Substrate processing equipment

Abstract

To provide a substrate processing device that forms a cavity in which internal wiring is exposed in an electronic substrate having internal wiring.SOLUTION: A substrate processing device 1 includes an end mill 15 in which a conductive plate 12 is placed on an IC card 2 which is one of electronic substrates, and that is a cutting tool, and a spindle 14 that can be electrically connected to a spindle housing. The spindle is at ground potential. The conductive plate is connected to a capacitance measuring device 16, the spindle is lowered, and the moment the cutting tool and an internal wiring of the electronic substrate come into contact, capacitance is generated between the conductive plate and the internal wiring. A control device 17 detects the increase in capacitance using the capacitance measuring device, and detects contact between the cutting tool and the internal wiring of the electronic substrate.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a substrate processing device for drilling and countersinking electronic substrates such as printed wiring boards and IC cards having internal wiring. [Background technology]

[0002] Cavity substrates used in semiconductor package fabrication include printed wiring boards and IC card substrates with internal wiring, some of which have exposed internal wiring in the cavity. Semiconductor chips and other components are mounted so that electrical continuity with the exposed wiring is achieved. One method for fabricating such cavity substrates is to pre-punch windows in required locations, such as the inner layer terminals and die pads, and then bond the substrates together with adhesive. In contrast, the inner layer machining method involves laminating the inner and outer layers together, then exposing the required portions of the inner layer through countersinking. This provides highly reliable insulation between circuits and excellent sealing properties, improving the reliability of moisture absorption and moisture permeation resistance. To ensure reliable exposure of the internal wiring, the inner layer machining method requires detection of contact between the internal wiring of the electronic substrate when drilling or end milling the substrate.

[0003] As shown in FIG. 1, Patent Documents 1 and 2 describe a substrate processing device that lowers a spindle 74 while a voltage is applied in advance between internal wiring 703 of an electronic substrate 70 and a drill 75, and stops the lowering of the spindle 74 the moment electrical conduction caused by contact between the internal wiring 703 and the drill 75 is detected, thereby exposing the internal wiring. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-135647 [Patent Document 2] Japanese Patent Application Publication No. 11-068324 Summary of the Invention [Problem to be solved by the invention]

[0005] The mechanism disclosed in Patent Documents 1 and 2 has the advantage of detecting contact between the drill 75 and the internal wiring 703 of the electronic substrate 70, thereby exposing the internal wiring 703 without having to remove it. However, because a voltage must be applied between the internal wiring 703 and the drill 75 before processing, the circuit wiring 78 of the voltage application circuit must be electrically connected to the internal wiring layer 703 at connection point 79 in advance. This presents a problem in that it can be difficult to connect the circuit wiring to a thin internal wiring layer. Another problem is that if the internal wiring layer 21 is not exposed to the outside, as in the unprocessed IC card 2 shown in Figure 2(b), it is impossible to provide circuit wiring for contact detection. Another problem is that the internal wiring layer and the voltage application circuit must be connected each time the substrate is set in the processing device, which increases the time required for substrate processing.

[0006] The present invention has been made in consideration of such problems, and its purpose is to realize a substrate processing device that can detect internal wiring layers with a simple configuration and form a cavity in which the internal wiring layers are exposed. [Means for solving the problem]

[0007] In order to solve the above problems, the substrate processing device of the present invention includes a stage for placing a substrate, a conductive plate that is in close contact with the electronic substrate on the upper or lower surface of the electronic substrate, a mechanism for positioning the electronic substrate, a conductive cutting tool that is movable in the X, Y, and Z directions, and an instrument for measuring the electrostatic capacitance between the conductive plate and the cutting tool. The substrate processing device is characterized by comprising a control device that receives a signal from a device that measures capacitance and controls the operation of the cutting tool, and detects contact of the cutting tool with the internal wiring of the substrate from a change in the measured capacitance value.

[0008] In addition to the above invention, it is preferable that the device for measuring the capacitance is a substrate processing device having a resolution capable of measuring capacitance of picofarads or less.

[0009] In addition to the above invention, the substrate processing device may be an IC card having an internal wiring layer made up of an antenna pattern and electrodes connected to an IC chip.

[0010] In addition, to solve the above problem, a substrate processing device is provided which includes a conductive plate that is in close contact with the upper surface of the electronic substrate, a conductive stage for placing the electronic substrate, a mechanism for positioning the electronic substrate, a conductive cutting tool, an instrument for measuring the sum of the capacitance between the conductive plate and the cutting tool and the capacitance between the stage and the cutting tool, and a control device that receives a signal from the instrument for measuring the capacitance and controls the operation of the cutting tool, and which detects contact of the cutting tool with internal wiring of the substrate from a change in the measured capacitance.

[0011] In addition to the above invention, it is preferable that the device for measuring the capacitance is a substrate processing device having a resolution capable of measuring capacitance of picofarads or less.

[0012] In addition to the above invention, the substrate processing device may be an IC card having an internal wiring layer made up of an antenna pattern and electrodes connected to an IC chip. [Effects of the Invention]

[0013] According to the present invention, it is possible to realize a substrate processing device that can expose the internal wiring of a substrate with a simple configuration. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a substrate processing apparatus according to a prior art example. [Figure 2] FIG. 1 is a schematic diagram of an IC card to be processed. [Figure 3]1 is a schematic view of a substrate processing apparatus according to an embodiment of the present invention; [Figure 4] 3A and 3B are top and side views of a conductive plate of a substrate processing apparatus according to an embodiment of the present invention. [Figure 5] 1 is an equivalent circuit diagram of a substrate processing apparatus according to an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the end mill coming into contact with the internal wiring layer of the IC card. [Figure 7] FIG. 10 is a schematic diagram of a substrate processing apparatus in which a conductive plate also serves as a stage. [Figure 8] 4 is a diagram showing an operation flow of the substrate processing apparatus of the present invention. FIG. [Figure 9] 10 is a diagram showing the change in capacitance measured when a hole is drilled in an IC card using the substrate processing device of the present invention. [Figure 10] FIG. 2 is a schematic diagram illustrating a second embodiment of the present invention. [Figure 11] FIG. 4 is an equivalent circuit diagram according to a second embodiment of the present invention. [Figure 12] FIG. 10 is an explanatory diagram of a substrate processing device when the electronic substrate is a multilayer wiring substrate. [Figure 13] FIG. 1 is a schematic diagram of a stage having an IC card positioning mechanism. [Figure 14] FIG. 1 is a schematic diagram of an IC card positioning mechanism with a conveyor belt. DETAILED DESCRIPTION OF THE INVENTION

[0015] First, an IC card 2, which is one of the electronic substrates processed by the substrate processing apparatus of the present invention, will be described with reference to FIG.

[0016] FIG. 2(a) is a top view of an IC card 2 capable of wirelessly exchanging information using near-field communication (NFC) or similar. FIG. 2(b) is a cross-sectional view of the IC card 2 before cavity processing. This IC card 2 has an internal wiring layer 21, which has electrodes for connecting to a coil antenna and an IC chip 25, sandwiched between insulating layers 22 and 23 made of PVC (polyvinyl chloride) or PET (polyethylene terephthalate). The portion of the top insulating layer 22 where the IC chip 25 will be embedded is cut using a cutting tool, a spindle and an end mill (or drill), to form a cavity 24. The IC card 2 is then completed by embedding the IC chip 25 in the cavity portion 24, as shown in FIG. 2(c).

[0017] In the manufacturing process of this IC card 2, when forming a cavity by cutting using a cutting tool such as a spindle and an end mill, it is necessary to expose the electrode portion of the internal wiring layer 21. If the cutting is shallow or if the electrode portion is removed by cutting too deeply, electrical continuity between the IC chip 24 and the coil antenna will be lost, resulting in a defective product. Therefore, when cutting the IC card 2 using a substrate processing device, it is required to be able to cut to the appropriate depth by detecting when the end mill has come into contact with the electrode portion of the internal wiring layer 21.

[0018] As can be seen from Figure 2(b), before the cavity is formed, the internal wiring layer 21 of the IC card 2 has no exposed portion. Therefore, with the conventional substrate processing device 7, it is difficult to detect contact between the drill 75 and the internal wiring layer 21 by establishing electrical continuity as shown in Figure 1. This is because the internal wiring layer 21 of the IC card 2 must be electrically connected to an external circuit before processing. Therefore, a contact detection mechanism that does not require electrical connection with the internal wiring layer 21 before processing the IC card 2 is required.

[0019] Next, the substrate processing apparatus of the present invention will be described with reference to FIGS.

[0020] FIG. 3 is a schematic diagram of a substrate processing device 1 of the present invention intended for use with an IC card 2. A spindle 14 equipped with an end mill 15, which is a cutting tool, is movable in the X, Y, and Z directions, and can cut the portion that will become the cavity 24 of the IC card 2. The spindle 14 is structured so that electrical continuity can be established from the end mill 15 to the spindle housing through a chuck. The housing of the spindle 14 is grounded by a ground wire. The cutting tool is not limited to a spindle and end mill; any tool that can cut while moving in the X, Y, and Z directions, such as a milling machine, can be used. However, the tool must be capable of establishing electrical continuity from the cutting tip to the housing.

[0021] An IC card 2 is placed on the stage 11. A conductive plate 121 is placed on the IC card 2, pressing it down from above to secure the IC card 2 in place. Figure 4 shows side and top views of the conductive plate 121. The conductive plate 121 has a cavity-processing window 122 in the area corresponding to the cavity of the IC card 2, through which an end mill 15 can be used to form the cavity in the IC card 2. The conductive plate 121 is also connected to a capacitance measuring device 16 via a shielded signal line. The shield of the shielded signal line is grounded along with the spindle 14. In this example, a CV converter CV-242M3 manufactured by NF Corporation was used as the capacitance measuring device 16. This CV converter outputs the measured capacitance as a voltage of 10 mV per 1 pF. The capacitance measuring device 16 can be any measuring device capable of measuring capacitance, such as an impedance analyzer, an LCR meter, or a digital multimeter capable of measuring capacitance, in addition to the CV converter used in this example. The measurement output from the capacitance measuring device 16 and the control line of the spindle 14 are connected to a control device 17 .

[0022] 5 is an equivalent circuit of the contact detection mechanism of the present substrate processing apparatus 1. In the substrate processing apparatus 1, as shown in FIG. 5(b), a parallel plate capacitor 321 is formed, with the internal wiring layer 21 of the IC card 2 and the conductive plate 121 as two electrodes and the IC card insulating layer 22 as a dielectric. When the end mill 15 is not in contact with the internal wiring layer 21 of the IC card 2, the switch 33 is in the OFF state. Then, when the spindle 14 is lowered and the end mill 15 comes into contact with the internal wiring layer 21 of the IC card 2 as shown in FIG. 6, the switch 33 is turned ON, and the capacitance of the capacitor 321 becomes measurable by the capacitance measuring device 16.

[0023] Here, the capacitance C of the capacitor 321 in FIG. 5 is calculated by the following equation, where S is the conductor surface area of ​​the internal wiring layer, d is the thickness of the insulating layer 22 from the top of the internal wiring layer 21 to the conductive plate 121, and ε is the dielectric constant of the insulating layer 22: C=εS / d (Equation 1) In the IC card 2 used in this embodiment, ε=2.61×10 -11 F / m, S = 4.0 × 10 -4 m 2 , d=0.3mm Therefore, the capacitance C is calculated to be approximately 34.8 pF using Equation 1. For this reason, it is preferable to use a capacitance measuring device 16 with the ability to measure capacitances of picofarads or less in this substrate processing device. The CV converter used in this example has a resolution of 0.01 pF, so it meets this condition.

[0024] Furthermore, as shown in Fig. 7, the substrate processing apparatus 1 of the present invention can use a stage 11 on the underside of the IC card 2 as a stage-cum-conductive plate 125 made of an electrically conductive material. The equivalent circuit 3 of the substrate processing apparatus 111 having this configuration is the same as that shown in Fig. 5, and the same effect as the substrate processing apparatus 1 of Fig. 3 can be obtained. In this case, the plate 123 on the top surface of the IC card 2 only needs to have the function of pressing down to fix the IC card, so there are no particular restrictions on the material.

[0025] The control device 17 controls the movement of the spindle 14 while monitoring the capacitance measurement value from the capacitance measuring device 16. In this embodiment, the control device 17 monitors the output voltage from the C / V converter.

[0026] The cavity processing of the IC card 2 will be explained with reference to the process chart of FIG.

[0027] [Step S1] First, the unprocessed IC card 2 is set on the stage 11. At this time, the IC card 2 is positioned.

[0028] Here, we will explain the positioning mechanism for the IC card 2. As shown in Fig. 3, positioning pins 13 can be provided on the stage 11 and used to position the IC card 2. Also, the IC card can be positioned by using a stage 180 that has been countersunk to fit the shape of the IC card, as shown in Fig. 13.

[0029] 14A and 14B are cross-sectional and top views, respectively. The conveyor belt 181 allows the IC card 2 to move left and right within the substrate processing apparatus 1. Therefore, when constructing a substrate processing apparatus (not shown) having multiple units, such as an IC card supply unit, an IC card processing unit, an IC card inspection unit, and a card storage unit, the positioning mechanism shown in FIG. 14 allows the IC card 2 to be freely moved between the units and automates the positioning of the IC card 2. The positioning mechanism shown in FIG. 14 also includes a card support stage 183 to prevent the IC card 2 from bending due to the conductive plate 121 being pressed against the top surface of the IC card 2.

[0030] In this way, various types of positioning mechanisms for the IC card 2 can be used, and are not limited to those shown here, and the type is not limited as long as the IC card 2 can be positioned.

[0031] [Step S2] Next, as shown in FIG. 3, the conductive plate 121 is placed on the IC card 2, and the IC card 2 is sandwiched and fixed between the conductive plate 121 and the stage 21.

[0032] [Step S3] After the IC card 2 and the conductive plate 121 are placed, the capacitance between the conductive plate 121 and the end mill 14 is monitored by the control device 17 using the capacitance measuring device 16 .

[0033] [Step S4] Next, the spindle 14 is lowered in the −Z direction, and the IC card 2 is cut by the end mill 15 .

[0034] [Step S5] As the spindle 14 is lowered, when the end mill 15 comes into contact with the internal wiring layer 21 of the IC card 2 as shown in Fig. 6, the switch 33 in Fig. 5 turns ON, and the capacitance C of the capacitor 321 formed between the conductive plate 121 and the internal wiring layer 21 is detected by the capacitance measuring device 16. In this embodiment, a C / V converter is used as the capacitance measuring device 16, so the output voltage of the C / V converter connected to the control device 17 rises.

[0035] [Step S6] When the control device 17 detects an increase in the output from the C / V converter, which is the capacitance measuring device 16, the downward movement of the spindle 14 is immediately stopped.

[0036] [Step S7] After the spindle 14 stops descending, the spindle 14 is moved in the XY directions to form a cavity 24 in the IC card 2 by cutting.

[0037] [Step S8] After the processing of the cavity 24 is completed, the spindle 14 is raised in the +Z direction. Through the above processing, the cavity 24 can be formed with the internal wiring layer 21 exposed on the bottom surface.

[0038] [Step S9] Finally, the IC chip 25 is bonded to the cavity 24, thereby completing the IC card 2.

[0039] To confirm the operation of the substrate processing apparatus 1 of this embodiment, we verified whether contact detection of the end mill 15 with the internal wiring layer 21 was possible. Figure 9 shows the experimental results. In Figure 9, the horizontal axis represents elapsed time, and the vertical axis represents capacitance measured by the C / V converter. Before the end mill 15 made contact, a capacitance of 275 pF was detected. This represents the state in which stray capacitance from the shielded cable used for wiring was detected. When the spindle 14 was lowered and the end mill 15 made contact with the internal wiring layer 21, the measured capacitance rose sharply to approximately 307 pF. When the spindle 14 was stopped from lowering approximately 10 s after contact detection and then raised, the measured capacitance rapidly decreased to the original value (275 pF). The actual increase in capacitance at this time was approximately 32 pF, which was close to the calculated value of the capacitance C of the capacitor 321 calculated using Equation 1 above. These experimental results confirmed that contact detection of the end mill 15 with the internal wiring layer 21 is possible using the substrate processing apparatus 1 of this embodiment. In actual cavity processing, after contact is detected, the spindle is moved in the XY direction to perform cutting.

[0040] A schematic diagram of a substrate processing apparatus as a second embodiment is shown in FIG. 10, and an equivalent circuit thereof is shown in FIG. 11. In this embodiment, not only the conductive plate 521 but also the stage 511 is electrically connected to a capacitance measuring device 516. With this configuration, the equivalent circuit is as shown in FIG. 9. In the equivalent circuit of FIG. 9, the capacitance C1 between the conductive plate 521 and the internal wiring layer 21 and the capacitance C2 between the stage 511 and the internal wiring layer 21 are connected in parallel. By connecting the two capacitors in parallel in this way, the capacitance detected by the capacitance measuring device 516 becomes C1 + C2, and therefore a larger capacitance can be detected by the measuring device 516. This enables more sensitive contact detection.

[0041] The substrate processing apparatus 1 of the present invention can also be applied to a multilayer wiring board having multiple internal wiring layers, as shown in FIG. 12(a). For example, for a multilayer wiring board 820 having three internal wiring layers (conductor layers), the capacitance detected by the capacitance measuring device 86 is detected relative to the cutting depth as shown in FIG. 12(b). First, the end mill 85 contacts the first conductor layer 823, increasing the capacitance. Then, as the end mill 85 penetrates the first conductor layer, the capacitance decreases. When the end mill 85 contacts the second conductor layer 824, the capacitance increases again. At this time, d in Equation 1 increases, so the increase in capacitance C decreases. Similarly, an increase in capacitance is detected when the cutting tool contacts the third conductor layer 825. In this way, the substrate processing apparatus 1 of the present invention can detect contact of the cutting tool with any conductor layer of the multilayer wiring board.

[0042] As described above, by using the substrate processing apparatus 1 of the present invention, a cavity in which the internal wiring layer 21 is reliably exposed can be formed in the IC card 2. By using the substrate processing apparatus of the present invention, a cavity in which the internal wiring layer is exposed can be formed with the simple configuration of placing a conductive plate on the IC card. Furthermore, since the substrate processing apparatus of the present invention does not require wiring on the internal wiring layer of the electronic substrate, it also has the effect of shortening processing preparation time.

[0043] The present invention is not limited to the above-described embodiment, and any modifications and improvements that can achieve the object of the present invention are included in the present invention. For example, the present invention can be used for printed circuit boards and multilayer boards other than IC cards. [Explanation of symbols]

[0044] 1 Substrate processing equipment 11 Stages 121 Conductive Plate 122 Cavity processing window 123 Card Press Plate 125 Conductive plate (also used as stage) 13 Locating pin 14 Spindle 15 End mill 16 Capacitance Measuring Instrument 17 Control device 180 Card fixing stage with counterbore 181 Card conveyor belt 182 guide rail 183 Card Support Stage 2. IC card 21 Internal wiring layer 22 Insulation layer (top) 23 Insulation layer (bottom) 24 cavities 25 IC chips 3 Equivalent circuit of the contact detection mechanism 321 Capacitor 33 Switch 511 Stage and conductive plate 521 Conductive Plate 514 Spindle 515 end mill 516 Capacitance Measuring Instrument 517 Control Device 60 Equivalent circuit of the second embodiment 621 Capacitor 622 Capacitor 63 Switch 7 Conventional substrate processing equipment 70 Printed wiring board 701 Upper insulating layer of printed wiring board 702 Lower insulating layer of printed wiring board 703 Internal conductor layer of printed wiring board 74 Spindle 75 end mill or drill 76 Power supply 77 Control Device 78 Contact detection wiring 79 Connection point between wiring and internal conductor layer 81 Stages 82 Conductive Plate 84 Spindle 85 End Mill 86 Capacitance Meter 820 Multilayer wiring board 822 Insulation layer 823 First conductor layer 824 Second conductor layer 825 Third conductor layer

Claims

1. A substrate processing device that exposes the internal wiring of an electronic substrate by cutting the electronic substrate, A stage for placing the substrate, a conductive plate that is in close contact with the electronic substrate on the upper or lower surface of the electronic substrate; a mechanism for positioning the electronic board; a conductive cutting tool that is movable in the X, Y, and Z directions; An instrument for measuring the capacitance between a conductive plate and a cutting tool; a control device that receives a signal from the capacitance measuring device and controls the operation of the cutting tool; A substrate processing device characterized in that it detects contact of a cutting tool with internal wiring of a substrate from a change in measured capacitance.

2. The device for measuring the capacitance is It has a resolution that can measure capacitance below picofarads. The substrate processing apparatus according to claim 1 .

3. the electronic substrate is an IC card having an internal wiring layer including electrodes connected to an IC chip; The substrate processing apparatus according to claim 1 or 2.

4. A substrate processing device that exposes the internal wiring of an electronic substrate by cutting the substrate, a conductive plate that is in close contact with the electronic substrate on the upper surface of the electronic substrate; A conductive stage for placing electronic boards, a mechanism for positioning the electronic board; Conductive cutting tools, an instrument for measuring the sum of the capacitance between the conductive plate and the cutting tool and the capacitance between the stage and the cutting tool; a control device that receives a signal from the capacitance measuring device and controls the operation of the cutting tool; A substrate processing device characterized in that it detects contact of a cutting tool with internal wiring of a substrate from a change in measured capacitance.

5. The device for measuring the capacitance is It has a resolution that can measure capacitance below picofarads. The substrate processing apparatus according to claim 4 .

6. the electronic substrate is an IC card having an internal wiring layer including electrodes connected to an IC chip; The substrate processing apparatus according to claim 4 or 5.

Images