KR100495151B1 - Test substrate for testing liquid state sealing material - Google Patents

Abstract

The present invention relates to a test substrate for testing a liquid encapsulation material that allows for testing the suitability of the substrate and the liquid encapsulant.

The present invention provides a substrate, a plurality of reference electrode patterns formed on the substrate, a plurality of test electrode patterns formed on the substrate in the same form as the plurality of reference electrode patterns and serving as a reference for a test; And an encapsulant formed on at least one test electrode pattern among the plurality of test electrode patterns.

With this configuration, the present invention can more reasonably and accurately evaluate the suitability of the properties of the wire bonding and the material of the liquid encapsulant. In addition, the present invention can accurately evaluate the degree of shrinkage and thermal expansion coefficient of the liquid encapsulant.

Description

TEST SUBSTRATE FOR TESTING LIQUID STATE SEALING MATERIAL}

The present invention relates to a test substrate for testing a liquid encapsulation material, and more particularly, to a test substrate for testing a liquid encapsulation material to enable testing of the suitability of the substrate and the liquid encapsulant.

In recent years, with the trend of miniaturization, weight reduction, high density, and high reliability of electronic devices, semiconductors are required to be highly integrated, multifunctional, high speed, high output, and high in reliability. Accordingly, miniaturization and weight reduction of related components such as semiconductors and passive devices (R, L, C) has emerged as a very important technical element. This requires increasing the wiring density of the board and reducing the size and weight of individual components or modules. In order to meet this demand, a low temperature co-fired ceramic (hereinafter referred to as "LTCC") technology has been proposed. LTCC refers to a technology for forming a substrate using a co-firing method of ceramic and metal at a low temperature of about 800 ~ 1000 ℃.

LTCC provides superior writing density and good electrical characteristics compared to conventional printed circuit board (PCB) technology or multi-chip module (MCM) technology.

Referring to FIGS. 1 and 2, a substrate module using LTCC includes a substrate 2 having a multilayer green sheet 10, a circuit device 20 disposed on the substrate 2, and a circuit device 20. In order to protect the substrate 2 is provided with a liquid sealing material 30 for sealing the circuit element 20.

The green sheet 10 uses a material formed of a composite of a ceramic and glass system used as a filler, or a material formed of a composite of a ceramic and glass-ceramic system used as a filler. In general, mechanical strength is much better for filler / glass-ceramic systems than for filler / glass systems. Drying thickness of 100 ~ by doctor-blade method by mixing a binder, a plasticizer, a solvent (solvant) and the like to the powder mixture of the filler / glass-ceramic of the above composition A green sheet of about 200 μm is formed.

In order to construct a multilayer circuit which is an advantage of the green sheet 10, circuit patterns L and C must be formed in the green sheet 10. To this end, the green sheet 10 is cut to the desired dimensions and the via-holes 22 are formed, and then the via-holes 22 are filled with the conductor paste. The via-hole 22 serves to connect the interlayer circuit. The green sheets 10 filled with the via-holes 22 are printed with circuit patterns L and C suitable for each layer. After drying the green sheet 10 on which the circuit patterns L and C are printed, the green sheet 10 constituting each layer is fired using a constant temperature and pressure. By this process, the board | substrate 10 which has a multilayer green sheet 10 is manufactured.

Accordingly, passive elements such as capacitors (C), resistors (R), and inductors (L) are stacked inside the substrate 2 by stacking and firing the green sheet 10 having the circuit patterns L and C formed thereon in multiple layers. It is mounted. Using this LTCC method, thin film multilayer circuits can be constructed, which is particularly advantageous when implementing bulky devices such as inductors.

The circuit device 20 is electrically connected to the wiring 12 formed on the substrate 2 by a process such as wire bonding or flip chip bonding. At this time, the wiring 12 is connected to the circuit patterns L and C through the via-hole 22.

The liquid encapsulant 30 encapsulates a space between the substrate 2 and the circuit device 20 by silicon or a thermosetting epoxy resin. The liquid encapsulant 30 encapsulates the space of the substrate 2 and the circuit element 20 to insulate the circuit element 20 and reduces the stress from the outside, thereby reducing the thermal stress and physical stress. 24) to maintain the connection reliability.

In the substrate module using the LTCC, deformation of the substrate occurs due to plastic shrinkage, which is a characteristic of glass ceramics, when the green sheet 10 laminate is simultaneously fired. In addition, the properties of the liquid encapsulant 30 will vary depending on the characteristics of the circuit and the substrate 2 implemented through a process such as wire bonding or flip chip bonding. Accordingly, the substrate module using the LTCC coated with the liquid encapsulant 30 is bent as shown in FIG. 3 as the liquid encapsulant 30 is cured. In other words, when the liquid encapsulation member 30 is cured by a predetermined temperature, the liquid encapsulation member 30 is connected between the circuit element 20 and the substrate 2 according to the stress generated by the difference in the shrinkage rate and the heat loss coefficient of the liquid encapsulation member 30. Poor connection of the wires 12 to be electrically connected may occur.

Such a poor connection of the wire 12 is detected according to the degree of warpage of the substrate module using the LTCC as shown in FIG. Thus, the degree of warpage of the substrate module using the LTCC is evaluated to determine the suitability of the liquid encapsulant 30 to the extent according to the difference in the shrinkage rate and the coefficient of thermal expansion of the liquid encapsulant 30. The determination of the applicability of the liquid encapsulation material 30 may be based on the potential of the multi-layer green sheet 10 and the circuit device 20 constituting the substrate 2 during curing of the liquid encapsulation material 30. There is a problem with the degree of accuracy because it does not detect stress. Such a problem is generated according to the sealing conditions and methods of the liquid encapsulant 30, and after the encapsulation, the defect factor cannot be confirmed.

On the other hand, in order to accurately determine the suitability of the liquid encapsulant 30, expensive equipment such as X-ray or precision ultrasonic apparatus (not shown) is required.

Accordingly, it is an object of the present invention to provide a test substrate for testing a liquid encapsulation material capable of testing the suitability of the substrate and the liquid encapsulant.

In order to achieve the above object, a test substrate for testing a liquid encapsulation material according to an embodiment of the present invention comprises a substrate, a plurality of reference electrode patterns formed on the substrate as a reference for the test, And a plurality of test electrode patterns formed on the substrate in the same form as a reference electrode pattern, and an encapsulant formed on at least one test electrode pattern among the plurality of test electrode patterns.

In the test substrate for testing the liquid encapsulation material, the reference electrode patterns each have a “T” shape and overlap with the first reference electrode pattern pair spaced by a predetermined distance, each having an “E” shape and alternate with each other. And a third reference electrode pattern pair having the same shape as that of the second reference electrode pattern pair and having opposite ends thereof opposed to each other.

In the test substrate for testing the liquid encapsulation material, the test electrode patterns may include a plurality of first test electrode patterns in which the first reference electrode pattern pairs are arranged in parallel, and the pair of second reference electrode patterns in parallel. And a plurality of third test electrode patterns in which the plurality of second test electrode patterns and the third reference electrode pattern pairs are arranged side by side.

The test substrate for testing the liquid encapsulation material is characterized in that the substrate is any one of a multilayer printed circuit board and a low temperature cofired ceramic substrate.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4 to 6.

4 and 5, a test substrate for testing a liquid encapsulation material according to an embodiment of the present invention includes a substrate 102 and a plurality of reference electrode patterns 150 formed on one side of the substrate 102. And first to third test electrode patterns 160, 170, and 180 formed to form a plurality of groups on the substrate 102.

The substrate 102 is composed of multilayered green sheets or multilayered printed circuit boards (PCBs), and the following description of the substrate will be described using green sheets as an example. Among these, the green sheet 110 uses a material formed of a composite of a ceramic and glass system used as a filler, or a material formed of a composite of a ceramic and glass-ceramic system used as a filler. In general, mechanical strength is much better for filler / glass-ceramic systems than for filler / glass systems. Drying thickness is 100 ~ by doctor-blade method by mixing binder, plasticizer, solvent, etc. with powder of filler / glass-ceramic having the above composition A green sheet of about 200 μm is formed.

In order to construct a multilayer circuit, which is an advantage of the green sheet 110, circuit patterns L and C must be formed in the green sheet 110. For this purpose, the green sheet 110 is cut to the desired dimensions and via-holes are formed, followed by filling the conductor paste into the via-holes. The via-hole serves to connect the interlayer circuits. The green sheet 110 filled with the via-holes is printed with circuit patterns L and C suitable for each layer. After drying the green sheets 110 on which the circuit patterns L and C are printed, the green sheets 110 constituting each layer are fired using a constant temperature and pressure. By this process, the board | substrate 110 which has a multilayer green sheet 110 is manufactured.

Accordingly, the substrate 102 is formed by stacking and firing the green sheet 110 on which the circuit patterns L and C are formed in multiple layers, thereby passive components such as capacitors C, resistors R, and inductors L formed therein. It is mounted. Using this LTCC method, a thin film multilayer circuit can be constructed, which is particularly advantageous when implementing a bulky device such as an inductor (L).

The plurality of reference electrode patterns 150 may be reference electrode patterns of test characteristics of each of the plurality of test electrode patterns 160, 170, and 180. To this end, the plurality of reference electrode patterns 150 are each electrically connected through the wire 153 and have a “T” shape and are spaced by a predetermined distance from the first reference electrode pattern pair 152, respectively, and “E”. The second reference electrode pattern pair 154 having the shape of a child and overlapping with each other and the second reference electrode pattern pair 154 having the same shape as the second reference electrode pattern pair 154 and having opposite ends of the third reference electrode pattern pair ( 156). In this case, the shape of the electrode pattern of each of the plurality of reference electrode patterns 150 may have different impedances. In addition, the shape of the electrode pattern of each of the plurality of reference electrode patterns 150 may have any shape in addition to the "T" shape "E" shape.

Each of the first to third reference electrode pattern pairs 152, 154, and 156 of the plurality of reference electrode patterns 150 may have a potential stress of the substrate 102 or an environment or an error from the substrate 102. It has an impedance to the characteristics of the substrate 102 according to. The impedance value from each of the first to third reference electrode pattern pairs 152, 154, and 156 becomes the base reference impedance of the substrate 102.

The first test electrode patterns 160 are arranged side by side with a plurality of wire-bonded first reference electrode pattern pairs 152 spaced at predetermined intervals on one side of the substrate 102. The second test electrode patterns 170 are arranged side by side with a plurality of second reference electrode pattern pairs 154 formed at one lower end of the substrate 102 at predetermined intervals. In addition, the third test electrode patterns 180 are disposed side by side with a plurality of third reference electrode pattern pairs 156 adjacent to the second test electrode patterns 170 and spaced apart from each other by a predetermined interval.

Each of the first to third test electrode patterns 160, 170, and 180 may have a shape for dispensing a liquid encapsulation material (not shown) to compare electrical characteristics before and after dispensing the liquid encapsulation material.

The test substrate for testing the liquid encapsulation material according to the embodiment of the present invention is a liquid encapsulation material encapsulating between the circuit device 120 and the substrate 102 formed on the substrate 102 as shown in FIG. The test 130 is used to determine the suitability of the material of the circuit element 120 and the liquid encapsulant 130 formed on the substrate 102. Here, the substrate 102 is, for example, laminated with a multilayer green sheet 110 for mounting passive elements L, R, and C therein.

In detail, a test method of a liquid encapsulation material using a test substrate may include first or second test electrode patterns of the first test electrode patterns 160 formed on the test substrate 102 for testing the liquid encapsulation material. The liquid encapsulant 130 is dropped on one of the portions 161 to 166 (Glob Top). For example, the liquid encapsulant 130 is dropped by using a dispensing unit in each of the odd-numbered test electrode patterns 161, 163, and 165 of the first test electrode patterns 160. Accordingly, the substrate 102 and the region including the wire 153 of each of the odd-numbered test electrode patterns 161, 163, and 165 of the first test electrode patterns 160 and the head portion of the “T” -shaped electrode patterns. ) Is encapsulated by the liquid encapsulant 130, while each of the even-most test electrode patterns 162, 164, and 166 of the first test electrode patterns 160 is not encapsulated.

The test substrate 102 for testing the liquid encapsulation material in which the liquid encapsulation material 130 is encapsulated in any of the test electrode patterns 161, 163, and 165 of the first test electrode patterns 160 is used. The user determines the suitability of the properties of the wire bonding and the material of the liquid encapsulant 130 (Matching Property). That is, the user detects a defect due to the phenomenon that the hardened liquid encapsulant 130 is separated from the substrate 102 due to cracks and moisture generated during the hardening process of the liquid encapsulant 130 formed on the substrate 102. You can do it. In addition, the user measures the impedance value of each of the first test electrode patterns 160 to compare the impedance value of the test electrode patterns coated with the liquid encapsulant 130 and the test electrode patterns that are not applied to the liquid encapsulant 130. The electrical characteristics before and after the application of) are primarily detected, and the impedance value detected first and the impedance of the first reference electrode pattern pair 152 of the plurality of reference electrode patterns 150 provided on the substrate 102 are measured. By comparing the values, the electrical properties before and after the application of the liquid encapsulant 130 are secondarily detected. Then, the user may finally determine whether the liquid encapsulant 130 is applied based on the second detected electrical characteristics. When it is determined that the liquid encapsulant 130 is suitable according to the final determination result, the liquid encapsulant 130 is dispensed on the substrate 102 as shown in FIG. 6, so that the substrate 102 and the circuit element 120 are disposed. Encapsulates the space between them.

Meanwhile, each of the second and third test electrode patterns 170 and 180 may determine suitability with the material of the liquid encapsulant 130 in the same manner as the first test electrode patterns 160 described above.

As such, the test substrate for testing the liquid encapsulation material according to the embodiment of the present invention can more accurately and reasonably evaluate the suitability of the material of the liquid encapsulation material 130. In addition, the test substrate for testing the liquid encapsulation material according to the embodiment of the present invention, as shown in FIG. 5, forms a predetermined pattern on the substrate 102 so that the material of the liquid encapsulation material 130 is the substrate 102. Assess the impact In addition, the test substrate for testing the liquid encapsulation material according to an embodiment of the present invention is able to track and confirm the failure factors accompanying the dispensing conditions and the dispensing method of the liquid encapsulant 130.

As described above, the test substrate for testing the liquid encapsulation material according to the embodiment of the present invention forms reference patterns and constant patterns on the substrate, and after dispensing the liquid encapsulant on the constant patterns, The electrical properties of certain patterns before and after dispensing the encapsulant are compared to determine the suitability of the material for the liquid encapsulant. Accordingly, the present invention can more reasonably and accurately evaluate the suitability of the properties of the wire bonding and the material of the liquid encapsulant. In addition, the present invention can accurately evaluate the degree of shrinkage and thermal expansion coefficient of the liquid encapsulant.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a cross-sectional view showing a low temperature cofired ceramic substrate.

FIG. 2 is a perspective view of the low temperature co-predetermined ceramic substrate shown in FIG. 1; FIG.

3 is a view showing the warpage of the substrate by the material properties of the liquid encapsulant shown in FIG.

4 is a plan view showing a test substrate for testing a liquid encapsulation material according to an embodiment of the present invention.

FIG. 5 is a plan view illustrating a liquid encapsulant dispensed on a test substrate illustrated in FIG. 4. FIG.

6 is a cross-sectional view showing a low-temperature cofired ceramic substrate dispensed with a liquid encapsulant.

<Description of Symbols for Main Parts of Drawings>

2, 102: substrate 10, 110: green sheet

20, 120: circuit element 22, 122: via hole

24, 124, 153: wire 30, 130: liquid sealing material

150 reference electrode patterns 152 first reference electrode pattern pair

154: second reference electrode pattern pair 156: third reference electrode pattern pair

160: first test electrode pattern 170: second test electrode pattern

180: third test electrode pattern

Claims (4)

Substrate, A plurality of reference electrode patterns formed on the substrate and serving as a reference for a test; A plurality of test electrode patterns formed on the substrate in the same form as the plurality of reference electrode patterns; And an encapsulant formed on at least one test electrode pattern of the plurality of test electrode patterns. The method of claim 1, The reference electrode patterns, A first reference electrode pattern pair each having a “T” shape and spaced apart by a predetermined distance; A second reference electrode pattern pair each having an "E" shape and overlapping with each other; And a third reference electrode pattern pair having the same shape as that of the second reference electrode pattern pair and having opposite ends facing each other. The method of claim 2, The test electrode patterns, A plurality of first test electrode patterns having the first reference electrode pattern pairs arranged side by side; A plurality of second test electrode patterns in which the pair of second reference electrode patterns are arranged in parallel; And a plurality of third test electrode patterns in which the pair of third reference electrode patterns are arranged side by side. The method of claim 1, The substrate, A test board for testing a liquid encapsulation material, characterized in that either a multilayer printed circuit board or a low temperature cofired ceramic substrate.