Square board type chip resistor

[Detailed Description of the Invention]

Field of the Invention The present invention relates to the corner guard type chip resistor machine with which high-density wiring circuits (hybrid IC etc.) are mainly equipped by the automatic mounting machine. PRIOR ART While the demand to small-and-light-izing of electronic equipment grows increasingly in recent years, in order to raise the wiring density of a circuit board, many very small corner guard type chip resistor machines have come to be used for a resistive element. Since this corner guard type chip resistor machine is mounted in a printed circuit board at high speed, being mounted by an automatic mounting machine is almost the case. For this reason, the request which raises the mounting quality of a corner guard type chip resistor machine is becoming strong. The structure of the conventional corner guard type chip resistor machine is shown in Drawing 2. A conventional high electric power type corner guard type chip resistor machine is with 96 alumina substrates 11, It comprises upper surface electrode layer 12 by a silver system thick film electrode, end face electrode layer 13 and resistance layer 14 by ruthenium series thick film resistance, the 1st glass layer 15 and seal glass layer 16 with the Howe silicic acid lead system glass which covers resistance layer 14, and 2nd glass layer 17. In order that solder material may raise a sex to an exposure electrode surface, nickel metal skin 18 and 5 n-Pb metal skin 19 are given by electrolysis Metsuki. Object of the Invention However, in order that the protection layer of the resistance object of the conventional corner guard type chip resistor machine may secure reliability, it has taken the glazing structure of three layers and comprises the 1st glass layer, a seal glass layer, and the 2nd glass layer. A coefficient of linear expansion is 64X10-7~66 X 10-7/'C in 590 degrees C~610 degreeC, and glass softening temperature forms this glass by calcinating this at the temperature of 580 degrees C~600 degreeC. In this case, the climax portion of a seal glass layer will remain in a glass surface, and the unevenness which is about 20~30micro will occur in it. In order to calcinate protection glass near glass softening temperature, glass does not fully fuse this but it is considered for climax of a seal glass layer to remain. When it is going to mount the corner guard type chip resistor machine which has unevenness in this surface in a printed circuit board etc. with an automatic mounting machine and a corner guard type chip resistor machine is sucked up by the adsorption pin of an automatic mounting machine, The subject that it becomes the form in which the adsorption bottle and the corner guard type chip resistor machine are carrying out point contact for unevenness of a glass surface, and a corner guard type chip resistor machine rotates in many cases, it is aslant mounted as shown in Drawing 3, and it could not mount in a printed circuit board correctly occurred. 20 -- a printed circuit board and 21 -- a conductor -- a part and 22 are corner guard type chip resistor machines. The softening temperature of ■ protection glass which calcinates the calcination temperature of ■ glass at the high temperature more than 640 degreeC, fully fuses protection glass, and makes surface unevenness small is conventionally lowered to a 550 degreeC grade as a measure for solving this subject, Glass was fully fused with the conventional calcination temperature, and examination of making surface unevenness small was able to be considered. However, if the variation in resistance will become large if calcination temperature is raised like ■, and the softening temperature of glass is lowered like ■, while a coefficient of linear expansion will become large, the acid resistance of glass also deteriorates. For this reason, it is since the stress inside the glass by the difference of the thermal expansion coefficient of glass and alumina substrates remained easily and also acid resistance has deteriorated, When giving electroplating to an exposure electrode surface, the glass surface was eroded by acid, internal stress tended to emit, and the subject that a crack occurred in a glass surface occurred. The present invention provides the corner guard type chip resistor machine which did not degrade the acid resistance of glass, either, and also made unevenness of the surface of glass small, and realized high mounting accuracy, without solving such a subject at once and enlarging resistance variation. Means for solving problem A corner guard type chip resistor machine of the present invention comprises: An insulating ceramic substrate, An upper surface electrode layer of a silver system thick film formed on the above-mentioned ceramic substrate, A resistance layer of a ruthenium series thick film which overlaps with a part of above-mentioned upper surface electrode layer, The softening temperature which covers the above-mentioned resistance layer completely is 550degreeC~570degreeC, and a coefficient of linear expansion is the 1st glass layer of 69X10-7~75X10-7 layer degreeC, Softening temperature formed on the 1st above-mentioned glass layer is 550degreeC~570degreeC, and a coefficient of linear expansion is a seal glass layer of 68X10-7~74 X 10-7 layer degreeC, An end face electrode layer of a silver system thick film in which softening temperature formed so that the above-mentioned seal glass layer may be completely covered on the 1st above-mentioned glass layer is 580degreeC~630degreeC, and a coefficient of linear expansion overlaps with the 2nd glass layer of 62x10-7~68 X 10-7 layer degreeC, and a part of above-mentioned upper surface electrode layer. OPERATION since the glass softening temperature of the 1st glass layer is low compared with calcination temperature (590degreeC) when it is alike and is based on this composition Since seal glass sinks in the 1st glass layer, and surface unevenness can be made small and the acid resistance of the 2nd glass layer has not deteriorated, glass is not eroded at the time of electric Metsuki, and a crack does not occur in a glass surface. Since the coefficient of linear expansion of the 2nd glass layer is the smallest, internal stress occurs in the direction which compresses the 2nd glass layer, and a crack does not occur further easily. Thereby, the corner guard type chip resistor machine which did not degrade the acid resistance of glass, either, and also made unevenness of the surface of glass small, and enabled high precision mounting can be provided, without enlarging resistance variation. EXAMPLE Hereinafter, the example of the present invention is described using Drawing 1. Drawing 1 is a sectional view showing one example of the present invention. In Drawing 1, it is a corner guard type chip resistor machine of the present invention, It consists of 96 alumina substrates 1, end face electrode layer 3 and resistance layer 4 by ruthenium series thick film resistance, the 1st glass layer 5 with the Howe silicic acid lead system glass which covers resistance layer 4, seal glass layer 6, and the 2nd glass layer 7. [ upper surface electrode layer 2 by a silver system thick film electrode, ] In order that with Handa may raise a sex to an exposure electrode surface, nickel metal skin 8 and 5 n-Pb metal skin 9 are given by electrolysis Metsuki. The details of the example of the present invention are explained using Drawing 2. First, Acceptance puts in 96 alumina substrates of the large version excellent in heat resistance and insulation. In order to divide into these alumina substrates the shape of a strip of paper, and in the shape of a piece of Pieces, the slot (it is metallic mold fabrication at the time of a green sheet) for division is formed. Next, a thick film silver paste is screen-stenciled on the above-mentioned 96 alumina substrates, and they are 6 minutes during a peak hour, and lN-0UT at the temperature of 850 degreeC by a belt type continuation calcination furnace. It calcinates by the profile for 45 minutes, and forms upper surface electrode layer 2. Next, the thick film resistance paste which makes RuO2 the main ingredients is screen-stenciled, and at a belt type continuation calcination furnace, it calcinates at the temperature of 850 degreeC by the profile for 6-minute during peak hour, and lN-0UT time 45 minutes, and forms resistance layer 4 so that it may overlap with a part of upper surface electrode layer 2. Next, in order to arrange the resistance of the above-mentioned resistance layer 4 between the above-mentioned upper surface electrode layers 2, by a laser beam, a part of above-mentioned resistance object layer 4 is destroyed, and resistance correction is made. The coefficient of linear expansion after calcination screen-stencils the 1st glass paste of 72±2X10-7 by 560 ±5-degreeC, and glass softening temperature dries by 150 degreeC with a near-infrared drying furnace for 10 minutes so that the above-mentioned resistance layer 4 may be covered completely. After the dried 1st glass paste, the coefficient of linear expansion after calcination screen-stencils the seal glass paste of 71±2X10-7 by 560 ±5-degreeC, and glass softening temperature dries by 110 degreeC with a near-infrared drying furnace for 10 minutes. The coefficient of linear expansion after calcination screen-stencils the 2nd glass paste of 65±2X10-7 by 603 ±15-degreeC, and glass softening temperature dries by 150 degreeC with a near-infrared drying furnace for 10 minutes so that a dried seal glass paste may be completely covered on the dried 1st glass paste. Then, they are 6 minutes during a peak hour, and IN=OUT at the temperature of 590 degreeC by a belt type continuation calcination furnace. It calcinates by the calcination profile of 5C1, and forms the 1st glass layer 5, seal glass layer 6, and the 2nd glass layer 7. next, in order to expose an end face electrode as a preparation process for forming an end face electrode, alumina substrates 1 are divided in the shape of a strip of paper, and strip-of-paper-like alumina substrates are obtained -- substrate division was performed in part. A thick film silver paste is applied to the side of the above-mentioned strip-of-paper-like alumina substrates with a roller so that it may overlap with a part of above-mentioned upper surface electrode layer 2, and it is the temperature of 600 degreeC by a belt type continuation calcination furnace, In order to calcinate by the calcination profile for lN-0UT 45 minutes and to form end face electrode layer 3 for 6 minutes during a peak hour, end face conductive paste printing and calcination are performed. Next, secondary board division which divides the strip-of-paper-like alumina substrates whose above-mentioned end face electrode layer 3 has been formed in the shape of a piece of Pieces as a preparation process of electrode Metsuki process J is performed, and piece of Pieces-like alumina substrates are obtained. And at the end, soldering of exposed upper surface electrode layer 2 and end face electrode layer 3 performs electrolysis Metsuki which forms nickel metal skin 8 and metal skin 9 of 5 n-Pb by electrolysis Metsuki for reservation of prevention of electrode Eaten at the time, and the reliability of soldering. according to the above process, the corner guard type thin film chip resistor machine by the example of the present invention was made as an experiment -- moreover As comparative example 1, glass softening temperature uses the 1st glass layer, a seal glass layer, and the 2nd glass layer, and the coefficient of linear expansion after 600±20degreeC and calcination uses the glass paste of 65±2x10-7, The corner guard type chip resistor machine calcinated by 640 degreeC was made as an experiment, and as comparative example 2, glass softening temperature used the 1st glass layer, a seal glass layer, and the 2nd glass layer, the coefficient of linear expansion after 550±20degreeC and calcination used the glass of 65±2X10-7, and it made the corner guard type chip resistor machine calcinated by 590 degreeC as an experiment. Performance comparison of the example of this present invention, comparative example 1, and comparative example 2 is shown in the 1st table. The characteristics (resistance temperature characteristics, the current noise characteristic, etc.) which were not shown in the 1st table checked that the example of the present invention, the conventional example, and comparative example 1. comparative example 2 had the equivalent performance. Since about 30 degreeC is also lower than calcination temperature, the corner guard type chip resistor machine of the present invention fully softens the glass softening temperature of the 1st glass layer and a seal glass layer, and the pinhole of the glass surface which often becomes a problem with a corner guard type chip resistor machine has also been improved. (Following space) The Table It can be said that the corner guard type chip resistor machine of the example of the present invention has the performance which the mounting performance was excellent in since unevenness of a glass surface was small (with no slanting * mounting), and acid resistance was also good, was conventionally equivalent compared with elegance also as for resistance variation, and excellent so that more clearly than the 1st table. In glass softening temperature, the coefficient of linear expansion after calcination is a glass paste of 72±2X10-7 at 560 ±5-degreeC to the 1st glass layer, as a seal glass layer -- glass softening temperature -- 560 ±5-degreeC -- the coefficient of linear expansion after calcination -- although glass softening temperature used the glass paste of 71±2x10-7 and the coefficient of linear expansion after calcination used the glass paste of 65±2x10 by 603 ±15-degreeC as the 2nd glass layer This does not limit a glass layer, and the softening temperature of this is 550degreeC~570degreeC (555 degrees C~565 degreeC is the optimal), and a coefficient of linear expansion is the 1st glass layer of 69X10-7~75X10''77-degreeC, softening temperature -- 550 degrees C~570 degreeC (555 degrees C~565 degreeC is the optimal) -- and a coefficient of linear expansion -- the seal glass layer of 68X10-7~74 X 10-7/'C, softening temperature -- 580 degrees C~630 degreeC (588 degrees C~618 degreeC is the optimal) -- and a coefficient of linear expansion should just be the 2nd glass layer of 62X10-7~68 X 10-7-/°C. In an example, although the Precoating glass for suppressing a resistance drift was not formed before resistance trimming, even if trimming is carried out and it makes a corner guard type chip resistor machine as an experiment after forming Precoating glass, it is checking that equivalent performance is got. EFFECT OF THE INVENTION The outstanding effect that the corner guard type chip resistor machine which the acid resistance of glass did not degrade the corner guard type chip resistor machine of the present invention, either, without enlarging resistance variation, and also made unevenness of the surface of glass small, and enabled high precision mounting can be provided is acquired so that more clearly than the above explanation.

[Brief Description of the Drawings]

The corner guard type chip resistor machine of the former [ Drawing / the sectional view showing the structure of the corner guard type chip resistor machine according / Drawing 1 / to one example of the present invention, the sectional view showing an example of the structure of the corner guard type chip resistor machine of the former / Drawing / 2 /, and / 3 ] is a state explanatory view when mounted aslant. 1 ...... 96 alumina substrates and 2 ...... an upper surface electrode layer and 3 ...... an end face electrode layer and 4 ...... a resistance layer and 5 ...... the 1st glass layer and 6 ...... a seal glass layer and 7 ...... the 2nd glass layer and 8 ...... nickel metal skin and 9 ...... 5 n-Pb metal skin.