JPH0454469A - Positioning signal processing system for ceramic wiring board inspection - Google Patents

Abstract

PURPOSE:To find the coordinate values of the center point of a connection pad by removing variation in the cre value of a cause detection signal and calculating the mean value of coordinate values of going and returning about the center point of the connection pad or the movement mean value of sampling data. CONSTITUTION:A low-pass filter removes the crest value variation from the detection signal Ss of a position sensor corresponding to the connection pad to obtain a signal Ss'. The signal Ss' is delayed by a time DELTAt depending upon the characteristics of the LPF. The mean value of the going and returning of the X- or Y- directional movement of the wiring substrate is calculated to eliminate the movement quantity due to the delay. Further, the detection signal Ss of the position sensor is stored in a memory successively and the movement mean value is calculated to accurately find the XY coordinates (Xc,Yc) of the center point of the connection pad from the signal Ss'.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positioning signal processing method for inspecting a ceramic wiring board, and more particularly to a method for processing a detection signal of a position sensor.

[Prior Art] In the hardware configuration of a computer, an IC board is formed and mounted by mounting and connecting an IC element to a printed wiring board. It is absolutely necessary that the wiring pattern of the printed wiring board has good conductivity itself and good insulation between each wiring pattern 7, and a continuity/insulation test is performed.

Traditionally, ceramic substrates with good insulation have been used as printed wiring boards, but recently, ultra-small ceramic wiring boards have been developed that can form high-density wiring patterns to accommodate the high degree of integration of IC elements. ing. This will be explained with reference to FIGS. 3(a), (b), and (c). figure(
In a), 1 indicates a ceramic substrate in which a plurality of ceramic wiring boards (hereinafter simply referred to as unit substrates) II are arranged at regular intervals, and FIG. 1B shows a unit board 11. The size of each unit substrate is, for example, a 12 mm square, and within this range, wiring pins Ill are implanted at each grid point at minute intervals with respect to the ceramic substrate 1. A circular gold-plated connection pad 2 for external connection is provided on the head of the wiring pin on the front side of the board, as shown in Figure (C). The diameter d of the connection pads is, for example, ~250 .mu.m, and the grid spacing is ~500 .mu.m, both of which are minute, and the number of wiring pins for each unit board reaches several hundred. The ceramic double board 1 is multi-layered, and each wiring pin is connected to each other according to a predetermined wiring pattern. In the inspection, each unit substrate of the ceramic substrate 1 is sequentially inspected, and when the inspection is completed, each unit substrate is individually cut and used.

Now, when conducting a continuity/insulation test for each unit board 11 for the above ceramic board 1, the connection pad 1
Of course, it is necessary to use a prober having probe pins with minute lattice spacing corresponding to 112, but it is also necessary to make the prober correspond to each unit board sequentially, connect each probe pin in a corresponding manner, and make proper contact with 112. It is necessary to. For this purpose, it is necessary to position the unit substrate 11 with respect to the prober. However, because ceramic substrates expand, contract, and distort during firing, positional deviations occur between the unit substrates, and it is difficult to accurately contact each probe pin with the corresponding connection N6 using methods such as simple positioning tools. Can not. In response to this, the inventor of this invention proposed an inspection device that performs accurate positioning.
A patent application has been filed for "Continuity/Insulation Inspection Device for Ceramic Wiring Boards."

The outline of the inspection device 2 according to the above patent application will be explained with reference to FIGS. 4(a), (b), and (C). In figure (a),
A mounting table 22 is fixed to a base board 211 constituting the frame 21, and the ceramic substrate 1 to be inspected is roughly positioned and placed thereon. The mounting table is a microprocessor (MPU)
) 23, the drive control circuit 24 moves/rotates in the X, Y, and θ directions.

On the other hand, a pressing plate 25 that moves up and down along the support column 212 of the frame is provided, and a prober 2B corresponding to the unit board 11 and a position sensor 27 for detecting the connection pad Ill of the unit board are fixed to this. The mounting table is moved in the X or Y direction and the connection pad is detected by the light spot Sp of the position sensor. The diameter of the optical spot Sp is, for example, several tenths smaller than that of the connection pad, so that the resolution is good.

Figure (b) shows the optical spot Sp and the detection signal Ss for the connection pad 112, and the detection signal Ss is the signal processing circuit 28.
The XY coordinate values (Xc, Yc) of the center point of the connection pad are calculated from the XY coordinate values (Xa, Ya) and (Xb, Yb) of the rising and falling points. Probe pin 2fi of the prober corresponding to the connection pad
The XY coordinate values of l are known in advance, and positioning is performed by moving/rotating the mounting table by the difference between this and the above coordinate values (Xc, Yc). Then, in response to a command from the MPU, the push control circuit 291 and push mechanism 292 lower the prober to bring the probe pin into proper contact with the connection pad.

[Problem to be solved] As mentioned above, the surface of the connection pad is plated with gold, but it has some unevenness, which causes uneven reflection, which can cause the peak value of the detection signal to fluctuate. Inevitable.

FIG. 4(C) shows an example of the fluctuating detection signal Ss. When detecting the rising and falling points of this signal, the position moves and the coordinates of the center point cannot be accurately determined.

On the other hand, it is necessary to use some method to remove fluctuations in the peak value and accurately determine the coordinate values of the center point.

It is an object of the present invention to provide a positioning signal processing method that removes fluctuations in the peak value of a detection signal and obtains accurate coordinate values of the center point of a connection pad in the inspection of an ultra-small ceramic wiring board.

[Means for Solving the Problems] The present invention provides an ultra-compact device in which a large number of wiring pins each having a circular connection pad for external connection on the head are implanted at points f at minute intervals. The ceramic wiring board is moved in the X or Y direction by a moving mechanism, the connection pad is detected by a position sensor, and the detection signal is processed by a microprocessor to calculate the XY coordinate values of the center point of the connection pad,
This is a positioning signal processing method used in inspections in which the ceramic wiring board is moved/rotated to position it relative to the corresponding prober, and the prober is pressed to bring the probe pins into contact with the connection pads.

The first method uses a low-pass filter to remove fluctuations in the peak value of the detection signal caused by uneven reflectance on the surface of the connection pad. The ceramic wiring board is moved back and forth in the X or Y direction with respect to the connection pad, and the average value of the XY coordinate values of the round trip with respect to the center point of the connection pad is calculated to eliminate the delay of the detection signal due to the low-pass filter.

The second method samples a detection signal whose peak value fluctuates at appropriate intervals, calculates a moving average value for an appropriate number of continuous sampling data for each peak value using a microprocessor, and connects each moving average value. This method uses a moving average curve to remove fluctuations in peak values.

[Effects] In the first positioning signal processing method according to the above, fluctuations in the peak value of the detection signal of the position sensor are removed by a low-pass filter. However, since the filter has delay characteristics, the coordinate values of the detection signal shift by that amount. In contrast, the X or Y position of the ceramic substrate relative to the position sensor
Move in the direction back and forth. Since the movement of the coordinate value due to each delay is in the opposite direction, it is canceled by taking the average value of the round trip, and the coordinate value of the center point of the connection pad is accurately calculated.

In the second positioning signal processing method, the detection signal is sampled at appropriate intervals, and a moving average value is calculated for an appropriate number of continuous sampling data.

The moving average curve connecting the moving average values is used to remove fluctuations and accurately calculate the coordinate values of the center points of the connection pads.

[Embodiment] With reference to FIGS. 1(a) and 1(b), a block configuration and detection signal processing for an embodiment of the first method of the positioning signal processing method according to the present invention will be explained. In figure (a),
The ceramic wiring board is moved in the X or Y direction, and the detection signal Ss of the position sensor 27 with respect to the connection pad is input to the signal processing circuit 28, adjusted to an appropriate level by the amplifier 281, and then processed by the low-pass filter (LPF) 282. Fluctuations in the peak value are removed to produce a signal SS'. The signal SS' is delayed by a time Δt due to the characteristics of the LPF. The same applies to the Y direction. In addition, the amount of movement Δ of the coordinates with respect to Δt
X or ΔY is determined by movement control data from the MPU 23. The signal SS' is shaped into a rectangular wave SR by the waveform shaping circuit 283, and is shaped into a rectangular wave SR by the sampling circuit 284.
MP is sampled by sampling pulses at appropriate intervals supplied from the sampling pulse circuit 285.
The coordinate values of the rising and falling points (Xa
, Ya) and (Xb, Yb) are obtained. In this case, the ceramic wiring board is moved back and forth in the X or Y direction as shown in Figure (b) in response to the delay of the signal SS described above. The left side of the drawing shows a state in which the spot Sp moves in the positive direction relative to the connection pad, and the right side shows a state in which it moves in the negative direction.

The delay time Δt of both is the same, but the sign of the movement amount ΔX or ΔY is opposite, so the left and right rectangular waves SRF,
If the average value of the coordinates XFa and XBa of the rising point of SRH is taken, the amount of movement ΔX due to delay is eliminated and the correct Xa is calculated. The same is true for the falling point xb
is calculated, and the correct coordinate value Ya is calculated for the Y direction as well.
, Yb are calculated. The coordinate values Xc and Yc of the center point are determined by averaging these coordinate values.

The block configuration and detection signal processing for the embodiment of the second method will be explained with reference to FIGS. 2(a), (b), and (c). In this case, the LPF282 in FIG. 1(a)
The waveform shaping circuit 283 is not necessary. In Figure (a), the detection signal Ss from the position sensor 27 is detected by the signal processing circuit 2.
The signal is adjusted to an appropriate level by the amplifier 281 of No. 8 and input to the sampling circuit 284, where it is sampled in the same manner as in the first method. Sampling data is MPU2
3 are sequentially stored in the memory (MEM) 231, and a moving average value is calculated using the method shown in FIG. 3(b). That is, for a point p at any X or Y coordinate, for example, five pieces of sampling data h (p-2) to h(
Find the average value H(p) of p+2). When the average value H(p) for each point is successively determined and connected as the point p moves, the detection signal Ss' of the moving average value shown in FIG. 3(c) is changed.

In this case, the larger the number of sampling data, the smoother the curve will be, but on the other hand, the resolution will be lower, so the number should be set appropriately depending on the actual situation. As described above, fluctuations in the peak value of the detection signal are removed, resulting in a smooth detection signal Ss', and the XY stock mark (Xc, Yc) of the center point of the connection pad can be accurately determined.

[Effects of the Invention] As is clear from the above description, in the first positioning signal processing method according to the present invention, fluctuations in the peak value of the detection signal are removed by the low-pass filter. However, the movement of the coordinate values of the detection signal due to the delay characteristics of the filter is eliminated by reciprocating the ceramic substrate in the X or Y direction and taking the average value of the detected coordinate values.

Furthermore, in the second method, the fluctuations are removed by sampling the detection signal whose peak value fluctuates at appropriate intervals and determining the moving average value of the sampling data for each sampling point. In both the first and second methods, the coordinate values of the center point of the connection pad are calculated accurately.
In continuity/insulation testing of ultra-small ceramic wiring boards formed by planting connection pads at minute grid intervals, the probe pins can be brought into proper contact with the connection pads to ensure highly reliable testing. Is there a big one?

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a block diagram and an explanatory diagram of detection signal processing in an embodiment of the first method of the positioning signal processing method for inspecting ceramic wiring boards according to the present invention, and FIG. a), (b) and (c) are the positioning signal processing method for a ceramic wiring board according to the present invention.
A block configuration diagram and an explanatory diagram of detection signal processing in an embodiment of the second method, FIGS. Plan view of pad, Figure 4 (a), (b)
and (c) are a configuration diagram of a ceramic wiring board inspection apparatus according to the patent application, an explanatory diagram of a method of processing a detection signal of a position sensor, and a waveform diagram of the detection signal. l...Ceramic board, 11...Ultra small ceramic wiring board (unit board),
111... Wiring pin, 112... Connection pad, 2.
...Ceramic wiring board inspection device, 2■...Frame, 211...Base II, 212...Support column, 21
3... Horizontal plate, 22... Mounting table, 23... Microprocessor (MPU), 231... Memory (MEM)
), 24... Drive control circuit, 25... Press plate, 26...
・Prober, 2G1... Probe pin, 27... Position sensor, 28... Signal processing circuit, 281... Amplifier, 282... Low pass filter, 283... Waveform shaping circuit, 284... - Sampling circuit, 285... Sampling pulse circuit, 291... Pressure control circuit, 2
92...Press mechanism.

Claims (2)

[Claims] (1) An ultra-small ceramic wiring board formed by planting a large number of wiring pins with circular connection pads for external connection on the head at grid points at minute intervals is moved by a moving mechanism to
Or move in the Y direction, detect the connection pad with a position sensor, process the detection signal with a microprocessor to calculate the XY coordinate values of the center point of the connection pad, and move/rotate the ceramic wiring board. In the continuity/insulation test, which is performed by positioning the prober against the corresponding prober and pressing the prober to bring the probe pin into contact with the connection pad, the peak value of the detection signal due to uneven reflection on the surface of the connection pad is Fluctuations are removed by a low-pass filter, the movement of the ceramic wiring board in the X or Y direction is reciprocated with respect to the connection pad, and the average of the respective XY coordinate values for the center point of the connection pad obtained by the reciprocation A positioning signal processing method for inspecting a ceramic wiring board, characterized in that the delay of the detection signal caused by the low-pass filter is canceled by calculating a value. (2) The detection signal whose peak value fluctuates due to reflection unevenness on the surface of the connection pad is sampled at appropriate intervals, and the moving average value for an appropriate number of continuous sampling data is calculated as above for each peak value. 2. The positioning signal processing method for inspecting ceramic wiring boards according to claim 1, wherein fluctuations in the peak value are removed by a moving average curve calculated by a microprocessor and connecting the respective moving average values.