TW200416405A - Electric test by anisotropic conductive film - Google Patents

Abstract

Anisotropic conductive electric test technology can be used to large electric circuit board. Under testing condition, all the points, which will be test, are being contacted under pressure. So it is used in mass production. This method can be used to test many different type boards. Most of the electric circuit board has an insulation protective layer, which makes it hard to reach the small test pad. The surface of the conductive film has small touch fingers can effectively make the electric contact. Since the contact is made by two surfaces through an elastomer sheet, therefore, no needle mark is left on the tested pads. The high capability for testing density circuit can easily be used for four points testing technical to obtain accurate resistance measurements of the circuit lines.

Description

V. Description of the invention (1) [Technical field to which the invention belongs] Mass-production test device and test method for electric film on a circuit board This invention relates to a method for using high-density unidirectional line resistance and insulation resistance between lines 0 [Previous Technology] Circuit boards are developed in the electronics industry. They are developed from single-panel, double-panel, and multiplex boards. Printed on two boards: for example, the board is used as an example. The purpose of the board is to direct the dense contact area: circuit contacts. Come out, and have a double :: = = = The lines in the area are getting more and more fine and the vias are getting smaller and smaller, plus, the technology is used to form a build-up board. At present, the probes are fixed to the 'position ^: 疋 twenty-bed method by a plastic plate, that is, the needle bed is pressed down during the test, and each probe is tied to :: = 接 = 针 J' The needle can be in contact with the circuit board. Each probe is designed to make the probe point denser and denser, but the probe is made thinner and finer. However, due to the limited connection, it is rough and belongs to a strong tube. The structure increases the thickness of the user's and because its spring sleeve is used on the circuit board with a shoulder distance below 300um. The 8-bed electrical measurement technology can no longer be more and more detailed, so it is more and more suitable for electric easy to tie the board = == in the subsequent use can not be tested with the components.% Because it is the point-to-face point of production ..... Ju chicken, under test 200416405 V. Description of the invention (2) ~ One-way conductive film is a mixture of metal particles in a polymer resin. This also means that the mixed metal particles are arranged in a series in the film. This metal string Arranged perpendicular to the main surface of the film. The US4820376 patent in the United States of America in 1989 disclosed that the unidirectional conductive film that shows conduction between the upper and lower sides under pressure is made of elastic silicone rubber as the insulator, and all particles of gold or silver are used as the conductor. "This kind of unidirectional conductive adhesive can be used in electronic surface adhesion technology, and can be used as a connector or electrical continuity test." In order to improve the continuity, plasma glue is used to remove the gel on the surface of the metal string on the film. When testing its resistance, a uniform pressure is applied to the surface of the vertical colloid to make the film thinner 'so that the particles in the colloid squeeze the circuits against each other and thus conduct. The flip chip technology of U.S. patent T955008 is to use bumps at the contacts that need to be conductive, so that it is easy to be conductive after being conductive. This kind of technology can also be used for testing technology of unidirectional conductive adhesive. That is, a bump is formed at the place where the conductivity is required, so that when the pressure is applied, there is a greater squeeze at the position of the test point, and the conduction is effectively turned on. In the eighth and two years of the Republic of China and eighty-five years, patents 61666 and 81905 revealed that placing a ferromagnetic metal block in a uniform and parallel magnetic field can enhance the magnetic field near this metal block, and make the The magnetically susceptible metal particles in the colloid form a regional agglomeration. After the colloid is hardened, the electronic component is fixed on the substrate and forms electrical conduction with the contact. From the prior art exemplified, the soil knows that the one-way conductive adhesive technology can be used for high-density connections, while the circuit board technology can disperse dense contact areas. The bump technology enhances the conductivity of specific locations. Ferromagnetic materials can Makes the magnetic field in a specific area stronger and can gather sense

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Electrical measurement of the board and how to magnetic metal particles, but there is no problem of Zhao 'nor how to solve the problem of forming a high-reliability electrical measurement method to solve the problem of scoring when testing current high-density circuit circuits, [Content] Circuit board The purpose of the circuit continuity of dense contacts is to solve high-density electrical resistance and insulation resistance. Problems to be solved ... 1. Structure and method of conducting high density contact 2. Test method without streaks. 3 Stable test structure and method. Features of the invention: A. Device: Uses a flexible high-density unidirectional guide _ Thunder ^ a. Connection on a one-way conductive adhesive formed by dots > +-a string of conductive paths, t of this path group takes 1 angle Pass through the two main surfaces of the upper and lower sides to form a unilateral a ^ electricity, through the conversion board, the conversion board: Universal guide is used to test the circuit board, X is called the fixture board. The conversion board is a double-sided board. The upper outer layer and the lower outer layer have the same number of contacts on both sides. The conversion board and the contact on the side of the layer board protrude from the board surface. The & The group of contacts on one side of the tested circuit board is opposite to each other. This surface is called a high-density contact-point surface. The grid layout of the other side of the conversion board is high. Density contact surface, for the test point group =

200416405 V. Description of the invention (4) The contacts of a high-density group of tested points on one side of the substrate under test form a pair of j-plane-to-plane unidirectional conductive films that are connected to each other under pressure because The surface of the bump on the board is a plane, and the surface of the tested point on the substrate is also a plane. The two planes are connected by a flexible unidirectional conductive film. It is a surface-to-surface connection. There is no tie mark left on the test pad of the board under test due to the sandwich of the elastic conductive film. The connection on the other side of the conversion board = arranged according to the grid, the grid conductive film, the grid conductive film: The conductive path group formed by the conductive particles on the film is perpendicular to the upper and lower main surfaces of the film. The conductive path group protrudes from the surface of its insulator and is arranged in a certain grid. The conductive part of the dog has a spacer to fix the protruding one. Position, the grid conductive film is connected to the grid plate that leads to the tester. The grid plate: also known as the grid plate, the conductive contacts on it are arranged in a matrix form according to the grid (gr id). The lattice distance matrix is consistent with the lattice position on the lattice conductive film, and is opposite to each other. There, the holes may be placed Sites plate probe, the probe with low electrical resistance wire measuring machine is turned on. The other side of the test board and another set of conversion board, one-way conductive film, grid conductive film, and grid board are also arranged in a corresponding manner and connected to the circuit of the electric tester. Electrical measuring device for unidirectional conductive adhesive ·· It consists of grid plate, grid conductive film, spacer plate, conversion plate, unidirectional conductive film, circuit board to be tested, single film, conversion plate, spacer plate, grid conductive film, The grid plates are sequentially formed, and after alignment, the board and the contacts between the boards are aligned vertically. B. Testing After the device is aligned, the upper grid plate is moved down during the test, or the lower grid plate is lowered and a certain pressure is applied to make the elastic unidirectional conductive film pass through one of the conversion plates.

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I 200416405 V. Description of the invention (5) The density of the bump contact group protruding from the surface of the board is in contact with the circuit board contact group circuit under test. Due to the relationship of the bump, the unidirectional conductive film is at the bump. Subjected to a large pressure strength, a good conduction is formed, and the contact group on the other side of the conversion board is conductively connected to the contact group on the grid plate by the upper and lower pressures, and the grid plate is lined up. It is connected with electrical tester components to measure the resistance value and insulation value of each line. (3j. Detailed description of the invention: diagram, meaning, component meaning The arrangement of the unidirectional conductive knee electrical measuring device is shown in Figure 1 as upper grid plate 60: upper grid conductive film 50, upper spacer plate 40, upper Conversion board 30,

Upper unidirectional conductive film 20, circuit board to be tested 10, lower unidirectional conductive film 21, lower conversion plate 31, lower spacer plate 41, lower grid conductive film 51, lower grid plate 61, and sequentially stacked Alignment: The joints between the board and the board are aligned up and down, and pressed up and down to make it elastic during the test

The early conductive film is squeezed by the bump 32 (second picture) on one side of the conversion board, and the contact 14 corresponding to the circuit board 10 is turned on. Figure 2 shows the AA of Figure} / Figure. The part is enlarged. The circuit board is composed of insulator 12 and contact 14 = and related lines (13a, 13b, 13c l3d). This circuit board can be = Single layer (if the lower outer layer has no contacts, the phase of 21, 31, 41, 51, 61 is not required), and it can also be a double-layer or multi-layer board, so its circuit can be on the surface (13a) = two =, also It can be inside the substrate (1 3b ~ 13d). In order to protect the outer layer circuit, there is a layer of insulating protective film 8 'one-way conductive film 20, 21 is made of silo, furnace wire gel 24 and conductive metal arranged in a string. Particle 26 sets of plates 30, 31 are connected to insulator 34 by insulator 38, metal bump 32 through metal, '36, and spacers 40, 41 are made of insulator 44 and

Page 10 200416405 V. Explanation of the invention (6) The two are = the lifetime of the conductive conductive ... 1, the conductive conductive piece 5 is better than 0's alignment and the longer body 54 and contact with Shanghai & Γ is made of silicon elastic rubber insulation 54 and a string of metal 56 inside the contact buckle. It is made of insulator 64 and pile t) U, bl 疋 mouth ftft and electrical tester cable are inserted through the probe Line speed is connected. The grid plate 6 °, 61 can also make the circuit pass through the board to the row machine and connect to it. I multi-layer board group 纟, and the conductive electrode contact 62 of the grid plate 60 is stacked by the connector with the cable and electrical sequencing. Lined up with the metal string 56 on the grid 1 μ50 and the contact 34 on the conversion board 30. This arrangement is configured so that the hard board and the elastic unidirectional conductive gel are spaced from each other. Evenly distributed 'to connect each contact and make it electrically connected. Figure 3 shows the arrangement of metal particle strings 26 in the film 20 in a conductive film. '24 is an insulating elastic colloid '. 3A is a plan view of the film, and 3β is a surface view. Metal particles can be seen in the surface view. The arrays 26 are arranged from the surface of one side of the film to the surface of the other side of the film. The plan view shows the distribution of each string of conductive particles. Each cluster of particles and its adjacent particles form a regular triangle distribution. This distribution pattern ensures high-density connection ability, because when the sides are the same length, the regular triangle is larger than the general square. There are many contacts. The conductive metal particles 26 are composed of a metal containing magnetic induction and a metal with low chemical conductivity and good conductivity. The magnetically sensitive metal is iron, hafnium, magnetic, chromium, molybdenum, hunger, titanium, etc., preferably ferromagnetic metal. , Metals with good conductivity and low chemical properties, such as gold, silver, copper, tin, etc. Usually the outer layer of metal with good magnetic permeability is plated with a metal with good conductivity and low chemical properties, such as the outer layer of nickel particles

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V. Description of the invention (7) The mine is gold or silver. Or a metal bond with good conductivity and a metal with good magnetic conductivity such as copper, gold or silver particles are plated with nickel, Ming and other metals. The particle size is 2-100um, and 10-60um is the most suitable. Insulating elastic colloid 24 is composed of high polymer, such as polymethylsiloxane. This product includes Dow Corning's Silastic E RTV (room temperature vulcanizing RTV) rubber, GE's GE 6 1 5/63 0, or polyester rubber, poly-urethane, polybutadiene, polyisoprene, or copolymer

Copolymer of Luriie outadiene and aery loni _______ ^ ^ ^ styrene butadiene, ethylene, poly ethyrene propylene, etc. Figure 4 shows the parallel magnetic field 1- The substrate 5 is placed in 1 and the surface is coated with a mixture of 24 insulating colloids and metal particles 26 with good conductivity and magnetic permeability. The parallel magnetic field is a space formed by the upper electromagnet metal pole 1 and the lower electromagnet metal pole 丨The size of the magnetic field is determined by the strength of the current in the coil 2. This parallel magnetic field can also be supplied by a permanent magnet. The metal particles 26 and the liquid compound that can be polymerized to form a colloid are mixed and coated on the etched surface of the substrate 5, 5 can be a non-ferromagnetic substrate, such as a substrate impregnated with glass cloth impregnated with epoxy resin and copper foil, because the surface of the metal surface is neatly arranged after etching (see Figure 3a):: 2 22 depth is less than half The thickness of the film (20), the metal particles are attracted to the magnetic field and fall into the hole. When 5 is placed on a uniform and parallel magnetic field center + + ^ is perpendicular to the plane 5 due to the magnetic field, so nearby particles gradually gather toward the hole. ^ Arranged 'by heating Compound 24 polymerized to form a solid gel,

I 200416405 body, a unidirectional conductive film that can be vertically conductive due to the arrangement of metal particles 20 'The conductive film made here is flat on one side and has a protruding hand (finger) shape on the other side, and has a tentacle shape when used One side faces the board under test 丨 0, and the flat side faces the conversion board 30. This tentacle shape makes the conductive sheet easier to deform after being compressed in the vertical direction, so it is easy to conduct electricity. ^ The road is often covered with an organic protective film (solder mask) 8, which is about 20-30 um on the printed circuit board, so the surface of the conductive contact (pad) is usually 20-3Oum lower than the surface of the organic protective film. As for the contacts, this tentacle shape makes the conductive adhesive easy to contact with the contacts, which increases the test reliability.

The orderly distribution increases the density that can be arranged without causing the conductive particle string to contact with the conductive particle string under pressure, reducing the possibility of short circuit, which is more advantageous because the metal It is carved, so coating a thinner photoresist on the substrate can obtain a small and dense distribution of pits, which enhances the performance of testing high-density circuit boards. Fig. 5 is another composition of Fig. 2. It replaces the grid unidirectional conductive film 50 and the grid plate 40 with another unidirectional conductive film 20. This device only needs to change the grid plate 60 during the test. The board and circuit board can be aligned, and the assembly is relatively simple and economical.

The sixth diagram is another composition of the second diagram. It is a four-point measurement for measuring low resistance, that is, the bump contact 3 2 of the conversion board 30 in FIG. 2. Contacts 32a and 32b replace each of the 32 contacts in the second figure. Contacts 32a and 32b are two non-conducting two contacts, 32a and 34a are conducting, 32b and 34b are conducting, and 34a and 34b are the two contacts. One supply current, the other contact is used to sense

Page 13 200416405 V. Description of the invention (9) Voltage measurement, the same as the other point on the circuit board 10 which can be connected to this point (can be connected to the same conversion board, or it can be connected to other sides of the circuit board) The side conversion board is connected) and there are two contacts 32a and 32b on the conversion board. One of them is used to supply current (I), and the other is used to sense voltage (V) to form four points. And the induced voltage can know the resistance of the line (ie R = V / I). The above-mentioned examples illustrate some of the characteristics of this patent. The basic functions and applications of this patent are not limited to the exemplified limited examples. For example, positive photoresist can be used for metal etching to make high-precision patterns. , Silicone rubber fluid can be added with platinum catalyst to accelerate the reaction. 'Controlling the aggregation of metal particles can use intermittent or fluctuating magnetic fields, etc. [Embodiment] Examples Example 1: Production of a unidirectional conductive film = 254 X 375ram with a 72um (20z) copper thick substrate, etched with 45 holes deep in a regular triangle arrangement at a distance of 90um. The diameter of the nickel particles with a diameter of 15% silver plating is 25 to 40 Um, and the SiUstic RTV silicon gel containing 15% of the particle volume is mixed and coated on the etching board to be 200um thick. After the substrate is thickened, the cured magnetic% is heated to 140

200416405 V. Description of the invention (ίο) Degree C ′ is cured in two hours. Remove the film. Place the conductive film flat on the copper surface, and use Keithley 196 System DMM to make a four-point probe measurement. Two points are connected to the copper surface, one is the current and the other is the voltage. The other two points are distinguished by current and voltage. The down force of the upper side of the unidirectional conductive film was 3g, and a resistance value of 80mohm was obtained. Example 2: Test of circuit board resistance A, high-density test Single-sided circuit board has contacts with diameters of 4, 5, 6mil, 25um thick protective film on the board surface, and double parallel lines with a length of 10mm. The two wires are separated by It is 3, 4, 5 mil, with 200uin thick unidirectional conductive film as described in Example 1, and a conversion board with 85 ~ 100un thick bump contacts. According to the device in Fig. 5, 2.5 The pressure of kg / cm2 was measured with Keithley 196 System DMM. The pressure was then increased to 4.5 kg / cni2, and the resulting resistance values are listed in Table — Table 1. Contacts or lines of conductive resistance and insulation resistance 2. 5 kg / cm24. 5 kg / cm2 Resistance value Ω Indentation Resistance value Ω Indentation Contact 4mi 10 · 650 No 0 · 635 No contact 5mi 10 · 504 No 0. 495 No contact 6mi 10 · 480 No 0 · 480 No

200416405 V. Description of the invention (π) Line spacing 3 mi1> 10 7 None> 10 7 Wireless pitch 4 mi1> 10 7 None> 10 7 Wireless pitch 5 mil> 10 7 None> 10 7 None tested from Table 1 There are no marks on the points. From the known printed circuit board technology, it is not easy to make 80um high bumps at a diameter of 4mil. To measure 4mil contacts, the diameter of the bump should be less than 3 · 5ro i 1, but use this one-way The conductive film can measure its resistance value, so the unidirectional conductive film has 45um contact fingers. B. The low-resistance test single-sided circuit board has a contact with a diameter of 6,8mil. According to the device in the sixth figure, a 200um thick unidirectional conductive film described in Example 1 is used, and there are 85 ~ 100 un thick bumps. The contact conversion board measures the resistance value with a Keithley 196 System DMM at a pressure of 2.5 kg / cm2 according to the device in Figure 6. The project has four-point measurement and two-point measurement. Contact point 6mill80mQ500mQ contact point 8πιΠ150ιηΩ400ιηΩ As can be seen from the table above, the four-point probe technology can be easily used in this high-density technology and accurate resistance values can be obtained. The overall effect of the invention: According to the above-mentioned one-way conductive adhesive electrical measurement technology, it is used to measure the circuit board of a large area, and the contacts on the circuit board to be measured during the measurement and the measurement board

Page 16 200416405 V. Description of the invention (12) " " " Each contact of '~ *-' is pressurized and then connected at the same time, so it is a mass-production electrical measurement technology. This technology can test circuit boards of various configurations.

There will be a layer of organic retaining film. If the contact is small, the general conductive film is not used to form an electrical connection. The V 丄 structure can be effective because the unidirectional conductive film used in this technology is soft to the touch. The bumps on the change board are connected with the small contacts. The contact method used in this technique is to make the surface of the fish and the surface of the surface through the unidirectional conductive film and the contact with the conversion board in one-way contact, so there is no streak and the test stability is high. High density as small as Imil) and high j. Because the conductive particle size is 10-100 um, so the distance between them can be). Measure the conversion board of 1 ί degree (which is used to disperse the high-density contacts to accurately measure electricity. ^ Density circuit board, using four-point probe technology can

Low resistance of the circuit. J

Page 17 200416405 The diagram briefly illustrates the first diagram, the unidirectional conductive adhesive test device diagram; grid plate 60, grid conductive glue. Sheet 50, spacer plate 40, conversion plate 30, unidirectional conductive film 20, the tested one The circuit board 10, the unidirectional conductive film 21, the conversion plate 31, the spacer plate 41, the grid conductive film 51, and the grid plate 61 are sequentially stacked. The second picture, part of the upper half of the unidirectional conductive adhesive test device circuit schematic diagram of each component, the third diagram, the unidirectional conductive adhesive test piece composition diagram, 3A is a plan view, 3B is a cutaway view, each point in 3A In 3B, it is a series of arranged metal particles.

In the fourth figure, a unidirectional conductive adhesive test piece is made into a device diagram. Due to the structure of the substrate, magnetically conductive particles are gathered in position, and the magnetic field of the electromagnet causes the particles to line up vertically. In the fifth figure, another part of the unidirectional conductive adhesive test device in the upper part is replaced with a unidirectional conductive adhesive test piece instead of a grid conductive film. Figure 6. The four-point test layout of the unidirectional conductive adhesive in the upper part, so that the resistance of the circuit on the board under test can be accurately measured.

Claims (1)

200416405 VI. Application patent scope '一 ^ — 1 · A mass production type electrical measurement technology that uses 焉 density unidirectional conductive adhesive to conduct electricity. The lamination method of the device and the device is that the elastic conductive film and the rigid circuit board are alternately laminated. 2. As described in 1, the high-density unidirectional conductive film is vertically conductive on the main surface, and the conductive metal strings are regularly arranged on the conductive film because the conductive metal strings are perpendicular to the main surface. 3. The method of arranging the unidirectional conductive glue-conducting metal strings as described in 2 is to make a uniform, parallel magnetic field through the regular arrangement on the substrate structure, so that the regional magnetic field has a strong and weak distribution, and a strong regional magnetic field attracts the sense. The magnetic metal particles make the metal strings into a regular arrangement. 4 · The arrangement pattern of metal strings is regular triangle. 5. One side of the manufactured unidirectional conductive film is tentacle-like protrusions, and the protrusion height is 0.5 to 3 times the concavity of the measuring point on the surface of the board under test. 6. The tentacle-type protrusion of the one-way conductive knee pads depends on the spacing structure. 7. The contact group on the high-density circuit board is connected by the contact points of the conversion board, and the circuit of the conversion board is dispersed to various grid points. The contact points connected to the high-density circuit board are the corresponding conductive bumps on the conversion board. After pressing, the unidirectional conductive film has low resistance at the contact point and conducts electricity. 8. High-density unidirectional conductive film The high density of the conductive string arrangement can make each electrode contact on the conversion board produce non-conducting two bump contacts. At the same time, the high-density unidirectional conductive film is connected to the test board at the same time. The same electrode is turned on, and the two bumps conduct current at one point and the other induced line voltage becomes a four-point probe measurement, which can be used for low resistance measurement. 9 · A needle bed can be used instead of the conversion board to test the electrical properties. The probe spot on the needle bed is unidirectional conductive adhesive ^ 200416405 # 、 Scope of patent application The probe end of the touch surface should be flat or round, and the length of the probe is only 15% to 85% of the thickness of the film. Page 20