Sensor package and method for manufacturing sensor package

Abstract

A sensor package (10 or 10A) comprises: a base material (20 or 20A) having a first surface (21) and a second surface (22) opposite to the first surface (21), and wiring (26); a chip (30) flip-chip connected to the first surface (21) of the base material; and an external conductor (60 or 60A) provided on the base material so as to be electrically connected to the wiring (26) of the base material. The chip (30) has a main surface (one main surface (31)) facing the first surface (21) of the base material, and a detection unit (100) provided on the main surface. The detection unit (100) is connected to the base material so as to be electrically connected to the wiring (26) of the base material. The base material has a through-hole (25) penetrating between the first surface (21) and the second surface (22).

Description

Sensor package and method for manufacturing the sensor package

[0001] The present disclosure relates to a sensor package and a method for manufacturing the sensor package.

[0002] BACKGROUND ART A sensor package having a sensor has been known in the art. Fig. 6 of Patent Document 1 discloses a sensor device including a chip having a detection unit (detection structure), a lead frame, bonding wires, a package, and the like.

[0003] JP 2010-50452 A

[0004] The sensor device disclosed in Patent Document 1 has a problem in that the quality of the detection unit deteriorates.

[0005] The present disclosure provides a sensor package and the like that can suppress deterioration in the quality of a detection unit.

[0006] A sensor package according to one embodiment of the present disclosure comprises a substrate having a first surface, a second surface facing away from the first surface, and wiring; a chip flip-chip connected to the first surface of the substrate; and an external conductor provided on the substrate so as to be electrically connected to the wiring of the substrate, wherein the chip has a main surface facing the first surface of the substrate and a detection unit provided on the main surface, the detection unit being connected to the substrate so as to be electrically connected to the wiring of the substrate, and the substrate has a through hole penetrating between the first surface and the second surface.

[0007] A method for manufacturing a sensor package according to one embodiment of the present disclosure includes the steps of forming a substrate having wiring and a through hole, forming a chip having a detection unit, and flip-chip connecting the chip to the substrate so that the detection unit faces the through hole of the substrate and is electrically connected to the wiring of the substrate.

[0008] According to the present disclosure, deterioration in the quality of the detection portion of the sensor package can be suppressed.

[0009] FIG. 1 is a cross-sectional view showing a sensor package of a comparative example. FIG. 2 is a view showing a convex mold and the like used when resin-molding the sensor package of the comparative example. FIG. 3 is a view showing an example of a problem that occurs in the sensor package of the comparative example. FIG. 4 is a cross-sectional view of the sensor package according to embodiment 1. FIG. 5 is a plan view of the sensor package according to embodiment 1. FIG. 6 is a bottom view of the sensor package according to embodiment 1. FIG. 7 is a view showing a state in which the sensor package is mounted on a printed circuit board. FIG. 8 is a cross-sectional view showing a detection unit of the sensor package. FIG. 9 is a flowchart showing a method for manufacturing the sensor package of embodiment 1. FIG. 10 is a cross-sectional view of the sensor package according to embodiment 2. FIG. 11 is a plan view of the sensor package according to embodiment 2. FIG. 12 is a bottom view of the sensor package according to embodiment 2. FIG. 13 is a view showing a state in which the sensor package is mounted on a printed circuit board. FIG. 14 is a flowchart showing a method for manufacturing the sensor package of embodiment 2.

[0010] (Background to the Invention of the Disclosure) The background to the invention of the disclosure will be described with reference to FIGS. 1 to 3. FIG.

[0011] FIG. 1 is a cross-sectional view showing a sensor package 510 of a comparative example.

[0012] The comparative sensor package 510 includes a chip 530 arranged on a substrate 520, a wire 550 connected to the chip 530, a resin coating portion 545 formed on the substrate 520 so as to cover a portion of the chip 530 and the wire 550, and an external terminal 560 electrically connected to the wire 550.

[0013] In the sensor package 510 of the comparative example, an opening 525 is formed in the resin coating portion 545 to expose the detection portion 600 provided on the chip 530. The opening 525 in the resin coating portion 545 is formed using, for example, a convex mold 592 having a convex shape.

[0014] FIG. 2 is a diagram showing a convex mold 592 and other components used when resin molding the sensor package 510 of the comparative example.

[0015] The sensor package 510 of the comparative example is formed, for example, by covering the chip 530 and wires 550 on the substrate 520 with a cavity mold 591 and then molding the resin. The opening 525 is formed by molding the resin while a convex mold 592 shown in FIG. 2 is brought into contact with the chip 530. However, when molding the resin while the convex mold 592 is brought into contact with the chip 530, the following problems may occur.

[0016] 3A and 3B are diagrams showing examples of problems that occur in the comparative sensor package 510. Fig. 3A shows an example in which resin leakage has occurred, and Fig. 3B shows an example in which cracks have occurred in the chip 530.

[0017] As described above, the opening 525 is formed by resin molding while the convex mold 592 is in contact with the tip 530, but the strong pressure generated within the cavity mold 591 can cause the resin material to enter between the convex mold 592 and the detection unit 600. In that case, as shown in Figure 3(a), the resin material comes into contact with the detection unit 600, causing a problem of a decrease in the detection accuracy of the detection unit 600.

[0018] On the other hand, in order to prevent resin from entering between the chip 530 and the convex mold 592, it is possible to press the convex mold 592 firmly against the chip 530. However, if the convex mold 592 is pressed too firmly, defects such as cracks will occur in the chip 530, as shown in Figure 3(b), which will cause a problem that detection by the detection unit 600 cannot be performed normally.

[0019] The sensor package etc. of the present disclosure has the following configuration in order to prevent deterioration of the quality of the detection unit.

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each embodiment described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, the arrangement and connection of the components, steps, the order of steps, and the like shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, each drawing is not necessarily an exact illustration. In each drawing, substantially identical components are assigned the same reference numerals, and duplicate explanations are omitted or simplified.

[0021] Furthermore, in this specification, terms indicating the relationship between elements, such as parallel, terms indicating the shape of elements, such as rectangular, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0022] In addition, in some drawings, X-axis, Y-axis, and Z-axis, which represent three mutually orthogonal directions, are shown, and these axes and axial directions along these axes may be used for explanation as necessary. Note that the axes are added for ease of understanding, and do not limit the direction or posture in which the sensor package is used.

[0023] First Embodiment [Configuration of Sensor Package] The configuration of a sensor package according to a first embodiment will be described with reference to FIGS.

[0024] Fig. 4 is a cross-sectional view of the sensor package 10 according to the first embodiment. Fig. 5 is a plan view of the sensor package 10. Fig. 6 is a bottom view of the sensor package 10. Fig. 4 is a cross-sectional view of the sensor package 10 taken along line IV-IV shown in Fig. 5. Note that in Fig. 4, the bumps 50, the wiring 26, and the external conductors 60 are also hatched.

[0025] 4, the sensor package 10 includes a substrate 20, a chip 30 connected to the substrate 20, and an external conductor 60 connected to the substrate 20. The chip 30 has a detection unit 100 for detecting the environmental condition (e.g., air quality) of the space in which the sensor package 10 is placed. A resin layer 40 is formed between the substrate 20 and the chip 30.

[0026] The substrate 20 is, for example, a ceramic substrate or a resin substrate, and has a plate-like shape. The substrate 20 has a first surface 21 and a second surface 22 facing away from the first surface 21. The first surface 21 and the second surface 22 are flat and parallel to each other. In this example, the first surface 21 is the back side of the substrate 20 (the negative side in the Z-axis direction), and the second surface 22 is the front side of the substrate 20 (the positive side in the Z-axis direction). When viewed from a direction perpendicular to the first surface 21, the substrate 20 has a rectangular shape (see FIG. 5 ).

[0027] The substrate 20 also has a plurality of wirings 26. The wirings 26 are patterned on the first surface 21 of the substrate 20. Note that some of the wirings 26 may be formed inside the substrate 20. The wirings 26 have a plurality of inner land electrodes connected to the chip 30 and a plurality of outer land electrodes connected to the external conductor 60 (not shown). The wirings 26 are formed to connect the inner land electrodes and the outer land electrodes.

[0028] The base material 20 has a through-hole 25 that penetrates between the first surface 21 and the second surface 22. The through-hole 25 is an air hole that communicates with the detection unit 100 from the outside, and penetrates the base material 20 in the thickness direction. In this example, one through-hole 25 is formed in the center of the base material 20.

[0029] The shape of the through-hole 25 is, for example, a square. The shape of the through-hole 25 is not limited to a square shape and may be a circle. The through-hole 25 is provided at a position corresponding to the detection unit 100 in two-dimensional coordinates with the first surface 21 as a plane. As shown in FIG. 5 , when viewed from a direction perpendicular to the first surface 21, the through-hole 25 overlaps with the detection unit 100. When viewed from a direction perpendicular to the first surface 21, the side surface (inner surface) 25a of the through-hole 25 is located outside the exposed portion 106e of the chip 30. The distance from the side surface 25a of the through-hole 25 to the edge of the exposed portion 106e of the detection unit 100 is, for example, 100 μm or more. The area of ​​the through-hole 25 is larger than the area of ​​the exposed portion 106e of the detection unit 100.

[0030] 4 , the chip 30 is flip-chip mounted on the substrate 20. The chip 30 is connected to the first surface 21 of the substrate 20 so that the detection unit 100 is electrically connected to the outer land electrodes of the wiring 26 of the substrate 20.

[0031] The chip 30 is a semiconductor chip and has a rectangular and plate-like shape. The area of ​​the chip 30 is smaller than the area of ​​the substrate 20, and the thickness of the chip 30 is thinner than the thickness of the substrate 20. The chip 30 has a main surface facing the first surface 21 of the substrate 20. In this embodiment, the main surface facing the first surface 21 of the substrate 20 is called the one main surface 31, and the main surface facing away from the one main surface 31 is called the other main surface 32. In this example, the one main surface 31 is the front side of the chip 30 (the positive side in the Z-axis direction), and the other main surface 32 is the back side of the chip 30 (the negative side in the Z-axis direction).

[0032] The above-described detection unit 100 is formed on one main surface 31 of the chip 30. The detection unit 100 is, for example, a hydrogen sensor that detects hydrogen. Note that the detection unit 100 may also be an environmental sensor that detects temperature, humidity, gas concentration, or airflow.

[0033] The detection unit 100 is provided at the center of the chip 30. The detection unit 100 is provided at a position corresponding to the through-hole 25 in two-dimensional coordinates with the one main surface 31 as a plane. The area of ​​the exposed portion 106e of the detection unit 100 is smaller than the area of ​​the through-hole 25. When viewed from a direction perpendicular to the one main surface 31, the exposed portion 106e of the detection unit 100 is located inside the side surface 25a of the through-hole 25. When the detection unit 100 is composed of multiple sensors, it is sufficient that each of the multiple sensors is located inside the side surface 25a of the through-hole 25. The detailed structure of the detection unit 100 will be described later.

[0034] The chip 30 further has a plurality of wirings 36 drawn out from the detection unit 100 to the outside, and a plurality of terminal portions 37 located at the outer ends of the wirings 36. The wirings 36 are formed so as to connect the detection unit 100 and the terminal portions 37. The wirings 36 and the terminal portions 37 are patterned on one main surface 31 of the chip 30. Note that a portion of the wirings 36 may be formed inside the chip 30.

[0035] The chip 30 is connected to the substrate 20 by a plurality of bumps 50. The plurality of bumps 50 are arranged around the periphery of the detection unit 100 and are formed in one-to-one correspondence with the plurality of terminal portions 37. The plurality of terminal portions 37 are connected to a plurality of inner land electrodes of the substrate 20 via the plurality of bumps 50.

[0036] The resin layer 40 is provided between the substrate 20 and the chip 30. The resin layer 40 serves as an underfill material that fills the gap between the substrate 20 and the chip 30. The thickness of the resin layer 40 is preferably, for example, 40 μm or more and 200 μm or less, and more preferably 60 μm or more and 100 μm or less. The material of the resin layer 40 is, for example, a heat-curing epoxy resin.

[0037] The resin layer 40 is provided between the first surface 21 of the substrate 20 excluding the through-hole 25 and one main surface 31 of the chip 30 so as not to cover the exposed portion 106e of the detection unit 100. The resin layer 40 is also provided between the substrate 20 and the chip 30 so as to cover the side surfaces of the plurality of bumps 50 without covering the exposed portion 106e of the detection unit 100. Specifically, the resin layer 40 is formed from the position of the outer peripheral edge of the chip 30 to a position directly below the side surface 25a of the through-hole 25 of the substrate 20 in two-dimensional coordinates with the one main surface 31 as a plane.

[0038] For example, the resin layer 40 is formed by flip-chip bonding the chip 30 to the substrate 20, and then injecting a liquid resin material between the chip 30 and the substrate 20 and allowing it to harden. After being injected between the chip 30 and the substrate 20, the liquid resin material spreads between the chip 30 and the substrate 20 due to capillary action. In this embodiment, because the through-hole 25 is formed in the substrate 20, the intrusion of the liquid resin material stops near the side surface 25a of the through-hole 25, and the resin layer 40 is not formed on the through-hole 25 or the exposed portion 106e of the detection unit 100. This ensures that the exposed portion 106e of the detection unit 100 is exposed, preventing a deterioration in the quality of the detection unit 100.

[0039] 4 is a ball-shaped solder member (solder ball), and is provided on the first surface 21 of the substrate 20 so as to be electrically connected to the wiring 26 of the substrate 20. The external conductor 60 is disposed so as to be located outside the chip 30 when viewed from a direction perpendicular to the first surface 21 (see FIG. 6).

[0040] The height dimension of the external conductor 60 is greater than the sum of the thickness dimension of the chip 30 and the thickness dimension of the bumps 50. In other words, the external conductor 60 protrudes outward beyond the chip 30 in a direction perpendicular to the first surface 21. Specifically, the external conductor 60 protrudes further away from the first surface 21 than the chip 30, using the first surface 21 as a reference. This structure enables the sensor package 10 to be easily mounted on a printed circuit board 81.

[0041] 7 is a diagram showing the sensor package 10 mounted on a printed circuit board 81. In FIG. 7, the bumps 50, the wiring 26, and the external conductors 60 are also hatched.

[0042] The printed circuit board 81 is a board that is built into an electrical device and has various surface-mount electronic components mounted thereon. The sensor package 10 is joined to the printed circuit board 81 using solder. The sensor package 10 is mounted on the printed circuit board 81 so that the first surface 21 of the substrate 20 faces the surface of the printed circuit board 81 and so that the other main surface 32 of the chip 30 faces the surface of the printed circuit board 81.

[0043] After the sensor package 10 is mounted on the printed circuit board 81, a potting resin 85 is formed on the printed circuit board 81. The potting resin 85 is formed on the printed circuit board 81 so as to cover the sides and lower space of the sensor package 10 without covering the second surface 22 side of the base material 20 of the sensor package 10. In the sensor package 10 of this embodiment, a resin layer 40 is provided around the detection unit 100, which can prevent the potting resin 85 from entering the detection unit 100. This can prevent a deterioration in the quality of the detection unit 100.

[0044] As described above, the sensor package 10 of this embodiment includes a substrate 20 having a first surface 21, a second surface 22 facing away from the first surface 21, and wiring 26, a chip 30 flip-chip connected to the first surface 21 of the substrate 20, and an external conductor 60 provided on the substrate 20 so as to be electrically connected to the wiring 26 of the substrate 20. The chip 30 has a main surface (one main surface 31) facing the first surface 21 of the substrate 20 and a detection unit 100 provided on that main surface, and is connected to the substrate 20 so as to be electrically connected to the wiring 26 of the substrate 20. The substrate 20 has a through hole 25 penetrating between the first surface 21 and the second surface 22.

[0045] In this way, by providing the through-holes 25 in the base material 20, the detection unit 100 can be reliably exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0046] [Configuration of the Detection Unit] The configuration of the detection unit 100 of the sensor package 10 will be described with reference to Fig. 8. Here, the detection unit 100 will be described as a hydrogen sensor, as an example.

[0047] FIG. 8 is a cross-sectional view showing the detection unit 100 of the sensor package 10.

[0048] The detection unit 100 is a fine structure that can be manufactured during the semiconductor manufacturing process, and is a wide-range hydrogen sensor that detects low and high concentrations of hydrogen. Its main components include a first electrode 103 and a second electrode 106 that are arranged with their main surfaces facing each other, a metal oxide layer 104 that is arranged in contact with the main surface of the first electrode 103 and the main surface of the second electrode 106, insulating films 107a to 107c, 109a, and 109b that cover the first electrode 103, the second electrode 106, and the metal oxide layer 104, a first terminal TE1 and a second terminal TE2 that are connected via a via to the other surface of the second electrode 106 that faces the main surface, and a third terminal BE that is connected via a via to the other surface of the first electrode 103 that faces the main surface. The insulating film 107b has an opening 106a that exposes the other surface of the second electrode 106 without being covered by the insulating film 107b, between the first terminal TE1 and the second terminal TE2 in a plan view of the second electrode 106.

[0049] The first electrode 103 is a planar electrode having two surfaces. One of the two surfaces (i.e., the upper surface in FIG. 8 ) of the first electrode 103 contacts the metal oxide layer 104, and the other surface (i.e., the lower surface in FIG. 8 ) contacts the insulating film 107a and the via 108. The first electrode 103 has a rectangular shape with the same size as the second electrode 106 when viewed perpendicular to the main surface. The first electrode 103 may be made of a material with a lower standard electrode potential than the metal constituting the metal oxide, such as tungsten, nickel, tantalum, titanium, aluminum, tantalum nitride, or titanium nitride. The higher the standard electrode potential, the more resistant the material to oxidation. The first electrode 103 in FIG. 8 is formed of, for example, a transition metal nitride such as tantalum nitride (TaN) or titanium nitride (TiN), or a laminate thereof.

[0050] The metal oxide layer 104 is sandwiched between the two opposing principal surfaces of the first electrode 103 and the second electrode 106 and is composed of a metal oxide as a resistive film having gas sensitivity, and has a resistance value that reversibly changes depending on whether or not hydrogen is contained in the gas with which the second electrode 106 is in contact. The metal oxide layer 104 may have the property that its resistance changes depending on the presence or absence of hydrogen. For example, the metal oxide layer 104 may be composed of an oxygen-deficient metal oxide. The base metal of the metal oxide layer 104 may be at least one selected from a transition metal such as tantalum (Ta), hafnium (Hf), titanium (Ti), zirconium (Zr), niobium (Nb), tungsten (W), nickel (Ni), or iron (Fe), and aluminum (Al).

[0051] Because transition metals can assume multiple oxidation states, different resistance states can be realized by oxidation-reduction reactions. Here, the "oxygen deficiency" of a metal oxide refers to the ratio of the oxygen deficiency in the metal oxide to the amount of oxygen in an oxide of a stoichiometric composition composed of the same elements as the metal oxide. Here, the oxygen deficiency is the value obtained by subtracting the amount of oxygen in the metal oxide from the amount of oxygen in the metal oxide of the stoichiometric composition. If there are multiple metal oxides of the same stoichiometric composition composed of the same elements as the metal oxide, the oxygen deficiency of the metal oxide is defined based on the one with the highest resistance value among those metal oxides of the stoichiometric composition. Metal oxides of the stoichiometric composition are more stable and have higher resistance values ​​than metal oxides of other compositions.

[0052] For example, when the base metal of the metal oxide layer 104 is tantalum (Ta), the oxide having the stoichiometric composition defined above is Ta. ２ O ５ Therefore, TaO ２．５ It can be expressed as: TaO ２．５ The oxygen deficiency of TaO is 0%. １．５The oxygen deficiency of an oxide having an oxygen excess is (2.5-1.5) / 2.5=40%. In addition, the oxygen deficiency of an oxygen-excess metal oxide is a negative value. In the present disclosure, unless otherwise specified, the oxygen deficiency can be a positive value, 0, or a negative value. An oxide with a small oxygen deficiency is closer to an oxide of a stoichiometric composition and therefore has a high resistance value, while an oxide with a large oxygen deficiency is closer to the metal that constitutes the oxide and therefore has a low resistance value.

[0053] 8 includes a first layer 104a in contact with the first electrode 103, a second layer 104b in contact with the first layer 104a and the second electrode 106, and an insulating isolation layer 104i. The oxygen deficiency of the second layer 104b is smaller than that of the first layer 104a. For example, the first layer 104a is made of TaO Ｘ The second layer 104b is made of Ta, which has a smaller oxygen deficiency than the first layer 104a. ２ O ５ The metal oxide layer 104 also has an insulating separation layer 104i on the outer periphery of the first electrode 103 in a plan view.

[0054] Here, planar view refers to viewing the detection unit 100 according to the present disclosure from a viewpoint in the stacking direction of Figure 8, in other words, viewing from a viewpoint in the normal direction of either the planar first electrode 103, the planar second electrode 106, etc., and refers to, for example, viewing the top surface of the detection unit 100 from a direction perpendicular to the main surface.

[0055] The resistance state of the metal oxide layer 104 decreases in accordance with (the greater the amount of) the hydrogen-containing gas in contact with the second electrode 106. Specifically, when the hydrogen-containing gas is present in the gas to be detected, hydrogen atoms are dissociated from the hydrogen-containing gas at the second electrode 106. The dissociated hydrogen atoms penetrate the metal oxide layer 104 and form impurity levels. In particular, they are concentrated near the interface with the second electrode 106, making the apparent thickness of the second layer 104b thinner. As a result, the resistance value of the metal oxide layer 104 decreases.

[0056] The second electrode 106 is a planar electrode with hydrogen dissociation properties and has two surfaces. One of the two surfaces (i.e., the lower surface in FIG. 8 ) contacts the metal oxide layer 104, and the other surface (i.e., the upper surface in FIG. 8 ) contacts the metal layer 106s and the ambient air. The second electrode 106 has an exposed portion 106e exposed to the ambient air within the opening 106a. The second electrode 106 is made of a material that has catalytic properties to dissociate hydrogen atoms from hydrogen-containing gas molecules, such as a noble metal such as platinum (Pt), iridium (Ir), or palladium (Pd), or nickel (Ni), or an alloy containing at least one of these. The second electrode 106 in FIG. 8 is assumed to be platinum (Pt). Two terminals, namely, a first terminal TE1 and a second terminal TE2, are connected to the second electrode 106.

[0057] The first terminal TE1 is connected to the second electrode 106 through a via 108 .

[0058] The second terminal TE2 is connected to the second electrode 106 through a via 108. The first terminal TE1 and the second terminal TE2 are connected to an external detection circuit that drives the detection unit 100 through openings TE1a and TE2a.

[0059] The first terminal TE1 and the second terminal TE2 are disposed at positions sandwiching the exposed portion 106e in a plan view of the second electrode 106. With this arrangement, when a predetermined voltage is applied between the first terminal TE1 and the second terminal TE2, electricity is passed through the exposed portion 106e of the second electrode 106, that is, a current flows through the exposed portion 106e. This passage of electricity through the exposed portion 106e of the second electrode 106 is thought to activate the hydrogen dissociation function of the exposed portion 106e. Note that the predetermined voltages may be voltages having opposite polarities.

[0060] When gas molecules containing hydrogen atoms come into contact with the exposed portion 106e while current is flowing through the exposed portion 106e, the resistance value between the first terminal TE1 and the second terminal TE2 of the detection unit 100 changes. The detection circuit detects this change in resistance value (this detection is also referred to as the "lateral mode"), thereby detecting gas molecules containing a low concentration of hydrogen atoms.

[0061] The third terminal BE is connected to the first electrode 103 via the opening BEa, the via 108, the wiring 114, and the via 108. The third terminal BE is connected to an external detection circuit that drives the detection unit 100 via the opening BEa. The detection unit 100 changes the resistance between the first electrode 103 and the second electrode 106 when gas molecules containing hydrogen atoms come into contact with the exposed portion 106e while current is flowing through the exposed portion 106e. In other words, the detection unit 100 changes the resistance between the third terminal BE and at least one of the first terminal TE1 and the second terminal TE2 when gas molecules containing hydrogen atoms come into contact with the exposed portion 106e while current is flowing through the exposed portion 106e. The detection circuit detects this change in resistance (this detection is also referred to as a "vertical mode"), thereby detecting gas molecules containing a high concentration of hydrogen atoms.

[0062] The insulating film 102, insulating films 107a to 107c, and insulating films 109a and 109b that cover the main part of the detection unit 100 are made of silicon oxide film, silicon nitride film, or the like.

[0063] A metal layer 106s is formed on the upper surface of the second electrode 106 other than the opening 106a. The metal layer 106s is made of, for example, TiAlN and is formed as an etching stopper for forming the via 108, but is not essential.

[0064] Furthermore, the stack of the first electrode 103, the metal oxide layer 104, and the second electrode 106 is an element that can be used as a memory element of a resistance change memory (ReRAM). In a resistance change memory, two states, a high resistance state and a low resistance state, of the states that the metal oxide layer 104 can take are utilized to form a digital memory element. The detection unit 100 of the present disclosure utilizes the high resistance state of the states that the metal oxide layer 104 can take.

[0065] In FIG. 8, the metal oxide layer 104 is TaO ｘ The first layer 104a is made of Ta, which has a low oxygen deficiency. ２ O ５ The example of the two-layer structure composed of the first layer 104b made of Ta and the second layer 104b made of Ta is shown. ２ O ５ or TaO ｘIt may also have a single layer structure made of the material.

[0066] [Method for Manufacturing Sensor Package] A method for manufacturing the sensor package 10 according to the first embodiment will be described with reference to FIG.

[0067] FIG. 9 is a flowchart showing a method for manufacturing the sensor package 10.

[0068] The manufacturing method of the sensor package 10 includes step S10 of forming a substrate 20 having wiring 26 and through holes 25, step S20 of forming a chip 30 having a detection unit 100, and step S30 of flip-chip connecting the chip 30 to the substrate 20 so that the detection unit 100 faces the through holes 25 of the substrate 20 and is electrically connected to the wiring 26 of the substrate 20.

[0069] The method for manufacturing the sensor package 10 further includes step S40 of forming a resin layer 40 between the substrate 20 and the chip 30, and step S50 of forming an external conductor 60 on the substrate 20.

[0070] The resin layer 40 is formed by pouring a liquid resin material between the substrate 20 and the chip 30 and curing the material. The viscosity of the liquid resin material at room temperature (25°C) is preferably, for example, 1 Pa·s or more and 100 Pa·s or less, and more preferably 4 Pa·s or more and 30 Pa·s or less.

[0071] The liquid resin material is applied, for example, from the outer periphery of the chip 30 into the gap between the chip 30 and the substrate 20. The resin material may be injected into one or more edges of the outer periphery of the chip 30. The gap between the chip 30 and the substrate 20 is preferably, for example, 40 μm to 200 μm, and more preferably 60 μm to 100 μm. When the liquid resin material is injected from the outer periphery, it penetrates and spreads between the chip 30 and the substrate 20 due to capillary action, protecting the bumps 50. Furthermore, a through-hole 25 is formed in the substrate 20, and penetration of the resin material due to capillary action stops near the side surface 25a of the through-hole 25. Therefore, the resin material is not formed on the exposed portion 106e of the detection unit 100, ensuring that the exposed portion 106e is exposed.

[0072] The manufacturing method of the sensor package 10 of this embodiment includes step S10 of forming a substrate 20 having wiring 26 and through holes 25, step S20 of forming a chip 30 having a detection unit 100, and step S30 of flip-chip connecting the chip 30 to the substrate 20 so that the detection unit 100 faces the through holes 25 of the substrate 20 and is electrically connected to the wiring 26 of the substrate 20.

[0073] In this way, by forming the through-holes 25 in the base material 20, the detection unit 100 can be reliably exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0074] Second Embodiment [Configuration of Sensor Package] The configuration of a sensor package 10A according to a second embodiment will be described with reference to Fig. 10 to Fig. 12. In the second embodiment, an example will be described in which the shape of the substrate 20A is not a plate shape but a case shape.

[0075] Fig. 10 is a cross-sectional view of the sensor package 10A according to embodiment 2. Fig. 11 is a plan view of the sensor package 10A. Fig. 12 is a bottom view of the sensor package 10A. Fig. 10 is a cross-sectional view of the sensor package 10A taken along line X-X shown in Fig. 11. Note that in Fig. 10, the bumps 50, the wiring 26, and the external conductors 60A are also hatched.

[0076] 10 , the sensor package 10A includes a substrate 20A, a chip 30 connected to the substrate 20A, and an external conductor 60A connected to the substrate 20A. The chip 30 has a detection unit 100 for detecting the environmental condition (e.g., air quality) of the space in which the sensor package 10A is placed. A resin layer 40 is formed between the substrate 20A and the chip 30.

[0077] The base material 20A is made of, for example, a ceramic material or a resin material and has a case-like shape. The base material 20A has a first surface 21 and a second surface 22 facing away from the first surface 21. The first surface 21 and the second surface 22 are both flat and parallel to each other.

[0078] The base material 20A has a recess 29 whose inner bottom surface is the first surface 21. The recess 29 accommodates a chip 30.

[0079] In addition, substrate 20A has a third surface 23 parallel to first surface 21 and second surface 22. Third surface 23 is located on the opposite side of first surface 21 from second surface 22 and on the outer periphery of recess 29. In other words, substrate 20A is composed of a cylindrical portion 28 extending perpendicular to the main surface of chip 30 and a plate-like portion 27 provided at one end of cylindrical portion 28, and third surface 23 is located at the other end of cylindrical portion 28. Substrate 20A has a rectangular shape when viewed from a direction perpendicular to first surface 21 (see FIG. 11 ).

[0080] The substrate 20A also has a plurality of wirings 26. The wirings 26 are formed on the first surface 21 of the substrate 20A and inside the substrate 20A. In this example, the wirings 26 are also formed inside the plate-shaped portion 27 and the cylindrical portion 28 of the substrate 20A. The wirings 26 have a plurality of inner land electrodes connected to the chip 30 and a plurality of outer land electrodes connected to the external conductor 60A (not shown). The wirings 26 are formed to connect the inner land electrodes and the outer land electrodes.

[0081] The base material 20A has a through-hole 25 that penetrates between the first surface 21 and the second surface 22. The through-hole 25 is an air hole that communicates with the detection unit 100 from the second surface 22 and penetrates the base material 20A in the thickness direction. In this example, one through-hole 25 is formed in the center of the base material 20A.

[0082] The shape of the through-hole 25 is, for example, a rectangle. The shape of the through-hole 25 is not limited to a rectangle and may be a circle. The through-hole 25 is provided at a position corresponding to the detection unit 100 in two-dimensional coordinates with the first surface 21 as a plane. As shown in FIG. 11 , when viewed from a direction perpendicular to the first surface 21, the through-hole 25 overlaps with the detection unit 100. When viewed from a direction perpendicular to the first surface 21, the side surface (inner surface) 25a of the through-hole 25 is located outside the exposed portion 106e of the chip 30. The area of ​​the through-hole 25 is larger than the area of ​​the exposed portion 106e of the detection unit 100.

[0083] 10 , the chip 30 is housed in a recess 29 of the substrate 20A and is flip-chip mounted to the substrate 20A. The chip 30 is connected to the first surface 21 of the substrate 20A so that the detection unit 100 is electrically connected to the outer land electrodes of the wiring 26 of the substrate 20A. Although the chip 30 is housed in the recess 29, the configuration of the chip 30 itself is the same as that of the first embodiment.

[0084] The resin layer 40 is provided between the substrate 20A and the chip 30. The resin layer 40 serves as an underfill material that fills the gap between the substrate 20A and the chip 30. The configuration of the resin layer 40 is substantially the same as that of the first embodiment. In this example, the outer peripheral side surface of the resin layer 40 contacts the inner peripheral side surface of the tubular portion 28 of the substrate 20A.

[0085] The sensor package 10A of the present embodiment further includes a resin sealing portion 45 for protecting the chip 30. The resin sealing portion 45 contacts the other main surface 32 of the chip 30 and a part of the resin layer 40, and fills the recess 29 so as to cover the other main surface 32 and the resin layer 40.

[0086] The sensor package 10A further includes a PTFE (polytetrafluoroethylene) film 76 for protecting the detection unit 100 from the external environment, and a cover unit 71.

[0087] The PTFE film 76 is a breathable film and is disposed on the second surface 22 so as to cover the through-hole 25 of the base material 20A. When viewed from a direction perpendicular to the second surface 22, the PTFE film 76 has a shape slightly larger than the through-hole 25. The PTFE film 76 is fixed to the base material 20A with, for example, an adhesive.

[0088] The cover portion 71 has a plate-shaped lid 72 and an adhesive layer 73 that adheres the lid 72. The cover portion 71 is provided so as to cover the through-hole 25, the PTFE film 76, and the second surface 22 of the base material 20A.

[0089] The lid 72 has the same shape and size as the base material 20A when viewed in a direction perpendicular to the second surface 22. The lid 72 is fixed to the base material 20A by an adhesive layer 73.

[0090] The adhesive layer 73 is frame-shaped and formed with a predetermined width and thickness along the outer periphery of the base material 20A and the lid 72. The adhesive layer 73 is interrupted midway in two regions of the outer periphery of the base material 20A and the lid 72. Gas permeation paths 74 that allow gas to pass through are formed in the two regions between the base material 20A and the lid 72 where the adhesive layer 73 is not formed. By providing the PTFE film 76 and the cover portion 71 on the through-hole 25 in this manner, the waterproofness and dustproofness of the sensor package 10A can be improved.

[0091] 12 is an external terminal formed by metal plating or the like. The external conductor 60A is provided on the third surface 23 of the substrate 20A so as to be electrically connected to the wiring 26 of the substrate 20A. The external conductor 60A is disposed so as to be located outside the chip 30 when viewed from a direction perpendicular to the first surface 21. This structure enables the sensor package 10A to be easily mounted on a printed circuit board 81.

[0092] Fig. 13 is a diagram showing a state in which the sensor package 10A is mounted on a printed circuit board 81. In Fig. 13, the bumps 50, the wiring 26, and the external conductors 60A are also hatched.

[0093] 13 , the sensor package 10A is joined to a printed circuit board 81 using solder. The sensor package 10A is mounted on the printed circuit board 81 so that the third surface 23 of the substrate 20A faces the surface of the printed circuit board 81.

[0094] After the sensor package 10A is mounted on the printed circuit board 81, a potting resin 85 is formed on the printed circuit board 81. The potting resin 85 is formed on the printed circuit board 81 so as to cover the sides of the sensor package 10A but not the cover portion 71 of the base material 20A of the sensor package 10A. In the sensor package 10A of this embodiment, a resin layer 40 is provided around the periphery of the detection unit 100, and a resin sealing portion 45 is provided in the recess 29 of the base material 20A so as to cover the other main surface 32 of the chip 30 and the resin layer 40, thereby preventing the potting resin 85 from entering the detection unit 100. This makes it possible to prevent a deterioration in the quality of the detection unit 100.

[0095] As described above, the sensor package 10A of the present embodiment includes a substrate 20A having a first surface 21, a second surface 22 facing away from the first surface 21, and wiring 26, a chip 30 flip-chip connected to the first surface 21 of the substrate 20A, and an external conductor 60A provided on the substrate 20A so as to be electrically connected to the wiring 26 of the substrate 20A. The chip 30 has a main surface (one main surface 31) facing the first surface 21 of the substrate 20A and a detection unit 100 provided on that main surface, and is connected to the substrate 20A so as to be electrically connected to the wiring 26 of the substrate 20A. The substrate 20A has a through-hole 25 penetrating between the first surface 21 and the second surface 22.

[0096] In this way, by providing the through-holes 25 in the base material 20A, the detection unit 100 can be reliably exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0097] [Method for Manufacturing Sensor Package] A method for manufacturing the sensor package 10A according to the second embodiment will be described with reference to FIG.

[0098] FIG. 14 is a flowchart showing a method for manufacturing the sensor package 10.

[0099] The manufacturing method of the sensor package 10A of the second embodiment includes step S10 of forming a substrate 20A having wiring 26 and through holes 25, step S20 of forming a chip 30 having a detection unit 100, and step S30 of flip-chip connecting the chip 30 to the substrate 20A so that the detection unit 100 faces the through holes 25 of the substrate 20A and is electrically connected to the wiring 26 of the substrate 20A.

[0100] The method for manufacturing the sensor package 10A further includes step S40 of forming a resin layer 40 between the substrate 20A and the chip 30, and step S50A of forming an external conductor 60A on the substrate 20A.

[0101] The manufacturing method of the sensor package 10A further includes step S60 of forming a resin sealing portion 45 in the recess 29 of the substrate 20A. The resin sealing portion 45 is formed by filling the recess 29 with a liquid potting resin and curing it so as to cover the other main surface 32 of the chip 30 and the resin layer 40.

[0102] The manufacturing method of the sensor package 10A also includes a step S70 of forming a PTFE film 76 on the top surface, which is the second surface 22, of the base material 20A. The PTFE film 76 is formed by adhering the PTFE film 76 to the second surface 22 so as to cover the through-holes 25.

[0103] The manufacturing method of the sensor package 10A also includes step S80 of forming a cover portion 71 on the top surface, which is the second surface 22, of the substrate 20A. The cover portion 71 is formed by bonding a plate-shaped lid 72 to the second surface 22 of the substrate 20A with an adhesive. The adhesive is applied to a predetermined width and thickness along the periphery of the substrate 20A and the lid 72. The adhesive is applied so as to be interrupted midway in two regions of the periphery of the substrate 20A and the lid 72. Gas permeation paths 74 that allow gas to pass through are formed between the substrate 20A and the lid 72 in the two regions where no adhesive is applied.

[0104] These steps manufacture the sensor package 10A of Embodiment 2. In the method of manufacturing the sensor package 10A of Embodiment 2, forming the through-holes 25 in the base material 20A also ensures that the detection unit 100 is exposed to the atmosphere. This makes it possible to prevent the quality of the detection unit 100 from deteriorating.

[0105] (Summary) A sensor package (10 or 10A) according to one embodiment of the present disclosure will be illustrated.

[0106] The sensor package (10 or 10A) of Example 1 includes a substrate (20 or 20A) having a first surface 21, a second surface 22 facing away from the first surface 21, and wiring 26, a chip 30 flip-chip connected to the first surface 21 of the substrate, and an external conductor (60 or 60A) provided on the substrate so as to be electrically connected to the wiring 26 of the substrate. The chip 30 has a main surface (one main surface 31) facing the first surface 21 of the substrate and a detection unit 100 provided on that main surface, and the detection unit 100 is connected to the substrate so as to be electrically connected to the wiring 26 of the substrate, and the substrate has a through-hole 25 penetrating between the first surface 21 and the second surface 22.

[0107] In this way, by providing the through-holes 25 in the base material, the detection unit 100 can be reliably exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0108] The sensor package of Example 2 is the sensor package described in Example 1, and further includes a resin layer 40 provided between the substrate and the chip 30. The resin layer 40 may be provided between the first surface 21 of the substrate and the main surface (one main surface 31) of the chip 30 so as not to cover the exposed portion 106e of the detection unit 100.

[0109] In this way, by providing the resin layer 40 so as not to cover the exposed portion 106e of the detection unit 100, the detection unit 100 can be reliably exposed to the atmosphere. This makes it possible to prevent a deterioration in the quality of the detection unit 100. Furthermore, by providing the resin layer 40, it is possible to improve the adhesion between the substrate and the chip 30.

[0110] The sensor package of Example 3 is the sensor package described in Example 2, and the resin layer 40 may be provided between the first surface 21 of the substrate excluding the through-hole 25 and the main surface (one main surface 31) of the chip 30 excluding the exposed portion 106e of the detection unit 100.

[0111] According to this configuration, the detection unit 100 can be reliably exposed to the atmosphere through the through-hole 25. This makes it possible to prevent the quality of the detection unit 100 from deteriorating.

[0112] The sensor package of Example 4 is the sensor package described in Example 2 or 3, in which the chip 30 is connected to the substrate via a plurality of bumps 50. The plurality of bumps 50 are provided around the periphery of the detection unit 100. The resin layer 40 may be provided between the substrate and the chip 30 so as to cover the side surfaces of the plurality of bumps 50 without covering the exposed portion 106e of the detection unit 100.

[0113] This allows the plurality of bumps 50 to be protected by the resin layer 40 while exposing the exposed portion 106e of the detection unit 100. This makes it possible to prevent a deterioration in the quality of the detection unit 100. Furthermore, it is possible to prevent the plurality of bumps 50 from corroding.

[0114] The sensor package of Example 5 is the sensor package according to any one of Examples 1 to 4, and when viewed from a direction perpendicular to the first surface 21, the through-hole 25 may overlap with the detection unit 100.

[0115] This configuration allows the detection unit 100 to be more easily exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0116] The sensor package of Example 6 is a sensor package described in any of Examples 1 to 5, and when viewed from a direction perpendicular to the first surface 21, the side surface 25a of the through hole 25 may be located outside the exposed portion 106e of the detection unit 100.

[0117] This ensures that the exposed portion 106e of the detection unit 100 is exposed and can be reliably exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0118] The sensor package of Example 7 is the sensor package according to any one of Examples 1 to 6, and the detection unit 100 may be a hydrogen sensor.

[0119] This makes it possible to provide a sensor package for detecting hydrogen.

[0120] The sensor package of Example 8 is a sensor package described in any one of Examples 1 to 7, in which the substrate 20 is plate-shaped, and the external conductor 60 is connected to the first surface 21 of the substrate 20 and may protrude outward beyond the chip 30 in a direction perpendicular to the first surface 21.

[0121] In this way, since the external conductor 60 protrudes outward beyond the chip 30, the sensor package 10 can be easily mounted on a printed circuit board 81, for example.

[0122] The sensor package of Example 9 is a sensor package described in any of Examples 1 to 7, in which the substrate 20A has a recess 29 with the first surface 21 as its inner bottom surface, and further has a third surface 23 located on the outer periphery of the recess 29, on the opposite side of the second surface 22 from the first surface 21, and the external conductor 60A may be provided on the third surface 23.

[0123] By forming the outer conductor 60A in this manner, the sensor package 10A can be easily mounted on a printed circuit board 81, for example.

[0124] The manufacturing method of the sensor package of Example 10 includes the steps of forming a substrate having wiring 26 and through-holes 25, forming a chip 30 having a detection portion 100, and flip-chip bonding the chip 30 to the substrate so that the detection portion 100 faces the through-holes 25 of the substrate and is electrically connected to the wiring 26 of the substrate.

[0125] In this way, by providing the through-holes 25 in the base material, the detection unit 100 can be reliably exposed to the atmosphere, thereby preventing the quality of the detection unit 100 from deteriorating.

[0126] The method for manufacturing a sensor package of Example 11 is the method for manufacturing a sensor package described in Example 10, and may further include a step of forming a resin layer 40 between the substrate and the chip 30.

[0127] This allows the resin layer 40 to protect the detection unit 100 .

[0128] The manufacturing method of the sensor package of Example 12 is the manufacturing method of the sensor package described in Example 11, and the resin layer 40 may be formed by injecting a liquid resin material between the substrate and the chip 30 and hardening it.

[0129] According to this, the penetration of the liquid resin material is stopped at the through-hole 25 provided in the base material 20, and the resin layer 40 is not formed on the through-hole 25 and the detection unit 100. This ensures that the detection unit 100 is exposed and can be reliably exposed to the atmosphere. This makes it possible to prevent the quality of the detection unit 100 from deteriorating.

[0130] (Other Embodiments) The sensor package and the method for manufacturing the sensor package according to the present disclosure have been described above based on the embodiments and modifications, but the present disclosure is not limited to these embodiments and modifications. As long as they do not deviate from the gist of the present disclosure, various modifications that would occur to a person skilled in the art to the present embodiments and modifications, and other forms constructed by combining some of the components in the embodiments and modifications, are also included within the scope of the present disclosure.

[0131] In embodiment 1, an example is shown in which no other member is provided on the through hole 25 of the substrate 20, but this is not limited to this, and as shown in embodiment 2, a PTFE membrane 76 may be provided on the through hole 25 of the substrate 20.

[0132] In embodiment 1, an example is shown in which no other components are provided on the second surface 22 of the substrate 20, but this is not limited to this, and as shown in embodiment 2, a cover portion 71 may be provided on the second surface 22 of the substrate 20.

[0133] In the second embodiment, an example is shown in which a PTFE film 76 is provided on the through hole 25 of the substrate 20A, but this is not limited thereto, and the PTFE film 76 does not have to be provided on the through hole 25 of the substrate 20A.

[0134] In embodiment 2, an example is shown in which a cover portion 71 is provided on the second surface 22 of the substrate 20A, but this is not limited to this, and the cover portion 71 does not have to be provided on the second surface 22 of the substrate 20A.

[0135] In the second embodiment, an example is shown in which the resin sealing portion 45 is provided in the recess 29 of the base material 20A, but this is not limiting, and the resin sealing portion 45 does not have to be provided in the recess 29 of the base material 20A.

[0136] The sensor package according to the present disclosure can be used, for example, as a gas sensor package to be mounted on a fuel cell vehicle.

[0137] 10, 10A Sensor package 20, 20A Base material 21 First surface 22 Second surface 23 Third surface 25 Through hole 25a Side surface 26 Wiring 27 Plate-shaped portion 28 Cylindrical portion 29 Recess 30 Chip 31 One main surface 32 Other main surface 36 Wiring 37 Terminal portion 40 Resin layer 45 Resin sealing portion 50 Bump 60, 60A External conductor 71 Cover portion 72 Lid 73 Adhesive layer 74 Gas permeation path 76 PTFE (polytetrafluoroethylene) film 81 Printed circuit board 85 Potting resin 100 Detection portion 102 Insulating film 103 First electrode 104 Metal oxide layer 104a First layer 104b Second layer 104i Insulating separation layer 106 Second electrode 106a, TE1a, TE2a, BEa Opening 106e Exposed portion 106s Metal layer 107a, 107b, 107c, 109a, 109b Insulating film 108 Via 114 Wiring TE1 First terminal TE2 Second terminal BE Third terminal

Claims

1. A sensor package comprising: a substrate having a first surface, a second surface facing the first surface, and wiring; a chip flip-chip connected to the first surface of the substrate; and an external conductor provided on the substrate so as to be electrically connected to the wiring of the substrate, wherein the chip has a main surface facing the first surface of the substrate and a detection unit provided on the main surface, the detection unit being connected to the substrate so as to be electrically connected to the wiring of the substrate; and the substrate having a through hole passing through between the first surface and the second surface.

2. The sensor package according to claim 1, further comprising a resin layer provided between the substrate and the chip, the resin layer being provided between the first surface of the substrate and the main surface of the chip so as not to cover the exposed portion of the detection unit.

3. The sensor package according to claim 2, wherein the resin layer is provided between the first surface of the substrate excluding the through-hole and the main surface of the chip excluding the exposed portion of the detection unit.

4. The sensor package according to claim 2, wherein the chip is connected to the substrate via a plurality of bumps, the plurality of bumps are provided around the detection section, and the resin layer is provided between the substrate and the chip so as to cover the side surfaces of the plurality of bumps but not to cover the exposed portion of the detection section.

5. A sensor package according to any one of claims 1 to 4, wherein the through-hole overlaps with the detection section when viewed from a direction perpendicular to the first surface.

6. A sensor package according to any one of claims 1 to 4, wherein when viewed from a direction perpendicular to the first surface, the side of the through hole is positioned outside the exposed portion of the detection section.

7. The sensor package according to any one of claims 1 to 4, wherein the detection unit is a hydrogen sensor.

8. A sensor package according to any one of claims 1 to 4, wherein the base material is plate-shaped, and the external conductor is connected to the first surface of the base material and protrudes outward beyond the chip in a direction perpendicular to the first surface.

9. A sensor package according to any one of claims 1 to 4, wherein the base material has a recess with the first surface as its inner bottom surface, and further has a third surface located on the outer periphery of the recess, on the opposite side of the second surface as viewed from the first surface, and the external conductor is provided on the third surface.

10. A method for manufacturing a sensor package, comprising the steps of: forming a substrate having wiring and through holes; forming a chip having a detection unit; and flip-chip connecting the chip to the substrate so that the detection unit faces the through holes of the substrate and is electrically connected to the wiring of the substrate.

11. The method for manufacturing a sensor package according to claim 10, further comprising the step of forming a resin layer between the substrate and the chip.

12. The method for manufacturing a sensor package according to claim 11, wherein the resin layer is formed by pouring a liquid resin material between the substrate and the chip and curing the material.

Images