2.5d injection molding module controllable warpage welding method

Abstract

The application provides a 2.5D injection molding module controllable warping welding method, and injection molding flip bumps are prepared for encapsulating the injection molding module, and the injection molding flip bumps and the front surface of the injection molding module form point interconnection materials; temporary bonding glue is applied between the bonding carrier plate and the back of the injection molding module to form a temporary bonding structure; the injection molding flip bump surface of the temporary bonding structure is flip mounted on a packaging substrate to realize electrical interconnection with the packaging substrate; after the flip welding is completed, the bonding carrier plate is separated from the back of the injection molding module by using a debonding method; injection molding flip bottom filling glue is filled in the gap between the packaging substrate and the injection molding module to wrap and protect the injection molding flip bumps, and the injection molding module-substrate encapsulation is realized. The 2.5D injection molding module controllable warping welding method can fundamentally solve the problems that the reflow warping of the injection molding module is difficult to predict and control, and can avoid flip bump virtual welding and bridging, and realize controllable adjustment of the height and form of the flip bump.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor packaging technology, and specifically relates to a controllable warpage welding method for 2.5D injection molded modules. Background Technology

[0002] As VLSI devices such as FPGAs, SoCs, CPUs, and GPUs evolve towards higher speeds, higher densities, and higher performance, single-chip flip-chip packaging is no longer sufficient to meet the demands of high-density packaging. A 2.5D packaging structure based on TSVs (Through-Silicon Vias) is now necessary. In CoWoS (Chip-on-Wafer-on-Substrate) packaging, reflow warpage of the CoW-reconstructed chip and substrate is a major cause of poor solder joints and bridging at C4 (controlled collapse chip connection) bumps during assembly, posing significant challenges to interconnect technology and device reliability.

[0003] Existing warpage control methods for injection molded parts are mostly focused on wafer-level warpage control, employing methods such as vacuum adsorption, rigid constraints, and temporary bonding. Research on warpage control during the reflow soldering process of injection molded parts is limited. Vacuum adsorption can achieve wafer-level warpage control, but the vacuum adsorption conditions are difficult to apply during the reflow soldering process of the injection molded module. Rigid constraints can easily damage the injection molded module and are unsuitable for the reflow soldering process. Temporary bonding can achieve reflow warpage control at the thin wafer level with minimal wafer damage, making it feasible for reflow warpage control of injection molded modules. However, there are no reports on using temporary bonding for flip-chip bonding of injection molded modules. Applying bonding adhesive between the back of the injection molded module and the bonding carrier shows promise for reflow warpage control. However, due to the presence of substrate reflow warpage, the flip-chip bonding joints between the injection molded module and the substrate still have a significant risk of poor soldering and bridging. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the inventors have conducted intensive research and provided a controllable warpage welding method for 2.5D injection molded modules, which effectively reduces heat-induced warpage during the reflow process of injection molded modules and avoids problems such as incomplete welding and bridging in C4 welding.

[0005] The technical solution provided by this invention is as follows:

[0006] A method for controllable warpage welding of 2.5D injection molded modules includes the following steps:

[0007] Injection molding flip bumps for injection molding module packaging are prepared, and the injection molding flip bumps are interconnected with the front side of the injection molding module; the injection molding module includes a chip with chip bumps and an adapter board, the chip bump side of the chip is flip-mounted on the adapter board, and the chip bumps are wrapped and protected by filler glue at the bottom of the chip;

[0008] A temporary bonding adhesive is applied between the bottom surface of the bonding carrier and the back of the injection mold to form a temporary bonding structure. The bonding carrier has a support structure, and the space between the support structures is formed to accommodate the injection mold.

[0009] The injection-molded flip-chip bumps of the temporary bonding structure are flip-chipped onto the packaging substrate to achieve electrical interconnection with the packaging substrate;

[0010] After the flip welding is completed, the bonding carrier is separated from the back of the injection molded module by debonding.

[0011] The injection-molded flip-chip bottom filler is filled into the gap between the packaging substrate and the injection-molded module to wrap and protect the injection-molded flip-chip bumps, thereby achieving injection-molded module-substrate encapsulation.

[0012] The controllable warpage welding method for 2.5D injection molded modules provided by the present invention has the following beneficial effects:

[0013] (1) The present invention adopts a 2.5D injection molding module controllable warp welding method, which can solve the problem that the large warp of the injection molding module chip reflow leads to the inability to form an effective interconnection, avoids the problem of false soldering and bridging caused by warp, realizes controllable adjustment of flip bump height and shape, and forms a low-cost integrated welding method.

[0014] (2) The present invention adopts a 2.5D injection molding module controllable warpage welding method, which is independent of the chip size of the injection molding module and has good compatibility with large-size 2.5D packaged injection molding modules.

[0015] (3) The present invention adopts a 2.5D injection molding module controllable warpage welding method. The bonding and debonding process of temporary bonding glue will not cause damage to the injection molding module chip, and has good process compatibility.

[0016] (4) The present invention adopts a 2.5D injection molding module controllable warpage welding method, and the temporary bonding carrier plate can be reused, which can reduce costs.

[0017] (5) The present invention adopts a 2.5D injection molding module controllable warp welding method, which has good consistency of the shape of the interconnection solder joints of the injection molding module and has higher reliability.

[0018] (6) The present invention adopts a 2.5D injection molding module controllable warpage welding method, which has low residual stress at the edge interconnection weld points of the injection molding module and better resistance to temperature cycling. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the controllable warpage welding method for injection molding modules according to Embodiment 2.5 of the present invention;

[0020] Figure 2 This is a schematic diagram of the injection molding module structure according to an embodiment of the present invention;

[0021] Figure 3(a) is a schematic diagram of the temporary bonding injection mold structure in Embodiment 1 of the controllable warpage welding method for 2.5D injection molded modules of the present invention;

[0022] Figure 3(b) is a schematic diagram of the temporary bonding injection mold structure in Embodiment 2 of the controllable warpage welding method for 2.5D injection molded modules of the present invention.

[0023] Figure 4 This is a schematic diagram of the temporary bonding interconnection structure between the injection molding module and the substrate in the controllable warpage welding method for 2.5D injection molding modules of the present invention.

[0024] Figure 5 This is a schematic diagram of the temporary bonding and debonding structure of the injection mold module carrier plate in the controllable warpage welding method of the 2.5D injection mold module of the present invention;

[0025] Figure 6 This is a schematic diagram of the bottom filling structure for the welding interconnection between the injection mold and the substrate in the 2.5D injection molded module controllable warpage welding method of the present invention;

[0026] Figure 7 This is a diagram illustrating the warpage control effect of the injection molding module in Example 1.

[0027] Figure 8 This is a diagram showing the warpage control effect of the injection molding module in Example 2.

[0028] Explanation of icon numbers:

[0029] 1-Packaging substrate; 2-Injection molded flip-chip underfill; 3-Injection molded flip-chip bump; 4-Adapter board; 5-Chip underfill; 6-Injection molded module; 7-Chip bump; 8-Chip I; 9-Chip II; 10-Temporary bonding adhesive; 11-Bonding carrier. Detailed Implementation

[0030] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0031] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0032] This invention provides a method for controllable warpage welding of 2.5D injection molded modules, comprising the following steps:

[0033] (I) Preparation of injection-molded flip bumps 3 for packaging injection-molded module 6, wherein injection-molded flip bumps 3 and the front side of injection-molded module 6 form interconnection material, see Figure 2 The injection molding module 6 includes chips (8, 9) with chip bumps 7 and an adapter plate 4. The chip bumps 7 of the chip are flipped onto the adapter plate 4, and the chip bumps 7 are wrapped and protected by the chip bottom filler glue 5.

[0034] In this step, the injection-molded flip bump 3 is SnAg ball, SnPb ball, Cu pillar or gold bump, etc., and can be prepared by drop ball method, electroplating method, laser ball implantation method, etc. The height of the injection-molded flip bump 3 is ≤300μm.

[0035] (ii) Temporary bonding adhesive 10 is applied between the bonding carrier plate 11 and the back of the injection mold 6 to form a temporary bonding structure. The bonding carrier plate 11 has a support structure, and the support structures form a space to accommodate the injection mold 6. See Figure 3a and Figure 3b The support structure can be a plate support, with the support structures forming a cavity to accommodate the injection molding module, or the support structure can be a four-corner support structure.

[0036] In this step, the bonding carrier plate adheres to the injection molding module through temporary bonding adhesive, suppressing warping during the module reflow process.

[0037] In this step, the temporary bond structure is formed in the following two ways:

[0038] (i) Temporary bonding adhesive 10 is applied to the bonding carrier plate 11, and then bonded to the back of the injection mold 6 to form a temporary bonding structure, see Figure 3a ;

[0039] (ii) Apply temporary bonding adhesive 10 to the back of the injection mold 6, and then attach it to the bottom surface of the bonding carrier plate 11 to form a temporary bonding structure. See Figure 3b .

[0040] In this step, the temporary bonding adhesive 10 is in the form of a dry film or glue, and is a temporary bonding material for UV laser debonding, thermal slip debonding, or mechanical debonding.

[0041] In this step, the thickness of the temporary bonding adhesive 10 is 30-50 μm, and the thickness uniformity is ≤10 μm.

[0042] In this step, the bonding carrier 11 is a glass carrier, a silicon carrier, or a metal carrier, etc. The support height C of the bonding carrier is C = A + B + D, where A is the thickness of the injection molding module, B is the thickness of the temporary bonding adhesive, and D is the height of the solder joint.

[0043] In this step, the solder joint height D can be adjusted by adjusting the support height C of the bonding carrier plate.

[0044] In this step, when the temporary bonding adhesive 10 is a temporary bonding material that is debonded by ultraviolet laser, the bonding carrier 11 is a glass carrier.

[0045] (III) The injection-molded flip-chip bumps of the temporary bonding structure are flip-chip bonded onto the packaging substrate 1 to achieve electrical interconnection with the packaging substrate 1. See Figure 4 .

[0046] In this step, the packaging substrate 1 is an Al2O3 high-temperature ceramic substrate, an LTCC low-temperature ceramic substrate, or a plastic encapsulation substrate, and the coplanarity of the packaging substrate 1 is better than 50μm.

[0047] In this step, the temporary bonding structure formed by the temporary bonding adhesive 10, the bonding carrier 11, and the injection molding module 6 is achieved through processes such as vacuum reflow welding, hot air reflow welding, infrared reflow welding, vapor phase reflow welding, hot press welding, or ultrasonic hot press welding, and is electrically interconnected with the packaging substrate 1 through the injection molded flip bumps 3.

[0048] In this step, the flip-chip bonding device formed by the temporary bonding structure and the packaging substrate 1 is a non-hermetic structure, which facilitates the subsequent debonding of the bonding carrier 11 and the injection molding module 6.

[0049] (iv) After the flip welding is completed, the bonding carrier plate 11 is separated from the back of the injection molded module 6 by debonding, see Figure 5 .

[0050] In this step, the debonding method is ultraviolet laser debonding, thermal slip debonding, or mechanical debonding, which corresponds to the material selection of the temporary bonding adhesive 10.

[0051] (V) Fill the gap between the injection molding flip-chip bottom filler 2 and the packaging substrate 1 and injection molding module 6 with the injection molding flip-chip bumps 3 to protect them, thereby achieving injection molding module-substrate encapsulation. See [link / details]. Figure 6 Although this process / structure does not exist, for a clearer understanding of the invention, a schematic diagram of the bonding injection molding module and substrate welding interconnection structure is provided when the bonding carrier plate 11 is not removed and the injection molding flip-chip bottom filler 2 is present, as shown below. Figure 1 As shown.

[0052] Example

[0053] Example 1

[0054] The first step is to prepare the injection-molded flip bumps 3 for the injection-molded module 6, such as... Figure 2 As shown. Injection-molded flip bumps were prepared using the falling ball method. The injection-molded flip bumps were SnAg balls with a height of 100 μm.

[0055] The second step involves applying temporary bonding adhesive 10 to the bonding carrier plate 11, and then bonding it to the back of the injection molding module 6 to form a temporary bonding structure, as shown in Figure 3(a).

[0056] The temporary bonding adhesive 10 is a dry film-form UV laser debonding temporary bonding material with a thickness of 30 μm and a thickness uniformity of 10 μm. The bonding carrier 11 is a glass carrier with a thickness of 0.5 mm. The carrier cavity height C = A + B + D, where A is the thickness of the injection molding module, B is the thickness of the temporary bonding adhesive, and D is the height of the solder joint formed by the injection molding flip bump 3 (70 μm).

[0057] The third step involves using a vacuum reflow soldering process to flip-chip the injection-molded bumps (3 sides) of the temporary bonding structure onto the packaging substrate 1, thereby achieving electrical interconnection between the temporary bonding structure and the packaging substrate 1. Figure 4 As shown. The packaging substrate 1 is an Al2O3 high-temperature ceramic substrate with a coplanarity of 30 μm.

[0058] The fourth step, after flip-chip bonding is completed, is to separate the bonding carrier plate 11 from the injection molding module using ultraviolet laser debonding, such as... Figure 5 As shown.

[0059] Fifth step: Fill the gap between the packaging substrate 1 and the injection molding module 6 with the injection molding flip-chip bottom filler 2. Wrap and protect the injection molding flip-chip bumps 3 to achieve injection molding module-substrate encapsulation, as shown. Figure 6 As shown. The warpage of the injection molded module was measured using a moiré pattern measuring device, resulting in a warpage cloud map of the injection molded module. Figure 7 (Left image) and the diagonal values ​​of the cloud map ( Figure 7 (See right figure). The results show that when the injection molded module is bonded to the glass substrate via the bonding film, the module warpage is controlled within 18μm. Due to the better flatness of the dry film, the module warpage can be effectively controlled.

[0060] Example 2

[0061] The first step is to prepare the injection-molded flip bumps 3 for the injection-molded module 6, such as... Figure 2 As shown, injection-molded flip bumps 3 were prepared using the laser ball-mounting method. The injection-molded flip bumps were SnPb balls with a height of 300 μm.

[0062] In the second step, the injection molding module 6 and the bonding carrier 11 are in wafer form. The temporary bonding adhesive 10 is applied to the back of the wafer of the injection molding module 6 using a wafer spin coating process. Then, the carrier wafer is pressed onto the temporary bonding adhesive 10. The temporary bonding structure is diced using a wafer dicing device, as shown in Figure 3(b).

[0063] The temporary bonding adhesive 10 is a heat-slip debonding temporary bonding material in adhesive form, with a thickness of 30-50 μm and a thickness uniformity of ≤10 μm. The bonding carrier (11) is a silicon carrier with a thickness of 1 mm and a carrier cavity height C = A + B + D, where A is the thickness of the injection molding module, B is the thickness of the temporary bonding adhesive, and D is the height of the solder joint formed by the injection molding flip bump 3, which is 220 μm.

[0064] The third step involves using a hot air reflow soldering process to flip-chip the injection-molded bumps (3 sides) of the temporary bonding structure onto the packaging substrate 1, thereby achieving electrical interconnection between the temporary bonding structure and the packaging substrate 1. Figure 4 As shown. The packaging substrate 1 is an LTCC low-temperature ceramic substrate with a coplanarity of 50 μm.

[0065] Fourthly, after the flip-chip welding is completed, the bonding carrier plate 11 is separated from the injection molding module using a hot-slip debonding method, such as... Figure 5 As shown.

[0066] Fifth step: Fill the gap between the packaging substrate 1 and the injection molding module 6 with the injection molding flip-chip bottom filler 2. Wrap and protect the injection molding flip-chip bumps 3 to achieve injection molding module-substrate encapsulation, as shown. Figure 6 As shown. The warpage of the injection molded module was measured using a moiré pattern measuring device, resulting in a warpage cloud map of the injection molded module. Figure 8 (Left image) and the diagonal values ​​of the cloud map ( Figure 8 (See right figure). The results show that after spin-coating and bonding the injection molded module to the silicon substrate, the module warpage was controlled within 24μm, and the warpage was effectively controlled.

[0067] This invention employs a controllable warpage soldering method for 2.5D injection molded modules, which solves the problem of large reflow warpage of injection molded module chips preventing the formation of effective interconnects, thus avoiding cold solder joints and bridging issues caused by warpage. The controllable warpage soldering method for 2.5D injection molded modules is independent of the chip size and has excellent compatibility with large-size 2.5D packaged injection molded modules. The temporary bonding adhesive bonding and debonding process does not damage the injection molded module chip, exhibiting excellent process compatibility. The temporary bonding carrier used is reusable, reducing costs. The interconnect solder joints of the injection molded module have good consistency in morphology, resulting in higher reliability. The residual stress at the edge interconnect solder joints of the injection molded module is low, providing better temperature cycling resistance.

[0068] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0069] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for controllable warpage welding of a 2.5D injection molded module, characterized in that, Includes the following steps: Injection molding flip bumps (3) for packaging injection molding module (6) are prepared, and injection molding flip bumps (3) are interconnected with the front side of injection molding module (6); the injection molding module (6) includes a chip with chip bumps (7) and an adapter board (4), the chip bump (7) side of the chip is flip-mounted on the adapter board (4), and the chip bump (7) is wrapped and protected by chip bottom filler glue (5); Temporary bonding adhesive (10) is applied between the bottom surface of the bonding carrier plate (11) and the back of the injection molding module (6) to form a temporary bonding structure. The bonding carrier plate (11) has a support structure, and a space for accommodating the injection molding module (6) is formed between the support structures. The injection-molded flip bump (3) surface of the temporary bonding structure is flip-molded onto the packaging substrate (1) to achieve electrical interconnection with the packaging substrate (1); After the flip welding is completed, the bonding carrier plate (11) is separated from the back of the injection molding module (6) by debonding. The injection molding flip bottom filler (2) is filled into the gap between the encapsulation substrate (1) and the injection molding module (6) to wrap and protect the injection molding flip bumps (3) and realize the encapsulation of the injection molding module-substrate. The support height C of the bonding carrier plate (11) is A+B+D, where A is the thickness of the injection molding module, B is the thickness of the temporary bonding adhesive, and D is the height of the solder joint formed by the injection molding flip bump. The height D of the solder joint can be adjusted by adjusting the support height C of the bonding carrier plate.

2. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The injection-molded inverted bump (3) is a SnAg ball, SnPb ball, Cu pillar or gold bump.

3. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The height of the injection molding inverted protrusion (3) is ≤300μm.

4. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The temporary bonding structure can be formed in the following two ways: (i) Apply temporary bonding adhesive (10) to the bonding carrier plate (11) and then attach it to the back of the injection molding module (6) to form a temporary bonding structure; (ii) Apply temporary bonding adhesive (10) to the back of the injection molding module (6) and then attach it to the bottom surface of the bonding carrier plate (11) to form a temporary bonding structure.

5. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The temporary bonding adhesive (10) is in the form of a dry film or glue, and is a temporary bonding material for UV laser debonding, thermal slip debonding, or mechanical debonding.

6. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The thickness of the temporary bonding adhesive (10) is 30-50 μm, and the thickness uniformity is ≤10 μm.

7. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The bonding carrier (11) is a glass carrier, a silicon carrier, or a metal carrier.

8. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The encapsulation substrate (1) is an Al2O3 high-temperature ceramic substrate, an LTCC low-temperature ceramic substrate, or a plastic encapsulation substrate, and the coplanarity of the encapsulation substrate (1) is better than 50 μm.

9. The controllable warpage welding method for 2.5D injection molded modules according to claim 1, characterized in that, The temporary bonding structure is achieved through vacuum reflow welding, hot air reflow welding, infrared reflow welding, vapor phase reflow welding, hot press welding or ultrasonic hot press welding processes, and is electrically interconnected with the packaging substrate (1) through injection molded flip bumps (3).

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