Method for inspecting semiconductor device

Abstract

To make it possible to easily inspect the bonding strength, etc. of a semiconductor element.SOLUTION: A semiconductor device inspection method includes a step of preparing a semiconductor device 10A in which a semiconductor element 12 is bonded to an upper surface of a substrate 11 via a bonding member 13, a step of breaking the bonding member 13 to peel the semiconductor element 12 from the substrate 11, a step of measuring the area of the bonding member 13 on the semiconductor element 12 side and / or the substrate 11 after breaking in a plan view and obtaining a determination value representing the measured area, and a step of comparing the determination value with a predetermined reference value, and determining the bonding state between the semiconductor element 12 and the substrate 11 as failing when the determination value is smaller than the reference value, and determines the bonding state between the semiconductor element 12 and the substrate 11 as passing when the determination value is equal to or more than the reference value.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a method for inspecting a semiconductor device, for example, a method for inspecting the bonding strength of a semiconductor element bonded to a substrate. [Background technology]

[0002] Various tests are performed on semiconductor devices. For example, a shear strength test is known to check the bonding strength of a semiconductor element bonded to a substrate via a bonding member such as a bump. As an example of a test method for testing the bonding strength between a semiconductor element and a substrate, Patent Document 1 discloses a method in which a locking part provided at the tip of a shear tool is inserted into the bonding gap between the substrate and the semiconductor element, and the locking part of the shear tool is used to lift the semiconductor element vertically from the upper surface of the substrate and peel it off, thereby measuring the bonding strength. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-163014 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a method for inspecting a semiconductor device that enables inspection of the bonding strength, etc. of a semiconductor element to be easily performed. [Means for solving the problem]

[0005] A method for inspecting a semiconductor device according to one embodiment of the present disclosure includes the steps of preparing a semiconductor device having a semiconductor element bonded to an upper surface of a substrate via a bonding member; breaking the bonding member to peel the semiconductor element from the substrate; measuring the area of ​​the bonding member in a planar view of the semiconductor element side and / or the substrate after breaking, and obtaining a judgment value representing the measured area; and comparing the judgment value with a predetermined reference value, and judging the bonding state between the semiconductor element and the substrate as failing if the judgment value is smaller than the reference value, and judging the bonding state between the semiconductor element and the substrate as passing if the judgment value is equal to or larger than the reference value. Effect of the Invention

[0006] According to an embodiment of the method for inspecting a semiconductor device of the present disclosure, the semiconductor element is peeled off from the substrate and the area of ​​the broken bonding member is measured, thereby making it possible to determine whether the bonding condition is pass or fail, thereby enabling simple inspection of the semiconductor device. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic perspective view showing an example of a semiconductor device; [Diagram 2] 2 is a partially enlarged cross-sectional view taken along line II-II of the semiconductor device shown in FIG. [Diagram 3] 4A to 4C are process diagrams showing steps of preparing a semiconductor device used in the inspection method according to the first embodiment. [Figure 4] 1 is a schematic side view showing an example of a peeling device used in a semiconductor device inspection method according to embodiment 1. FIG. [Diagram 5] 1 is a schematic configuration diagram showing a measuring device and a determining unit used in a method for inspecting a semiconductor device according to embodiment 1. FIG. [Figure 6] FIG. 2 is a partially cross-sectional plan view showing a plurality of bonding members and a shear tool arranged on a substrate. [Figure 7] FIG. 7A is an enlarged cross-sectional view showing a state in which the bonding member remains on the semiconductor element side after interfacial peeling, and FIG. 7B is an enlarged cross-sectional view showing a state in which the bonding member remains on the substrate side after interfacial peeling. [Figure 8]FIG. 8A is a schematic diagram showing the state of the joined members before joining, and FIG. 8B is a schematic diagram showing the state of the joined members after joining. [Figure 9] FIG. 4 is a schematic diagram showing an example of a joined member after joining. [Figure 10] 1 is a graph showing the relationship between the area ratio and the fracture temperature obtained by a peel test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] First, one of the points of interest of the present disclosure will be described. As shown in Figs. 1 and 2, there is a semiconductor device that is configured by covering a semiconductor element 12 with a resin 18 in a state where the semiconductor element 12 is bonded to a substrate 11 via bonding members 13 such as bumps. In such a semiconductor device 10, a plurality of bonding members 13 are disposed at a distance from each other between a lower surface 12a of the semiconductor element 12 and an upper surface 11a of the substrate 11, and the semiconductor element 12 is flip-chip mounted on the substrate 11. For example, in a semiconductor element 12 having positive and negative electrodes on the lower surface 12a, the positive and negative electrodes and the positive and negative wirings 15 on the upper surface 11a of the substrate 11 are bonded by conductive bonding members 13. Therefore, between at least two bonding members 13 connected to each electrode, a gap 14 is generated by the bonding members 13 between the lower surface 12a of the semiconductor element 12 and the upper surface 11a of the substrate 11.

[0009] In the semiconductor device 10 having this structure, the resin 18 can also be disposed in the gap 14 between the upper surface 11a of the substrate 11 and the lower surface 12a of the semiconductor element 12. For example, in the semiconductor device 10 in which the semiconductor element 12 is the light-emitting element 16, the resin 18 disposed in the gap 14 can be added with a white powder such as a light-reflecting material that reflects light, thereby reflecting the light emitted downward from the light-emitting element 16 and reducing the amount of light escaping to the substrate 11 side. This can improve the light extraction efficiency as a light-emitting device. In this semiconductor device 10, it is required that the semiconductor element 12 and the substrate 11 are bonded with a strength that takes into consideration the influence of thermal stress due to the expansion and contraction of the resin 18 caused by the heat generated by the semiconductor element 12 and the thermal history during mounting and use of the semiconductor device 10.

[0010] In the present disclosure, the area of ​​the fractured portion after fracture is measured, and a judgment value obtained based on this area is compared with a predetermined reference value to judge the acceptability of the bonded state.

[0011] The present disclosure will be described in more detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present disclosure. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members.

[0012] Furthermore, the embodiments shown below are specific examples of the technical ideas of the present disclosure, and do not limit the present disclosure to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present disclosure. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0013] [Embodiment 1] The method for inspecting a semiconductor device according to the first embodiment is a method for inspecting the bonding strength of a semiconductor element bonded onto a substrate via a bonding member. The method for inspecting a semiconductor device includes the steps of preparing a semiconductor device in which a semiconductor element is bonded onto an upper surface of a substrate via a bonding member, breaking the bonding member to peel off the semiconductor element from the substrate, measuring the area of ​​the bonding member after breaking on the semiconductor element side and / or the substrate in a plan view to obtain a judgment value representing the measured area, and comparing the judgment value with a predetermined reference value, and judging the bonding state between the semiconductor element and the substrate as failing if it is smaller than the reference value, and judging the bonding state between the semiconductor element and the substrate as passing if it is equal to or larger than the reference value.

[0014] In the semiconductor device inspection method, as shown in FIG. 3C, a semiconductor device 10A in which a semiconductor element 12 is bonded to an upper surface 11a of a substrate 11 via a bonding member 13 is inspected for bonding strength between the semiconductor element 12 and the substrate 11 using an inspection device. FIG. 4 shows an example of a peeling device 2 used in a process of peeling the semiconductor element 12 from the substrate 11, and FIG. 5 shows an example of a measuring device 3 used in a process of measuring the area of ​​the bonding member 13 after fracture to obtain a judgment value, and an example of a judgment unit 4 used in a process of comparing the judgment value with a predetermined reference value to judge pass / fail. Note that the inspection device 1 shown in these figures shows an example of the peeling device 2, the measuring device 3, and the judgment unit 4 for realizing the operation in each process, and the present disclosure does not limit the peeling device, the measuring device, and the judgment unit to the configurations shown in each drawing.

[0015] [Step of Preparing Semiconductor Device 10A] (Semiconductor device 10A, 10) In this step, as shown in Fig. 3C, a semiconductor device 10A is prepared in which a semiconductor element 12 is bonded to an upper surface of a substrate 11 via a bonding member 13. The semiconductor device 10A shown in Fig. 3C includes a semiconductor element 12, a substrate 11 having the semiconductor element 12 bonded to its upper surface, and a plurality of bonding members 13 that bond an upper surface 11a of the substrate 11 to a lower surface 12a of the semiconductor element 12. This semiconductor device 10A corresponds to an intermediate product in the middle of manufacturing the semiconductor device 10 shown in Figs. 1 and 2. In the inspection method according to the first embodiment, inspection is performed on this intermediate semiconductor device 10A.

[0016] (Semiconductor element 12) The semiconductor element 12 is preferably a semiconductor element that can be flip-chip mounted. For example, it is preferable that the semiconductor element 12 has a structure in which positive and negative electrodes are provided on the same side. Examples of the semiconductor element 12 include a light emitting element and a protective element.

[0017] (Substrate 11) The substrate 11 is a member for arranging the semiconductor element 12 mounted on the upper surface 11a at a predetermined position and electrically connecting it, and has wiring 15 made of a metal film provided on the upper surface of the substrate 11. An example of such a substrate 11 is a ceramic substrate provided with wiring 15 at least on its upper surface.

[0018] (Joint member 13) A plurality of bonding members 13 are provided between the lower surface 12a of the semiconductor element 12 and the upper surface 11a of the substrate 11, spaced apart from each other. The bonding members 13 are conductive and electrically connect the semiconductor element 12 and the substrate 11. Examples of the conductive bonding members 13 include gold, silver, copper, aluminum, and alloys containing these. Specifically, the bonding members 13 are bumps, ball-shaped conductive members, and columnar conductive members formed by plating. For example, the semiconductor element 12 to be flip-chip mounted has positive and negative electrodes on the lower surface 12a of the semiconductor element 12. The positive and negative electrodes and the positive and negative wirings 15 on the upper surface 11a of the substrate 11 are bonded by the conductive bonding members 13. To bond the lower surface 12a of the semiconductor element 12 and the upper surface 11a of the substrate 11, first, as shown in FIG. 3A, a plurality of bonding members 13 are placed on the positive and negative wirings 15 provided on the upper surface 11a. Then, as shown in Fig. 3B, the semiconductor element 12 is placed on the bonding members 13, and as shown in Fig. 3C, the bonding members 13 are pressed by the lower surface 12a of the semiconductor element 12 to bond the semiconductor element 12 to the positive and negative wirings 15 on the upper surface 11a of the substrate 11 via the bonding members 13. The bonding members 13 are deformed by the load caused by the pressing, and can bond the semiconductor element 12 and the substrate 11. Note that the pressing may be performed while applying ultrasonic waves. At this time, gaps 14 are formed between the multiple bonding members 13 arranged between the upper surface 11a of the substrate 11 and the lower surface 12a of the semiconductor element 12.

[0019] Each electrode of the semiconductor element 12 is connected to the wiring 15 provided on the substrate 11 via a plurality of bonding members 13, as shown in FIG. 2. For example, a plurality of bonding members 13 are disposed on each of the positive and negative electrodes disposed on the lower surface 12a of the semiconductor element 12, which is rectangular in plan view. That is, two or more bonding members 13 are bonded to one electrode. In this manner, the bonding members 13 can be disposed at desired positions relative to the positive and negative electrodes. At this time, a gap is also formed between the lower surface 12a of the semiconductor element 12 and the upper surface 11a of the substrate 11, between the plurality of bonding members disposed on the positive and negative electrodes. Although FIG. 3C shows the semiconductor device 10A in which one semiconductor element 12 is disposed on one substrate 11, the semiconductor device can have a plurality of semiconductor elements disposed on one substrate.

[0020] In the manufacturing process of semiconductor device 10, semiconductor device 10A, which is an intermediate product of semiconductor device 10, has resin 18 disposed on upper surface 11a of substrate 11, around semiconductor element 12, and in gap 14 formed between substrate 11 and semiconductor element 12, as shown in Fig. 2. Semiconductor device 10 shown in Fig. 2 uses light-emitting element 16 as semiconductor element 12, has phosphor plate 17 disposed on the upper surface of light-emitting element 16, and further has second resin 19 disposed around phosphor plate 17. In this manner, semiconductor device 10 is manufactured.

[0021] The inspection method disclosed herein is an inspection method carried out to inspect whether semiconductor element 12 is bonded to substrate 11 with a strength sufficient to prevent it from peeling off due to stress caused by the expansion of resin 18, and can be performed using intermediate semiconductor device 10A in a state where resin 18 is not filled in.

[0022] [Step of Peeling Off Semiconductor Element 12 from Substrate 11] (Peeling device 2) In this step, the peeling device 2 is used to break the bonding members 13 of the semiconductor device 10A, and peel the semiconductor element 12 from the substrate 11. As shown in FIG. 4, the peeling device 2 is equipped with a shear tool 21 for peeling the semiconductor element 12 from the substrate 11. A test device used for a die shear strength test can be used as the peeling device 2. The peeling device 2 preferably uses a device that peels the semiconductor element 12 in a direction away from the substrate 11. This breaks the bonding members 13 in the pulling direction, and the semiconductor element 12 can be peeled off from the substrate 11.

[0023] In the peeling device 2 shown in FIG. 4, a shear tool 21 is placed on the side of the semiconductor device 10A placed on a horizontal work table 22, and the shear tool 21 is moved horizontally to apply a stress for peeling the semiconductor element 12 in a direction that relatively separates the semiconductor element 12 from the upper surface 11a of the substrate 11 (i.e., in the direction indicated by the arrow in FIG. 2). The shear tool 21 shown in FIG. 4 has a protrusion 23 at its tip that contacts the outer periphery of the lower surface 12a of the semiconductor element 12. The protrusion 23 has an inclined surface 23a that is inclined with respect to the moving direction of the shear tool 21 as a pressing portion that contacts the semiconductor element 12. The tip of the inclined surface 23a is inserted between the lower surface 12a of the semiconductor element 12 and the upper surface 11a of the substrate 11, and the inclined surface 23a can be brought into contact with the outer periphery of the lower surface of the semiconductor element 12 (for example, the lower right corner of the semiconductor element 12 in FIG. 4). With this configuration, when the shear tool 21 is moved toward the semiconductor element 12 in parallel to the upper surface 11a of the substrate 11, the contact position of the protrusion 23 of the shear tool 21 with the semiconductor element 12 shifts upward. In other words, as the tip of the protrusion 23 enters between the semiconductor element 12 and the substrate 11, the contact position of the protrusion 23 and the semiconductor element 12 moves upward along the inclined surface 23a of the protrusion 23. As a result, the stress acting on the contact position acts to push the semiconductor element 12 upward. In this way, by providing the protrusion with the inclined surface 23a, the shear tool 21 can apply stress in a direction to peel the semiconductor element 12 from the upper surface of the substrate 11 while moving the shear tool 21 in a direction parallel to the work table 22 and the upper surface of the semiconductor element 12, and the bonding member 13 can be broken to peel the semiconductor element 12 from the substrate 11. The shear tool 21 is manufactured from a high-speed tool steel such as SKH51 so that the protruding portion 23 at the tip can press the outer periphery of the thin semiconductor element 12 .

[0024] The inclination angle (α) of the inclined surface 23a of the shear tool 21 with respect to the horizontal plane, in other words, the inclination angle with respect to the bottom surface of the semiconductor element 12, is preferably 30 degrees or more and 60 degrees or less. This allows the tip of the protrusion 23 of the shear tool 21 to be easily inserted between the semiconductor element 12 and the substrate 11, and also makes it easy to apply stress in a direction to peel the semiconductor element 12 from the top surface 11a of the substrate 11. With this structure, even when the shear tool 21 is used with the horizontal work table 22 or a horizontal movement mechanism (not shown), it is possible to apply stress to peel the semiconductor element 12 in a direction to lift it up from the top surface of the substrate.

[0025] 6, the inclined surface 23a of the protrusion 23 at the tip of the shear tool 21 contacts and presses against the outer periphery 12b of the semiconductor element 12 over a predetermined width. In this way, the shear tool 21, which has the inclined surface 23a as the pressing surface, has the tip edge 23b parallel to the opposing edge of the substrate 11, so that the inclined surface 23a can be brought into contact with and pressed against the outer periphery, which is one side of the lower surface of the semiconductor element 12, which has a rectangular planar shape.

[0026] The peeling device does not necessarily have to be a test device used for die shear strength testing, and various structures that can simply peel the semiconductor element away from the substrate can be used. The peeling device does not need to measure the breaking load. This is because the inspection device measures the bonding strength of the bonding members using the area of ​​the bonding members in a plan view after breaking as a parameter different from the breaking load.

[0027] In addition, the relative movement between the semiconductor element and the shear tool in the peeling device is not limited to a configuration in which the semiconductor element is fixed and the shear tool is moved. For example, it goes without saying that the relative movement between the semiconductor element and the shear tool can be achieved by fixing the shear tool and moving the semiconductor element toward the shear tool.

[0028] [Process of measuring the bonded members after fracture to obtain a judgment value] In this process, the area of ​​the bonding member 13 after fracture in a planar view is measured on the side of the substrate 11 from which the semiconductor element 12 has been peeled off and / or on the side of the semiconductor element 12 from which it has been peeled off from the substrate 11, and a judgment value representing this area is obtained from the measured area.

[0029] (Measuring device 3) The measuring device 3 is a device that measures the area in a plan view of the bonding member 13 after fracture. As shown in Fig. 5, the measuring device 3 includes a measuring device 31 that measures the bonding member 13 after fracture of the substrate 11 and / or the semiconductor element 12, an image processing unit 32 that acquires the area of ​​the fractured portion 13a from the data detected by the measuring device 31, and a calculation unit 33 that calculates a judgment value used for judging the bonding strength from the area acquired by the image processing unit 32.

[0030] (Measuring instrument 31) The measuring device 31 obtains an image of the surface shape of the bonding member 13 after breaking in a plan view, and measures the area of ​​the broken portion 13a of the broken bonding member 13. The measuring device 31 measures the area of ​​the broken portion 13a of the bonding member 13 remaining on the upper surface 11a of the substrate 11 with the substrate 11 placed on the measuring table 34. Alternatively, although not shown, the measuring device 31 measures the broken portion of the bonding member remaining on the lower surface of the semiconductor element with the semiconductor element placed on the measuring table. The measuring device 31 is preferably a three-dimensional measuring device capable of three-dimensional measurement. As such a three-dimensional measuring device, for example, a shape analysis laser microscope is used. The shape analysis laser microscope is a microscope that can measure the surface shape of an object using laser light, and can perform non-contact and non-destructive inspection. Instead of a laser microscope, a microscope or an optical microscope can be used as the measuring device. The measuring device 31, which is a three-dimensional measuring device, is in a state where it is measuring the bonding member 13 remaining on the substrate 11 after fracture, and can, for example, detect the shape of the bonding member 13 in a space a predetermined distance away from the top surface 11a of the substrate 11, thereby making it possible to clearly distinguish it from metal parts such as wiring 15 provided on the top surface 11a of the substrate 11 while making the measurement.

[0031] (Image processing unit 32) The image processing unit 32 acquires the area value of the broken portion 13a from the image obtained by measuring with the shape analysis laser microscope. For example, the image processing unit 32 identifies the broken portion 13a of the bonding member 13 from a three-dimensional image of the bonding member 13 acquired with the shape analysis laser microscope, which is the measuring instrument 31, and acquires the area value. Furthermore, the image processing unit 32 can acquire the area value of the broken portion 13a while judging the fracture state of the bonding member 13. For example, if the bonding state of the bonding member 13 with the substrate 11 or the semiconductor element 12 is insufficient, it is considered that the bonding member 13 peels off at the interface with the substrate 11 or the semiconductor element 12 without breaking. In such a case, the image processing unit 32 judges the success or failure of the bonding state from the image obtained with the measuring instrument 31. For example, in the case of interface peeling at the boundary surface with the substrate 11 as shown in FIG. 7A, the image processing unit 32 judges that the bonding is insufficient by judging that the interface peeling occurs on the substrate 11 side because the area of ​​the bonding member 13 on the upper surface 11a of the substrate 11 cannot be acquired. Furthermore, in the case of interfacial peeling at the boundary surface with the semiconductor element 12 as shown in FIG. 7B, the image processing unit 32 is unable to obtain the area of ​​the bonding member 13 on the lower surface 12a of the semiconductor element 12, and therefore determines that interfacial peeling has occurred on the semiconductor element 12 side, and that bonding is insufficient.

[0032] (Computation unit 33) The calculation unit 33 calculates a judgment value used to judge the bonding strength from the value of the area of ​​the broken portion 13a acquired by the image processing unit 32. For example, the calculation unit 33 can set the judgment value to the value of the area of ​​the broken portion 13a acquired by the image processing unit 32. This method is the simplest way to determine the judgment value.

[0033] Furthermore, the calculation unit 33 can calculate an area ratio, which is a ratio to a standard cross-sectional area serving as a reference for the joining member 13, from the area value acquired by the image processing unit 32, and output the calculated area ratio as a judgment value. In this method, the area ratio is calculated as follows.

[0034] (1) Determine the standard cross-sectional area of ​​the joint member 13 The semiconductor element 12 to be bonded to the substrate 11 has a bonding strength required according to its type, shape, size (i.e., the area of ​​the bonding surface), use conditions, etc., and is determined as a design requirement value. Therefore, the standard cross-sectional area (Sa) is calculated based on the required bonding area (Sn) calculated for each product, taking into account thermal shock and thermal resistance, and the number of bonding members 13 used to bond one semiconductor element 12. That is, the area per bonding member, which is a value obtained by dividing the required bonding area (Sn) required when bonding one semiconductor element 12 to the substrate 11 by the number (n) of bonding members, is determined as the standard cross-sectional area (Sa). For example, as shown in FIG. 8A, when a substantially spherical bonding member 13A is pressed by bonding, it is deformed into a substantially cylindrical bonding member 13B as shown in FIG. 8B. The cross-sectional area of ​​the bonding member in this state, in other words, the design cross-sectional area per bonding member, is set as the standard cross-sectional area (Sa) of the bonding member 13. Here, the standard cross-sectional area (Sa) is calculated by the following (Equation 1).

[0035] Standard cross-sectional area (Sa) = required joint area (Sn) / number of joint members (n) ... (Formula 1)

[0036] (2) Calculation of area ratio In contrast, as shown in FIG. 9, the actually joined joining member 13 is not deformed into a perfect circle, so the joining area changes depending on the shape after deformation, and the joining strength also differs. In general, when a certain amount of metal is spread out in a plane, the area can be made the widest by stretching it into a perfect circle. Therefore, the area becomes smaller as the shape after stretching becomes more distorted from a circle. In addition, the joining area of ​​the metal joining member also differs depending on the degree to which it is crushed. That is, when the approximately spherical joining member 13A is not sufficiently crushed, the joining area becomes smaller and the joining strength decreases. Therefore, in the case of the metal joining member 13, the joining strength can be detected by measuring the cross-sectional area when a certain amount of the joining member 13 is crushed. Here, the amount of the joining member 13 used is adjusted according to the substrate or semiconductor element, so in order to detect the relative joining strength, the ratio of the measured cross-sectional area (Sx) to the standard cross-sectional area (Sa) serving as a reference is calculated as the area ratio (Px). Here, the area ratio (Px) is calculated by the following (Equation 2).

[0037] Area ratio (Px)[%]={Measured cross-sectional area (Sx) / Standard cross-sectional area (Sa)}×100...(Formula 2)

[0038] Furthermore, the calculation unit 33 can calculate the diameter of the joining member 13 from the area detected by the image processing unit 32, and output the calculated diameter as a judgment value. As described above, the approximately spherical joining member 13A is deformed into an approximately cylindrical joining member 13B as shown in FIG. 8B by the pressure during joining. The diameter of the joining member in this state, for example, the design diameter of the joining member 13 formed into a circle, is set as the standard diameter (La). Therefore, the standard diameter (La) is calculated based on the above-mentioned standard cross-sectional area (Sa) to calculate the outer diameter equivalent to the diameter when the cross section is deformed into a perfect circle, and the calculated outer diameter is set as the standard diameter (La). Here, the standard diameter (La) is calculated by the following (Equation 3).

[0039] Standard diameter (La)=2×{standard cross-sectional area (Sa) / π} 1 / 2 ...(Formula 3)

[0040] In contrast, since the actually welded joint members are not deformed into a perfect circle as shown in Fig. 9, the outer diameter (Lx) equivalent to the diameter when the cross section is deformed into a circle is calculated based on the measured cross-sectional area (Sx), and the calculated outer diameter (Lx) is output as the judgment value. Here, the outer diameter (Lx) is calculated by the following (Equation 4).

[0041] Outer diameter (Lx)=2×{measurement cross-sectional area (Sx) / π} 1 / 2 ...(Formula 4)

[0042] Furthermore, the calculation unit 33 can also calculate an outer diameter ratio (Lx / La) which is the ratio of the outer diameter (Lx) calculated from the measured cross-sectional area (Sx) to the standard diameter (La) as a judgment value.

[0043] In the above process of obtaining the judgment value, the judgment value can be obtained from the measured value of the area of ​​at least one of the plurality of bonding members 13. This makes it possible to measure the area of ​​at least one of the bonding members 13, rather than measuring the areas of all of the plurality of bonding members 13, and to determine whether the required bonding strength is obtained.

[0044] For example, in a semiconductor device 10A, a semiconductor element 12 is bonded to a substrate 11 via a plurality of bonding members 13 arranged vertically and horizontally, as shown in Fig. 6. In this case, among the plurality of bonding members 13 arranged vertically and horizontally, the areas of bonding members 13 located on the outer periphery and bonding members 13 located inside the outer periphery, as indicated by a chain-line circle, can be measured to obtain a plurality of judgment values. By measuring the bonding members 13 located near the corners and the center among the plurality of bonding members 13 arranged vertically and horizontally, the overall condition of the bonding members 13 can be inferred, enabling efficient inspection of the bonding strength.

[0045] Here, as shown in Fig. 6, in the semiconductor device 10A, in the peeling process described above, a plurality of bonding members 13 are arranged in a matrix at positions that are the intersections of a plurality of parallel lines that are parallel to the four sides of the semiconductor element 12 that is rectangular in plan view. Of the plurality of bonding members 13 arranged in this manner, it is desirable to select the bonding members 13 in the intermediate region 28 excluding the proximal region 26 that is closest to one side of the outer edge of the lower surface that the shear tool 21 abuts against when peeling the semiconductor element 12 in the peeling process and the remote region 27 that is farthest from the side that the shear tool 21 abuts against. This is because in the proximal region 26 that is closest to the shear tool 21, there is a risk that the bonding members 13 will be damaged by the protruding portion 23 of the shear tool 21, and in the remote region 27 that is farthest from the shear tool 21, there is a risk that the bonding members 13 will be broken in a state in which they spread horizontally when broken. Therefore, by selecting the bonding members 13 in the intermediate region 28, there is a feature that the bonding members 13 in an ideal broken state that is broken in a direction away from the upper surface of the substrate 11 can be selected and measured.

[0046] [Process to judge the pass / fail of the bonded state] In this step, a judgment value obtained from the area of ​​the bonded member 13 after breaking is compared with a predetermined reference value to judge whether the bonded state between the semiconductor element 12 and the substrate 11 is acceptable or not.

[0047] (Judgment part 4) The inspection device 1 shown in Fig. 5 includes a judgment unit 4 that judges the pass / fail of the bonded state by comparing a judgment value output from the measurement device 3 with a predetermined reference value. The judgment unit 4 stores a preset predetermined reference value in order to judge the pass / fail of the connection state from the judgment value input from the measurement device 3. If the input judgment value is smaller than the reference value, the judgment unit judges the bonded state between the semiconductor element 12 and the substrate 11 to be unacceptable, and if the input judgment value is equal to or larger than the reference value, the judgment unit judges the bonded state between the semiconductor element 12 and the substrate 11 to be acceptable.

[0048] Here, the reference value stored in the judging unit 4 is a reference value that is set in advance for judging the pass / fail of the bonded state from the judgment value input from the measuring device 3. For example, when the judgment value is the area value of the bonded members 13, the reference value is the area value that is the criterion for passing the bonded state, when the judgment value is the area ratio of the bonded members 13, the reference value is the area ratio that is the criterion for passing the bonded state, and when the judgment value is the diameter of the bonded members, the reference value is the diameter that is the criterion for passing the bonded state.

[0049] Here, the reference value used in the judgment process is, for example, a value that can judge whether the bonding strength required for the bonding member of the semiconductor device is satisfied, and is set in various ways depending on the semiconductor device to be inspected. For example, in a semiconductor device designed so that the semiconductor element is not peeled off when the resin filled around the semiconductor element thermally expands, the reference value is set so as to satisfy the bonding strength that keeps the bonding member in a state where it is not broken even when the resin thermally expands due to a temperature rise.

[0050] Furthermore, the reference value for preventing the joining member from breaking even when the resin undergoes thermal expansion can also be found by the following method.

[0051] [Step of determining the predetermined reference value] In this process, first, a semiconductor device 10 shown in Fig. 1 and Fig. 2 is prepared as a reference device in which a resin 18 is placed between a semiconductor element 12 and a substrate 11. A semiconductor device having the same specifications as the semiconductor device to be inspected is used as the reference device for determining the reference value. A thermal load is applied to this reference device, and a peeling test is performed in which the semiconductor element 12 is peeled off from the substrate 11. A predetermined reference value is calculated based on the temperature history at the time of fracture and the area of ​​the bonding member 13 in a top view after fracture. This method makes it possible to determine whether the semiconductor device 10 to be inspected has a bonding strength that takes into account the thermal expansion of the resin 18 by a simple method of measuring the area of ​​the bonding member after peeling.

[0052] (Peel test) The peel test is carried out according to the following procedure. 1. Prepare a plurality of reference devices. The reference device has a semiconductor element bonded to the upper surface of a substrate via a bonding member, and resin is placed in the gap between the semiconductor element and the substrate. The reference device has the same number of bonding members as the semiconductor devices to be inspected. Here, the reference device is described as having a total of 30 gold bumps arranged vertically and horizontally in a 5 x 6 pattern as bonding members. These reference devices are divided into several groups based on the outer diameter (Lx) of each bonding member. The outer diameter (Lx) of the bonding member is detected, for example, by measuring the horizontal length of an X-ray transmission image obtained by irradiating X-rays. The plurality of reference devices are divided into first to third groups based on the outer diameters L1 to L3 (where L1>L2>L3). 2. A thermal load is applied to the reference device for each group to break the bonded material. The temperature at which the bonded material breaks is detected as the destruction temperature (Tx), and the average value is calculated for each group. 3. The area of ​​the broken part of the joint member broken by the thermal expansion of the resin is measured in a plan view, and the area ratio (Px) is calculated by the above-mentioned method based on these measured cross-sectional areas (Sx). The average value of the calculated area ratios (Px) is calculated for each group.

[0053] The values ​​obtained in this manner are as follows: Group 1: Outside diameter (L1), average fracture temperature (T1), average area ratio (P1) Group 2: Outside diameter (L2), average fracture temperature (T2), average area ratio (P2) Group 3: Outside diameter (L3), average fracture temperature (T3), average area ratio (P3) However, T1>T2>T3 and P1>P2>P3.

[0054] A graph showing the above values ​​is shown in FIG. 10. The graph shown in FIG. 10 shows the relationship between the area ratios (P1, P2, P3) and the destruction temperatures (T1, T2, T3) when the horizontal axis is the area ratio (Px) and the vertical axis is the destruction temperature (Tx). From this graph, it can be seen that there is a correlation, particularly a positive correlation, between the area ratio (Px) and the destruction temperature (Tx). Therefore, a predetermined reference value can be determined by calculating the area ratio (Px) for a specific destruction temperature (Tx) based on a function calculated from these values. For example, the lower limit area ratio (Pmin) at the lower limit temperature (Tmin) when the semiconductor device generates heat due to the heat generation of the resin is calculated based on the function showing the correlation. A predetermined percentage, for example, a margin of 3 to 10%, can be given to the lower limit area ratio (Pmin) obtained at this time, to obtain a reference area ratio (Pk) that is the reference value of the area ratio.

[0055] As described above, there is a correlation between the area ratio (Px) and the fracture temperature (Tx) obtained from the bonded member that breaks due to the thermal expansion of the resin, and the reference value used in the judgment unit 4 can be determined based on this correlation. In this way, by providing a process for determining the reference value by a peel test as a pre-process of the judgment process, it becomes possible to obtain the reference area ratio (Pk) required for the bonded member that breaks due to the thermal expansion of the resin, and thus to make a more accurate judgment.

[0056] The above method shows an example of determining the reference area ratio (Pk) that serves as the reference value when the judgment value is the area ratio (Px) by a peel test. In a similar manner, the reference value when the judgment value is the measured cross-sectional area (Sx) or the outer diameter (Lx) or the outer diameter ratio (Lx / La) can also be determined by a peel test.

[0057] The present disclosure can also be implemented in the following manner.

[0058] [Section 1] A method for inspecting a semiconductor device, comprising the steps of: preparing a semiconductor device having a semiconductor element bonded to an upper surface of a substrate via a bonding member; breaking the bonding member to separate the semiconductor element from the substrate; A step of measuring an area of ​​the semiconductor element side and / or the substrate in a plan view of the bonding member after fracture, and obtaining a judgment value representing the measured area; a step of comparing the judgment value with a predetermined reference value, and judging the bonding state between the semiconductor element and the substrate as unacceptable if the judgment value is smaller than the reference value, and judging the bonding state between the semiconductor element and the substrate as acceptable if the judgment value is equal to or larger than the reference value; A semiconductor device inspection method comprising:

[0059] [Section 2] A method for inspecting a semiconductor device according to item 1, A method for manufacturing a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is a value of the measured area.

[0060] [Section 3] 2. The method for inspecting a semiconductor device according to claim 1, A method for inspecting a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is an area ratio that represents a ratio of the measured area to a standard cross-sectional area that serves as a reference for the bonding member.

[0061] [Section 4] A method for inspecting a semiconductor device according to item 1, A method for manufacturing a semiconductor device, in the step of obtaining the judgment value, the judgment value being a value of a diameter of the joining member calculated from the measured value of the area.

[0062] [Section 5] A method for inspecting a semiconductor device according to claim 1, In the step of preparing the semiconductor device, the semiconductor element is bonded to the substrate via a plurality of the bonding members; A method for manufacturing a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is obtained from a measurement value of an area of ​​at least one of the plurality of bonding members. This makes it possible to measure the area of ​​at least one of the bonding members rather than measuring the area of ​​all of the bonding members, and to determine whether or not the required bonding strength is obtained.

[0063] [Section 6] Item 6. A method for inspecting a semiconductor device according to item 5, A method for manufacturing a semiconductor device, in which the process of obtaining the judgment value is a process of measuring the areas of bonding members located on the inner and outer periphery of the plurality of bonding members, and bonding members located inside the outer periphery, to obtain a plurality of the judgment values. This makes it possible to efficiently inspect the strength of joints by measuring the corners and middle joints among joints arranged in multiple tiers and inferring the condition of the entire joint from the joints in representative positions.

[0064] [Section 7] Item 7. A method for inspecting a semiconductor device according to item 6, the step of peeling the semiconductor element from the substrate includes pressing a shear tool against an outer periphery of the semiconductor element to peel the semiconductor element; A method for inspecting a semiconductor device, in which the process of obtaining the judgment value is a process of measuring the area of ​​the joining members located in an intermediate region among the plurality of joining members, excluding the outer peripheral edge region pressed by the shear tool and the opposite region facing the outer peripheral edge pressed by the shear tool, to obtain the judgment value. This has the advantage that by selecting bonding members in an intermediate region excluding the outer peripheral edge region, which is the proximal region that is closest to the edge that the shear tool contacts when peeling the semiconductor element in the peeling process, and the remote region, which is the opposite region facing the outer peripheral edge that is pressed by the shear tool, it is possible to select and measure bonding members that are in a broken state in the direction away from the top surface of the substrate.

[0065] [Section 8] A method for inspecting a semiconductor device according to any one of claims 1 to 7, Prior to the determining step, a step of determining the predetermined reference value is included; The step of determining the predetermined reference value comprises: preparing a reference device in which a resin is disposed between the semiconductor element and the substrate; a peel test is performed in which a thermal load is applied to the reference device, and the joining member is broken by thermal expansion of the resin, thereby peeling the semiconductor element from the substrate; A method for inspecting a semiconductor device, the method comprising: calculating the predetermined reference value based on an area of ​​the joint member in a top view after fracture. This makes it possible to determine whether the semiconductor device being inspected has a bonding strength that takes into account the thermal expansion of the resin by the simple method of measuring the area of ​​the bonding member after peeling.

[0066] [Section 9] A method for inspecting a semiconductor device according to any one of claims 1 to 7, comprising: In the step of peeling the semiconductor element from the substrate, The method for inspecting a semiconductor device includes peeling the semiconductor element in a direction away from the substrate. In this way, by peeling the semiconductor element away from the substrate, the bonding member is broken by the tensile force, and the fracture surface of the bonding member can be broken in a state that is easy to measure, and the area can be measured stably and accurately. In addition, since the semiconductor element is peeled away from the substrate, the bonding strength can be measured in a state similar to the peeling of the semiconductor element caused by the thermal expansion of the resin.

[0067] [Section 10] A method for inspecting a semiconductor device according to any one of claims 1 to 7, comprising: The method for inspecting a semiconductor device, wherein the semiconductor element is a light-emitting element. [Industrial Applicability]

[0068] The method for inspecting a semiconductor device according to the present disclosure enables a pass / fail judgment of the bonding state by peeling a semiconductor element from a substrate and measuring the area of ​​the broken bonding member, thereby enabling simple inspection of a semiconductor device. It is possible to effectively prevent the bonding member from being broken due to thermal expansion of the resin filled in the substrate. [Explanation of symbols]

[0069] 1. Inspection equipment 2…Peeling device 3. Measuring equipment 4…Judgment section 10, 10A...Semiconductor device 11...Substrate 11a…Top surface 12...Semiconductor element 12a…Bottom surface 12b...Outer edge 13, 13A, 13B...Jointing members 13a…Fracture 14…Gap 15…Wiring 16...Light emitting element 17...Phosphor plate 18…Resin 19…Second resin 21. Share tools 22. Workbench 23...Protrusion 23a…Slanted surface 23b...Tip edge 26…Proximity Zone 27...Remote Area 28...middle area 31…Measuring instrument 32... Processing section 33...Arithmetic section

Claims

1. A method for inspecting a semiconductor device, comprising the steps of: preparing a semiconductor device having a semiconductor element bonded to an upper surface of a substrate via a bonding member; breaking the bonding member to separate the semiconductor element from the substrate; A step of measuring an area of ​​the semiconductor element side and / or the substrate in a plan view of the bonding member after fracture, and obtaining a judgment value representing the measured area; a step of comparing the judgment value with a predetermined reference value, and judging the bonding state between the semiconductor element and the substrate as unacceptable if the judgment value is smaller than the reference value, and judging the bonding state between the semiconductor element and the substrate as acceptable if the judgment value is equal to or larger than the reference value; A semiconductor device inspection method comprising:

2. 2. The method for inspecting a semiconductor device according to claim 1, A method for inspecting a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is a value of the measured area.

3. 2. The method for inspecting a semiconductor device according to claim 1, A method for inspecting a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is an area ratio that represents a ratio of the measured area to a standard cross-sectional area that serves as a reference for the bonding member.

4. 2. The method for inspecting a semiconductor device according to claim 1, A method for inspecting a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is a value of a diameter of the bonding member calculated from the measured value of the area.

5. 2. The method for inspecting a semiconductor device according to claim 1, In the step of preparing the semiconductor device, the semiconductor element is bonded to the substrate via a plurality of the bonding members; A method for inspecting a semiconductor device, wherein in the step of obtaining the judgment value, the judgment value is obtained from a measurement value of an area of ​​at least one of the plurality of bonding members.

6. 6. A method for inspecting a semiconductor device according to claim 5, comprising the steps of: A method for inspecting a semiconductor device, wherein the process of obtaining the judgment value is a process of measuring the areas of the bonding members located inside and on the outer periphery of the plurality of bonding members, and the bonding members located inside the outer periphery, to obtain the plurality of judgment values.

7. 7. A method for inspecting a semiconductor device according to claim 6, comprising the steps of: the step of peeling the semiconductor element from the substrate includes pressing a shear tool against an outer periphery of the semiconductor element to peel the semiconductor element; A method for inspecting a semiconductor device, in which the process of obtaining the judgment value is a process of measuring the area of ​​the joining members located in an intermediate region among the plurality of joining members, excluding the outer peripheral edge region pressed by the shear tool and the opposite region facing the outer peripheral edge pressed by the shear tool, to obtain the judgment value.

8. 8. A method for inspecting a semiconductor device according to claim 1, comprising: Prior to the determining step, a step of determining the predetermined reference value is included; The step of determining the predetermined reference value comprises: preparing a reference device in which a resin is disposed between the semiconductor element and the substrate; a peel test is performed in which a thermal load is applied to the reference device, and the joining member is broken by thermal expansion of the resin, thereby peeling the semiconductor element from the substrate; A method for inspecting a semiconductor device, the method comprising: calculating the predetermined reference value based on an area of ​​the joint member in a top view after fracture.

9. 8. A method for inspecting a semiconductor device according to claim 1, comprising: In the step of peeling the semiconductor element from the substrate, The method for inspecting a semiconductor device includes peeling the semiconductor element in a direction away from the substrate.

10. 8. A method for inspecting a semiconductor device according to claim 1, comprising: The method for inspecting a semiconductor device, wherein the semiconductor element is a light-emitting element.

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