Semiconductor chip bonding structure and semiconductor chip bonding method

Abstract

This allows for the re-mounting of semiconductor chips using a simplified process in the event of connection failures. [Solution] A semiconductor chip bonding structure comprising a circuit board, a resin core made of a crosslinkable resin, and a metal plating covering the surface of the resin core, a bump electrode provided on the main surface of the circuit board, a semiconductor chip bonded to the main surface of the circuit board via the bump electrode, and an adhesive layer provided between the circuit board and the semiconductor chip to bond the circuit board and the semiconductor chip, wherein the adhesive force of the adhesive layer is stronger than the repulsive force of the resin core on the bump electrode compressed by the semiconductor chip.

Description

Technical Field

[0001] The present invention relates to a bonding structure of semiconductor chips and a method for bonding semiconductor chips.

Background Art

[0002] In recent years, the development of micro-LED displays using light-emitting diodes such as LEDs (Light Emitting Diodes) as pixels has been underway.

[0003] In a micro-LED display in which a large number of LED chips are mounted on a circuit board as pixels, there may be a defective LED chip with a poor electrical or physical connection between the LED chip and the circuit board.

[0004] For example, in Patent Document 1 below, in order to remove a defective LED chip, it is disclosed that a defective portion is removed by laser irradiation to a depth at which a lower circuit that supplies power necessary for the operation of the LED chip appears.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, if the defective portion is removed too much, in order to remount the LED chip, it becomes necessary to reform the bonding structure that connects the LED chip and the circuit board again.

[0007] Therefore, the present invention proposes a novel and improved bonding structure of semiconductor chips and a method for bonding semiconductor chips, which enable remounting of semiconductor chips in a simpler process when a mounting defect of a semiconductor chip occurs. [Means for solving the problem]

[0008] To solve the above problems, according to one aspect of the present invention, a semiconductor chip bonding structure is provided, comprising a circuit board, a resin core made of a crosslinkable resin and a metal plating covering the surface of the resin core, a bump electrode provided on the main surface of the circuit board, a semiconductor chip bonded to the main surface of the circuit board via the bump electrode, and an adhesive layer provided between the circuit board and the semiconductor chip to bond the circuit board and the semiconductor chip, wherein the adhesive force of the adhesive layer is stronger than the repulsive force of the resin core on the bump electrode compressed by the semiconductor chip.

[0009] Furthermore, in order to solve the above problems, according to another aspect of the present invention, a method for joining a semiconductor chip is provided, comprising the steps of: forming a bump electrode on the main surface of a circuit board, wherein the surface of a resin core made of a crosslinkable resin is covered with metal plating; providing an adhesive layer on the main surface of the circuit board; and joining a semiconductor chip to the main surface of the circuit board via the bump electrode, thereby bonding the circuit board and the semiconductor chip with the adhesive layer, wherein the adhesive force of the adhesive layer is stronger than the repulsive force of the resin core of the bump electrode compressed by the semiconductor chip. [Effects of the Invention]

[0010] As described above, according to the present invention, when a connection failure occurs in a semiconductor chip, it becomes possible to remount the semiconductor chip using a simpler process. [Brief explanation of the drawing]

[0011] [Figure 1] This is a longitudinal cross-sectional view illustrating the configuration of the junction structure of a semiconductor chip according to one embodiment of the present invention. [Figure 2] This is a longitudinal cross-sectional view showing the state of the semiconductor chip before bonding according to the same embodiment. [Figure 3]This is a longitudinal cross-sectional view showing the state of the semiconductor chip after bonding according to the same embodiment. [Figure 4] This is a longitudinal cross-sectional view showing the state of the bump electrodes after the semiconductor chip has been removed. [Modes for carrying out the invention]

[0012] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. In this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0013] <1.Joint structure> First, with reference to Figure 1, the semiconductor chip junction structure 1 according to one embodiment of the present invention will be described. Figure 1 is a longitudinal cross-sectional view illustrating the configuration of the semiconductor chip junction structure 1 according to one embodiment of the present invention.

[0014] As shown in Figure 1, the bonding structure 1 includes, for example, a circuit board 100, bump electrodes 140, a semiconductor chip 110, a stopper 120, and an adhesive layer 130. The bonding structure 1 is a laminate in which the semiconductor chip 110 is bonded to the main surface of the circuit board 100. In the bonding structure 1, the semiconductor chip 110 is physically fixed to the main surface of the circuit board 100 by the adhesive force of the adhesive layer 130. In addition, the bump electrodes 140 can be electrically connected to the chip electrodes 111 of the semiconductor chip 110 over a wider area by being compressed and deformed between the semiconductor chip 110 and the circuit board 100.

[0015] Although Figure 1 and other diagrams illustrate a structure in which only one semiconductor chip 110 is provided on the main surface of the circuit board 100, a large number of semiconductor chips 110 (not shown) are actually bonded to the main surface of the circuit board 100 in a two-dimensional arrangement.

[0016] The circuit board 100 is a substrate provided with circuit wirings 105 on its main surface that are electrically connected to each of the semiconductor chips 110. The circuit wirings 105 may be composed of a metal such as, for example, gold, silver, copper, or aluminum. The circuit wirings 105 can supply power to or input / output control signals to each of the semiconductor chips 110 joined on the main surface of the circuit board 100 via bump electrodes 140 and chip electrodes 111 described later.

[0017] The circuit board 100 may be, for example, a glass substrate, a glass epoxy substrate, an epoxy substrate, a polyimide substrate, or a (meth)acrylic substrate, etc., or may be a flexible substrate composed of polyester or polyethersulfone, etc. The circuit board 100 is, for example, a pixel array substrate of a micro LED display having a rectangular shape with a side length of several tens of cm to 1 m.

[0018] The bump electrodes 140 are electrodes provided in a convex shape on the main surface of the circuit board 100 and are electrically connected to the circuit wirings 105. The bump electrodes 140 electrically connect the circuit wirings 105 on the main surface of the circuit board 100 and the semiconductor chips 110. Specifically, the bump electrodes 140 are electrically connected to the chip electrodes 111 of the semiconductor chips 110 joined on the circuit board 100. The shape of the bump electrodes 140 may be a convex shape such as a cylindrical shape, a cylindrical shape with a rounded tip, a conical shape, a frustum shape, a hemispherical shape, or a flattened spherical shape. However, in order to more surely form the connection with the chip electrodes 111, the shape of the bump electrodes 140 is preferably a cylindrical shape or a cylindrical shape with a rounded tip.

[0019] More specifically, the bump electrodes 140 are configured as resin core electrodes including a resin core 141 composed of an organic resin and a metal coating 143 covering the surface of the resin core. According to such a structure, when the bump electrodes 140 are compressed between the circuit board 100 and the semiconductor chips 110, the resin core 141 is deformed, so that the bump electrodes 140 can surely connect with the chip electrodes 111 of the semiconductor chips 110 over a wider area.

[0020] The resin core 141 is composed of a crosslinkable resin having springiness. The resin core 141 may be composed of a crosslinkable resin such as, for example, an acrylic resin, an epoxy resin, a polyimide resin, or a silicone resin. Alternatively, the resin core 141 may be composed of a crystalline resin having springiness. By being composed of these springy resins, when the semiconductor chip 110 is removed and released from the compression between the circuit board 100 and the semiconductor chip 110, the resin core 141 can return to its original shape by the repulsive force of the spring.

[0021] The metal film 143 may be composed of one or more metals such as, for example, gold, nickel, copper, silver, tin, and palladium. The metal film 143 is formed as a thin film on the surface of the resin core 141 (the upper surface and the side surface when the resin core 141 has a cylindrical shape) using, for example, plating or sputtering.

[0022] Two bump electrodes 140 may be provided corresponding to one semiconductor chip 110 (corresponding to the positive and negative electrodes of the semiconductor chip 110, respectively). For example, two bump electrodes 140 may be two-dimensionally arranged on the main surface of the circuit board 100 corresponding to each of the semiconductor chips 110 two-dimensionally arranged on the main surface of the circuit board 100.

[0023] The semiconductor chip 110 is an electronic component made of semiconductor material. The semiconductor chip 110 is bonded to the main surface of the circuit board 100 via bump electrodes 140. For example, the semiconductor chip 110 may be an LED (Light-Emitting Diode) chip made of a compound semiconductor such as gallium nitride, gallium arsenide, or silicon carbide. The semiconductor chip 110, which is an LED chip, is provided in a two-dimensional arrangement on the main surface of the circuit board 100 as a pixel of a micro-LED display. Alternatively, the semiconductor chip 110 may be an IC (Integrated Circuit) chip made of silicon. The semiconductor chip 110, which is an IC chip, is provided in a two-dimensional arrangement on the main surface of the circuit board 100 for each group of LED chips, for example, as a pixel control IC that controls the LED chips of a micro-LED display.

[0024] A chip electrode 111 is provided on the surface of the semiconductor chip 110 facing the main surface of the circuit board 100, and is in contact with a bump electrode 140. The chip electrode 111 is electrically connected to the circuit wiring 105 provided on the circuit board 100 via the bump electrode 140. Two chip electrodes 111 (positive and negative electrodes) may be provided for each semiconductor chip 110. The chip electrode 111 may be made of a metal such as gold, nickel, copper, silver, or aluminum.

[0025] The stopper 120 is provided projecting from the main surface of the circuit board 100 so as to surround the entire circumference of the area where the semiconductor chip 110 is bonded. In other words, the stopper 120 is provided projecting from the main surface of the circuit board 100 so as to separate the areas where the semiconductor chip 110 is bonded from each other. The stopper 120 may be made of a patterned organic resin. For example, the stopper 120 may be made of one or more organic resins such as polyolefin resin, acrylic resin, epoxy resin, silicone resin, polyimide resin, polyalkylene terephthalate resin, polysulfone resin, polycarbonate resin, polyamide resin, phenolic resin, melamine resin, urethane resin, and urea resin.

[0026] The stopper 120 functions as a guide to hold the semiconductor chip 110 in place so that it does not shift laterally when the circuit board 100 and the semiconductor chip 110 are joined together. The stopper 120 also functions to hold the adhesive layer 130 that bonds the semiconductor chip 110 and the circuit board 100 around the semiconductor chip 110. Furthermore, when the circuit board 100 and the semiconductor chip 110 are joined together, the stopper 120 comes into contact with the collet 200 (described later) that presses the semiconductor chip 110 from the back surface, thereby controlling the amount of pressure the semiconductor chip 110 applies to the circuit board 100.

[0027] The adhesive layer 130 is provided in the area surrounded by the stopper 120 and adheres the semiconductor chip 110 and the circuit board 100. Specifically, the adhesive layer 130 is provided by thermal curing a thermosetting adhesive that is filled in the space surrounded by the semiconductor chip 110, the circuit board 100, and the stopper 120. For example, the adhesive layer 130 may be composed of a phenolic thermosetting adhesive, an epoxy thermosetting adhesive, or an acrylic thermosetting adhesive. The adhesive layer 130 is filled in the space surrounded by the stopper 120 in its pre-thermal state and is thermally cured when the semiconductor chip 110 and the circuit board 100 are joined, thereby adhering the semiconductor chip 110 and the circuit board 100.

[0028] In the bonding structure 1 according to this embodiment, the resin core 141 of the bump electrode 140 is made of a springy, crosslinkable resin. As a result, even if the bump electrode 140 is deformed by compression from the semiconductor chip 110 bonded to the circuit board 100, it can return to its original shape due to the spring-like repulsive force of the resin core 141 when the semiconductor chip 110 is removed. Therefore, in the bonding structure 1 according to this embodiment, when the semiconductor chip 110 mounted on the circuit board 100 is removed, the bump electrode 140 can be restored to its original state that allows for the re-mounting of the semiconductor chip 110.

[0029] Furthermore, in the bonding structure 1 according to this embodiment, the resin materials of the adhesive layer 130 and the resin core 141 are selected such that the adhesive strength of the adhesive layer 130 is stronger than the spring repulsive force of the resin core 141. For example, if the resin materials of the adhesive layer 130 and the resin core 141 are thermosetting resins, it is preferable that the Young's modulus of the thermosetting resin constituting the adhesive layer 130 after curing is higher than the Young's modulus of the thermosetting resin constituting the resin core 141 after curing. By appropriately selecting the resin materials of the adhesive layer 130 and the resin core 141 as described above, the adhesive layer 130 can maintain a state in which the resin core 141 is compressed between the semiconductor chip 110 and the circuit board 100. However, depending on the surface condition of the semiconductor chip 110 and the circuit board 100, the adhesive strength of the adhesive layer 130 may be stronger than the repulsive force of the resin core 141, regardless of the Young's modulus of the adhesive layer 130 and the resin core 141. In such cases, the cured Young's modulus of the thermosetting resin constituting the adhesive layer 130 may be less than or equal to the cured Young's modulus of the thermosetting resin constituting the resin core 141.

[0030] <2.Joining method> Next, the method for joining the semiconductor chip 110 according to this embodiment will be described with reference to Figures 2 to 4. Figure 2 is a longitudinal cross-sectional view showing the semiconductor chip 110 before joining according to this embodiment. Figure 3 is a longitudinal cross-sectional view showing the semiconductor chip 110 after joining according to this embodiment. Figure 4 is a longitudinal cross-sectional view showing the bump electrode 140 after the semiconductor chip 110 has been removed.

[0031] As shown in Figure 2, when a semiconductor chip 110 is bonded to a circuit board 100, the circuit board 100 is provided with bump electrodes 140 and stoppers 120, and an adhesive layer 130 is formed by filling the area surrounded by the stoppers 120 with thermosetting adhesive.

[0032] At this time, the height of the bump electrode 140 is higher than the height of the bump electrode 140 shown in Figure 1 when the semiconductor chip 110 is mounted on the circuit board 100. The bump electrode 140 is compressed and deformed between the circuit board 100 and the semiconductor chip 110 when the semiconductor chip 110 is mounted on the circuit board 100, resulting in the height shown in Figure 1.

[0033] On the other hand, a collet 200 for pressing the semiconductor chip 110 is provided on the side of the semiconductor chip 110 opposite to the side on which the chip electrodes 111 are located. The collet 200 is a flat jig made of a rigid material such as glass or silicon, having a main surface area larger than that of the semiconductor chip 110. The collet 200 can uniformly press the entire surface of the semiconductor chip 110 against the circuit board 100. The collet 200 may also be a flat jig having a main surface area large enough to press multiple semiconductor chips 110.

[0034] Next, as shown in Figure 3, the semiconductor chip 110 is pressed against the circuit board 100 via the collet 200. The amount of pressure the semiconductor chip 110 exerts on the circuit board 100 is controlled by the contact between the peripheral edge of the collet 200 protruding from the semiconductor chip 110 and the stopper 120. As the semiconductor chip 110 is pressed against the circuit board 100, the bump electrode 140 is compressed and deformed by the chip electrode 111 of the semiconductor chip 110. Furthermore, when the adhesive layer 130 is heated in this state, the adhesive layer 130 is thermally cured, and the semiconductor chip 110 is physically fixed to the circuit board 100. Through these steps, the semiconductor chip 110 is mounted on the circuit board 100, and the bonded structure 1 shown in Figure 1 is formed.

[0035] However, the semiconductor chip 110 may have mounting defects resulting in poor electrical or physical connection with the circuit board 100. In particular, when multiple semiconductor chips 110 are mounted on the circuit board 100 simultaneously, some of the semiconductor chips 110 may have mounting defects. In such cases, the defective semiconductor chip 110 is removed from the circuit board 100 and then remounted onto the circuit board 100.

[0036] Specifically, when the adhesive layer 130 is removed by etching or ashing, the semiconductor chip 110 becomes detached from the circuit board 100 (i.e., not physically fixed). As a result, the semiconductor chip 110 can be removed from the circuit board 100.

[0037] At this time, as shown in Figure 4, the bump electrode 140 is restored to its shape before the semiconductor chip 110 was mounted by the spring force of the resin core 141, because the compressive force caused by the pressing between the semiconductor chip 110 and the circuit board 100 is removed. In other words, the circuit board 100 and the bump electrode 140 can be returned to the state before the semiconductor chip 110 was mounted, as shown in Figure 2.

[0038] According to this, the circuit board 100 can be made ready for mounting the semiconductor chip 110 again by filling the area surrounded by the stopper 120 on the circuit board 100 with a thermosetting adhesive, without replacing or repairing the bump electrodes 140. Furthermore, the bump electrodes 140 can be restored to their original shape more quickly by heating them after removing the semiconductor chip 110 from the circuit board 100.

[0039] In this embodiment, the bump electrode 140 is composed of a resin core 141 that has spring properties (crosslinkable resin or crystalline resin). Therefore, the bump electrode 140 can elastically deform in response to an external force and exhibit a restorative force that returns it to its original shape when the external force is removed. As a result, the bonding structure 1 according to this embodiment makes it possible to remount the semiconductor chip 110 after removing it from the circuit board 100 without replacing or repairing the bump electrode 140.

[0040] The bonding structure 1 according to this embodiment, as described above, can simplify or eliminate the process of restoring the bump electrode 140 after removing the defective semiconductor chip 110 from the circuit board 100. Therefore, the bonding structure 1 according to this embodiment can further reduce the repair time for the defective semiconductor chip 110. Therefore, the bonding structure 1 according to this embodiment can further reduce the manufacturing cost of the microLED display.

[0041] Although preferred embodiments of the present invention have been described in detail above with reference to the attached drawings, the present invention is not limited to these examples. It is clear to any person with ordinary skill in the art to which the present invention belongs that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these are also understood to fall within the technical scope of the present invention. [Explanation of symbols]

[0042] 1...Bonding structure, 100...Circuit board, 105...Circuit wiring, 110...Semiconductor chip, 111...Chip electrode, 120...Stopper, 130...Adhesive layer, 140...Bump electrode, 141...Resin core, 143...Metal coating, 200...Collet

Claims

1. Circuit board and The circuit board includes a resin core made of a crosslinkable resin and a metal plating covering the surface of the resin core, and a bump electrode provided on the main surface of the circuit board, A semiconductor chip bonded to the main surface of the circuit board via the bump electrodes, An adhesive layer is provided between the circuit board and the semiconductor chip to bond the circuit board and the semiconductor chip, Equipped with, A semiconductor chip bonding structure wherein the adhesive strength of the adhesive layer is stronger than the repulsive force of the resin core of the bump electrode compressed by the semiconductor chip.

2. The bonding structure for a semiconductor chip according to claim 1, wherein the crosslinkable resin includes an epoxy resin, an acrylic resin, a polyimide resin, or a silicone resin.

3. The semiconductor chip bonding structure according to claim 1 or 2, wherein the semiconductor chip is an LED chip or an IC chip that controls the light emission of the LED chip.

4. The semiconductor chip bonding structure according to claim 1 or 2, wherein the resin core is compressed between the semiconductor chip and the circuit board.

5. The adhesive layer and the resin core are each composed of a thermosetting resin. The bonding structure for a semiconductor chip according to claim 1 or 2, wherein the Young's modulus of the cured adhesive layer is higher than the Young's modulus of the cured resin core.

6. The steps include forming bump electrodes on the main surface of a circuit board by covering the surface of a resin core made of a crosslinkable resin with metal plating, The steps include: providing an adhesive layer on the main surface of the circuit board; The steps include: bonding a semiconductor chip to the main surface of the semicircular circuit board via the bump electrodes, and bonding the circuit board and the semiconductor chip with the adhesive layer; Includes, A method for joining semiconductor chips, wherein the adhesive strength of the adhesive layer is stronger than the repulsive force of the resin core of the bump electrode compressed by the semiconductor chip.

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