KR100823469B1 - Displacement detection device - Google Patents

Abstract

In a displacement detection device using an IC chip in a regulating plate, silicon fragments may fall off from incomplete chipping during or during mounting operations, which may adversely affect the performance of the displacement detection device. The angle formed between the back grinding trace of the IC wafer and the vertical line with respect to the IC chip side ridge is less than 45 degrees, more preferably 10 degrees to 45 degrees, to reduce chipping including incomplete chipping occurring on the side ridge of the IC chip. can do. It is possible to avoid using an IC chip having incomplete chipping on the side ridges as a regulating plate, and to provide a highly reliable displacement detection device.

Displacement detection chip, flexible deformation part, IC chip, grinding, chipping

Description

Displacement detection device

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective schematic view of an IC chip for explaining angles and chippings formed by the grinding marks and vertical lines of the present invention.

Fig. 2 is a graph showing the relationship between the chipping incidence rate (%) and the angle formed by the grinding marks with respect to the vertical line in the present invention.

3 is an exploded perspective view of the acceleration sensor of Example 2;

4 is a cross-sectional view taken along the line IV-IV of FIG. 3 showing an acceleration sensor of Example 2. FIG.

5A and 5B are perspective views of an acceleration sensor element used for the acceleration sensor of the third embodiment.

6 is a perspective view of an acceleration sensor device equipped with an acceleration sensor and an IC on a substrate.

7 is a cross-sectional view of an acceleration sensor provided with a control plate of a conventional example.

8 is a diagram showing a schematic structure of a pressure sensor in which a conventional IC chip is used for a regulating plate.

The present invention is applicable to an acceleration sensor, a pressure sensor, a gyro sensor, and the like, and relates to a compact and high-precision displacement detection device manufactured using semiconductor manufacturing technology, and in particular, includes a displacement detection chip and an IC chip having a flexible deformation part. Relates to a displacement detection device

Micro-Electro-Mechanical-System (MEMS) technology, which combines mechanical and / or material technology with semiconductor manufacturing process technology to form three-dimensional microstructures with both mechanical and electrical functions on semiconductor substrates, is a broad field. Is being used by. In particular, it is being applied to the field of sensors such as compact and high precision acceleration sensor, pressure sensor, gyro sensor. These sensors make a flexible deformation part by MEMS technology, and measure the displacement amount by converting the displacement of the flexible deformation part into an electrical signal in a piezo resistor or the like. Although the structure of the flexible deformation part is slightly different depending on the use of the displacement detection device, it is the same in terms of converting the displacement of the flexible deformation part into an electrical signal, and thus, for example, an acceleration sensor or a pressure sensor depending on the cause of providing the displacement to the flexible deformation part. It is called.

As a method of converting the displacement of the flexible deformation part into an electric signal, there are a piezo resistor type, a capacitive type, a piezoelectric type, and the like. Either way, the output voltage is small, from a few mV to a few 10mV. Therefore, in order to cope with a wide range of applications such as automobiles, aircrafts, portable terminal devices, toys, etc., it is necessary to equip a circuit for amplifying the output voltage. The acceleration sensor device disclosed in Japanese Patent Laid-Open No. 2003-28891 is shown in an external perspective view of FIG. 6. The acceleration sensor device 75 of FIG. 6 has an IC 73 having an acceleration sensor 10, an amplification circuit, and the like mounted on a substrate 71. However, in such a structure, it is difficult to miniaturize the acceleration sensor device.

Sensitivity and impact resistance change depending on the shape of the flexible deformation portion formed by using MEMS technology on a silicon substrate. In general, when the flexible deformation portion is thickened, the impact resistance is improved, but the sensitivity is lowered. On the contrary, when the flexible deformation portion is thinned to obtain the desired sensitivity, the sensitivity is improved but the impact resistance is decreased. Both sensitivity and impact resistance are difficult. When excessive force is applied to the flexible deformation portion, an acceleration sensor provided with a regulating plate that regulates the movement of the flexible deformation portion so that the flexible deformation portion does not deform more than a predetermined amount is disclosed in Japanese Patent Application Laid-Open No. 4-274005 and Japanese Unexamined Patent Publication. It is described in patent publication No. 8-233851.

7 shows an acceleration sensor provided with such a regulating plate. The acceleration sensor element 20 has a flexible deformable portion 11, a weight 12, and a support frame 13 formed of silicon. Although not shown, the flexible deformation unit 11 is provided with a piezoresistive element. When acceleration is applied to the acceleration sensor element 20, the weight 12 vibrates up and down or left and right, and the flexible deformation portion 11 deforms (displaces), so that the resistance of the piezo resistor is changed, so that the resistance change is converted into an electrical signal. To get the output. The regulating plates 14 and 15 are fixed to the upper and lower sides of the support frame 13 with adhesives 16 and 17. The amount of deformation of the flexible deformation portion in the gap g1 between the top surface of the acceleration sensor element 20 and the bottom surface of the regulating plate 14 and the bottom surface of the weight 12 and the top surface of the regulating plate 15 is determined. Regulate. When an excessive external force is applied, the top surface of the acceleration sensor element or the bottom surface of the weight is in contact with the regulating plate, and the deformation of the acceleration sensor element is prevented without damaging the flexible deformation portion without giving the deformation of g1 and g2 or more to the flexible deformation portion 11. I improve impact resistance.

An example in which an IC chip is used instead of silicon or soda-lime glass for the control plate to achieve further miniaturization is described in Japanese Laid-Open Patent Publication No. 2005-169541. The Japanese Patent Document discloses a structure in which an IC chip is used as a control plate facing the top surface of the acceleration sensor element. This replaces the regulating plate 14 of FIG. 7 with an IC chip. By using the regulation plate as an IC chip, the number of parts is reduced and miniaturized. In addition, by utilizing the fact that the IC chip is close to the acceleration sensor element, by mounting the temperature compensation circuit of the piezoresistive element or the like on the IC chip, a higher accuracy acceleration sensor can be realized.

Japanese Laid-Open Patent Publication No. 2005-169541 discloses a pressure sensor using an IC chip as a regulating plate, and a sectional view of the schematic structure thereof is shown in FIG. When pressure is applied as indicated by the arrow through the opening 25 at the bottom of the pressure vessel composed of the flexible deformable portion 21 and the fixed portion 22, the flexible deformed portion 21 is displaced to swell upward. In a detection unit (not shown) such as a piezoresistive element provided in the flexible deformation unit 21, the displacement is converted into an electric signal. When excessive pressure is applied to the flexible deformation portion, the upper surface of the flexible deformation portion 21 and the lower surface of the IC chip 24 come into contact with each other, and the flexible deformation portion 21 is not given to the flexible deformation portion 21 without giving the deformation amount greater than or equal to the gap g1. It prevents negative damage and obtains impact resistance of the pressure sensor element. The gap g1 between the upper surface of the flexible deformation portion 21 and the lower surface of the IC chip 24 is formed of an adhesive agent 23 including a spacer.

By providing a restricting plate that regulates the displacement amount of the flexible deformation portion, the impact resistance of the displacement detecting device can be improved, and by using the restricting plate as an IC chip, a compact and high-precision displacement detecting device can be realized. However, during the manufacture of a large number of displacement detection devices, a displacement detection device that causes malfunction due to silicon debris that appears to be generated from an IC chip occurs with a very low frequency of occurrence. After disassembling and inspecting the displacement detecting device which caused the malfunction, it was found that silicon debris entered the gap between the flexible deformable part and the IC chip, thereby inhibiting the movement of the flexible deformed part. By contrasting the chipped portion of the IC chip side ridge with the silicon chips entering the gap, it was confirmed that the silicon chips originated from the IC chip.

In the displacement detection device, the displacement detection chip and the IC chip mounted on the displacement detection chip are housed in the protective case. The silicon debris generated from the IC chip is confined in the protective case and moves inside the protective case, so that the silicon debris is sandwiched between the flexible deformable portion of the displacement detection chip and the IC chip, and the sandwiched silicon debris obstructs the movement of the flexible deformed portion.

The IC chip was obtained by cutting the IC wafer, but chipping occurring in the side ridges of the IC chip was not particularly problematic as long as it did not affect the IC circuit. In addition, if the chipped silicon fragments are completely removed from the IC chip, the chipped silicon fragments do not enter the gap between the flexible deformable portion and the IC chip, thereby preventing the movement of the flexible deformed portion. Problematic chipping is incomplete chipping, ie, silicon fragments partially retained on the IC substrate, where silicon fragments remain in the damaged area, and silicon fragments are removed from portions of the incomplete chipping during or during mounting of the displacement detection device. This adversely affects the performance of the displacement detection device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an IC chip without incomplete chipping, which is used for a regulating plate for regulating the amount of displacement of a flexible deformation portion of a displacement detection device.

Displacement detection device of the present invention,

A displacement detection chip having a flexible deformation portion displaced by an external force and extracting the displacement of the flexible deformation portion as a detection signal;

An IC chip having a circuit for electrically processing the detection signal from the displacement detection chip, the back surface being disposed opposite the flexible deformation portion at a predetermined interval from the flexible deformation portion to mechanically restrict the excessive deformation of the flexible deformation portion,

With a protective case housing the displacement detection chip and the IC chip, the grinding traces on the back of the IC chip are at an angle of 0 degrees to 45 degrees with respect to the vertical line to a side ridge to the IC chip side ridge.

The grinding direction on the back surface of the IC chip is the direction of the grinding trace left on the IC chip, and is the angle between the vertical line and the grinding trace with respect to the side ridge of the IC chip. An angle of 45 degrees means an angle of plus / minus 45 degrees with respect to the vertical line. In other words, the grinding trace with respect to the side ridge has an angle of 45 degrees or 135 degrees. When the angle formed by the grinding direction (grinding trace) and the vertical line with respect to the side ridge is from 0 degrees to 45 degrees, the occurrence rate of chipping including incomplete chipping occurring in the side ridge can be minimized.

The thickness of the silicon wafer for IC is mainly 525 µm and 625 µm, and the surface of the silicon wafer has a polished surface capable of mirror polishing and vacuum suction. When the IC wafer is used for a regulating plate that regulates the amount of displacement of the flexible deformation portion of the displacement detection device, since the thickness is too thick at a thickness of 500 µm or more, the back surface is ground to 100 to 300 µm thickness after fabrication of the IC circuit. A waterproof sheet is attached to the surface on which the IC circuit is formed to protect the IC circuit, and the back surface is ground with a diamond grindstone while adding a grinding liquid. The surface roughness of grinding is about 0.1 to 0.2 µm at Rmax. It can be seen empirically that the frequency of chipping of the side roughness side ridge on the back surface of the IC wafer when cut with the IC chip is related. The larger the surface roughness, the more chipping occurs on the side ridge. If the back surface is polished to reduce chipping, the polishing takes not only work time but also grinding, rather than polishing, because the function of the IC circuit may be impaired due to a rise in temperature during polishing. In addition, since the vacuum chuck of the thinned IC wafer is hardly performed, the polishing surface is not necessary on the handling surface, and the grinding surface is sufficient.

In the displacement detection apparatus of the present invention, it is preferable that the grinding trace on the back surface of the IC chip is an angle of 10 degrees to 45 degrees with respect to the vertical line with respect to the IC chip side ridge.

By making the angle between the vertical line and the grinding trace of the IC chip at 10 degrees to 45 degrees, chipping including incomplete chipping occurring in the side ridge can be greatly reduced. In grinding traces at an angle of less than 10 degrees from the vertical line, the frequency of chipping is about 1/20 as compared to 45 degrees or more. When the surface roughness of the back surface rises to the polished surface of 0.01 µm or less at Rmax, the occurrence frequency of chipping decreases even at an angle of 45 degrees or more, but hardly changes at 0.2 µm from the surface roughness Rmax 0.05 on the back surface. Therefore, when cutting an IC wafer whose grinding surface is the back surface with an IC chip, by defining the angle formed by the grinding trace and the cutting direction, chipping including incomplete chipping occurring in the side ridge can be reduced.

In a displacement detection device using a rectangular IC chip, the grinding traces on the back of the IC chip are at an angle of 0 to 45 degrees with respect to the vertical line with respect to one side ridge of the IC chip having a rectangular shape, and the other side ridge is adhesive It is preferable to adhere to the displacement detection chip by

If the grinding traces on the back surface of the IC chip are at an angle of 0 degrees to 45 degrees with respect to the vertical line with respect to one side ridge of the rectangular IC chip, the occurrence rate of incomplete chipping in the one side ridge can be reduced. The rectangular IC chip has a side ridge with one side ridge at an angle of 90 degrees. Therefore, in the other side ridge of the rectangular IC chip, the incidence rate of incomplete chipping may increase. By adhering the other side ridges, it is possible to prevent peeling of the silicon debris from incomplete chipping caused on the other side ridges. In that case, if the grinding traces on the back surface of the IC chip with respect to the vertical line with respect to the one side ridge are at an angle of 20 degrees to 45 degrees, the generation rate of chipping generated on the one side ridge can be almost zero.

It is preferable that an IC chip is rectangular, and the grinding trace on the back surface of an IC chip is an angle of 0 degree | time to 20 degree with respect to the perpendicular | vertical line with respect to one side ridge of the IC chip which made the rectangle.

When the trace of grinding on the back surface of the IC chip is an angle of 0 to 20 degrees with respect to the vertical line with respect to one side ridge of the rectangular IC chip, the IC with respect to the vertical line with respect to the other side ridge in the side ridge of the other side of the IC chip. Grinding traces on the back surface of the chip are at an angle of 70 degrees to 90 degrees. If the grinding traces are 0 to 20 degrees and 70 to 90 degrees with respect to the vertical line to the side ridges, the incidence of incomplete chipping is small, so that silicon fragments resulting from incomplete chipping can be prevented.

Since the IC circuit pattern cannot be cut by disregarding the IC circuit pattern, the IC wafer is set in the grinding machine so that the grinding direction becomes a predetermined angle with respect to the cutting direction. In the case of using a rotary grinding machine, when the IC wafer is set in the same direction, the grinding direction changes at the outer peripheral position and the inner peripheral position of the table. Therefore, it is good to change the direction of the IC wafer by the position in the circumferential direction so that the grinding trace is at a predetermined angle.

By defining the angle between the back grinding trace of the IC wafer and the IC chip cutting direction, chipping including incomplete chipping occurring in the side ridges of the IC chip can be reduced. The use of an IC chip having incomplete chipping on the side ridge in the regulating plate was eliminated, and a reliable displacement detection device could be provided.

Example

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described in detail using drawing. In order to make description easy, the same code | symbol is used for the same component and site | part.

Example 1

The relationship between the grinding trace of an IC wafer, the angle of a cutting direction, and the frequency of chipping is demonstrated. First, the grinding, cutting method, conditions, etc. used for data collection are demonstrated. The IC wafer having a silicon thickness of 525 mu m was thinned to 250 mu m by silicon grinding, and then cut into IC chips (2.6 mm x 2.2 mm) with a cutting grindstone. A waterproof sheet was attached to the IC circuit surface to protect the IC circuit from the grinding liquid used at the time of grinding. For grinding, a rotary grinding wheel was used to grind the # 2000 diamond grindstone at about 6000 rpm. The surface roughness of the grinding surface was 0.13 µm in Rmax and 0.014 µm in Ra. Measurement of Rmax and Ra was based on JISB0601. Since the thickness of the IC circuit portion is about 5 mu m, the thickness to be cut is about 255 mu m. The IC wafer was attached to the adhesive sheet, and the IC wafer was cut to about half the thickness of the adhesive sheet. For cutting, a diamond grinder of # 3000 was rotated at a high speed of 3 to 40,000 rpm using a dicer to cut. The grinding liquid was used at the time of cutting.

In FIG. 1, the shape of the chipping and the angle which a grinding trace and a vertical line make is shown. Since all of the IC wafers were ground from the inner circumference to the outer circumference of the table of the rotary grinding table, the grinding marks 50 could be obtained from 0 degrees to 90 degrees with respect to the vertical line to the side ridge of the IC chip after dicing. When grinding with a grinding wheel having a rotating shaft on a secant line away from the rotation center of the rotary table of the rotary grinding machine, the IC wafer set on the inner circumferential side of the rotary table of the grinding table is set on the outer circumferential side of the same rotary table. In general, the wafer has a larger grinding trace than the wafer. The angle of the grinding trace 50 with respect to the vertical line 55 with respect to the side ridge 53 of the IC chip 24 is θa, and the grinding trace with respect to the vertical line 56 with respect to the side ridge 54 of the IC chip 24. An angle of 50 is represented by θb. The angle and chipping between the vertical lines and the grinding traces of the side ridges of about 100,000 IC chips were investigated. The side ridges to be investigated for chipping will be about 400,000 side ridges, four times the number of IC chips. The angle between the vertical line and the grinding trace with respect to the side ridges was grouped at 5 degree intervals from 0 to 5 degrees, 6 to 10 degrees, ..., 85 to 90 degrees to obtain chipping incidence at every 5 degree intervals.

As shown in FIG. 1, chipping ignores the IC circuit 52 side only for the silicon substrate 51 side (rear side) of the IC chip 24. As shown in FIG. Chipping has a defect width of 3 µm or more at right angles (direction away from side ridge and thickness direction on the surface of the silicon substrate) from the side ridges 53 and 54 of the silicon substrate of the IC chip 24, and the chipping is a side ridge. Whether or not was examined. The defect widths of the complete chipping 60 and the incomplete chipping 61 generated in the side ridges are represented by Wea and Web, respectively, and their values were 3 µm or more. Similarly, the chipping 62 of each part is also represented by the missing width Wca from the side ridge 53 and the missing width Wcb from the side ridge 54. When the defect width Wca from the side ridge 53 is 3 μm or more and the defect width Wcb from the side ridge 54 is less than 3 μm, the side ridge 53 has chipping 62 and the side ridge 54 is chipped. Was not. In the case where both Wca and Wcb are 3 µm or more, chipping occurs in the side ridge 53 and the side ridge 54. Since incomplete chipping and complete chipping need to be distinguished, when incomplete chipping and complete chipping are mixed in one side ridge, counting is performed for each of incomplete chipping and complete chipping.

The chipping incidence (vertical axis) is shown in FIG. 2 in relation to the angle (horizontal axis) of the grinding trace with respect to the vertical line. The angle which a grinding trace makes with respect to a perpendicular | vertical line is 5 degrees when it is less than 0-5 degrees, 10 degrees when it is 5 degrees or more and less than 10 degrees, and it shows 90 degrees in 85 degrees or more and 90 degrees. The chipping incidence rate is expressed as a percentage by subtracting the side ridge number with chipping from the side ridge number inspected. The incidence of chipping is divided into complete chipping (white) and incomplete chipping (diagonal). As can be seen from FIG. 2, chipping of about 5% occurs when the angle of the grinding trace is greater than 0 degrees and less than 10 degrees. The incidence of chipping was 0% when the angle of the grinding trace was 10 or more and less than 45 degrees. When the angle of the grinding trace was 45 degrees or more, chipping began to occur, and the incidence was the highest at 55 degrees or more and less than 60 degrees, representing 53%. It was found that there was an area where chipping was less likely to occur at the angle of the grinding trace. The ratio of incomplete chipping to complete chipping was approximately 1: 8 regardless of the angle of the grinding trace.

From these results, it turns out that it is most preferable to make the angle which a grinding trace makes with respect to a perpendicular line to 10 degrees or more and less than 45 degrees. When the angle is 0 degrees or more and less than 10 degrees, the chipping incidence is about 5%, and more than 45 degrees is very small compared to the chipping incidence. The highly reliable displacement detection device is obtained by using the range of 0 degree or more and less than 45 degree compared with the displacement detection apparatus produced irrespective of the angle of a grinding trace.

Chipping, which must be a problem as a displacement detection device, is incomplete chipping in which silicon fragments remain in the damaged area. Incomplete chipping causes silicon fragments to fall off during or during the mounting operation of the displacement detection device, adversely affecting the performance of the displacement detection device. From the results of this example, the total number of incomplete chippings is about 1/20 by making the angle of the grinding marks less than 45 degrees in comparison with the incomplete chippings in the case of producing regardless of the angle of the conventional grinding marks. Incomplete chipping is zero when the angle is greater than 10 degrees and less than 45 degrees. In other words, it can be said that an accident incidence rate is 1/20 by setting the angle of the grinding traces to less than 45 degrees, and an accident incidence rate is 0 by setting it to 10 or more and less than 45 degrees.

In the rectangular IC chip 24 as shown in FIG. 1, one side ridge 53 and the other side ridge 54 are perpendicular to each other. When the grinding marks 50 are at an angle of 0 to 20 degrees with respect to the vertical line 55 with respect to one side ridge 53, the grinding marks 50 are perpendicular with respect to the other side ridge 54 90 to 70 degrees relative to). The chipping incidence in the side ridges 53 is 5% or less, and the chipping incidence in the side ridges 54 is 12% at most. Even when the chipping prevention measures such as adhesion to the side ridge of the rectangular IC chip are not taken, if the angle of the grinding trace is 0 to 20 degrees with respect to the vertical line with respect to one side ridge, the chipping including the other side ridge is included. Even if the incidence rate is large, the incidence of incomplete chipping can be further reduced.

Example 2

Using an IC chip with incomplete chipping, an acceleration sensor, a kind of displacement detection device, was mounted. 3 is an exploded perspective view of the attached acceleration sensor. In FIG. 3, the acceleration sensor element 20 is electrically connected to the IC chip 24 by the lead wire 4, and the terminal 5 of the protective case 2 from the IC chip 24 to the wire 4 ′. It is connected to the external terminal 6. The protective case cover 3 is fixedly sealed to the protective case 2 to which the acceleration sensor 10 is mounted. The piezoresistive element of the acceleration sensor element 20 is omitted. 4 shows the IV-IV cross section of FIG. 3. The acceleration sensor element 20 is composed of a weight 12, a support frame 13, and a flexible deformation part 11. A piezoresistive element (not shown) is formed in the lead wire 4 connection surface of the flexible deformation part 11. The IC chip 24 is disposed opposite the flexible deformable portion at a predetermined distance g1 from the flexible deformable portion (or arm) 11 of the acceleration sensor element 20, and restricts excessive movement of the flexible deformable portion. . The IC chip 24 receives a signal from a piezoresistive element and performs signal processing. The support frame 13 and the protective case cover 3 are bonded to the protective case 2 with the adhesives 7 and 8. When an external force is applied to the acceleration sensor element 20, the weight 12 suspended on the flexible deformable portion 11 moves to bend the flexible deformable portion 11, and the deflection amount is detected by the piezoresistive element and output as a voltage.

An acceleration sensor (Sample A) with incomplete chipping was mounted using 300 IC chips having incomplete chipping 61 shown in Fig. 1 having a width Web of 3 µm to 63 µm. The length of incomplete chipping ranged from 19 μm to 367 μm. For comparison, an equal number of acceleration sensors (Sample B) using IC chips without incomplete chipping were also installed.

An acceleration sensor of each of Sample A and Sample B was mounted on the exciter, and the output was measured by applying an acceleration of 20G. Except for the accelerometer which showed abnormal output, the acceleration sensors were dropped five times freely from the height of 1m to a plate of 100mm thick, and then the output was measured by applying an acceleration of 20G, and the number of the accelerometer showing the abnormal output was investigated. . When the acceleration sensor falls free from the above-mentioned height, an impact of about 1500 to 2000G is applied to the acceleration sensor, and the flexible deformation portion of the acceleration sensor element collides with the back surface of the IC chip.

In the measurement before freely dropping the acceleration sensor, abnormal output was found in three samples A and one sample B. When these acceleration sensors were disassembled and irradiated, two pieces of sample A contained silicon fragments between the bottom of the acceleration sensor element and the bottom of the protective case. The fact that the silicon fragments fell out of the incomplete chipping portion of the IC chip was confirmed by contrasting the shapes. Since no excessive impact is given to the accelerometer, the silicon debris is thought to have been dropped for some reason during the mounting operation. The remaining one of Sample A and one of Sample B appear to be caused by damage to the flexible deformation portion during the mounting operation, not due to incomplete chipping of the IC chip.

After drop impacts were applied to 297 samples A and 299 samples B except for the initial accidental product, abnormal output was 1 in sample A and 0 in sample B. When the acceleration sensor showing an abnormal output was disassembled and irradiated, silicon debris fell from the IC chip, and was sandwiched between the upper surface of the flexible deformation portion and the back surface of the IC chip. The size of the sandwiched silicon debris was 20 μm × 18 μm × 170 μm. A gap g1 between the upper surface of the flexible deformation portion and the back surface of the IC chip was mounted so as to be 15 mu m. It is considered that when the impact was applied and moved downward, the gap became larger and the silicon debris was inserted and it did not fall off. It was unknown whether the dropping of the silicon fragments collided with the flexible deformation part at the time of the impact, or if it occurred only by the impact. From this result, it was confirmed that incomplete chipping of the IC chip is one of the causes of the accidents occurring when the acceleration sensor is used. One out of 297 acceleration sensors mounted using IC chips with incomplete chipping had an accident, so the incidence was 1/297.

From the results of Example 1 and Example 2, after the product is shipped, the number of occurrences of an accident due to incomplete chipping of the IC chip is estimated. Regardless of the angle of grinding marks, 12.4% of chipping occurs on the side ridges among 100,000 IC chips. As described above, 11.1% of incomplete chippings during chipping and 1/297 = 0.33% probability of an accident due to incomplete chippings dropping out during use of the acceleration sensor. 100,000 pieces x 12.4% x 11.1% x 0.33% = 4.5 pieces. In conventional acceleration sensors using IC chips manufactured regardless of the angle of grinding trace, there is a risk of an accident of 4.5 pieces per 100,000 units. In comparison, the use of the IC chip of the present invention, which defines an angle with respect to the cutting direction of the grinding traces of the IC chip, makes it possible to almost zero the occurrence of in-use accidents caused by incomplete chipping and more reliable. It can supply high acceleration sensor. Similarly, although the pressure sensor and the gyro sensor were examined, it was almost the same as the result of the acceleration sensor.

Example 3

5A and 5B show an acceleration sensor element used in the acceleration sensor of Example 3 in a perspective view. On the acceleration sensor element 20 of FIG. 5A, the IC chip 24 'is bonded to the support frame of the acceleration sensor element with adhesive 7' three side ridges of the rectangular IC chip 24 '. The side ridge 53 of the IC chip 24 'is not bonded to the support frame. An IC circuit is formed on the upper surface of the IC chip 24 ', and the back surface (the surface facing the acceleration sensor element 20) of the IC chip 24' is ground in the same manner as shown in FIG. Is a predetermined dimension, and a grinding trace of 15 to 30 degrees is attached to the vertical line with respect to the side ridge 53. The side ridges 53 with the grinding traces of 15 to 30 degrees with respect to the vertical lines are free of chipping as described in the first embodiment. Since the grinding traces have an angle of 75 to 60 degrees with respect to the vertical line with respect to the side ridge 54 perpendicular to the side ridge 53, the side ridge 54 is 5 to 6 as can be seen from the graph of FIG. Incomplete chipping incidence of%. Since the three side ridges, including two side ridges 54 with 5-6% incomplete chipping incidence, are fixed with adhesive 7 ', the incomplete chippings in the side ridges 54 are fixed with adhesive. Therefore, it does not come off during manufacture and use.

On top of the acceleration sensor element 20 of FIG. 5B, an IC chip 24 ″ is attached to the support frame of the acceleration sensor element with two side ridges 54 of the rectangular IC chip 24 ″ with an adhesive 7 ″. Similar to the IC chip 24 'described above, the IC chip 24 " has a grinding trace of 15 to 30 degrees with respect to the vertical line with respect to the side ridge 53. As shown in FIG. There is no chipping in the side ridges 53. Since the grinding traces are 75 to 60 degrees with respect to the vertical line with respect to the side ridge 54 perpendicular to the side ridge 53, the side ridge 54 has an incomplete chipping occurrence rate of 5 to 6%. However, since the side ridges 54 are secured to the support frames with an adhesive 7 ", there is no fear that incomplete chippings on their side ridges may come off during manufacture or use.

In the acceleration sensor of the third embodiment, the risk of accidents can be made smaller than that of the second embodiment.

According to the present invention, it is possible to provide an IC chip without incomplete chipping, which is used for a regulating plate that regulates the amount of displacement of the flexible deformation portion of the displacement detection device.

Claims (5)

delete delete A displacement detecting chip having a flexible deformation portion displaced by an external force and extracting the displacement of the flexible deformation portion as a detection signal; And a circuit for electrically processing the detection signal from the displacement detection chip, the back surface being disposed opposite the flexible deformation portion at a predetermined distance from the flexible deformation portion to mechanically restrict excessive deformation of the flexible deformation portion. IC chip, A protective case accommodating the displacement detection chip and the IC chip, The IC chip is rectangular, and the trace of grinding on the back of the IC chip is an angle of 0 degrees to 45 degrees with respect to the vertical line with respect to one side ridge of the rectangular IC chip, and the side ridge perpendicular to the one side ridge is attached to the adhesive. And a displacement detection device adhered to the displacement detection chip. 4. The displacement detection device according to claim 3, wherein the grinding trace on the back surface of the IC chip is an angle of 10 degrees to 45 degrees with respect to the vertical line with respect to the one side ridge of the IC chip having a rectangular shape. delete

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