JP2005057248A - Characteristic impedance inspection apparatus for circuit wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a characteristic impedance inspection apparatus for a circuit wiring board that inspects characteristic impedance while winding off reel formed products, has a function for discriminating the quality of the products, for grasping manufactured conditions thereof, or for providing the feedback of information to adjust manufacturing conditions to an abnormal manufacturing process and individually associates relations between the products and the results. <P>SOLUTION: The characteristic impedance inspection apparatus inspects an object to be inspected while winding off the object, winds up to a reel form after the inspection, and provides the manufacturing process for the feedback of the identification of failure causes or the information to adjust the manufacturing conditions based on the obtained product information. A conduction and disconnection inspecting portion 20 is provided behind an inspection portion 10. A means for inspecting with reading identification codes added to the products is provided so as to associate individual products with manufacturing histories thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an inspection apparatus for guaranteeing the characteristic impedance of a circuit wiring board including a high-speed signal line on which a semiconductor element is mounted.

  At present, the speeding up of semiconductor devices is remarkable. For example, Pentium (registered trademark) 4 of an Intel CPU exceeds 3 GHz, and RDRAM of a RAMBUS memory has 800 MHz. Therefore, high-speed signal characteristics have been required for circuit wiring boards including substrate boards used for these components.

  That is, since the wavelength becomes shorter as the frequency becomes higher, it has become impossible to ignore even a short line length such as a semiconductor package. For example, since the wavelength is 10 cm at 3 GHz, including the connection length with the peripheral components in which the device is used, the length can be longer than the wavelength, so that the signal reflection cannot be ignored. Therefore, characteristic impedance matching, which has not been particularly problematic in the past, has been required.

  In a wiring board, there are the following factors as manufacturing factors that determine characteristic impedance. (1) Conductor line width, (2) Conductor thickness, (3) Insulating layer thickness composed of polyimide base material and adhesive layer, (4) Dielectric layer thickness on conductor line, (5) Insulating material Dielectric constant. In order to manufacture a substrate with controlled characteristic characteristic impedance, it is necessary to control these factors.

  As a manufacturing method, there is a case where a product is manufactured in the form of a reel in order to manufacture the above-mentioned elements with high-speed signal characteristics and mass-production of a circuit board.

  Conventionally, the inspection for such a product is for checking whether or not an individual product falls within the acceptance criteria for a certain acceptance / rejection criterion. That is, it is for judging the quality of individual products and selecting them, and is intended to prevent the outflow of defective products. Therefore, it has been performed for the purpose of product quality assurance before shipment.

  However, in recent years, as the quality of products has been demanded, the difficulty of manufacturing has increased and the manufacturing yield has fallen. Therefore, as a countermeasure, it is necessary to grasp not only the quality of the product but also the badness of the product and the bad manufacturing process.

  In order to do so, the inspection device has been required to be able to grasp the quality of the product as inspection information and to feed back information that can identify the cause of the product defect or adjust the manufacturing conditions of the manufacturing process. .

  Originally, the inspection of characteristic impedance included implications for process monitoring in addition to product quality selection. For example, the circuit wiring pattern on the polyimide substrate has irregularities, so even if it is manufactured under equipment conditions with a constant insulating layer thickness, the final product may not have the characteristic impedance as designed. there were. Therefore, if other manufacturing factors that determine the characteristic impedance are constant, it is possible to specify the insulation layer thickness defect by measuring the characteristic impedance value of the product.

If you want to use the measurement results of characteristic impedance for the purpose of such process monitoring, there is a demand to perform the inspection process after forming the inner layer circuit, after forming the outer layer circuit, or after applying the solder resist. come. Then, an inspection apparatus capable of inspecting the reel form is required.

  However, there is no device for inspecting the characteristic impedance of a tape-like circuit board in a reel-to-reel configuration.

  Further, in the inspection of single wafers of products, there is a problem that productivity (the number of production per unit time) does not increase. For passive components such as semiconductor packages, it has been an important problem to suppress the manufacturing cost as much as possible. However, the drop in productivity was also costly.

  Further, if the product and the inspection result are associated with each other at 1: 1, an identification code must be attached to the product itself so that the product can be read.

  The present invention has been made in view of the above problems. In other words, in order to solve the above problem, a device that can inspect the characteristic impedance while unwinding a reel-shaped product and wind it up to the reel shape. For example, it has a function to detect abnormalities in the conductor line width and conductor thickness of products by performing characteristic impedance inspection after etching, or a function to feed back information for adjusting manufacturing conditions to abnormal manufacturing processes. It is another object of the present invention to provide a circuit wiring board characteristic impedance inspection apparatus capable of associating products with inspection results on a 1: 1 basis.

  It is another object of the present invention to provide an inspection apparatus that combines a characteristic impedance inspection function and a continuity / disconnection inspection function.

  The present invention relates to a circuit wiring board characteristic impedance inspection apparatus manufactured by a reel-to-reel process in which a long base material is used to continuously form a wiring board, and a reel-shaped inspection object is unwound from the reel. The circuit wiring board is characterized in that after inspection, it is wound up in a reel form, and based on the product information obtained by the inspection, information for identifying the cause of failure or adjusting manufacturing conditions is fed back to the manufacturing process. Is a characteristic impedance inspection apparatus.

  According to another aspect of the present invention, there is provided the characteristic impedance inspection apparatus for circuit wiring board according to the invention, further comprising a continuity / disconnection inspection section after the inspection section for performing the inspection. is there.

  Further, according to the present invention, in the characteristic impedance inspection apparatus for circuit wiring boards according to the above invention, when performing the inspection, the inspection is performed while reading the identification code added to the product so that each product can be associated with the manufacturing history. A characteristic impedance inspection apparatus for a circuit wiring board, characterized by comprising means for performing.

According to the characteristic impedance inspection apparatus of the first and second aspects, the characteristic impedance can be inspected while the reel-shaped circuit wiring board is unwound from the reel state. According to this inspection apparatus, quality control of a product can be performed not only for quality determination of a single product, but also for immediate feedback of the inspection result to the manufacturing process, thereby increasing productivity and reducing costs.
In addition, measurement results can be collected in time series. This is possible for the first time by inspecting the reel form that the product does not have to be numbered and the inspection surface and orientation do not change. Since it is possible to match the quality results of the product with the history information, it can be used for process management of the manufacturing process.

  In addition, according to the characteristic impedance inspection apparatus of the third aspect, by having means for recognizing the identification code attached to the product itself, it becomes possible to associate each product with the inspection result, and the inspection conditions and the like later. It is possible to follow the history of In the future, this means can also be used to determine the sampling timing and the number of sampling.

  If it is possible to grasp the product quality and manufacturing condition abnormality from the inspection results obtained in the form of a reel, it is possible to return to the manufacturing process at an early stage without interposing another processing process such as cutting.

Further, as a secondary effect that the inspection can be performed in the reel form, there is an improvement in tact time, that is, an improvement in productivity, due to the ease of handling the product and the reduction of the handling time.
As described above, according to the characteristic impedance inspection apparatus of the present invention, the manufacturing process management means can be used without being limited to the quality control means at the time of product shipment.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 shows an overall view of a characteristic impedance inspection apparatus for a circuit wiring board according to the present invention. As shown in FIG. 1, in FIG. 1, the left side is a product unwinding side, and the right side is a product winding side. There is a product unwinding shaft 1 at the upper part on the unwinding side, and an interlayer paper take-up shaft 2 for winding up an interlayer paper (also referred to as a spacer) contained between the products at the lower part. On the winding side, there are a product winding shaft 3 and an interlayer paper unwinding shaft 4 for unwinding the interlayer paper. The inspection unit 10 is configured between the unwinding side and the winding side.

  Static electricity generated in a reel product having a thin base material is a fatal problem for a measuring instrument for measuring characteristic impedance. This is because the unit that measures the characteristic impedance is a measuring instrument that generates a signal with a fast rise time of around 45 ps and measures the reflected signal, called the TDR (Time Domain Reflectometry) method. This measuring instrument is not resistant to the incident voltage and is normally about ± 2 V, and therefore, when a voltage that reaches several kV such as static electricity is applied, it is destroyed immediately.

  In order to remove static electricity generated between thin substrates such as products and interlayer paper, a static eliminator 5 is installed between the unwinding shaft of the product and the inspection unit. This may be a conductive brush or the like, but a non-contact type such as an ion generating type is preferred in order not to damage the product.

  Furthermore, it is necessary to be able to remove static electricity also on the inspection stage 8 to which the product to be inspected and the measuring instrument are connected via the probe 7. However, the inspection stage 8 itself cannot be made of a conductive metal in order to inspect electric characteristics. Therefore, the non-contact type static eliminator 5 is also used here.

  The reel product unwinding, conveyance, and feed amount control are controlled by the unwinding amount of a unwinding motor (not shown). The product is fixed on the inspection stage 8 by suction.

As shown in an example in FIG. 2, the circuit wiring board is measured at a characteristic impedance test pattern 11 that is manufactured under the same conditions as the high-speed signal transmission line and arranged on the four sides near the periphery of the circuit wiring board. is there. By inspecting the test pattern 11 for inspecting the characteristic impedance, the characteristic impedance is guaranteed.

  When measuring and testing the characteristic impedance, if the wiring pattern in the product itself is inspected, the distance between the signal pin and the ground pin will vary, and the position will of course vary. This either increases the inspection time or increases the cost of preparing an inspection jig for each product.

  The same applies to the inspection of the printed wiring board. However, when the characteristic impedance is inspected, an inspection test pattern 11 is provided on a substrate in a certain imposition unit so that the inspection can be performed.

  For this purpose, test patterns 11 for characteristic impedance inspection, which are manufactured under the same conditions as the high-speed signal transmission line and are arranged on the four sides in the vicinity of the periphery of the circuit wiring board, are created at the same time as the product. I will do it.

  By making it possible to contact the test pattern 11 for testing the characteristic impedance with a probe dedicated for high-frequency measurement, it is possible to perform testing without increasing time and cost even if the product changes.

  A fine pitch probe in which the ground (G) pin and the signal (S) pin are separated by about 200 μm pitch is used in order to inspect the characteristic impedance of the object to be inspected in contact with the characteristic impedance inspection test pattern. An example of the probe sequence is shown as (12) in FIG.

  And in order to control this probe, the displacement meter (not shown) which can sense the height direction of a Z-axis is equipped. By measuring each time measurement is performed during automatic inspection and controlling the amount of movement of the fine pitch probe based on the result, the object can be brought into contact with the object accurately.

  The probing mechanism is controlled by a moving stage 13 of XYZθ.

  For example, the process monitoring in this inspection apparatus is as follows.

  (1) Conductor line width, (2) Conductor thickness, (3) Insulating layer thickness composed of polyimide base material and adhesive layer, (4) Dielectric on conductor line as manufacturing factors that determine characteristic impedance Among the elements of the layer thickness and (5) dielectric constant of the insulating material, for example, by measuring (1) conductor line width and (2) conductor thickness in advance, and then measuring characteristic impedance, (5) Since the dielectric constant of the insulating material is known, (3) the thickness of the insulating layer composed of the polyimide base material and the adhesive layer, and (4) the thickness of the dielectric layer on the conductor line are obtained.

  This information is fed back to the previous process, and each manufacturing condition is changed. That is, (3) when there is an abnormality in the thickness of the insulating layer composed of the polyimide base material and the adhesive layer, for example, the pressure for laminating the polyimide base material and the insulating layer is changed, and (4) the dielectric on the conductor line When the body layer thickness is abnormal, for example, the film thickness for printing the dielectric layer (solder resist) is changed.

  The inspection apparatus of the present invention may be combined not only with a single-function inspection apparatus but also with other conventional manufacturing apparatuses. For example, an inspection apparatus that combines a characteristic impedance inspection apparatus and a continuity / disconnection inspection apparatus that is an electrical inspection of a product may be used.

  FIG. 3 shows, as an example, an inspection apparatus in which a characteristic impedance inspection unit and a continuity / disconnection inspection unit are combined.

  In order to ensure the correspondence with each product, an identification code (for example, a two-dimensional code) is attached to the product. Equipped and record the inspection result together with the identification code number.

According to the characteristic impedance inspection apparatus shown in FIG. 1 and FIG. 3, the identification code attached to the product is inspected while being read by the two-dimensional code reader 6 so that the history of the product produced in the reel form is completely grasped. It becomes possible to track.

Next, feedback of information for adjusting manufacturing conditions and product quality assurance by performing inspection will be described based on product information in the inspection apparatus of the present invention.
First, based on the arrangement of the test pattern 11 for inspection as shown in FIG. 2, the test pattern 11 for inspection is assigned in consideration of the imposition and size of the product. Basically, at least as many test patterns 11 for inspection as the number of stacked circuit boards to be produced are arranged, and depending on the characteristics of product production, the longitudinal flow direction or the width direction, Arrangement is made so that information that can be an important factor in feedback is extracted. It is desirable to design the line structure (strip structure, microstrip structure) and type (single-end line, differential line) according to the actual signal transmission form of the product part.

  However, it should be noted that, as described in the section [0025], the test pattern 11 for inspection is produced under the same conditions so as not to increase time and cost even if the product is changed. For example, the pitch (interval) between the signal pin and the ground pin and the pin configuration (GSG, GS, SG, etc.) are preferably unified and fixed. In addition, the test pattern 11 for inspection described in the section [0027] is arranged, but if this can also be realized, a fixed arrangement is desirable from the viewpoint of the item [0025].

According to the present invention, the test pattern 11 for inspection of a reel-shaped product is inspected by the TDR method. However, when probing is possible to the extent that the transmission line of the product part is not scratched, or whether or not there is a scratch, it depends on the transmission line arranged in the actual product part instead of the test pattern 11 for inspection. Inspection is also acceptable.
And the result of the obtained measurement value is classified for each test pattern 11 (11a to 11d) for inspection, specifically, classification by arrangement direction, classification by position in the width direction, manufacturing stability and manufacturing process. Divide it into arbitrary categories according to its features, and grasp the tendency from the beginning to the end of the reel. Specifically, as shown in FIG. 4 and Table 1, it is desirable to make it visually easy to understand.

つまり、この特性インピーダンスの検査により得られた検査結果を製品情報として、製造工程へフィードバックすることにより、製造工程における不安定箇所の追求であるとか、製品の出来不出来を顕著にし、製造の安定化や品質の向上に貢献することが可能となる。

In other words, the inspection results obtained by this characteristic impedance inspection are fed back to the manufacturing process as product information, thereby pursuing unstable parts in the manufacturing process or making the product unsatisfactory and making the product stable. It is possible to contribute to improvement and quality improvement.

  With regard to quality assurance, which is the original inspection purpose, by using the inspection result of the test pattern 11 for inspection over the entire product obtained by the item [0041], it can be said that the inspection is not completely complete by sampling inspection until now. It is possible to guarantee all systems by inspecting all systems.

Actually, since the characteristic impedance of the test pattern 11 alone does not guarantee the characteristic impedance of the product, several samples are extracted from the reel, such as the first part, the middle part, and the last part. Actual product pattern (effective area)
The characteristic impedance of the transmission line of the unit 14 and the characteristic impedance of the test pattern 11 for inspection are inspected to confirm that they are consistent, and as a result, all the characteristic impedances of the products over the entire reel product are guaranteed.

  When the characteristic impedance of the actual product pattern (effective area) portion 14 cannot actually be measured (when no measurable transmission line is arranged), the actual product pattern as shown in FIG. 5 is representative. A second inspection test pattern 31 incorporating such a pattern is produced in the actual product pattern (effective area) portion 14, and the second inspection test pattern 31 is the first part and the last part of the reel-shaped product. Or, if possible, it is inserted into the central portion or the like, and manufactured under the same manufacturing conditions as the actual product pattern (effective area) portion 14, and the characteristic impedance of the transmission line of the second test pattern 31 for inspection as described above, The characteristic impedance of the test pattern 11 for inspection is inspected to confirm that they are consistent, and as a result, the characteristic impedance of the product over the entire reel product The scan guaranteed 100%.

  In addition, since the measured value of characteristic impedance varies depending on the type of TDR measuring machine, the guarantee of the characteristic impedance is actually performed by the TDR measuring machine specified by the customer. Then, an inspection apparatus equipped with a plurality of TDR measuring machines or a plurality of inspection apparatuses equipped with each TDR measuring machine according to requests from a plurality of customers is required, and enormous costs are required.

  However, by guaranteeing the product by the method of [0045], it is sufficient to inspect the characteristic impedance using a customer-specified TDR measuring machine at the time of sampling inspection. The type of TDR measuring machine used in the present invention is not questioned. This is because the characteristic impedance inspection apparatus according to the present invention mainly focuses on the variation of the characteristic impedance across the reel-shaped product rather than the absolute value of the characteristic impedance itself. The result of the variation and the measurement of the absolute value by sampling inspection. This is because the characteristic impedance of the product is comprehensively guaranteed by combining the results.

1 is an overall view of a characteristic impedance inspection apparatus for a circuit wiring board according to the present invention. It is explanatory drawing which shows the example of arrangement | positioning of the test pattern for a characteristic impedance test, and a probe. It is explanatory drawing which shows an example of the test | inspection apparatus at the time of combining a characteristic impedance test | inspection part and a continuity / disconnection test part. It is explanatory drawing which shows the example of the test pattern for a test | inspection, the example of arrangement | positioning of a probe, and the method of summarizing a test result. It is explanatory drawing which shows the example of arrangement | positioning of the 2nd test pattern for a test | inspection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Product unwinding axis | shaft 2 ... Interlayer paper winding axis | shaft 3 ... Product winding axis | shaft 4 ... Interlayer paper unwinding axis | shaft 5 ... Static elimination device 6 ... Two-dimensional code reader 7 ... Probe 8 ... Inspection stage 10 ... Inspection unit 11 ... Inspection test pattern 11a ... Inspection test pattern a
11b ... test pattern b for inspection
11c ··· Test pattern c for inspection
11d ··· Test pattern d for inspection
DESCRIPTION OF SYMBOLS 12 ... Probe arrangement | sequence 13, 23 ... XYZ (theta) movement stage 14 ... Product real pattern (effective area) part 20 ... Conductivity / disconnection test apparatus 21 ... Flying prober part 22 ... Flying probe 31 ... Second test pattern

Claims (3)

  In a characteristic impedance inspection apparatus for a circuit wiring board manufactured by a reel-to-reel process that continuously forms a wiring board using a long base material, an inspection object in a reel form is inspected while being unwound from the reel, Characteristic impedance inspection of circuit wiring board, which is wound on a reel after inspection and based on product information obtained by inspection, information for identifying the cause of defects or adjusting manufacturing conditions is fed back to the manufacturing process apparatus.   The characteristic impedance inspection apparatus for a circuit wiring board according to claim 1, further comprising a continuity / disconnection inspection section after the inspection section for performing the inspection.   3. The apparatus according to claim 1, further comprising means for performing an inspection while reading an identification code added to a product so that each product can be associated with a manufacturing history when the inspection is performed. Circuit wiring board characteristic impedance testing equipment.

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