Testing method

Abstract

To provide an inspection method for inspecting whether a chip is normally connected to a board.SOLUTION: An inspection method includes: a preparation step 1 for preparing a workpiece in which a semiconductor chip having a bump on one surface is mounted on a board through the bump; a laser beam irradiation step 3 for applying laser beams to the semiconductor chip from the other surface and reflowing the bump included in an irradiated range of the workpiece; a temperature information acquisition step 4 for capturing the irradiated range by a thermal camera while applying laser beams to the semiconductor chip and acquiring temperature information; a storage step 2 for previously storing reference temperature information as temperature information when the semiconductor chip and the board are normally joined by irradiation of laser beams; and a determination step 5 for determining whether the semiconductor chip and the board are normally joined by irradiation with laser beams on the basis of the reference temperature information stored in the storage step 2 and the temperature information acquired by the temperature information acquisition step 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inspection method.

Background Art

[0002] In the manufacturing process of semiconductor devices, one method of electrically connecting a chip and an external terminal is a flip-chip mounting method in which the electrode of the chip and the electrode on the package substrate are faced to each other and connected via bumps.

[0003] Generally, in flip-chip mounting, a mass reflow process in which the entire substrate is heated for bonding or a TCB (Thermo-Compression Bonding) process in which each chip is heated and pressurized for bonding is adopted. However, the mass reflow process has a problem of thermal stress due to heating the entire substrate, and the TCB process has a problem of poor productivity such as taking a long time to cool the bonder head.

[0004] As a process having an advantage over the above processes, a laser reflow process in which a chip is connected to an electrode on a substrate by laser irradiation has been proposed (see Patent Documents 1 and 2). In the laser reflow process, since heat is not applied to the entire substrate, thermal stress can be reduced, and there is an advantage that higher productivity can be obtained than the TCB process by irradiating laser light to a plurality of chips.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in the process described above, a continuity test is necessary to determine whether the bonding is good or bad, specifically whether the chip is connected to the substrate. However, in mass-produced products where evaluation daisy-chains or similar structures are not formed, there was no method to test the quality of the bonding.

[0007] This invention has been made in view of the above problems, and its purpose is to provide an inspection method for checking whether a chip is properly connected to a substrate. [Means for solving the problem]

[0008] To solve the above-mentioned problems and achieve the objective, the present invention provides an inspection method for inspecting the bonding state between a semiconductor chip and a substrate, comprising: a preparation step of preparing a workpiece in which a semiconductor chip having bumps on one side is placed on a substrate via the bumps; a laser beam irradiation step of irradiating the semiconductor chip with laser light from the other side opposite to the one side to reflow the bumps included in the irradiation area of ​​the workpiece; a temperature information acquisition step of imaging the irradiation area with a thermal camera while irradiating the semiconductor chip with laser light and acquiring temperature information; further comprising a storage step of pre-storing reference temperature information, which is the temperature information when the semiconductor chip and the substrate are properly bonded by the irradiation of laser light; and further comprising a determination step of determining whether the semiconductor chip and the substrate have been properly bonded by the irradiation of laser light based on the reference temperature information stored in the storage step and the temperature information acquired in the temperature information acquisition step. The temperature information includes the time variation of the highest temperature in the irradiated area while the laser light is being irradiated. It is characterized by the following:

[0009] Furthermore, in the inspection method of the present invention, The irradiated area is divided into multiple regions, The temperature information is, Time variation of the maximum temperature in each region when the laser light is irradiated. It may include.

[0011] Furthermore, in the inspection method of the present invention, in the determination step, if there is a region in the temperature information acquired in the temperature information acquisition step that is hotter than the reference temperature information stored in the storage step, it may be determined that the semiconductor chip and the substrate are not properly bonded. [Effects of the Invention]

[0012] This invention allows for testing whether a chip is properly connected to a substrate. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a flowchart showing the flow of the inspection method according to the embodiment. [Figure 2] Figure 2 is a perspective view of the workpiece prepared in the preparation steps shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of the main part of the workpiece shown in Figure 2. [Figure 4] Figure 4 is a plan view showing the evaluation chip. [Figure 5] Figure 5 is a graph showing an example of a cross-sectional temperature profile stored in the memory step shown in Figure 1. [Figure 6] Figure 6 shows an example of a thermographic image stored in the memory step shown in Figure 1. [Figure 7] Figure 7 is a graph showing the time change of the maximum temperature stored in the memory step shown in Figure 1. [Figure 8] Figure 8 is a cross-sectional view of a key part of the workpiece showing one state of the laser light irradiation step shown in Figure 1. [Figure 9] Figure 9 is a graph showing an example of a cross-sectional temperature profile obtained in the temperature information acquisition step shown in Figure 1. [Figure 10] Figure 10 is an example of a thermographic image acquired in the temperature information acquisition step shown in Figure 1. [Figure 11] Figure 11 is a graph showing the time change of the maximum temperature obtained in the temperature information acquisition step shown in Figure 1.

Best Mode for Carrying Out the Invention

[0014] A mode (embodiment) for carrying out the present invention will be described in detail while referring to the drawings. The present invention is not limited by the content described in the following embodiments. Also, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Also, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[0015] 〔Embodiment〕 An inspection method according to an embodiment of the present invention will be described based on the drawings. FIG. 1 is a flowchart showing the flow of the inspection method according to the embodiment. As shown in FIG. 1, the inspection method includes a preparation step 1, a storage step 2, a laser light irradiation step 3, a temperature information acquisition step 4, and a determination step 5.

[0016] (Preparation Step 1) FIG. 2 is a perspective view of a workpiece 100 prepared in the preparation step 1 shown in FIG. 1. FIG. 3 is a cross-sectional view of a main part of the workpiece 100 shown in FIG. 2. FIG. 4 is a plan view showing an evaluation chip. As shown in FIGS. 2 and 3, the workpiece 100 includes a substrate 110 and a semiconductor chip 120 having bumps 130.

[0017] The preparation step 1 is a step of preparing a workpiece 100 on which a semiconductor chip 120 is placed on a substrate 110. At this time, the semiconductor chip 120 is placed on the surface 111 side of the substrate 110 with the surface 111 side facing upward via the bumps 130 in a state where one surface (surface 121) having the bumps 130 faces downward.

[0018] In this embodiment, the substrate 110 is rectangular in shape. The substrate 110 is, for example, a PCB (Printed Circuit Board) substrate or a device wafer before it is divided into chips. Multiple semiconductor chips 120 are arranged on the surface 111 side of the substrate 110 via bumps 130. Each semiconductor chip 120 has one or more bumps 130 on its surface 121. The bumps 130 are protruding terminals provided on the surface 121 of the semiconductor chip 120.

[0019] The semiconductor chip 120 connects to electrodes on the substrate 110 when the bumps 130 are heated and melted. In other words, the workpiece 100 prepared in preparation step 1 is intended to be flip-mounted onto the substrate 110 by reflowing the bumps 130 with laser light 21 (see Figure 8).

[0020] In addition to the semiconductor chip 120 arranged on the substrate 110 via bumps 130 as in the embodiment, the workpiece 100 may also be a stack of multiple semiconductor chips 120 with bumps 130 between each semiconductor chip 120, etc.

[0021] Later, in order to explain the correlation between temperature information and the quality of bonding, the following explanation will use an evaluation chip with a daisy-chain capable of acquiring the conductivity status of multiple regions 124-1, 124-2, 124-3, 124-4, and 124-5 as the semiconductor chip 120, as shown in Figure 4. However, in the inspection method of the present invention, the semiconductor chip 120 does not need to have a daisy-chain.

[0022] (Memory Step 2) Memory step 2 is a step in which reference temperature information, which is temperature information for when the semiconductor chip 120 and the substrate 110 are successfully bonded by irradiation with laser light 21, is stored in advance. Memory step 2 may be performed before preparation step 1.

[0023] The reference temperature information is information obtainable from a thermal image captured by a thermal camera, and is the same type of temperature information as the temperature information obtained in the temperature information acquisition step 4 described later. In the storage step 2 of the embodiment, the evaluation chip shown in Figure 4 is irradiated with laser light 21 under the same conditions as the laser light irradiation step 3 described later, and the temperature information obtained when conductivity is confirmed in all of regions 124-1, 124-2, 124-3, 124-4, and 124-5 is stored in advance as reference temperature information.

[0024] Figure 5 is a graph showing an example of a cross-sectional temperature profile stored in memory step 2 shown in Figure 1. The temperature information includes, for example, a temperature profile at a predetermined cross-section of the semiconductor chip 120, as shown in Figure 5. The temperature profile is a table or graph showing the relationship between the temperature and time at each part of the predetermined cross-section of the semiconductor chip 120. In this embodiment, the predetermined cross-section is the cross-section passing through the diagonal indicated by the dashed line in the plan view of the semiconductor chip 120 shown in Figure 4. The predetermined cross-section passes through regions 124-1, 124-5, and 124-3.

[0025] The temperature information shown in Figure 5 represents the temperature distribution at each position along the cross-section shown in Figure 4. Furthermore, the reference temperature information shown in Figure 5 includes temperature distribution information immediately after the start of laser beam 21 irradiation and immediately before the end of laser beam 21 irradiation, under the same irradiation conditions as described in laser beam irradiation step 3 below. In the example shown in Figure 5, the cross-sectional temperature profile shows a tendency for the temperature in region 124-1 to be slightly higher and the temperature in region 124-3 to be lower immediately after the start of laser beam 21 irradiation. Also, the cross-sectional temperature profile shows a tendency for the temperature in region 124-1 to be slightly higher, but the temperature distribution to become flatter immediately before the end of laser beam 21 irradiation.

[0026] Figure 6 is an example of a thermographic image stored in memory step 2 shown in Figure 1. The temperature information includes, for example, a thermographic image of the top surface of the semiconductor chip 120, as shown in Figure 6. In the thermographic image shown in Figure 6, white indicates high temperature, black indicates low temperature, and higher brightness indicates higher temperature.

[0027] The temperature information shown in Figure 6 indicates the temperature distribution on the upper surface of the semiconductor chip 120. The reference temperature information shown in Figure 6 also includes temperature distribution information immediately before the laser irradiation 21 is terminated, under the same irradiation conditions as described in laser irradiation step 3. In the example shown in Figure 6, the thermographic image shows a tendency for brightness to be generally constant in the region inside the outer edge of the semiconductor chip 120. Note that in memory step 2, the temperature distribution, converted numerically based on the brightness of the thermographic image, may be stored linked to two-dimensional coordinates.

[0028] Figure 7 is a graph showing the time variation of the maximum temperature stored in memory step 2 shown in Figure 1. Temperature information includes, for example, the time variation of the maximum temperature as shown in Figure 7. The maximum temperature is obtained from, for example, a thermographic image as shown in Figure 6. The maximum temperature is obtained for each region 124-1, 124-2, 124-3, 124-4, and 124-5, and the temperature corresponding to the brightest area in each region is obtained as the maximum temperature.

[0029] The temperature information shown in Figure 7 indicates the time variation of the maximum temperature in each region 124-1, 124-2, 124-3, 124-4, and 124-5 on the upper surface of the semiconductor chip 120. The reference temperature information shown in Figure 7 also includes the time variation of the maximum temperature when the laser beam 21 is irradiated under the same irradiation conditions as described in laser beam irradiation step 3 below. In the example shown in Figure 7, all regions 124-1, 124-2, 124-3, 124-4, and 124-5 show a tendency for little difference in the maximum temperature regardless of the time variation.

[0030] (Laser light irradiation step 3) Figure 8 is a cross-sectional view of the main part of the workpiece 100 showing one state of laser irradiation step 3 shown in Figure 1. Laser irradiation step 3 is a step in which laser light 21 is irradiated onto the semiconductor chip 120 to reflow the bumps 130 included in the irradiation area 123 of the workpiece 100.

[0031] Step 3 of the laser irradiation is performed by a laser irradiation device, for example, which includes a holding table on which the workpiece 100 is placed and a laser irradiation unit that irradiates laser light 21. In step 3 of the laser irradiation, first, the substrate 110 of the workpiece 100 is held on the holding surface of the holding table. At this time, the holding surface holds the back surface 112 of the substrate 110, and the semiconductor chip 120 is placed on the front surface 111 of the substrate 110 via bumps 130. Next, the irradiation part that irradiates the laser light 21 of the laser irradiation unit is brought opposite the holding table, and alignment is performed to position the irradiation area with the semiconductor chip 120.

[0032] In laser irradiation step 3, the semiconductor chip 120 is irradiated with laser light 21 from the other side (back surface 122) opposite to the side (front surface 121) having the bumps 130. In the laser irradiation step 3 of this embodiment, the workpiece 100 is irradiated with laser light 21 for 1 second under the condition that the processing point output is 102W. As a result, the bumps 130 corresponding to the irradiation area of ​​the laser light 21 on one side (front surface 121) of the semiconductor chip 120 that has been irradiated with laser light 21 are reflowed, and the semiconductor chip 120 is bonded to the substrate 110.

[0033] (Temperature information acquisition step 4) Step 4, which involves irradiating the semiconductor chip 120 with laser light 21 and imaging the irradiated area 123 (see Figure 8) with a thermal camera (infrared camera) to acquire temperature information. The temperature information is information obtainable from the thermal image captured by the thermal camera and is the same type of temperature information as the reference temperature information stored in storage step 2. Specifically, the temperature information includes, for example, the temperature profile at a predetermined cross-section of the semiconductor chip 120, temperature distribution information on the upper surface of the semiconductor chip 120, and the time change of the maximum temperature.

[0034] In the workpiece 100 (evaluation chip) from which temperature information was acquired in the examples shown in Figures 9 to 11 of the following explanation, continuity was confirmed in regions 124-1, 124-2, and 124-5, but continuity was not confirmed in regions 124-3 and 124-4.

[0035] First, we will explain the case in step 4 of acquiring temperature information where a temperature profile at a predetermined cross-section of the semiconductor chip 120 is acquired as temperature information, that is, the case where the temperature profile at a predetermined cross-section of the semiconductor chip 120 is stored in advance in step 2 of storage.

[0036] Figure 9 is a graph showing an example of a cross-sectional temperature profile acquired in step 4 of the temperature information acquisition shown in Figure 1. The cross-sectional temperature profile acquired in step 4 is acquired for the cross-section where the cross-sectional temperature profile stored in step 2 was measured. Furthermore, the cross-sectional temperature profile acquired in step 4 includes temperature distribution information for both immediately after the start of laser irradiation 21 in step 3 and immediately before the end of laser irradiation 21. This temperature distribution information is acquired under conditions where the laser irradiation conditions, number of samples, measurement time from the start of laser irradiation, etc., are equivalent to the reference temperature information stored in step 2 beforehand.

[0037] In the example shown in Figure 9, the acquired cross-sectional temperature profile showed a tendency for the temperature in region 124-1 to be slightly higher immediately after the start of irradiation with laser light 21. Furthermore, the cross-sectional temperature profile showed a tendency for the temperature in region 124-3 to be higher immediately before the end of irradiation with laser light 21.

[0038] Next, we will explain the case in step 4 of acquiring temperature information where a thermographic image of the top surface of the semiconductor chip 120 is acquired as temperature information, that is, the case where a thermographic image of the top surface of the semiconductor chip 120 is stored in advance in step 2 of storage.

[0039] Figure 10 is an example of a thermographic image acquired in the temperature information acquisition step 4 shown in Figure 1. The thermographic image acquired in the temperature information acquisition step 4 is captured under the same imaging conditions as the thermographic image stored in the storage step 2. The thermographic image acquired in the temperature information acquisition step 4 also includes temperature distribution information of the upper surface of the semiconductor chip 120 immediately before the laser irradiation 21 is terminated in the laser irradiation step 3. This temperature distribution information is acquired under conditions where the laser irradiation conditions, number of samples, measurement time from the start of laser irradiation, etc., are the same as the reference temperature information stored in the storage step 2.

[0040] In the example shown in Figure 10, the thermographic image showed that in the region inside the outer edge of the semiconductor chip 120, the upper region in Figure 10 (corresponding to regions 124-3 and 124-4 in Figure 4) had high brightness, while the region from the center to the bottom (regions 124-1, 124-2, and 124-5 in Figure 4) tended to have lower brightness compared to the upper region. In step 4 of temperature information acquisition, if the temperature distribution converted to numerical values ​​based on the brightness of the thermographic image in step 2 was stored linked to two-dimensional coordinates, the temperature distribution may be acquired numerically in a similar manner.

[0041] Next, we will explain the case in step 4 of acquiring temperature information where the time change of the maximum temperature is acquired as temperature information, that is, the case where the time change of the maximum temperature is stored in advance in step 2 of storage.

[0042] Figure 11 is a graph showing the time variation of the maximum temperature acquired in step 4 of the temperature information acquisition shown in Figure 1. The time variation of the maximum temperature acquired in step 4 of the temperature information acquisition is measured for each region where the time variation of the maximum temperature stored in step 2 of the memory was measured. In addition, the time variation of the maximum temperature acquired in step 4 of the temperature information acquisition includes the time variation of the maximum temperature when the laser light 21 is irradiated in step 3 of the laser light irradiation. Such time variation information of the maximum temperature is acquired under conditions where the laser irradiation conditions, number of samples, measurement time from the start of laser irradiation, etc., are the same as the reference temperature information stored in advance in step 2 of the memory.

[0043] In the example shown in Figure 11, the time variation of the maximum temperature showed a tendency for the maximum temperatures in regions 124-3 and 124-4 to be higher than those in regions 124-1, 124-2, and 124-5 at the peak time.

[0044] (Judgment Step 5) The determination step 5 is a step in which, based on the reference temperature information stored in the storage step 2 and the temperature information acquired in the temperature information acquisition step 4, it is determined whether or not the semiconductor chip 120 and the substrate 110 have been properly bonded by irradiation with laser light 21.

[0045] First, an example of a determination method will be described for cases where the reference temperature information stored in memory step 2 and the temperature information acquired in temperature information acquisition step 4 include a temperature profile at a predetermined cross-section of the semiconductor chip 120. In determination step 5, the quality of the bond is determined by comparing the temperature information, including the cross-sectional temperature profile shown in Figure 9, acquired in temperature information acquisition step 4, with the reference temperature information shown in Figure 5, which is stored in advance in memory step 2.

[0046] Specifically, for example, a temperature error tolerance range may be set in advance based on the cross-sectional temperature profile of the reference temperature information shown in Figure 5. If the cross-sectional temperature profile obtained in temperature information acquisition step 4 is within the error tolerance range, it may be determined that the joint was successfully formed. If there are areas where the error tolerance range is exceeded, it may be determined that the joint was not successfully formed.

[0047] The correlation between the cross-sectional temperature profile and the bonding condition will be explained. Here, it is preferable that the temperature is constant in the irradiated area 123 (see Figure 8) of the semiconductor chip 120 where the laser beam 21 is irradiated. That is, the temperature distribution along the cross-section of the workpiece 100 is ideally a rectangular wave shape with a steep base and a flat peak.

[0048] In the determination step 5, as shown in Figure 5, if the profile immediately before the end of irradiation with the laser beam 21 is flat, it can be determined that the bonding is good. Also, as shown in the example in Figure 9, if the profile immediately before the end of irradiation with the laser beam 21 is tilted, it can be determined that a bonding failure occurred in the high-temperature region.

[0049] Next, an example of a determination method will be described for cases where the reference temperature information stored in memory step 2 and the temperature information acquired in temperature information acquisition step 4 include a thermographic image of the top surface of the semiconductor chip 120. In determination step 5, the quality of the bond is determined by comparing the temperature information, including the thermographic image shown in Figure 10, acquired in temperature information acquisition step 4, with the reference temperature information shown in Figure 6, which is stored in advance in memory step 2.

[0050] Specifically, for example, a temperature error tolerance range is predetermined based on the temperature distribution information in the thermographic image of the upper surface of the semiconductor chip 120, as shown in Figure 6. If the temperature distribution obtained from the thermographic image acquired in the temperature information acquisition step 4 shown in Figure 10 is within the error tolerance range, it is determined that the bonding was successful. If there are areas where the temperature exceeds the error tolerance range, it is determined that the bonding was not successful.

[0051] The correlation between the temperature distribution on the upper surface and the bonding condition will be explained. Here, it is preferable that the temperature is constant in the irradiated area 123 (see Figure 8) of the semiconductor chip 120 where the laser beam 21 is irradiated. That is, in the thermographic image, it is ideal that the brightness of the workpiece 100 is constant in the region inside the outer edge.

[0052] In the determination step 5, as shown in Figure 6, if the brightness is constant in the region inside the outer edge of the semiconductor chip 120, it can be determined that the bonding is good. Also, as shown in the example in Figure 10, if there is unevenness in brightness in the region inside the outer edge of the semiconductor chip 120, it can be determined that a bonding defect has occurred in the region with higher brightness.

[0053] Next, an example of a determination method will be described for cases where the reference temperature information stored in memory step 2 and the temperature information acquired in temperature information acquisition step 4 include the time variation of the maximum temperature. In determination step 5, the quality of the bond is determined by comparing the temperature information, which includes the time variation of the maximum temperature shown in Figure 11 and was acquired in temperature information acquisition step 4, with the reference temperature information shown in Figure 7, which was previously stored in memory step 2.

[0054] Specifically, for example, a temperature error tolerance range is predetermined based on the time variation of the maximum temperature in the reference temperature information shown in Figure 7. If the time variation of the maximum temperature obtained in temperature information acquisition step 4 shown in Figure 11 is within the error tolerance range, it is determined that the connection was successful. If there are any points where the error tolerance range is exceeded, it is determined that the connection was not successful.

[0055] The correlation between the time variation of the maximum temperature and the bonding condition will be explained. Here, in the irradiated area 123 (see Figure 8) of the semiconductor chip 120 irradiated by the laser beam 21, it is preferable that the maximum temperature is the same in each region 124-1, 124-2, 124-3, 124-4, and 124-5. That is, in terms of the time variation of the maximum temperature, it is ideal that the data for each region 124-1, 124-2, 124-3, 124-4, and 124-5 overlap with each other regardless of the passage of time.

[0056] In judgment step 5, as shown in Figure 7, if the data for each region 124-1, 124-2, 124-3, 124-4, and 124-5 generally overlap at all times, it can be determined that the bonding is good. On the other hand, as shown in the example in Figure 11, if there are areas where the data for each region 124-1, 124-2, 124-3, 124-4, and 124-5 do not overlap, it can be determined that a bonding failure occurred in the high-temperature region.

[0057] In addition, in judgment step 5, the highest temperature in the reference temperature information may be used as a threshold, and if the highest temperature in the temperature information exceeds the threshold, it may be determined that a bonding failure has occurred.

[0058] Thus, in the determination step 5, regardless of which example uses temperature information, if there is a region in the temperature information acquired in the temperature information acquisition step 4 that is hotter than the reference temperature information stored in the storage step 2, it can be determined that the semiconductor chip 120 and the substrate 110 are not properly bonded.

[0059] Furthermore, while the above describes cases where a bonding failure is determined to have occurred in a high-temperature region, a bonding failure may also be determined to have occurred if, for example, the temperature variation within the cross-section (cross-sectional temperature profile) or on the top surface (thermographic image) of the semiconductor chip 120 exceeds a predetermined range, or if the minimum temperature is below a predetermined value. In this case, as a determination method, pattern matching may be performed to determine the similarity between a reference cross-sectional temperature profile or thermographic image and a newly acquired cross-sectional temperature profile or thermographic image.

[0060] As described above, the inspection method according to the embodiment measures the temperature change during bonding using a thermal camera and compares it with the temperature change in the case of successful bonding, which is stored in advance in memory step 2, to determine whether the bonding was performed successfully. This makes it possible to inspect the quality of the connection at the same time as bonding, so it becomes possible to remove semiconductor chips 120 with poor connections, or to reprocess and reconnect them, thereby contributing to an improvement in yield.

[0061] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core of the present invention. For example, memory step 2 may be performed before preparation step 1. Also, for example, in a manufacturing line, if laser irradiation and inspection are performed successively on multiple identical workpieces 100, memory step 2 may be performed only once in total.

[0062] Furthermore, the cross-section from which the cross-sectional temperature profile is obtained is, in this embodiment, a cross-section passing through the diagonal in a plan view of the semiconductor chip 120, as shown by the dashed line in Figure 4, passing through regions 124-1, 124-5, and 124-3. However, it may also be a cross-section passing through the opposite diagonal, i.e., regions 124-2, 124-5, and 124-4, and both may be stored and determined simultaneously.

[0063] Furthermore, the inspection method of the present invention may further include a removal step in which the semiconductor chip 120 determined to have a bonding defect in the determination step 5 is stored and removed so as not to be used in subsequent processes. Furthermore, the method may further include a rebonding step in which the semiconductor chip 120 determined to have a bonding defect in the determination step 5 is rebonded by irradiating it with laser light 21 again and pressing it with a glass substrate.

[0064] Furthermore, the laser irradiation device for implementing the inspection method of the present invention may be equipped with a display device, which maps the locations of the defective joints of the semiconductor chip 120 determined to be defective in the determination step 5 and displays them on the display device. Alternatively, the laser irradiation device for implementing the inspection method of the present invention may be equipped with a notification device, which, if the number of defective joints of the semiconductor chip 120 determined to be defective in the determination step 5 exceeds a predetermined amount, may determine that there is some abnormality in the laser irradiation device and issue an alarm to the notification device. [Explanation of Symbols]

[0065] 1. Preparation Steps 2 Memory Steps 3. Laser beam irradiation step 4. Step to acquire temperature information 5. Judgment Steps 21 Laser light 100 Workpiece 110 circuit boards 111 Surface 112 Back side 120 semiconductor chips 121 Surface (one side) 122 Reverse side (the other side) 123 Irradiation area 124-1, 124-2, 124-3, 124-4, 124-5 area 130 Bump

Claims

1. A testing method for inspecting the bonding state between a semiconductor chip and a substrate, A preparation step for preparing a workpiece in which a semiconductor chip having bumps on one side is placed on a substrate via the bumps, A laser beam irradiation step involves irradiating the semiconductor chip with laser light from the other side opposite to the one side to reflow the bumps included in the irradiation area of ​​the workpiece, A temperature information acquisition step involves irradiating the semiconductor chip with the laser light while imaging the irradiated area with a thermal camera and acquiring temperature information, Equipped with, The system further includes a storage step for pre-storing reference temperature information, which is temperature information for when a semiconductor chip and a substrate are properly bonded by laser irradiation. The system further includes a determination step that determines whether the semiconductor chip and the substrate have been properly bonded by the irradiation of the laser light, based on the reference temperature information stored in the storage step and the temperature information acquired in the temperature information acquisition step. The temperature information is, This is characterized by including the time change of the highest temperature in the irradiated area when the laser light is being irradiated, Testing method.

2. The irradiated area is divided into a plurality of regions, The temperature information is characterized by including the time variation of the highest temperature in each region when the laser light is irradiated. The inspection method according to claim 1.

3. In this determination step, If, in the temperature information acquired in the temperature information acquisition step, there is a region that is hotter than the reference temperature information stored in the storage step, The method is characterized by determining that the semiconductor chip and the substrate are not properly bonded. The inspection method according to claim 1 or 2.

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