Three-dimensional stacked shielding structure and preparation method thereof

Abstract

The invention discloses a three-dimensional stacked shielding structure and a preparation method thereof.The shielding structure comprises a first chip and a second chip, and the first chip and the second chip are each provided with two rows of radio frequency ground bonding pads arranged oppositely and signal transmission bonding pads arranged on the peripheries of the radio frequency ground bonding pads; signal transmission double-layer gold-based nail head salient points are bonded on a signal transmission bonding pad of the first chip, two columns of radio frequency ground bonding pads oppositely arranged on the first chip are sequentially bonded and interconnected through shielding gold wires, and single-layer nail head salient points are bonded at bonding points of the shielding gold wires and the radio frequency ground bonding pads. The single-layer nail head salient point and the bonding point are combined to form a grounding double-layer gold-based nail head salient point, and the second chip is inversely arranged on a combined body formed by the first chip, the signal transmission double-layer gold-based nail head salient point and the grounding double-layer gold-based nail head salient point to form a three-dimensional stacked structure. The problem of electromagnetic interference between the upper layer and the lower layer caused by insufficient height of the air cavity in the three-dimensional stacked structure of the microwave chip can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of microelectronic packaging, and in particular relates to a three-dimensional stacked shielding structure and a preparation method thereof. Background Art

[0002] With the development demand of miniaturization and high integration of microwave products, three-dimensional integration technology has been widely used. In the microwave chip flip-chip structure, due to the small size and low height of the micro-bumps, it is difficult to form a high air cavity, that is, the isolation is not enough, which leads to the inter-layer crosstalk and self-excitation of microwave signals during the transmission of the upper and lower chips, seriously affecting the product performance;

[0003] To solve the above problems, at present, for example, Chinese invention patent CN114300446B discloses a chip stacking shielding structure and a manufacturing method, which realizes the external electromagnetic shielding of the structure by arranging metal shielding wires on the periphery of the three-dimensional stacking structure. However, it cannot solve the problem of electromagnetic signal crosstalk between layers within the three-dimensional stacking structure.

[0004] For example, Chinese patent CN110868793A discloses a three-dimensional integrated microwave circuit shielding structure, which uses shielding grounding solder balls to form a closed shield. However, this structure is mainly used for board-level flip-chip, and the solder balls are large in size, which is not suitable for chip-level flip-chip.

[0005] For example, Chinese patent CN114373740B discloses an electromagnetic shielding packaging structure, an electronic device module and a manufacturing method, wherein two sections of a lead are respectively conductively connected to a first shielding member and a second shielding member to achieve electromagnetic isolation between adjacent devices. The process is relatively complex to implement and is only applicable to structures with large air cavity heights inside components, and cannot be applied to chip-level flip-chip micromodules with air cavities of only tens of microns.

[0006] That is, the current existing technology is difficult to solve the problem of inter-layer crosstalk and self-excitation in the microwave chip flip-chip structure during the transmission of microwave signals between the upper and lower chips. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a three-dimensional stacked shielding structure and a preparation method thereof, wherein shielding gold wires are bonded between parallel RF ground pads, and the bonding points of the shielding gold wires are used as lower-layer micro-bumps to combine with the single-layer nail head bumps on the shielding gold wires to form grounded double-layer gold-based nail head bumps, and signal transmission pads located outside the RF ground pads are bonded to the signal transmission double-layer gold-based nail head bumps, and the first chip and the second chip are flipped to form a three-dimensional stacked structure. The array composed of shielding gold wires in the air cavity of the structure can well isolate the upper and lower microwave signals, thereby solving the problem of electromagnetic interference between the upper and lower layers caused by insufficient air cavity height in the three-dimensional stacked structure of microwave chips.

[0008] The object of the present invention is achieved through the following technical solutions:

[0009] A three-dimensional stacked shielding structure comprises a first chip and a second chip, wherein the first chip and the second chip are each provided with two rows of oppositely arranged radio frequency ground pads and signal transmission pads arranged outside the radio frequency ground pads, the signal transmission pads of the first chip are bonded with signal transmission double-layer gold-based nail head bumps, the two rows of oppositely arranged radio frequency ground pads on the first chip are bonded and interconnected in sequence through shielding gold wires, the shielding gold wires are bonded with single-layer nail head bumps at the bonding points between the shielding gold wires and the radio frequency ground pads, the single-layer nail head bumps are combined with the bonding points to form grounded double-layer gold-based nail head bumps, and the second chip is flipped on a combination consisting of the first chip, the signal transmission double-layer gold-based nail head bumps and the grounded double-layer gold-based nail head bumps to form a three-dimensional stacked structure.

[0010] In one embodiment, the signal transmission pad on the second chip is bonded to the signal transmission double-layer gold-based stud bump, and the radio frequency ground pad on the second chip is bonded to the ground double-layer gold-based stud bump.

[0011] In one embodiment, it also includes an adapter board arranged between the first chip and the second chip, one side of the adapter board is bonded to the signal transmission double-layer gold-based nail head bumps and the grounding double-layer gold-based nail head bumps, and the other side is bonded to the second chip through the double-layer gold-based nail head bumps. The adapter board is provided with a cavity structure located between two rows of oppositely arranged RF ground pads. Through this embodiment, an adapter board with a cavity structure is arranged between the first chip and the second chip to increase the height of the air cavity between the first chip and the second chip, improve the isolation between the two, and at the same time avoid the situation where the shielding gold wire is too close to the upper chip to cause a contact short circuit.

[0012] In one embodiment, the two ends of the shielding gold wire are bonded to the relatively set RF ground pads by ball welding, and the solder balls at the welding points are combined with the single-layer stud bumps bonded to the shielding gold wires to form grounded double-layer gold-based stud bumps. Through this embodiment, the two ends of the shielding gold wire are bonded to the relatively set RF ground pads by ball welding, and the two columns of RF ground pads are successively arranged with shielding gold wires along their arrangement direction, and the array composed of multiple shielding gold wires isolates the upper and lower microwave signals.

[0013] In one embodiment, the surfaces of the radio frequency ground pad and the signal transmission pad are both gold-plated.

[0014] In one embodiment, the signal transmission double-layer gold-based stud bumps are bonded to the signal transmission pads of the first chip by a wire bonding machine.

[0015] In one embodiment, the diameter of the signal transmission double-layer gold-based stud bump is 1 / 2 of the diameter of the signal transmission pad. times, n is greater than 1.

[0016] The present invention also provides a method for preparing a three-dimensional stacked shielding structure, which is used to prepare the above-mentioned three-dimensional stacked shielding structure, comprising the following steps:

[0017] Step S1, bonding a signal transmission double-layer gold-based stud bump on a signal transmission pad of a first chip by a wire bonding machine;

[0018] Step S2, bonding shielding gold wires sequentially between two rows of oppositely arranged RF ground pads of the first chip through a ball bonding process;

[0019] Step S3, bonding a single layer of gold-based nail head bumps on the shielding gold wire at the ball welding points of the two ends of the shielding gold wire and the radio frequency ground pad;

[0020] Step S4, flip-chip the second chip onto the assembly consisting of the first chip, the signal transmission double-layer gold-based stud bumps and the grounding double-layer gold-based stud bumps to form a three-dimensional stacked structure.

[0021] In one embodiment, in step S4, it further includes:

[0022] The assembly is placed on the hot plate surface of the flip chip bonder, and vacuum is applied to fix the assembly. The flip chip bonder absorbs the second chip and flips it over. The alignment of the first chip and the second chip is identified by the equipment identification system. The nozzle applies pressure and ultrasound to complete the thermal ultrasonic welding of the first chip and the second chip.

[0023] In one embodiment, in step S4, it further includes:

[0024] Place the adapter plate with a cavity structure on the surface of the hot table of the flip chip welder, apply vacuum to fix the adapter plate, the flip chip welder sucks the assembly and flips it over, completes the alignment recognition of the assembly and the adapter plate through the equipment recognition system, applies pressure and ultrasound through the suction nozzle to complete the thermal ultrasonic welding of the assembly and the adapter plate, bond a double-layer gold-based nail head bump on the adapter plate, and place it on the surface of the hot table of the flip chip welder, apply vacuum to fix it, the flip chip welder sucks the second chip and flips it, completes the alignment recognition of the assembly and the second chip through the equipment recognition system, and applies pressure and ultrasound through the suction nozzle to complete the thermal ultrasonic welding of the adapter plate and the second chip.

[0025] The beneficial effects of the present invention are:

[0026] A shielding gold wire is bonded between parallel RF ground pads, and the bonding points of the shielding gold wire are used as the lower layer micro-bumps to combine with the single-layer nail head bumps on the shielding gold wire to form a grounded double-layer gold-based nail head bump. The signal transmission pads located outside the RF ground pad are bonded to the signal transmission double-layer gold-based nail head bumps, and the first chip and the second chip are flipped to form a three-dimensional stacked structure. The array composed of the shielding gold wires in the air cavity of the structure can well isolate the upper and lower microwave signals, thereby solving the electromagnetic interference problem between the upper and lower layers caused by insufficient air cavity height in the three-dimensional stacked structure of microwave chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0028] Figure 1 A schematic structural diagram of an embodiment of the present invention is shown;

[0029] Figure 2 Shows Figure 1 A schematic diagram of a top perspective structure of the embodiment shown;

[0030] Figure 3 A schematic structural diagram showing another embodiment of the present invention;

[0031] Figure 4 A schematic flow chart of steps S1 to S3 in the preparation method of the present invention is shown;

[0032] Figure 5 A schematic diagram showing an embodiment of step S4 in the preparation method of the present invention

[0033] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0034] Reference numerals:

[0035] 101 - first chip, 102 - second chip, 103 - signal transmission double-layer gold-based stud bump, 104 - grounding double-layer gold-based stud bump, 105 - shielding gold wire, 106 - adapter board, 107 - double-layer gold-based stud bump. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings.

[0037] The present invention provides a three-dimensional stacked shielding structure, such as Figure 1 and Figure 2As shown, it includes a first chip 101 and a second chip 102, and both the first chip 101 and the second chip 102 have two rows of oppositely arranged radio frequency ground pads and signal transmission pads arranged outside the radio frequency ground pads. The signal transmission pads of the first chip 101 are bonded with signal transmission double-layer gold-based nail head bumps 103, and the two rows of oppositely arranged radio frequency ground pads on the first chip 101 are bonded in sequence through shielding gold wires 105. The shielding gold wires 105 are bonded with single-layer nail head bumps at the bonding points between the shielding gold wires 105 and the radio frequency ground pads, and the single-layer nail head bumps are combined with the bonding points to form grounded double-layer gold-based nail head bumps 104, and the second chip 102 is flipped on the combination composed of the first chip 101, the signal transmission double-layer gold-based nail head bumps 103 and the grounded double-layer gold-based nail head bumps 104 to form a three-dimensional stacked structure;

[0038] It should be noted that two rows of oppositely arranged RF ground pads are arranged in the central area of ​​the first chip 101 and the second chip 102, and a circle of signal transmission pads in a rectangular structure is arranged around the RF ground pads. By bonding a shielding gold wire 105 between the parallel RF ground pads, and using the bonding point of the shielding gold wire 105 as the lower layer micro-bump, it is combined with the single-layer nail head bump on the shielding gold wire 105 to form a grounded double-layer gold-based nail head bump 104, and the signal transmission double-layer gold-based nail head bump bonded on the signal transmission pad is formed. Point 103, the first chip 101 and the second chip 102 are flipped to form a three-dimensional stacking structure. In the formed three-dimensional stacking structure, the array composed of multiple shielding gold wires 105 can well isolate the upper and lower microwave signals, and solve the electromagnetic interference problem between the upper and lower layers caused by insufficient air cavity height in the three-dimensional stacking structure of microwave chips. The first chip 101 and the second chip 102 can be made of silicon, gallium arsenide, gallium nitride, glass, ceramics and other materials, and the RF ground pad and the signal transmission pad are plated materials that meet gold bonding requirements;

[0039] Specifically, the signal transmission pad on the second chip 102 is bonded to the signal transmission double-layer gold-based nail head bump 103, and the radio frequency ground pad on the second chip 102 is bonded to the ground double-layer gold-based nail head bump 104. In this embodiment, the first chip 101 is used as a basis, and the ground double-layer gold-based nail head bump 104 and the signal transmission double-layer gold-based nail head bump 103 can also be bonded to the second chip 102, and then the first chip 101 is flipped thereon;

[0040] In one embodiment, Figure 3 As shown, it also includes an adapter board 106 arranged between the first chip 101 and the second chip 102, one side of the adapter board 106 is bonded to the signal transmission double-layer gold-based nail head bump 103 and the grounding double-layer gold-based nail head bump 104, and the other side is bonded to the second chip 102 through the double-layer gold-based nail head bump 107, and a cavity structure located between two rows of oppositely arranged RF ground pads is opened on the adapter board 106;

[0041] It should be noted that the three-dimensional stacking structure provided in this embodiment further includes a transfer plate 106 with a cavity structure disposed between the first chip 101 and the second chip 102, so as to increase the height of the air cavity between the first chip 101 and the second chip 102, improve the isolation between the two, and avoid the shielding gold wire 105 being too close to the upper chip to cause a contact short circuit;

[0042] Specifically, the two ends of the shielding gold wire 105 are bonded to the relatively arranged RF ground pads by ball welding, and the solder balls at the welding points are combined with the single-layer nail head bumps bonded to the shielding gold wire 105 to form a grounded double-layer gold-based nail head bump 104, and the surfaces of the RF ground pads and the signal transmission pads are gold-plated. The signal transmission double-layer gold-based nail head bumps 103 are bonded to the signal transmission pads of the first chip 101 by a wire bonding machine. That is, the two ends of the shielding gold wire 105 are bonded to the relatively arranged RF ground pads by ball welding, and the two columns of RF ground pads are sequentially arranged with shielding gold wires 105 along their arrangement direction. The array composed of multiple shielding gold wires 105 isolates the upper and lower microwave signals;

[0043] In one embodiment, the diameter of the signal transmission double-layer gold-based stud bump 103 is 1 / 100 of the diameter of the signal transmission pad. times, n is greater than 1, such as the diameter of the signal transmission double-layer gold-based stud bump 103 is the diameter of the signal transmission pad or wait;

[0044] In one embodiment, Figure 1 As shown, the first chip 101 is a gallium arsenide chip with an outer size of 1.5mm×2.0mm, and the signal transmission pad and the radio frequency ground pad thereon are gold-plated, and the pad size is 100um×100um. The second chip 102 is a silicon chip with the same outer size as the first chip 101, and the pad thereon is also the same as the pad on the first chip 101. The signal transmission double-layer gold-based nail head bump 103 is bonded to the signal transmission pad of the first chip 101 by a wire bonding machine. The bump diameter is 80um and the bump thickness is 60um. The shielding gold wire 105 has a diameter of 25um and is bonded to two opposite RF ground pads on the first chip 101. Multiple shielding gold wires 105 are bonded sequentially on two rows of RF ground pads. The prepared shielding gold wire 105 has a span of 0.6mm and a welding point height of 28um between the shielding gold wire 105 and the RF ground pad. The grounding double-layer gold-based stud bump 104 consists of a welding point and a single-layer stud bump on the shielding gold wire 105. The bump diameter is 80um and the total bump thickness is 60um. The second chip 102 is flip-chip mounted on the first chip 101 by a flip-chip bonding machine.

[0045] In one embodiment, Figure 3 As shown, the first chip 101 is a radio frequency chip, made of glass, with an outer size of 3.0mm×3.0mm, and the signal transmission pad and the radio frequency ground pad thereon are gold-plated on the surface, and the pad size is 100um×100um. The second chip 102 is a radio frequency chip, made of glass, with the same appearance as the first chip 101, and the pad thereon is also the same as the pad of the first chip 101. The adapter board 106 provides signal transmission for the first chip 101 and the second chip 102, and is made of glass, with an outer size of 3.0mm×3.0mm, and a 1.0mm×1.0mm cavity structure in the middle, and the surface pad is gold-plated. The signal transmission double-layer gold-based nail head bump 103 is bonded to the signal transmission pad of the first chip 101 by a wire bonding machine, and the bump diameter is 75um , the bump thickness is 45um, the shielding gold wire 105 has a diameter of 25um, which is bonded to two opposite RF ground pads on the first chip 101, and multiple shielding gold wires 105 are bonded sequentially on the two rows of RF ground pads. The prepared shielding gold wire 105 has a span of 1.2mm, and the height of the welding point between it and the RF ground pad is 22um. The grounding double-layer gold-based nail head bump 104 consists of a welding point and a single-layer nail head bump on the shielding gold wire 105, with a bump diameter of 75um and a total bump thickness of 45um. The adapter plate 106 is thermally ultrasonically flipped on the first chip 101 by a flip-chip welder, and then a double-layer gold-based nail head bump 107 is prepared on the upper layer of the adapter plate 106. After the preparation is completed, the second chip 102 is bonded to the double-layer gold-based nail head bump 107 of the adapter plate 106 by a flip-chip welder;

[0046] The present invention also provides a method for preparing a three-dimensional stacked shielding structure, which is used to prepare the three-dimensional stacked shielding structure provided in the above embodiment, comprising the following steps:

[0047] Step S1, bonding a signal transmission double-layer gold-based stud bump on a signal transmission pad of a first chip by a wire bonding machine;

[0048] Step S2, bonding shielding gold wires sequentially between two rows of oppositely arranged RF ground pads of the first chip through a ball bonding process;

[0049] Step S3, bonding a single layer of gold-based nail head bumps on the shielding gold wire at the ball welding points of the two ends of the shielding gold wire and the radio frequency ground pad;

[0050] Step S4, flip-chipping the second chip onto the assembly consisting of the first chip, the signal transmission double-layer gold-based stud bumps, and the grounding double-layer gold-based stud bumps to form a three-dimensional stacking structure;

[0051] It should be noted that in step S2, after using the spark rod to discharge a molten ball at the tip of the shielding gold wire, first bond a gold bump on the RF ground pad on the right side of the two opposite RF ground pads, and move the splitter to the top of the RF ground pad on the left side, and the spark rod discharges a molten ball at the tip of the shielding gold wire to complete the bonding of the shielding gold wire to form a first welding point, and the splitter rises to a safe height, and bends the heat-affected area of ​​the shielding gold wire through a first section of retreat movement, and the bent shielding gold wire is pressed tightly on the first welding point, and pressure and ultrasound are applied to bond the heat-affected area of ​​the shielding gold wire to the first welding point, and then the splitter moves through a normal arc trajectory to the gold bump surface of the RF ground pad on the right side, and completes the bonding of the shielding gold wire and the gold bump to form a second welding point. The first welding point and the second welding point serve as micro-bumps, and together with the single-layer gold-based nail head bump bonded in step S3, form a grounded double-layer gold-based nail head bump;

[0052] In one embodiment, Figure 1 and Figure 4 As shown, step S4 also includes:

[0053] The assembly is placed on the hot plate surface of the flip chip bonder, and vacuum is applied to fix the assembly. The flip chip bonder absorbs the second chip 102 and flips it over. The first chip 101 and the second chip 102 are identified by the device identification system. The nozzle applies pressure and ultrasound to complete the thermal ultrasonic welding of the first chip 101 and the second chip 102, thus forming a Figure 1 The three-dimensional stacked shielding structure shown;

[0054] In one embodiment, Figure 4 and Figure 5 As shown, step S4 also includes:

[0055] The adapter plate with the cavity structure is placed on the surface of the hot table of the flip-chip bonder, and a vacuum is applied to fix the adapter plate by adsorption. The flip-chip bonder absorbs the assembly and flips it over. The device identification system completes the alignment identification of the assembly and the adapter plate 106. The suction nozzle applies pressure and ultrasound to complete the thermal ultrasonic welding of the assembly and the adapter plate 106. A double-layer gold-based stud bump 107 is bonded to the adapter plate 106, and the adapter plate is placed on the surface of the hot table of the flip-chip bonder, and a vacuum is applied to fix it by adsorption. The flip-chip bonder absorbs the second chip 102 and flips it over. The device identification system completes the alignment identification of the assembly and the adapter plate 102. The suction nozzle applies pressure and ultrasound to complete the thermal ultrasonic welding of the adapter plate 107 and the second chip 102, thus forming a structure as shown in FIG. Figure 5 The three-dimensional stacked shielding structure shown increases the height of the air cavity between the first chip 101 and the second chip 102, thereby improving the isolation between the two and avoiding the situation where the shielding gold wire 105 is too close to the upper chip and causes a contact short circuit;

[0056] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the features of the various dependent claims and herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with the individual embodiments may be used in other embodiments.

Claims

1. A three-dimensional stacked shielding structure, characterized in that: The invention comprises a first chip and a second chip, wherein the first chip and the second chip each have two rows of oppositely arranged radio frequency ground pads and signal transmission pads arranged outside the radio frequency ground pads, the signal transmission pads of the first chip are bonded with signal transmission double-layer gold-based nail head bumps, the two rows of oppositely arranged radio frequency ground pads on the first chip are bonded and interconnected in sequence through shielding gold wires, the shielding gold wires are bonded with single-layer nail head bumps at the bonding points between the shielding gold wires and the radio frequency ground pads, the single-layer nail head bumps are combined with the bonding points to form grounded double-layer gold-based nail head bumps, and the second chip is flipped on a combination consisting of the first chip, the signal transmission double-layer gold-based nail head bumps and the grounded double-layer gold-based nail head bumps to form a three-dimensional stacked structure.

2. A three-dimensional stacked shielding structure according to claim 1, characterized in that: The signal transmission pads on the second chip are bonded to the signal transmission double-layer gold-based stud bumps, and the radio frequency ground pads on the second chip are bonded to the grounding double-layer gold-based stud bumps.

3. A three-dimensional stacked shielding structure according to claim 1, characterized in that: It also includes an adapter board arranged between the first chip and the second chip, one side of the adapter board is bonded and interconnected with the signal transmission double-layer gold-based nail head bumps and the grounding double-layer gold-based nail head bumps, and the other side is bonded and interconnected with the second chip through the double-layer gold-based nail head bumps, and a cavity structure is provided on the adapter board between two rows of oppositely arranged RF ground pads.

4. The three-dimensional stacked shielding structure according to claim 1, characterized in that: The two ends of the shielding gold wire are bonded to the oppositely arranged radio frequency ground pads through ball welding, and the solder balls at the welding points are combined with the single-layer stud bumps bonded on the shielding gold wire to form grounded double-layer gold-based stud bumps.

5. The three-dimensional stacked shielding structure according to claim 1, characterized in that: The surfaces of the radio frequency ground pad and the signal transmission pad are both gold-plated.

6. The three-dimensional stacked shielding structure according to claim 1, characterized in that: The signal transmission double-layer gold-based stud bumps are bonded to the signal transmission pads of the first chip by a wire bonding machine.

7. The three-dimensional stacked shielding structure according to claim 1, characterized in that: The diameter of the signal transmission double-layer gold-based stud bump is times, n is greater than 1.

8. A method for preparing a three-dimensional stacked shielding structure, used for preparing the three-dimensional stacked shielding structure according to any one of claims 1 to 7, characterized in that: The steps include: Step S1, bonding a signal transmission double-layer gold-based stud bump on a signal transmission pad of a first chip by a wire bonding machine; Step S2, bonding shielding gold wires sequentially between two rows of oppositely arranged RF ground pads of the first chip through a ball bonding process; Step S3, bonding a single layer of gold-based nail head bumps on the shielding gold wire at the ball welding points of the two ends of the shielding gold wire and the radio frequency ground pad; Step S4, flip-chip the second chip onto the assembly consisting of the first chip, the signal transmission double-layer gold-based stud bumps and the grounding double-layer gold-based stud bumps to form a three-dimensional stacked structure.

9. The method for preparing a three-dimensional stacked shielding structure according to claim 8, characterized in that: In step S4, it also includes: The assembly is placed on the hot plate surface of the flip chip bonder, and vacuum is applied to fix the assembly. The flip chip bonder absorbs the second chip and flips it over. The alignment of the first chip and the second chip is identified by the equipment identification system. The nozzle applies pressure and ultrasound to complete the thermal ultrasonic welding of the first chip and the second chip.

10. The method for preparing a three-dimensional stacked shielding structure according to claim 8, characterized in that: In step S4, it also includes: Place the adapter plate with a cavity structure on the surface of the hot table of the flip chip welder, apply vacuum to fix the adapter plate, the flip chip welder sucks the assembly and flips it over, completes the alignment recognition of the assembly and the adapter plate through the equipment recognition system, applies pressure and ultrasound through the suction nozzle to complete the thermal ultrasonic welding of the assembly and the adapter plate, bond a double-layer gold-based nail head bump on the adapter plate, and place it on the surface of the hot table of the flip chip welder, apply vacuum to fix it, the flip chip welder sucks the second chip and flips it, completes the alignment recognition of the assembly and the second chip through the equipment recognition system, and applies pressure and ultrasound through the suction nozzle to complete the thermal ultrasonic welding of the adapter plate and the second chip.

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