted position; an XYZ three-axis sliding table for moving the chip to the bonding platform; the bonding head assembly comprises a 6-DoF piezoelectric platform for adjusting the angle of the chip in six degrees of freedom, a micropore array suction disc and a machine vision positioning module; the bonding platform is a telescopic adjustable flat heat plate platform; the adjustable flat heat plate platform is provided with a heat plate and an infrared laser array for heating during the bonding process, and the heat plate is provided with 128 independent temperature control units; the 6-DoF piezoelectric platform, the micropore array suction disc, the machine vision positioning module, the heat plate and the infrared laser array are electrically connected with a photon AI processing system.

[0007] Further, it further comprises a lower annular mounting frame provided on the adjustable flat heat plate platform and an upper annular mounting frame provided separately and aligned with the chip during bonding, wherein the lower annular mounting frame and the upper annular mounting frame include the 6-DoF piezoelectric platform and the heat plate in the ring, and the infrared laser array is equally distributed and mounted inside the lower annular mounting frame and the upper annular mounting frame.

[0008] Further, the machine vision positioning module comprises an image acquisition unit for acquiring the alignment profile of the chip and the substrate, a data processing unit for calculating and adjusting the alignment position and angle, an auxiliary sensor network for detecting the curling distance of the chip and the substrate, and an execution feedback unit.

[0009] Further, the data processing unit and the execution feedback unit are electrically connected with the photon AI processing system and controlled by the photon AI processing system.

[0010] Further, the infrared laser array is provided with a quantum dot temperature measurement film for detecting the bonding temperature.

[0011] Further, the infrared laser array has 128 independent temperature control zones, and the spatial density of the quantum dot temperature measurement film is 100 points / mm 2 .

[0012] Further, the micropore array suction disc is made of a ceramic substrate laser drilled.

[0013] Further, the micropore array suction disc has a suction hole density of 500 holes / cm 2 The beneficial effects of the present embodiment are that: 1、In the prior art, to solve the warping problem of the chip, a metal or ceramic tray is usually used to fix the substrate and the chip to ensure the flatness of the substrate during high-temperature processing. A double-layer clamp is usually used to clamp, and a uniform pressing method is used to ensure that the bonding interface is uniformly stressed and the structural stability is maintained. However, this method is only a rough mechanical correction using mechanical hard pressing and rigid limiting, and cannot eliminate the stress concentration between the chip and the substrate during the bonding process. Although it can temporarily flatten, the stress remains causes the rebound after cooling, which causes micro-cracks. Therefore, the application has a 6-DoF piezoelectric platform, a heat plate with independent temperature control, and an infrared laser array. Therefore, when the stress concentration between the chip and the substrate occurs during the bonding process, the application can generate a reverse curvature by rotating the chip through the 6-DoF piezoelectric platform, and can tilt and press the substrate to offset the curvature and flatten it. In combination with the heat plate and the temperature gradient of the infrared, the expansion amount is controlled, and the warping of the bonding control is well controlled. The maximum warping amount of the bonding is reduced from 152 μm to 4.8 μm, which is reduced by 96.8%.

[0014] 2、The temperature gradient of the heat plate 128 partitioned by the independent temperature control unit is compressed to ±0.3℃, which eliminates the thermal strain from the root cause. Most temperature control is on the upper and lower surfaces of the bonded chip and substrate, but when warping occurs at the edge, the expansion amount of the lateral side of the substrate and chip is the key to eliminate the thermal strain force. However, the temperature control on the upper and lower surfaces cannot reach the lateral side of the substrate and chip in time, so timely temperature control will also cause warping. The application sets an infrared laser array on the lateral side of the substrate and chip during bonding to perform temperature compensation, so the corresponding speed is faster, the warping suppression effect is better, and the application divides the infrared laser array into upper and lower parts mounted on the upper and lower ring-shaped mounts. The lateral sides of the substrates and chips with different expansion amounts can be independently temperature-compensated, so the temperature difference between the chip and the substrate is controlled, and the edge expansion amount is controlled, so the warping suppression effect is better. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The structure of the application is shown in the figure. DETAILED DESCRIPTION

[0016] The following will be further described in detail through specific embodiments: The reference numerals in the accompanying drawings include: feeding assembly 1, chip adsorption head 11, sliding device 12, connecting rod 13, gantry slide rail 2, gantry slider 21, gantry beam 22, Y-axis moving assembly 3, telescopic slide 31, telescopic slider 32, Z-axis moving assembly 4, vertical slide plate 41, vertical slide 42, vertical slider 43, 6-DoF piezoelectric platform 5, micro-hole array suction cup 51, machine vision positioning module 52, adjustable leveling hot plate platform 6, telescopic support leg 61, lower annular mounting bracket 62, support plate 63, hot plate 64, infrared heater 7, and upper annular mounting bracket 71.

[0017] Implementation, for example, attached Figure 1 As shown: A chip packaging and bonding device, such as Figure 1 As shown in the structure, it includes an organic frame, within which a gantry slide rail 2 is provided. The gantry slide rail 2 comprises two parallel gantry frame structures, each supported by two columnar support legs. Therefore, the gantry slide rail includes four columnar support legs. Figure 1 The direction is described. A feeding assembly 1 is provided on the left rear support leg. The feeding assembly 1 includes a wafer disk (not shown in the figure) that carries multiple chips to be bonded. The rear end of the feeding assembly 1 is provided with a sliding device 12 that can slide up and down along the support leg of the gantry slide rail 2. The sliding device 12 is connected to the chip adsorption head 11 through a connecting rod 13. The chip adsorption head 11 includes a rotating assembly connected to the connecting rod 13 and a negative pressure adsorption assembly for adsorbing chips. Therefore, the chip adsorption head 11 can rotate around the connecting rod 13. When the chip is in the wafer disk, the front side of the chip to be bonded is facing up and the bonding bumps are facing up. When performing flip bonding, the chip needs to be flipped in a "front-down" manner so that the bumps are aligned with the substrate pads. Therefore, the chip adsorption head 11 of this application can adsorb the chip from the wafer disk and then rotate around the connecting rod 13 so that the lower end of the chip adsorption head 11 rotates to the upper end, and then the chip is placed on the chip adsorption head 11 with the front side facing down and the back side facing up, which facilitates the subsequent flip bonding.

[0018] The gantry slide rail 2 consists of two parallel gantry beams 22 of a gantry frame structure. The front and rear sides of the gantry beams 22 are provided with grooves, through which gantry sliders 21 are connected. This allows the gantry sliders 21 to slide left and right along the gantry beams 22, forming an X-axis moving assembly. A Y-axis moving assembly 3 is connected to the upper surface of the gantry sliders 21. The Y-axis moving assembly 3 includes a telescopic groove 31 on the upper surface of the gantry sliders 21, within which a telescopic slider 32 is disposed. A Z-axis moving assembly 4 is connected to the front end of the telescopic slider 32. Specifically, a vertical slide plate 41 is fixedly connected to the front end of the telescopic slider 32. The vertical slide plate 41 has a vertical slide groove 42, within which a vertical slider 43 is disposed. A 6-DoF piezoelectric platform 5 is installed at the lower end of the vertical slider 43.

[0019] 6-DoF piezoelectric platform 5 can adsorb the chip on the chip adsorption head 11 upside down, and the back surface upward, and use the XYZ three-axis slide table formed by the X-axis moving assembly, Y-axis moving assembly 3, Z-axis moving assembly 4, so that the 6-DoF piezoelectric platform 5 can adjust the position of the chip in the X, Y, Z direction in the plane; X, Y, Z respectively represent the X-axis, Y-axis and Z-axis in the Cartesian coordinate system, the X direction is the horizontal direction in the horizontal plane, the Y direction is the vertical direction in the horizontal plane, and the Z direction is the vertical direction perpendicular to the horizontal plane; The X-axis moving assembly, Y-axis moving assembly 3 and Z-axis moving assembly 4 realize the position movement in the X, Y, Z direction through the platform driving motor, so as to realize the transfer of the chip from the chip adsorption head 11 to the bonding area.

[0020] A bonding platform is arranged below the 6-DoF piezoelectric platform 5, and the bonding platform is an adjustable flat hot plate platform 6 with telescopic structure. The adjustable flat hot plate platform 6 includes telescopic legs 61 for telescopic extension, a support plate 63 for supporting the substrate to be bonded, and a hot plate 64 for heating. The four telescopic legs 61 of the adjustable flat hot plate platform are respectively located at the four corners of the support plate, and can be independently telescoped and form a slidable hinge with the bottom of the support plate 63. Therefore, the four telescopic legs 61 can realize the leveling of the horizontal degree of the platform through telescopic extension. The substrate to be bonded is placed on the top surface of the hot plate 64. The hot plate 64 is used for supporting the substrate to be bonded and heating the chip and the substrate to be bonded during bonding. The hot plate 64 is divided into 128 independent temperature control units, which can independently control the bonding temperature of the center and the edge of the chip and the substrate to be bonded during bonding. A lower annular mounting frame 62 is arranged on the end surface of the adjustable flat hot plate platform 6, and a femtosecond laser interferometer and an infrared laser array are arranged on the inner side of the lower annular mounting frame 62. Therefore, the femtosecond laser interferometer can monitor the curling condition of the substrate to be bonded from the side.

[0021] The 6-DoF piezoelectric platform 5 is also configured with a micropore array suction disc 51 and a machine vision positioning module 52. The micropore array suction disc 51 is a ceramic substrate + laser drilling (Ø5μm), and the adsorption hole density is 500 holes / cm 2The machine vision positioning module 52 is mainly used for adsorbing the chip. The machine vision positioning module 52 comprises an image acquisition unit, a data processing unit, an auxiliary sensor network and an execution feedback unit. The execution feedback unit is electrically connected with the 6-DoF piezoelectric platform 5. The alignment mark and the leveling mark are arranged on the chip and the substrate. The machine vision positioning module 52 is used for identifying the alignment mark and the leveling mark of the upper chip and the lower substrate, and acquiring the position information of the leveling mark, the position information and the angle information of the alignment mark. The position of the chip is adjusted by the execution feedback unit and the 6-DoF piezoelectric platform 5. The image acquisition unit of the machine vision positioning module 52 comprises an industrial camera. The industrial camera is located on the top of the adjustable hot plate platform 6 and is electrically connected with the data processing unit, the auxiliary sensor network and the execution feedback unit. A microscope capable of amplifying images is arranged on the front side of the industrial camera. The industrial camera can realize the focusing adjustment of the mark on the chip by the up-down movement of the Z-axis movement assembly 4. After the focusing adjustment, the industrial camera can automatically determine the contour of the alignment mark and the leveling mark and transmit the data to the data processing unit. The auxiliary sensor network comprises a femtosecond laser interferometer installed on the annular mounting frame 62. The femtosecond laser interferometer also transmits the initial warping data of the substrate to the data processing unit. The data processing unit calculates the position and the angle required for the alignment of the alignment mark and the leveling mark of the chip and the substrate, and generates a control signal for controlling the action of the 6-DoF piezoelectric platform 5 in the execution feedback unit.

[0022] The image acquisition unit of the machine vision positioning module 52 identifies the alignment mark and the leveling mark of the upper chip and acquires the position information and the angle information of the mark. The data processing unit calculates the position and the angle information of the alignment mark and the leveling mark according to the acquired position information and angle information. The 6-DoF piezoelectric platform 5 is controlled by the execution feedback unit to move in multiple directions to adjust the position and the angle of the upper chip, so that the upper chip is parallel and aligned with the lower substrate, and the coplanarity error is reduced. The in-situ permanent bonding of the upper chip and the lower substrate is realized on the adjustable hot plate platform 6.

[0023] An infrared heater 7 is also arranged beside the adjustable hot plate platform 6. The infrared heater 7 comprises an infrared laser array and a quantum dot temperature measurement film installed on the upper annular mounting frame 71 and the lower annular mounting frame 62. The infrared laser array has 128 independent temperature control zones. The spatial density of the quantum dot temperature measurement film is 100 points / mm 2When bonding, the adjustable flat hot plate platform 6 gradually lifts the platform under the extension of the telescopic legs 61, and after the lower annular mounting frame 62 contacts the upper annular mounting frame 71, the adjustable flat hot plate platform 6 retreats by a certain distance (20-100 pm, which can also be adjusted according to actual production), and adjusts the flatness of the adjustable flat hot plate platform 6. Under the action of the micro-hole array suction disc 51 and the machine vision positioning module 52 on the 6-DoF piezoelectric platform 5, the micro-hole array suction disc 51 sucks the chip, adjusts the flatness of the chip, and aligns the chip with the substrate. After that, it moves downward to make the chip contact the substrate for bonding. All components and monitoring sensors that need to be controlled in this application are electrically connected to the photonic AI processing system, of which the 6-DoF piezoelectric platform, the micro-hole array suction disc, the machine vision positioning module, the hot plate, the infrared laser array, the femtosecond laser interferometer, and the quantum dot temperature measurement film must be electrically connected to the photonic AI processing system.

[0024] During the bonding process, the chip and the substrate deform due to the difference in thermal expansion coefficient during heating: the substrate (organic material, CTE≈18 ppm / ℃) expands quickly, and the chip silicon (CTE≈2.6 ppm / ℃) expands slowly, so a thermal stress gradient is generated at their interface, and the edge of the chip curls upward (typical value 50-200 pm). The femtosecond laser interferometer and the quantum dot temperature measurement film detect the change, and the photonic AI processing system responds quickly by controlling the 6-DoF piezoelectric platform 5 and the infrared laser array to control the temperature gradient, while slightly rotating the chip to suppress the curling. The technical principle of temperature gradient control to suppress curling is to use temperature difference to reduce the expansion difference between the substrate and the chip, and to reduce the height difference caused by curling. The dynamic leveling principle of slight rotation is as follows: when the substrate expands and the chip expands to generate curling curvature, the chip generates reverse curvature by rotating, and the tilt forces the substrate to be pressed down, so that the curvature is offset.

[0025] The process is as follows: When the edge curls up, 1, the femtosecond laser interferometer detects that the edge curling is >20 pm; the quantum dot temperature measurement film detects that the temperature is <200℃; output instruction: the hot plate 64 independent temperature control unit controls the bonding edge to rise by 50℃; the 6-DoF piezoelectric platform 5 controls the chip to rotate: θx=+0.02°, and the infrared laser array compensates the temperature rise of the edge of the substrate, so that the temperature of the edge of the substrate rises by 50℃. 2, the femtosecond laser interferometer detects that the edge curling is >20 pm, and the quantum dot temperature measurement film detects that the temperature is ≥200℃, the hot plate 64 independent temperature control unit controls the bonding center to drop by 50℃; the 6-DoF piezoelectric platform 5 controls the chip to rotate: θx=+0.02°.

[0026] When the center is concave: 1. When the femtosecond laser interferometer detects an edge gap >30μm and the quantum dot temperature sensing film detects a temperature <200℃, the independent temperature control unit of the hot plate 64 controls the bonding center to heat up by 30℃; the 6-DoF piezoelectric platform 5 raises the control chip 25μm in the Z-axis direction. 2. When the femtosecond laser interferometer detects an edge gap >30μm and the quantum dot temperature sensing film detects a temperature greater than 200℃, the independent temperature control unit of the hot plate 64 controls the bonding edge to cool down by 30℃, and the 6-DoF piezoelectric platform 5 raises the control chip 25μm in the Z-axis direction.

[0027] When this application is applied to production, the rotation angle and temperature change range of the anti-curling control can be adjusted according to the curvature of the produced products to adapt to the different substrate materials and chips of different companies. As production progresses, the adjustment parameters become more and more accurate, and the anti-curvature effect becomes better and better.

[0028] Meanwhile, in the control of heating and cooling, when the edge needs to be heated, the infrared laser array works in conjunction with heating compensation to make the edge heat up to the specified value quickly.

[0029] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A chip packaging and bonding apparatus, characterized in that: It includes a feeding assembly, a bonding head assembly, and a bonding platform; The feeding assembly includes a chip suction head for rotating the chip to form an inverted position; and an XYZ three-axis slide for moving the chip to the bonding platform. The bonding head assembly includes a 6-DoF piezoelectric platform for adjusting the chip angle in six degrees of freedom, a micro-hole array chuck, and a machine vision positioning module. The bonding platform is an adjustable flat hot plate platform with a telescopic structure; the adjustable flat hot plate platform is equipped with a hot plate that can heat the bonding process and an infrared laser array, and the hot plate is divided into 128 independent temperature control units. The 6-DoF piezoelectric platform, micro-hole array suction cup, machine vision positioning module, hot plate, and infrared laser array are all electrically connected to the photonic AI processing system.

2. The chip packaging and bonding apparatus according to claim 1, characterized in that: It also includes a lower annular mounting bracket set on an adjustable hot plate platform and an upper annular mounting bracket that is aligned with the chip during bonding and is set separately. The lower and upper annular mounting brackets include the 6-DoF piezoelectric platform and the hot plate within the ring. The infrared laser array is equally distributed and installed inside the lower and upper annular mounting brackets.

3. The chip packaging and bonding apparatus according to claim 1, characterized in that: The machine vision positioning module includes an image acquisition unit for acquiring the alignment contours of the chip and the substrate, a data processing unit for calculating and adjusting the alignment position and angle, an auxiliary sensor network for detecting the warp distance between the chip and the substrate, and an execution feedback unit.

4. The chip packaging and bonding apparatus according to claim 3, characterized in that: The data processing unit and the execution feedback unit are electrically connected to the photonic AI processing system and are controlled by the photonic AI processing system.

5. The chip packaging and bonding apparatus according to claim 1, characterized in that: The infrared laser array is equipped with a quantum dot thermometric membrane for detecting bonding temperature.

6. The chip packaging and bonding apparatus according to claim 5, characterized in that: The infrared laser array has 128 independent temperature control zones, and the quantum dot thermometric film has a spatial density of 100 points / mm². 2 .

7. The chip packaging and bonding apparatus according to claim 1, characterized in that: The microporous array suction cup is made by laser drilling into a ceramic substrate.

8. The chip packaging and bonding apparatus according to claim 7, characterized in that: The microporous array suction cup has an adsorption pore density of 500 pores / cm². 2 .

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