Techniques for adhesive control between a substrate and a die

Abstract

Method for manufacturing a housing assembly comprising the following: Formation of at least one cavity in a substrate; Separating a second substrate to form a large number of dies; Attaching at least one bond contact surface to a surface of one die from the plurality of dies; Deposition of a sacrificial material layer on the surface of the die, wherein the sacrificial material layer covers at least part of a bond contact area from the at least one bond contact area; Introducing an adhesive into a cavity from the at least one cavity; and Place the die into the cavity and bring it into contact with the adhesive.

Description

background

[0001] Conventional manufacturing processes used in the production of semiconductor devices employ microlithography to structure integrated circuits onto a circular wafer formed from a semiconductor such as silicon. Typically, the structured wafers are segmented into individual integrated circuit chips, or dies, to separate the integrated circuits. The individual integrated circuit chips are then assembled or packaged using a variety of packaging techniques to form semiconductor devices that can be mounted on a printed circuit board.

[0002] Over the years, packaging technologies have evolved to create smaller, cheaper, more reliable, and more environmentally friendly packages. For example, chip-scale packaging techniques have been developed that use directly surface-mountable packages with a footprint no larger than 1.2 times the area of ​​the integrated circuit chip. Wafer-level packaging is an emerging chip-scale packaging technique that encompasses a variety of methods for packaging integrated circuit chips at the wafer level, prior to segmentation. Wafer-level packaging extends wafer fabrication processes by incorporating component interlinking and component protection operations. Consequently, wafer-level packaging streamlines the manufacturing process by enabling the integration of wafer fabrication, packaging, testing, and burn-in operations at the wafer level.

[0003] According to US 7,842,887 B2, a multilayer printed circuit board (PCB) features an integrated circuit (IC) chip pre-mounted in a core substrate and a transition layer provided on a pad of the IC chip. This allows the IC chip to be electronically connected to the PCB without the use of lead elements and a sealing resin. Providing the copper transition layer on the pad also prevents resin residue from forming on the pad and improves the connection properties between the pad and a via hole, thus enhancing reliability.

[0004] US Patent 2012 / 091594 A1 discloses a method for manufacturing a chip package, which includes providing a substrate comprising a first recess with a recess base and recess sidewalls. A chip with a back side is inserted into the recess such that the chip does not protrude from the recess and a gap remains between the recess sidewalls and the chip, with the back side of the chip resting against the recess base. The gap is filled with a filler material. To adhere the chip to the recess, adhesive may have been pre-applied to the recess, for example, by dispensing, jetting, drop application, or screen printing. Alternatively, the adhesive may have been applied to the back side of the component.

[0005] US 5,949,133 A describes a circuit module comprising at least one high-temperature semiconductor chip with chip pads, a substrate with a substrate metallization, and an applied flexible pattern of electrical conductors. The applied flexible pattern of electrical conductors comprises a plurality of integral interconnect segments, wherein at least one of the integral interconnect segments includes first and second leg sections and a shelf section. The shelf section is spaced apart from the at least one semiconductor chip and substrate and is connected by the first leg section to a selected chip pad and by the second leg section to another selected chip pad or a selected section of the substrate metallization. Summary

[0006] Semiconductor devices are described that employ techniques designed to control the adhesive deposition between a substrate and a die. Wafer-level chip-scale packages contain a chip-support substrate with cavities for receiving a die. For example, the cavities can be beveled cavities designed to receive the die, with an adhesive (e.g., an epoxy or glue) holding the die within the cavity. In one embodiment, a sacrificial layer is provided on an upper surface of the die to protect the surface and bond contact surfaces thereon from excess adhesive. The sacrificial layer and the excess adhesive are subsequently removed from the die and / or the chip support. In another embodiment, the die includes a die-attachment film on an underside of the die to bond the die to the cavity of the substrate.The die is placed into the cavity using heat and pressure to cause part of the die attachment film to flow from the underside of the die to a side surface of the substrate cavity.

[0007] This summary is intended to present a selection of concepts in simplified form, which are described in more detail below. This summary is not intended to define crucial properties or essential features of the claimed subject matter of the invention, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Drawings

[0008] The detailed description is given with reference to the accompanying figures. The use of the same reference number in different places in the description and in the figures may indicate similar or identical elements. Fig. Figure 1A is a schematic sectional side view showing a wafer-level chip-scale packaged device with a die that is to be attached to a substrate using an adhesive. Fig. Figure 1B is a schematic sectional view showing the wafer-level chip-scale package component of Fig. 1B represents the die mounted on the substrate. Fig. 2A is a schematic partial sectional view of a die mounted on a substrate according to an exemplary embodiment of the present disclosure, wherein the die contains a sacrificial layer on an upper surface of the die. Fig. 2B is a schematic partial sectional view of the substrate of Fig. 2A mounted dies, with the sacrificial layer removed. Fig. 3A is a schematic partial sectional view of the substrate of Fig. 2A mounted dies, wherein the substrate contains a sacrificial layer on an upper surface of the substrate. Fig. 3B is a schematic partial sectional view of the substrate of Fig. 3A mounted dies, with the sacrificial layers removed from the die and the substrate. Fig. Figure 4A is a schematic partial sectional view of a die with a die attachment film on a subsurface of the die according to an exemplary embodiment of the present disclosure, wherein the die is to be placed under pressure onto a heated substrate. Fig. 4B is a schematic partial sectional view of the substrate of Fig. 4A mounted dies, with part of the die mounting film flowing out from under the die. Fig. Figure 5 is a flowchart illustrating an exemplary method for manufacturing a housing assembly according to an embodiment of the present disclosure. Fig. Figure 6 is a flowchart illustrating an exemplary method for manufacturing a housing assembly according to an embodiment of the present disclosure. Fig. Figure 7 is a schematic partial sectional view of a housing structure of a die mounted on a substrate according to an exemplary embodiment of the present disclosure. Fig. Figure 8 is a schematic partial sectional view of a housing structure containing solder bumps according to an exemplary embodiment of the present disclosure. Detailed description Overview

[0009] Wafer-level packaging enables the fabrication of semiconductor devices that are more cost-effective, have smaller form factors, and exhibit lower parasitic effects than devices manufactured using many other packaging techniques. However, the peak spacing of wafer-level packages decreases more rapidly than the pad spacing of printed circuit boards (PCBs). Substrates are designed with cavities (e.g., chamfered, rectangular, etc.) to accommodate dies, allowing the peak spacing of the wafer-level package to fan out (e.g., with rewiring layers) to match the PCB pad spacing. The die can be mounted to the substrate using an adhesive, such as an epoxy, glue, etc. For example, as in Fig. 1A and Fig. Figure 1B shows a die 50 designed to be mounted into a cavity 52 of a substrate 54 by means of an adhesive 56. The die 50 contains a plurality of bond contact surfaces 58 to provide electrical connection options for the die 50. Fluid properties of the adhesive can cause the adhesive to affect the sidewalls of the substrate and overflow onto a top surface of the die, which can impair the bond contact surface on the die (e.g., coat it, cover it, or otherwise block its electrical conductivity). For example, when the die 50 is placed into the cavity 52, some 60 of the adhesive 56 may flow onto a top surface 62 of the die and cover at least part of one or more bond contact surfaces 58.

[0010] Accordingly, semiconductor devices are described that employ techniques designed to control the adhesive application between a substrate and a die, and are designed for wafer-level chip-scale packaging. For example, the substrate may contain cavities (e.g., chamfered, rectangular, etc.) designed to receive the die. The die is mounted in the cavity using an adhesive (e.g., an epoxy or glue). In one embodiment, a sacrificial layer is provided on an upper surface of the die to protect the surface and bond contact surfaces thereon from excess adhesive. The sacrificial layer and the excess adhesive are subsequently removed from the die and / or the chip carrier. In another embodiment, the die includes a die-attachment film on an underside of the die to adhere the die to the cavity of the substrate.The die is placed into the cavity using heat and pressure to cause part of the die attachment film to flow from the underside of the die to a side surface of the substrate cavity. Examples of implementation

[0011] The Fig. Figures 2A to 4B represent a wafer-level chip-scale package 100 according to exemplary embodiments of the present disclosure. As shown, the devices 100 include a die 102 configured to be mounted onto a substrate 104 via an adhesive 106. The substrate 104 contains one or more cavities 108 formed therein. The size and / or shape of the die 102 can depend on the complexity, configuration, design features, etc., of the integrated circuits to be implemented in the wafer-level chip-scale package 100. The size and / or shape of the cavities 108 can depend on the corresponding size and / or shape of the die 102. For example, the cavities 108 can have beveled sidewalls extending outwards from a bottom surface of the substrate 104, as shown in the figures. Fig. Figures 2A to 4B are shown. In some embodiments, the cavities 108 may include sidewalls extending vertically from a base surface of the substrate to form a square or rectangular cavity 108. In some embodiments, the cavities 108 may form irregular or unstructured shapes. The cavities 108 may be formed in the substrate by etching the substrate, such as by standard etching methods. For example, the cavities 108 may be etched into the substrate 104 using a wet etching method (using a wet etching agent such as potassium hydroxide), a dry etching method (e.g., plasma etching), such as deep reactive ion etching (DRIE), or a combination of both.

[0012] In one embodiment as in Fig. As shown in Figure 2A, the wafer-level chip-scale package 100 includes a sacrificial layer 110 arranged on an upper surface 112 (e.g., the surface distal to the substrate 104) of the die 102. The sacrificial layer 110 is configured to cover at least a portion of the upper surface 112 of the die 102 to provide protection for the die 102. For example, the sacrificial layer 110 can cover one or more bond contact surfaces 114 of the die 102 to prevent contact between the bond contact surfaces 114 and any excess adhesive 106. The sacrificial layer 110 can be a polymer layer, a coating layer, and so on, applied to the die 102 by a variety of deposition methods, such as deposition techniques, sputtering techniques, and so on.In one or more embodiments, the material of the sacrificial layer 110 is selected based on a desired interaction between the layer and the adhesive, such as by specifying a contact angle of the material or a wetting behavior of the material. For example, in one embodiment, the sacrificial layer 110 contains PBO (poly(p-phenylene-2,6-benzobisoxazole)) or another polymer.

[0013] In certain embodiments, the sacrificial layer 110 is applied to the die 102 before the die 102 is placed onto the adhesive 106 in the cavity 108 of the substrate 104. Once the die 102 is mounted, the sacrificial layer 110 can be removed to remove any excess adhesive (in Fig. 2A as 116) to remove the substance that has accumulated on the sacrificial layer 110. The technique for removing the sacrificial layer 110 depends on the material used for the sacrificial layer 110. For example, the sacrificial layer 110 can be removed with a solvent such as NMP (N-methyl-2-pyrrolidone), which is designed to dissolve or weaken the binding capacity of at least part of the sacrificial layer 110. Fig. Figure 2B shows an embodiment of the component 100 in which the sacrificial layer 110 (and associated excess adhesive) has been removed. In one embodiment, the adhesive 106 is at least partially cured with NMP before the sacrificial layer 110 is removed. This partial curing can prevent the removal of the adhesive 106 with the solvent used to remove the sacrificial layer 110. For example, an epoxy adhesive can be cured at approximately 120 °C for about one hour to develop resistance that prevents the adhesive from being removed by the NMP solvent. In one or more embodiments, the component 100 can be post-treated after the sacrificial layer 110 has been removed to remove some of the excess adhesive from near the top surface 112 of the die 102.For example, a high-pressure water jet can be used to wipe away the parts of the excess adhesive that were in contact with the sacrificial layer 110 before the sacrificial layer 110 was removed.

[0014] In one or more embodiments, such as in Fig. As shown in Figure 3A, the component 100 includes the sacrificial layer 110 on the die 102 and an additional sacrificial layer 118 on an upper surface 120 of the substrate 104. The sacrificial layer 118 on the substrate 104 can comprise the same or a different material than that of the sacrificial layer 110 on the die 102. The sacrificial layer 118 can be configured to provide a protective function for the upper surface 120 of the substrate 104. For example, the sacrificial layer 118 can cover at least part of the upper surface 120 to prevent contact between the upper surface 120 and any excess adhesive 106. Fig. Figure 3B shows the component 100 after the sacrificial layers 110, 118 have been removed (e.g., by dissolving them with an NMP solvent) and the excess adhesive 106 has been washed off the surfaces 112, 120. As can be seen, the top surface 112 of the die 102 and the top surface 120 of the substrate 104 are essentially free of the adhesive 106, with the die 102 mounted in the cavity 108.

[0015] In one or more embodiments, such as in Fig. 4A and Fig. As shown in Figure 4B, the component 100 contains the die 102 to be mounted in the cavity 108 of the substrate 104. In these embodiments, the adhesive is a die-attachment film 400 attached to a lower surface 402 of the die 102. For example, the die-attachment film 400 can be integrated as part of the saw foil used during the segmentation or singulation process to produce the die 102, causing the die-attachment film 400 to be attached to the lower surface 402 of the die 102. In embodiments, the die-attachment film 400 has a thickness of less than approximately 75 micrometers, and in one particular embodiment, it has a thickness of approximately 30 micrometers. The die fixing film 400 can be plastic, so that the die fixing film 400 can flow out under pressure and temperature within the cavity 108 from below the die 102.For example, in one or more embodiments, the die 102 with the die-fixing film 400 is placed under pressure into the cavity 108 of the substrate 104, whereby the substrate 104 is actively heated, which causes the die-fixing film 400 to flow out from below the die 102, as in . Fig. 4B shown. The die-attachment film 400 can flow out from below the die 102 to come into contact with one or more side walls 404 of the die 102. For example, in one embodiment, the die-attachment film 400 can flow out from below the die 102 to come into contact with one or more side walls 404 at a height of approximately one-quarter of the height of the side wall 404 from the upper surface of the die (e.g., from the upper surface 112, as shown in Fig. (3B shown) to come into contact. For example, the die-attachment film 400 can come into contact with the side wall 404 from the cavity 108 upwards, thus covering approximately three-quarters of the distance between the cavity 108 and the upper surface 112 of the die 102. In embodiments, the die-attachment film 400 comes into contact with the side wall 404 at the upper surface 112 of the die 102. For example, the die-attachment film 400 can come into contact with the side wall 404 from the cavity 108 upwards to the upper surface 112 of the die 102. However, if the die 102 is inserted under controlled pressure and temperature, the application of the die-attachment film 400 can be controlled to prevent overflow onto the upper surface 112 of the die.

[0016] In embodiments, the component 100 includes one or more of the sacrificial layer 110 on the die 102 and the sacrificial layer 118 on the substrate in combination with the die adhesion film 400 on the die 102. Such a combination can help prevent excess die adhesion film 400 that may occur due to undesirable process conditions, including, but not limited to, unclean / inaccurate die insertion. Exemplary manufacturing processes

[0017] Fig. Figure 5 presents an exemplary process 500 that uses wafer-level packaging techniques to manufacture semiconductor devices, such as the one described in Fig. The components shown in 2A to 3B number 100. In the illustrated process 500, at least one cavity is formed in a substrate (block 502). For example, as in Fig. Figures 2A to 4B show the cavity 108 formed in the substrate 104, for example by an etching technique. Sequence 500 also includes the singulation of a second substrate to form a plurality of dies (Block 504). Die 102 represents an exemplary die singulated from a substrate. Sequence 500 also includes the attachment of at least one bond contact surface to a surface of one die from the plurality of dies (Block 506). As shown in Fig. As shown in Figures 2A to 4B, bond contact surfaces 114 are attached to the upper surface 112 of the die 102. Block 508 of the drain 500 represents the deposition of a sacrificial material layer on the surface of the die, wherein at least a portion of the sacrificial material layer covers at least a portion of a bond contact surface from the at least one bond contact surface. For example, as shown in Fig. 2A and Fig. Figure 3A shows that the sacrificial layer 110 is applied to the upper surface 112 of the die 102 and covers at least part of one or more bond contact surfaces 114 of the die 102. The sacrificial layer 110 can prevent contact between the bond contact surfaces 114 and any excess adhesive 106, where the adhesive could interfere with the electrical connection function of the bond contact surface 114. Block 510 of the drain 500 represents the introduction of an adhesive into a cavity from the at least one cavity. For example, an epoxy- or glue-based adhesive can be introduced into a cavity 108, as shown in Fig. 2A to 3B are shown. Sequence 500 further includes inserting the die into the cavity and into contact with the adhesive (block 512). For example, as shown in Fig. 2A to 3B shown, the die is placed in the cavity 108 and in contact with the adhesive 106 to mount the die 102 on the substrate 104.

[0018] Now, with reference to Fig. Figure 6 shows an exemplary process 600 that uses wafer-level packaging techniques to manufacture semiconductor devices, such as those described in the Fig. 4A and Fig. 4B shows the building elements 100. In the illustrated process 600, at least one cavity is formed in a substrate (block 602). For example, as in Fig. Figure 4A shows the cavity 108 formed in the substrate 104, for example by an etching technique. Sequence 600 also includes the singulation of a second substrate to form a plurality of dies (block 604). Die 102 represents an exemplary die singulated from a substrate. Sequence 600 also includes the attachment of at least one bond contact surface to a surface of one die from the plurality of dies (block 606). As shown in Fig. As shown in Figures 2A to 4B, bond contact surfaces 114 are attached to the upper surface 112 of the die 102. Block 608 of the process 600 represents the attachment of a layer of a die bonding film to a subsurface of the die, the subsurface of the die being opposite the surface of the die with the at least one bond contact surface. For example, as shown in Fig. Figure 4A shows the die-attachment film 400 attached to the underside 402 of the die 102, the underside 402 generally facing opposite the upper surface 102 with the bond contact surfaces 114 attached thereto. The block 610 of the drain 600 represents the placement of the die into the cavity, with the die-attachment film coming into contact with the cavity. For example, as shown in Fig. 4A and Fig. 4B shows the die 102 being placed into the cavity 108, with the die fixing film 400 in contact with the cavity 108 of the substrate 104.

[0019] Processes 500 and 600 may further include a step of forming a passivation layer (e.g., a dielectric layer with a conformal or flattened surface) on the substrate. Fig. 7 and Fig. Figure 8 shows a passivation layer 700 formed on an upper surface 702 of the substrate 104 according to embodiments of the present disclosure. In embodiments, the passivation layer 700 is also formed over the cavity 108 and on the upper surface 112 of the die 102. In embodiments, steps 500 and 600 include a step of forming a pattern, etching the passivation layer to create openings (i.e., vias) to the metal of the top level of the embedded die, and metallizing in the vias and on the passivation layer to form metal intermediate connections 704 of a rewiring layer. In embodiments, the rewiring layer rewires some or all connections from the area coinciding with the die 102 to the area coinciding with the support substrate 104. This configuration can be described as a fanning structure.In fanned-out embodiments, the top surface of the substrate can be used to extend the connection area between the support substrate and the active circuitry of the die. In embodiments, processes 500 and 600 further include a step of forming solder bumps on the rewiring layer. Such a rewiring layer can be used to allow larger solder bumps that would otherwise not fit within the original area of ​​the embedded die. Fig.Figure 8 shows the solder bumps 706 on the rewiring layer. In embodiments, the housing structures described here contain multiple dies (e.g., two or more) placed on the substrate. For example, the substrate may contain multiple cavities, with one die placed in one cavity and another die placed in an adjacent cavity. Where the housing contains multiple dies, the dies may be electrically connected to one or more other dies in the housing. By using multiple dies, one or more of the dies may differ from each other in function, size, configuration, and so on.

Claims

[1] Method for manufacturing a housing assembly comprising the following: Formation of at least one cavity in a substrate; Separating a second substrate to form a large number of dies; Attaching at least one bond contact surface to a surface of one die from the plurality of dies; Deposition of a sacrificial material layer on the surface of the die, wherein the sacrificial material layer covers at least part of a bond contact area from the at least one bond contact area; Introducing an adhesive into a cavity from the at least one cavity; and Place the die into the cavity and bring it into contact with the adhesive. [2] Method according to claim 1, further comprising removing the sacrificial material layer from the surface of the die after placing the die in contact with the adhesive. [3] Method according to claim 2, wherein the removal of the sacrificial material layer includes the addition of a solvent to the sacrificial material layer. [4] Method according to claim 3, wherein the solvent contains N-methyl-2-pyrrolidone (NMP). [5] Method according to claim 2, further comprising at least partially curing the adhesive before removing the sacrificial layer. [6] Method according to claim 2, further comprising treating the die with a pressurized fluid to remove excess adhesive that was previously in contact with the sacrificial layer before the sacrificial layer was removed. [7] Method according to claim 1, wherein the sacrificial layer contains poly(p-phenylene-2,6-benzobisoxazole) (PBO). [8] Method according to claim 1, wherein the sacrificial layer contains a cover coat layer. [9] Method according to claim 1, further comprising the deposition of a second sacrificial material layer on a surface of the substrate adjacent to the cavity formed by the at least one cavity. [10] Method according to claim 9, further comprising removing the second sacrificial material layer from the surface of the substrate after placing the die in contact with the adhesive. [11] Method according to claim 1, wherein the adhesive touches a side wall of the die after the die has been brought into contact with the adhesive, and wherein the adhesive touches the side wall on the surface of the die. [12] Method according to claim 1, wherein the adhesive touches a side wall of the die at a point between the surface of the die and the cavity after the die has been brought into contact with the adhesive. [13] Method for manufacturing a housing assembly comprising the following: Formation of at least one cavity in a substrate; Separating a second substrate to form a large number of dies; Attaching at least one bond contact surface to a surface of one die from the plurality of dies; Attaching a layer of a die bonding film to a subsurface of the die, wherein the subsurface of the die is opposite to the surface of the die with the at least one bond contact area; and Placing the die into a cavity from at least one cavity with the die fixing film in contact with the cavity and further comprising the deposition of a sacrificial material layer on the surface of the die, wherein the sacrificial material layer covers at least part of a bond contact area from the at least one bond contact area. [14] Method according to claim 13, further comprising heating the substrate at least before or during the placement of the die into the cavity. [15] Method according to claim 13, wherein placing the die into the cavity includes applying pressure to the die during the placement of the die into the cavity. [16] Method according to claim 13, wherein the die fixing film has a thickness of less than approximately 75 micrometers. [17] Method according to claim 16, wherein the die fixing film has a thickness of approximately 30 micrometers. [18] Method according to claim 13, further comprising removing the sacrificial material layer from the surface of the die after placing the die into the cavity with the die fixing film in contact with the cavity. [19] Method according to claim 18, wherein the removal of the sacrificial material layer includes adding a solvent to the sacrificial material layer. [20] Method according to claim 13, further comprising the deposition of a second sacrificial layer on a surface of the substrate adjacent to the cavity formed by the at least one cavity. [21] Method according to claim 20, further comprising removing the second sacrificial material layer from the surface of the substrate after placing the die into the cavity with the die fixing film in contact with the cavity. [22] Method according to claim 13, wherein the die fixing film contacts a side wall of the die after the die has been placed in the cavity, and wherein the die fixing film contacts the side wall on the surface of the die. [23] Method according to claim 13, wherein the die fixing film contacts a side wall of the die at a point between the surface of the die and the cavity after the die has been placed in the cavity.

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