Semiconductor device and method for manufacturing the same

Abstract

To provide a semiconductor device capable of preventing occurrence of voids, and a method for manufacturing the same.SOLUTION: A method for manufacturing a semiconductor device includes a step of flip chip mounting a second chip 20 on a first chip, and a step of filling a resin between the first chip and the second chip. A surface 22 facing the first chip in the second chip has a central part 30 and an outer peripheral part 32. An insulation film 28 is provided on the central part and the outer peripheral part. A first electrode 50 (electrodes 50a and 50B) is provided in a part positioned on the outer peripheral part 32 in the insulation film 28. Wettability to the resin on the surface of the first electrode 50 is higher than wettability to the resin of the insulation film 28. A length L5 in an X-axis direction of the electrode 50a is shorter than a length L2 of a sensor chip 20. A length L6 in a Y-axis direction of the electrode 50b is shorter than a length L4 of the sensor chip 20.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor device and a method for manufacturing the same. [Background technology]

[0002] BACKGROUND ART There is known a technique for forming a semiconductor light receiving element by flip-chip mounting a chip having a photodiode or the like onto a chip having an IC (integrated circuit) or the like using bumps (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-163808 [Patent Document 2] Japanese Patent Publication No. 2022-147340 Summary of the Invention [Problem to be solved by the invention]

[0004] After flip-chip mounting, resin is filled between the chips. This can create voids in the resin, potentially reducing mechanical durability. Therefore, the objective of this invention is to provide a semiconductor device that can prevent voids from occurring, and a method for manufacturing such a semiconductor device. [Means for solving the problem]

[0005] A method for manufacturing a semiconductor device according to the present disclosure includes the steps of flip-chip mounting a second chip to a first chip and filling resin between the first chip and the second chip, wherein the surface of the second chip facing the first chip has a central portion and an outer periphery, insulating films are provided on the central portion and the outer periphery, a first electrode is provided on a portion of the insulating film located on the outer periphery, the wettability of the surface of the first electrode to the resin is higher than the wettability of the insulating film to the resin, and the length of the first electrode in the circumferential direction of the second chip is shorter than the length of the portion of the outer periphery where the insulating film is exposed. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a semiconductor device capable of preventing the occurrence of voids and a method for manufacturing the same. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is a plan view illustrating a semiconductor device according to the embodiment. [Figure 1B] FIG. 1B is a cross-sectional view illustrating an example of a semiconductor device. [Figure 2A] FIG. 2A is a plan view illustrating an example of a sensor chip. [Figure 2B] FIG. 2B is an enlarged view of the sensor chip. [Figure 2C] FIG. 2C is a cross-sectional view illustrating an example of the sensor chip. [Figure 3A] FIG. 3A is a flowchart illustrating a method for manufacturing a semiconductor device. [Figure 3B] FIG. 3B is a flowchart illustrating a method for manufacturing a semiconductor device. [Figure 4A] FIG. 4A is a cross-sectional view illustrating a method for manufacturing a semiconductor device. [Figure 4B] FIG. 4B is a cross-sectional view illustrating a method for manufacturing a semiconductor device. [Figure 4C] FIG. 4C is a cross-sectional view illustrating a method for manufacturing a semiconductor device. [Figure 4D]FIG. 4D is a cross-sectional view illustrating a method for manufacturing a semiconductor device. [Figure 5A] FIG. 5A is a plan view illustrating a method for manufacturing a semiconductor device. [Figure 5B] FIG. 5B is a plan view illustrating the method for manufacturing the semiconductor device. [Figure 5C] FIG. 5C is a plan view illustrating the method for manufacturing a semiconductor device. [Figure 6A] FIG. 6A is a plan view illustrating a sensor chip of a semiconductor device according to a comparative example. [Figure 6B] FIG. 6B is a plan view illustrating a method for manufacturing a semiconductor device in a comparative example. [Figure 7] FIG. 7 shows the results of the wettability evaluation. [Figure 8] FIG. 8 is a plan view illustrating the sensor chip according to the second embodiment. [Figure 9] FIG. 9 is a plan view illustrating the sensor chip according to the third embodiment. [Figure 10] FIG. 10 is a plan view illustrating the sensor chip according to the fourth embodiment. [Figure 11] FIG. 11 is a plan view illustrating the sensor chip according to the fifth embodiment. [Figure 12] FIG. 12 is a plan view illustrating the sensor chip according to the sixth embodiment. [Figure 13] FIG. 13 is a plan view illustrating the sensor chip according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Description of the embodiments of the present disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0009] One aspect of the present disclosure is a method for manufacturing a semiconductor device, the method comprising: (1) flip-chip mounting a second chip on a first chip; and filling a gap between the first chip and the second chip with resin; a surface of the second chip facing the first chip has a central portion and an outer periphery; an insulating film is provided on the central portion and the outer periphery; a first electrode is provided on a portion of the insulating film located on the outer periphery; the wettability of a surface of the first electrode with respect to the resin is higher than the wettability of the insulating film with respect to the resin; and the length of the first electrode in the circumferential direction of the second chip is shorter than the length of a portion of the outer periphery where the insulating film is exposed. The proportion of the first electrode with high wettability in the periphery is low, and the proportion of the insulating film with low wettability is high. The resin flows less quickly around the periphery. The resin reaches the central portion before it wraps around the periphery. This prevents voids from occurring. (2) In the above (1), the length of the first electrode may be one-third or less of the outer periphery of the second chip. This reduces the speed at which the resin flows around the periphery, thereby preventing voids from occurring. (3) In the above (1) or (2), the insulating film may be a nitride film, and the surface of the first electrode may be made of gold or platinum. The proportion of the first electrode, which has high wettability, in the periphery of the outer periphery is low, and the proportion of the insulating film, which has low wettability, is high. The resin flows less quickly around the periphery, preventing voids from forming. (4) In any of (1) to (3) above, a plurality of the first electrodes may be provided on the outer periphery, and the plurality of first electrodes may surround the central portion. Since the speed at which the resin flows around the outer periphery is reduced, the occurrence of voids can be prevented. Since the plurality of first electrodes are fixed to the first chip, the mechanical strength of the semiconductor device is increased. (5) In any of (1) to (4) above, the step of filling the resin may include the steps of heating the first chip and the second chip, supplying the resin to the end of the heated second chip, causing the supplied resin to move through the outer periphery and the central portion, and hardening the resin. The resin moves through the central portion before moving through the entire outer periphery. Air is less likely to be mixed in, and the occurrence of voids can be prevented. Hardening the filled resin increases the mechanical strength of the semiconductor device. (6) In any of the above (1) to (5), the outer periphery of the first chip may have a plurality of grooves in a portion close to the position where the resin is supplied. The resin passes through the grooves and flows toward the center. This can prevent the occurrence of voids. (7) In any of the above (1) to (6), the second chip may have a plurality of mesas in the central portion thereof, and second electrodes may be provided on the plurality of mesas, and the flip-chip mounting step may include connecting the first and second electrodes to the first chip with bumps. Preventing the generation of voids stabilizes the connection between the second electrodes and the first chip, thereby increasing the mechanical strength of the semiconductor device. (8) A semiconductor device comprising a first chip, a second chip flip-chip mounted on the first chip, and a resin filled between the first chip and the second chip, wherein the surface of the second chip facing the first chip has a central portion and an outer periphery, an insulating film is provided on the central portion and the outer periphery, an electrode is provided on a portion of the insulating film located on the outer periphery, the wettability of the surface of the electrode with respect to the resin is higher than the wettability of the insulating film with respect to the resin, and the length of the electrode in the circumferential direction of the second chip is shorter than the length of the portion of the outer periphery where the insulating film is exposed. The proportion of the electrode with high wettability relative to the periphery is low, and the proportion of the insulating film with low wettability is high. The resin flows less quickly around the periphery. The resin reaches the center before it wraps around the periphery. This prevents voids from occurring.

[0010] [Details of the embodiments of the present disclosure] Specific examples of semiconductor devices and manufacturing methods thereof according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0011] (Semiconductor Devices) Fig. 1A is a plan view illustrating a semiconductor device 100 according to an embodiment. Fig. 1B is a cross-sectional view illustrating the semiconductor device 100, taken along line AA in Fig. 1A.

[0012] As shown in FIGS. 1A and 1B, the semiconductor device 100 has an IC (Integrated Circuit) chip 10 (first chip) and a sensor chip 20 (second chip). The IC chip 10 has, for example, an ROIC (Readout IC, readout circuit). The sensor chip 20 is a focal plane array (FPA) that receives light such as infrared light and outputs an electrical signal. The planar shapes of the IC chip 10 and the sensor chip 20 are rectangular.

[0013] In the Z-axis direction, the IC chip 10 and the sensor chip 20 face each other and are spaced apart. Two sides of the IC chip 10 and two sides of the sensor chip 20 are parallel to the X-axis. Two other sides of the IC chip 10 and two other sides of the sensor chip 20 are parallel to the Y-axis. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other.

[0014] As shown in FIG. 1A, the IC chip 10 is larger than the sensor chip 20. The length L1 of the IC chip 10 in the X-axis direction is larger than the length L2 of the sensor chip 20. The length L3 of the IC chip 10 in the Y-axis direction is larger than the length L4 of the sensor chip 20. The length L1 of the IC chip 10 is, for example, 15 mm. The length L3 is, for example, 6 mm. The length L2 of the sensor chip 20 is, for example, 13 mm. The length L4 is, for example, 4 mm.

[0015] The thickness of the IC chip 10 is, for example, 750 μm. The thickness of the sensor chip 20 is, for example, 575 μm. The distance between the IC chip 10 and the sensor chip 20 in the Z-axis direction is, for example, 15 μm.

[0016] 1B, the sensor chip 20 is flip-chip mounted on the IC chip 10. A surface 12 of the IC chip 10 faces a surface 22 of the sensor chip 20. The IC chip 10 and the sensor chip 20 are electrically connected by a plurality of bumps 26. The surfaces 12 and 22 are parallel to the XY plane.

[0017] Resin 24 (underfill) is filled between surface 12 and surface 22. Resin 24 is a thermosetting epoxy resin or the like. The hardened resin 24 fixes the IC chip 10 and the sensor chip 20 to each other, increasing the mechanical durability of the semiconductor device 100.

[0018] Fig. 2A is a plan view illustrating the sensor chip 20. Fig. 2B is an enlarged view of the sensor chip 20. Figs. 2A and 2B illustrate a surface 22 of the sensor chip 20.

[0019] As shown in FIGS. 2A and 2B, the surface 22 of the sensor chip 20 has a central portion 30 and an outer peripheral portion 32. A recess 31 is provided between the central portion 30 and the outer peripheral portion 32. The central portion 30 is located at the center of the sensor chip 20 in the XY plane. The recess 31 is a groove that is located outside the central portion 30 and surrounds the central portion 30. The outer peripheral portion 32 is located on the outer periphery of the sensor chip 20 and surrounds the central portion 30 and the recess 31. The outer peripheral portion 32 and the recess 31 have a closed shape in the XY plane, such as a rectangular ring shape.

[0020] The outer peripheral portion 32 has a portion 32a, a portion 32b, a portion 32c, and a portion 32d. The portions 32a and 32b are parallel to the X-axis direction and face each other. The portions 32c and 32d are parallel to the Y-axis direction and face each other.

[0021] As shown in FIG. 2B, a plurality of mesas 34 are provided in the central portion 30. The mesas 34 are arranged in a two-dimensional grid. For example, the mesas 34 are periodically arranged in the X-axis direction and the Y-axis direction. The pitch between the mesas 34 is, for example, 30 μm or 90 μm. One mesa 34 corresponds to one pixel. The number of pixels is, for example, 512×640 pixels, 256×320 pixels, or 32×128 pixels. Bumps 26 are provided on the mesas 34.

[0022] 2A and 2B, a plurality of electrodes 50 (first electrodes) are provided on the outer peripheral portion 32. A portion 37 of the outer peripheral portion 32 is located between the electrodes 50, where no electrode 50 is provided and the insulating film 28 is exposed. As shown in FIG. 2B, a plurality of bumps 26 are provided on the electrode 50.

[0023] As shown in FIG. 2A, four electrodes 50 are spaced apart from one another and surround the central portion 30. Two of the four electrodes 50 are electrodes 50a and the other two are electrodes 50b. Electrode 50a is parallel to the X-axis direction. Electrode 50a is provided on portions 32a and 32b of the outer peripheral portion 32. Electrode 50b is parallel to the Y-axis direction. Electrode 50b is provided on portions 32c and 32d of the outer peripheral portion 32. The width W1 of electrode 50 is, for example, 500 μm.

[0024] The length L5 of electrode 50a in the X-axis direction is smaller than the length L2 of the sensor chip 20, and is, for example, 4 mm. The length L6 of electrode 50b in the Y-axis direction is smaller than the length L4 of the sensor chip 20, and is, for example, 1 mm. The total length L of the four electrodes 50 in the circumferential direction of the sensor chip 20 is calculated using the following equation (1), and is, for example, 10 mm. L = 2 × L5 + 2 × L6 (1) The outer periphery length L0 of the sensor chip 20 is calculated from the following equation (2) and is, for example, 34 mm. L0 = 2 × L2 + 2 × L4 (2) The circumferential length La of the portion 37 of the outer periphery 32 where the insulating film 28 is exposed is approximately equal to L0-L. The total length L of the electrode 50 is shorter than the length La of the portion 37 and is ⅓ or less of the circumferential length L0 of the sensor chip 20.

[0025] FIG. 2C is a cross-sectional view illustrating the sensor chip 20, taken along line AA in FIG. 2B. The IC chip 10 and resin 24 are omitted from FIG. 2C. The sensor chip 20 includes a substrate 40, a contact layer 41, a light-receiving layer 42, a wide gap layer 44, a wide gap layer 46, and a contact layer 48. The contact layer 41 is stacked on one surface of the substrate 40. In the central portion 30 and the peripheral portion 32, the light-receiving layer 42, the wide gap layer 44, the wide gap layer 46, and the contact layer 48 are stacked in this order on the surface of the contact layer 41 opposite the substrate 40. A recess 31 is provided between the central portion 30 and the peripheral portion 32. The light-receiving layer 42, the wide gap layer 44, the wide gap layer 46, and the contact layer 48 are not provided in the recess 31.

[0026] The substrate 40 is made of, for example, indium phosphide (InP) and is semi-insulating by being doped with iron (Fe). The thickness of the substrate 40 is, for example, 575 μm. The contact layer 41 is made of, for example, n-type indium phosphide (n-InP). The thickness of the contact layer 41 is, for example, 2 μm. The contact layer 41 is doped with silicon (Si) as an n-type dopant. The silicon concentration is about 2×10 18 cm -3 The absorption layer 42 is made of, for example, undoped indium gallium arsenide (InGaAs). The absorption layer 42 has a thickness of, for example, 3.5 μm. The band gap at room temperature is, for example, 0.75 eV.

[0027] The wide gap layer 44 is made of, for example, n-InP. The thickness is, for example, 0.5 μm. The wide gap layer 44 is doped with Si. The concentration of Si is about 2×10 18 cm -3The wide gap layer 46 is made of, for example, p-type indium phosphide (p-InP). Its thickness is, for example, 0.2 μm. The wide gap layer 46 is doped with, for example, zinc (Zn) as a p-type dopant. The concentration of Zn is about 5×10 18 cm -3 The contact layer 48 is made of, for example, p-InGaAs. Its thickness is, for example, 0.1 μm. The contact layer 48 is doped with, for example, Zn. The concentration of Zn is about 1×10 19 cm -3 is.

[0028] Each mesa 34 includes a wide gap layer 44, a wide gap layer 46, and a contact layer 48. A recess 35 is provided between two adjacent mesas 34. In the Z-axis direction, the recess 35 penetrates the contact layer 48 and the wide gap layer 46 and extends partway through the wide gap layer 44. The multiple mesas 34 are separated from one another by the recess 35. The width of the recess 35 is, for example, 5 μm. In the central portion 30, the absorption layer 42 and the wide gap layer 44 are provided below the multiple mesas 34.

[0029] The mesa 34, the recess 35, the recess 31, and the outer periphery 32 are covered with an insulating film 28. The insulating film 28 has openings on the mesa 34 and in the recess 31. The contact layer 48 of the mesa 34 is exposed from the openings in the insulating film 28. An electrode 52 (second electrode) is provided on the mesa 34 and is electrically connected to the contact layer 48.

[0030] The electrode 50 is provided on a portion of the insulating film 28 that covers the outer periphery 32. The electrode 50 is insulated from the contact layer 48 by the insulating film 28. The wiring 51 extends from the outer periphery 32 to the recess 31, is electrically connected to the electrode 50, and is electrically connected to the contact layer 41 within the recess 31. The electrode 50 is electrically connected to the contact layer 41 by the wiring 51.

[0031] The electrode 50 includes a metal layer 53 and a metal layer 54. The metal layer 53 is a laminated film formed by sequentially stacking, for example, a titanium (Ti) layer and a nickel (Ni) layer. The metal layer 54 is formed of, for example, gold (Au), is in contact with the metal layer 53, and forms the surface of the electrode 50. The electrode 52 includes a metal layer 55 and a metal layer 56. The metal layer 55 is formed of, for example, Ti. The metal layer 56 is formed of, for example, platinum (Pt). The bumps 26 are formed of a metal such as indium (In) and are provided on the surfaces of the electrodes 50 and 52. FIG. 2C illustrates a cross section including the bumps 26. At positions of the electrode 50 where the bumps 26 are not provided, the Au metal layer 54 is exposed.

[0032] The insulating film 28 is a passivation film and is made of a nitride such as silicon nitride (SiN), an oxide such as silicon oxide (SiO2), or an oxynitride such as silicon oxynitride (SiON). An insulating film 29 is provided on the surface of the substrate 40 opposite the contact layer 41. The insulating film 29 is an anti-reflection film and is made of a nitride such as SiN. The thickness of the insulating film 28 is, for example, 200 nm. The thickness of the insulating film 29 is, for example, 140 nm or more and 160 nm or less.

[0033] 1B, the sensor chip 20 is electrically connected to the IC chip 10 by bumps 26. For example, near-infrared light passes through the insulating film 29 and is absorbed by the light-receiving layer 42 of the sensor chip 20. The light-receiving layer 42 absorbs the light and generates carriers (electron-hole pairs). The carriers are output from the sensor chip 20 as a photocurrent and input to the IC chip 10.

[0034] (Manufacturing method) For example, by metalorganic vapor phase epitaxy (MOVPE), contact layer 41, absorption layer 42, wide gap layer 44, wide gap layer 46, and contact layer 48 are epitaxially grown in this order on substrate 40. Recess 31 is formed by removing portions of contact layer 48, wide gap layer 46, wide gap layer 44, and absorption layer 42, for example, by dry etching. Recess 35 is formed in central portion 30 by removing portions of contact layer 48, wide gap layer 46, and wide gap layer 44, for example, by dry etching. A plurality of isolated mesas 34 are formed.

[0035] An insulating film 28 is formed by plasma CVD (PECVD: Plasma Enhanced Chemical Vapor Deposition) or the like. Openings are formed in the insulating film 28 by forming a resist pattern and wet etching using buffered hydrofluoric acid or the like. Electrodes 50, 52, and wiring 51 are formed by vacuum deposition and lift-off. An insulating film 29 is formed on the back surface of the substrate 40 by PECVD. Indium bumps 26 are formed on the electrodes 50 and 52.

[0036] 3A and 3B are flowcharts illustrating a method for manufacturing the semiconductor device 100, showing the steps after manufacturing the IC chip 10 and the sensor chip 20. The surface 12 of the IC chip 10 and the surface 22 of the sensor chip 20 are placed opposite each other, and the chips are aligned. A reflow process is performed to perform flip-chip mounting (step S10). Self-alignment between the IC chip 10 and the sensor chip 20 is achieved due to the surface tension of the molten bumps 26, etc. The IC chip 10 and the sensor chip 20 are connected by the bumps 26. Resin 24 is filled between the surfaces 12 and 22 (step S12). The semiconductor device 100 is formed through the above steps.

[0037] FIG. 3B shows step S12 (filling of resin 24) in FIG. 3A in detail. FIGS. 4A to 4D are cross-sectional views illustrating a method for manufacturing the semiconductor device 100. FIGS. 5A to 5C are plan views illustrating a method for manufacturing the semiconductor device 100. FIGS. 4A to 5C show the steps from after flip-chip mounting until the resin 24 is filled. As shown in FIG. 4A, immediately after flip-chip mounting, no resin is filled between the sensor chip 20 and the IC chip 10.

[0038] As shown in FIG. 3B, the IC chip 10 and the sensor chip 20 are heated to a temperature of, for example, about 80°C to 100°C (step S20). As shown in FIGS. 4B and 5A, the IC chip 10 and the sensor chip 20 are placed on a heater stage 60. The IC chip 10 is in contact with the surface of the heater stage 60. The heater stage 60 has a built-in heater, which increases the temperatures of the IC chip 10 and the sensor chip 20. As shown in FIG. 5A, the IC chip 10 is larger than the sensor chip 20 in the XY plane, and the end of the IC chip 10 is located outside the sensor chip 20.

[0039] As shown in Fig. 3B, resin 24 is supplied (step S22). As shown in Fig. 5B, resin 24 is dropped multiple times from nozzle 62 onto end portion 10a of IC chip 10. Multiple pieces of resin 24 are provided on end portion 10a. At a temperature of, for example, about 80°C to 100°C, resin 24 is molten.

[0040] As shown in Fig. 4C, the dropped resin 24 flows due to capillary action and moves between the IC chip 10 and the sensor chip 20 (step S24 in Fig. 3B). In Fig. 5C, the flow of the resin 24 is schematically shown by arrows. The resin 24 flows through the central portion 30 and the outer peripheral portion 32 of the sensor chip 20, and reaches from the end 10a of the IC chip 10 to the opposite end 10b.

[0041] If the resin 24 flowing in the outer peripheral portion 32 flows around the entire edge 10b faster than the resin 24 flowing in the central portion 30, air is trapped inside the resin 24, causing voids. This reduces the durability of the bumps 26 around the voids, and the mechanical strength of the semiconductor device 100 decreases.

[0042] In the first embodiment, the flow speed of the resin 24 is controlled by utilizing the difference in wettability between the central portion 30 and the outer peripheral portion 32. Before the resin 24 flows around the outer peripheral portion 32, the resin 24 flows through the central portion 30 and reaches the end portion 10b. Air is expelled from the central portion 30 sandwiched between the IC chip 10 and the sensor chip 20, making it difficult for voids to occur.

[0043] As shown in Fig. 4D, the IC chip 10 and the sensor chip 20 are set in a furnace 64. Heat treatment is performed in the furnace 64 under conditions of, for example, 120°C and 4 hours. The resin 24 is hardened by the heat treatment (step S26 in Fig. 3B).

[0044] (Comparative Example) 6A is a plan view illustrating a sensor chip 20 of a semiconductor device according to a comparative example. One electrode 50 is provided on an outer peripheral portion 32 of the sensor chip 20. The electrode 50 surrounds the central portion 30. The electrode 50 is not provided on a portion 33 of the outer peripheral portion 32. In other words, the electrode 50 is provided continuously on the outer peripheral portion 32 in the circumferential direction, except for portion 33. In the comparative example, the circumferential length of the electrode 50 is, for example, 29 mm, which is longer than the length of portion 33 and is, for example, 60% or more of the outer circumferential length L0 of the sensor chip 20.

[0045] 6B is a plan view illustrating a method for manufacturing a semiconductor device according to a comparative example, illustrating a step corresponding to that shown in FIG. 5C. Resin 24 flows faster in outer peripheral portion 32 than in central portion 30. Before resin 24 reaches central portion 30, part 33 of outer peripheral portion 32 is closed by resin 24. Air is likely to remain in resin 24, creating voids.

[0046] (wettability) The flow rate of the resin 24 depends on the wettability of the surface with respect to the resin 24. As shown in FIG. 2C, the surface of the sensor chip 20 is mainly formed of an insulating film 28, an electrode 50, and an electrode 52. The insulating film 28 is, for example, a SiN film. The surface of the electrode 50 is, for example, Au. The surface of the electrode 52 is, for example, Pt. The wettability of the resin on these three surfaces is evaluated.

[0047] SiN, Au, and Pt films are deposited on silicon wafers. The SiN film is deposited using a PECVD system. The Au and Pt films are deposited using an evaporation system. The SiN film is 200 nm thick. The Au film is 600 nm thick. The Pt film is 80 nm thick. Thermosetting epoxy resin is dropped at regular intervals from a dispenser onto the SiN, Au, and Pt films. The temperature of the dispenser nozzle is set to 40°C. The amount of resin per drop is between 0.012 mg and 0.013 mg. The diameters of multiple resin droplets are measured within one minute of dropping. The diameter of the resin droplets is larger on surfaces with high wettability. The diameter is smaller on surfaces with low wettability.

[0048] Figure 7 shows the results of the wettability evaluation. From left to right on the horizontal axis, the SiN film, Pt film, and Au film are shown. The vertical axis represents the diameter of the resin droplets. The circles represent the diameter of the resin droplets on the SiN film. The triangles represent the diameter of the resin droplets on the Pt film. The squares represent the diameter of the resin droplets on the Au film. The diameter of the resin droplets on the SiN film is approximately 700 μm to 750 μm. The diameters on the Pt and Au films are greater than 850 μm and less than 1100 μm. The diameters on the Pt and Au films are larger than those on the SiN film. The wettability of Pt and Au to resin is higher than that of SiN.

[0049] As shown in FIGS. 6A and 6B, in the comparative example, the electrodes 50 are located on the four sides of the sensor chip 20 and are provided continuously around the outer periphery 32 except for the portion 33. The electrodes 50 occupy a larger proportion of the periphery 32 than the insulating film 28. The surface of the electrode 50 is made of, for example, Au. As shown in FIG. 7, the wettability of Au to resin is higher than that of SiN. The resin 24 spreads over the electrode 50 and flows quickly around the outer periphery 32. Before spreading to the central portion 30, the resin 24 wraps around the outer periphery 32 and fills the portion 33. The trapped air creates voids.

[0050] According to the first embodiment, after the sensor chip 20 is flip-chip mounted on the IC chip 10, the resin 24 is filled in. As shown in FIGS. 2A and 2B , electrodes 50 are provided on the outer peripheral portion 32 of the sensor chip 20. The electrodes 50 are not provided on a portion 37 of the outer peripheral portion 32, and the insulating film 28 is exposed. The total length L of the electrodes 50 is smaller than the length La of the portion 37. The electrodes 50, which have high wettability, occupy a small proportion of the perimeter of the outer peripheral portion 32, while the insulating film 28, which has low wettability, occupies a large proportion. The resin 24 moves quickly on surfaces with high wettability and slowly on surfaces with low wettability. The resin 24 flows less quickly through the outer peripheral portion 32 than in the comparative example. Before the resin 24 completely covers the outer peripheral portion 32, it spreads to the central portion 30. The resin 24 permeates the central portion 30, expelling air from between the sensor chip 20 and the IC chip 10. This prevents voids from forming. The mechanical strength of the semiconductor device 100 is increased.

[0051] The total length L of the electrodes 50 is ⅓ or less of the outer circumferential length L0 of the sensor chip 20. Compared to the comparative example, the speed at which the resin 24 flows around the outer circumferential portion 32 is reduced, thereby preventing the occurrence of voids. The total length L of the electrodes 50 may be ⅓ or less, ¼ or less, ⅕ or less, etc., of the outer circumferential length L0 of the sensor chip 20.

[0052] The insulating film 28 is a nitride film, and is formed of, for example, SiN. The surface of the electrode 50 is formed of a metal layer 54 of Au. The insulating film 28 has low wettability with respect to the resin 24, while the electrode 50 has high wettability. The proportion of the electrode 50, which has high wettability, relative to the circumferential length of the outer periphery 32 is low, while the proportion of the insulating film 28, which has low wettability, is high. The speed at which the resin 24 flows through the outer periphery 32 decreases. The occurrence of voids can be prevented.

[0053] The surface of the electrode 50 is made of metal and is formed of Au or Pt. As shown in FIG. 7, the wettability of Pt is similar to that of Au and higher than that of SiN. The insulating film 28 may be formed of a silicon oxide film such as SiO2 or SiON, or a silicon oxynitride film, in addition to SiN. The wettability of nitrides, oxides, and oxynitrides to resin is lower than that of Au and Pt. The length L of the electrode 50 containing Au or Pt is reduced to 1 / 3 or less of the length L0 of the outer periphery 32. A portion 37 of the outer periphery 32 is covered with nitride. This reduces the flow rate of the resin 24 through the outer periphery 32, preventing voids from forming.

[0054] As shown in FIG. 2A, the sensor chip 20 has multiple electrodes 50. An electrode 50 is provided on each of portions 32a, 32b, 32c, and 32d of the outer periphery 32. The four electrodes 50 are spaced apart from one another. As shown in FIG. 6A, in the comparative example, one electrode 50 is provided continuously on all four sides. According to the first embodiment, the total length of the electrodes 50 is smaller than in the comparative example. This reduces the flow rate of the resin 24 through the outer periphery 32, preventing voids from occurring.

[0055] 2B, a plurality of bumps 26 are provided on the electrodes 50. Four electrodes 50 are connected to the IC chip 10 by the bumps 26. The portions 32a, 32b, 32c, and 32d are fixed to the IC chip 10 by the bumps 26. This increases the mechanical strength of the semiconductor device 100.

[0056] As shown in FIG. 2B , multiple mesas 34 are provided in the central portion 30 of the sensor chip 20. The multiple mesas 34 are connected to the IC chip 10 by bumps 26. Each mesa 34 functions as one pixel. The signals output from the mesas 34 are processed by the IC chip 10. Because voids are less likely to occur, the connection between the multiple mesas 34 and the IC chip 10 is stable. The semiconductor device 100 can detect light such as near-infrared light. Because the electrodes 52 in the central portion 30 and the electrodes 50 in the peripheral portion 32 are connected to the IC chip 10 by bumps 26, the mechanical strength of the semiconductor device 100 is increased.

[0057] As shown in FIG. 3B, the process of filling the resin 24 includes the steps of heating, supplying, moving, and hardening the resin 24. The resin 24 is supplied to the end 10a of the heated IC chip 10. The molten resin 24 moves through the outer periphery 32 and the central portion 30, filling the IC chip 10. Before moving through the entire outer periphery 32, the resin 24 moves through the central portion 30 and reaches the end 10b. This prevents air from being mixed in, thereby preventing the occurrence of voids. The filled resin 24 hardens, fixing the sensor chip 20 to the IC chip 10. The mechanical strength of the semiconductor device 100 is increased.

[0058] 5B, multiple drops of resin 24 are dispensed onto one end 10a of the IC chip 10. Resin 24 may be dispensed onto two or more ends.

[0059] Second Embodiment FIG. 8 is a plan view illustrating a sensor chip 20 according to the second embodiment. Description of the same configuration as in the first embodiment will be omitted. As shown in FIG. 8, a plurality of grooves 66 are provided in a portion 32a of the outer peripheral portion 32 of the sensor chip 20. The grooves 66 are not provided in positions overlapping with the electrodes 50, but are provided in positions of the insulating film 28 spaced apart from the electrodes 50. The grooves 66 are recessed from the surface of the insulating film 28. The depth of the grooves 66 in the Z-axis direction is, for example, not less than 4 μm and not more than 6 μm.

[0060] The width W2 of the groove 66 in the X-axis direction is, for example, 5 μm or more and 10 μm or less. The grooves 66 are parallel to the Y-axis direction and extend from the end of the sensor chip 20 to the recess 31. The multiple grooves 66 are arranged periodically in the X-axis direction. The number of grooves 66 is, for example, 220.

[0061] Before flip-chip mounting, grooves 66 are formed by dry etching the insulating film 28 of the sensor chip 20. After flip-chip mounting, the portion 32a of the outer periphery 32 is located near the end 10a of the IC chip 10. Resin 24 is dripped onto the end 10a.

[0062] According to the second embodiment, the groove 66 functions as a path for the resin 24. As shown in FIG. 5B, the resin 24 supplied to the end portion 10a flows through the groove 66 of the sensor chip 20 by capillary action toward the central portion 30. The flow of the resin 24 toward the central portion 30 is promoted, and the flow rate increases. The total length L of the electrode 50 is smaller than the length La of the portion 37 and is equal to or less than one-third of the length L0 of the outer peripheral portion 32. The speed at which the resin 24 flows around the outer peripheral portion 32 decreases. This prevents voids from occurring.

[0063] Third Embodiment 9 is a plan view illustrating a sensor chip 20 according to the third embodiment. Description of the same configuration as in the first or second embodiment will be omitted. Of the outer periphery 32 of the sensor chip 20, electrodes 50 are provided on portions 32a and 32b. No electrodes 50 are provided on portions 32c and 32d, which are covered with an insulating film 28.

[0064] According to the third embodiment, the total length L of the electrodes 50 is 2×L5, which is shorter. The portion 37 of the outer periphery 32 other than the electrodes 50 is covered with the insulating film 28. This further reduces the speed at which the resin 24 wraps around the outer periphery 32. This makes it possible to prevent voids from occurring.

[0065] <Fourth embodiment> 10 is a plan view illustrating a sensor chip 20 according to the fourth embodiment. Description of the same configuration as any of the first to third embodiments will be omitted. An electrode 50 is provided on a portion 32a of the outer periphery 32 of the sensor chip 20. No electrode 50 is provided on portions 32b, 32c, and 32d, which are covered with an insulating film 28.

[0066] According to the fourth embodiment, the length of the electrode 50 is L5, which further reduces the speed at which the resin 24 wraps around the outer periphery 32. This makes it possible to prevent voids from occurring.

[0067] Fifth Embodiment 11 is a plan view illustrating a sensor chip 20 according to the fifth embodiment. Description of the same configuration as any of the first to fourth embodiments will be omitted. Electrodes 50 are provided on portions 32a and 32d of the outer periphery 32 of the sensor chip 20. No electrodes 50 are provided on portions 32b and 32c, which are covered with an insulating film 28.

[0068] According to the fifth embodiment, the total length L of the electrodes 50 is L5+L6. The speed at which the resin 24 wraps around the outer periphery 32 decreases, which makes it possible to prevent voids from occurring.

[0069] Sixth Embodiment 12 is a plan view illustrating a sensor chip 20 according to the sixth embodiment. Description of the same configuration as any of the first to fifth embodiments will be omitted. Two electrodes 50a are provided in a portion 32a of the outer peripheral portion 32 of the sensor chip 20. Two electrodes 50a are provided in a portion 32b. The space between the two electrodes 50a and between the electrode 50a and the electrode 50b are covered with an insulating film 28.

[0070] According to the sixth embodiment, the total length of the electrode 50 is further shortened, and the speed at which the resin 24 wraps around the outer periphery 32 is further reduced, thereby making it possible to prevent the occurrence of voids.

[0071] As in the first to sixth embodiments, the number of electrodes 50 may be four, four or less, or four or more. Electrodes 50 may be provided at all four ends of the sensor chip 20, or at least one end. Multiple electrodes 50 may be provided at one end. The total length L of the electrodes 50 is shorter than the portion 37 of the outer periphery 32, and is, for example, one-third or less of the circumferential length L0 of the sensor chip 20.

[0072] Seventh Embodiment FIG. 13 is a plan view illustrating a sensor chip 20 according to the seventh embodiment. Description of the same configuration as any of the first to sixth embodiments will be omitted. The electrode 50 is L-shaped. One electrode 50 is provided on the outer circumferential portion 32 of the sensor chip 20, from portion 32a to portion 32c. Another electrode 50 is provided on the outer circumferential portion 32 of the sensor chip 20, from portion 32b to portion 32d. Portion 37 is located between the two electrodes 50 and is covered with an insulating film 28. The total length L of the two electrodes 50 is smaller than the length of portion 37 in the circumferential direction and is equal to or less than one-third of the circumferential length L0 of the sensor chip 20.

[0073] According to the seventh embodiment, the speed at which the resin 24 flows around the outer periphery 32 decreases, thereby preventing the occurrence of voids.

[0074] In the third to seventh embodiments, a plurality of grooves 66 may be provided in the portion 32a of the sensor chip 20, similar to the second embodiment.

[0075] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present disclosure as described in the claims. [Explanation of symbols]

[0076] 10 IC chip 10a, 10b end 12, 22 sides 20 sensor chips 24 Resin 26 Bump 28, 29 Insulating film 30 Central part 31, 35 Recess 32 Outer periphery 32a, 32b, 32c, 32d, 33, 37 parts 34 Mesa 40 boards 41, 48 Contact layer 42 Light-receiving layer 44, 46 Wide gap layer 50, 50a, 50b, 50c, 50d, 52 electrodes 51 Wiring 53, 54, 56, 55 metal layer 60 heater stage 62 nozzles 64 Furnace 100 Semiconductor device

Claims

1. flip-chip mounting a second chip to the first chip; and filling a space between the first chip and the second chip with resin, a surface of the second chip facing the first chip having a central portion and an outer circumferential portion; an insulating film is provided on the central portion and the outer periphery; a first electrode is provided on a portion of the insulating film located in the outer periphery; the wettability of the surface of the first electrode with respect to the resin is higher than the wettability of the insulating film with respect to the resin; A method of manufacturing a semiconductor device, wherein the length of the first electrode in the circumferential direction of the second chip is shorter than the length of a portion of the outer periphery where the insulating film is exposed.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the length of the first electrode is equal to or less than one-third of the periphery of the second chip.

3. the insulating film is a nitride film, 3. The method for manufacturing a semiconductor device according to claim 1, wherein the surface of the first electrode is made of gold or platinum.

4. a plurality of the first electrodes are provided on the outer periphery; 3. The method for manufacturing a semiconductor device according to claim 1, wherein the plurality of first electrodes surround the central portion.

5. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the resin filling step includes the steps of: heating the first chip and the second chip; supplying the resin to the end of the heated second chip; moving the supplied resin around the outer periphery and the central portion; and hardening the resin.

6. The method for manufacturing a semiconductor device according to claim 5 , wherein the outer periphery of the first chip has a plurality of grooves in a portion close to a position where the resin is supplied.

7. a plurality of mesas are provided in the central portion of the second chip; a second electrode is provided on the plurality of mesas; The flip-chip mounting step includes:

3. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of connecting the first electrode and the second electrode to the first chip by bumps.

8. A first chip; a second chip flip-chip mounted on the first chip; a resin filled between the first chip and the second chip, a surface of the second chip facing the first chip having a central portion and an outer circumferential portion; an insulating film is provided on the central portion and the outer periphery; an electrode is provided on a portion of the insulating film located in the outer periphery; the wettability of the surface of the electrode with respect to the resin is higher than the wettability of the insulating film with respect to the resin; A semiconductor device in which the length of the electrodes in the circumferential direction of the second chip is shorter than the length of the portion of the outer periphery where the insulating film is exposed.

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