JP2005166759A - Method of manufacturing laminated electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminated electronic part in which chipping in a cutting step, re-adhering of chips, or mist adhering to each chip can be prevented, and adhering or chipping of the chips to each other in a drying step after barrel polishing and which can improve productivity. <P>SOLUTION: In the method of manufacturing the laminated electronic part, a laminated substrate of green state before cutting is dried at a temperature and a time in a manner that a binder is not decomposed so that the residual solvent of the laminated substrate is set within 2.0-2.5 wt%. Thus, re-adhering of chips, or mist adhering to each chip can be prevented. Thereafter, the chip obtained by the cutting is dried at a temperature and a time in such a manner that the binder is not decomposed. Thus, the residual solvent of the laminated substrate is set within 0.2-1.5 wt%. Thus, the adhesion of the chips to each other can be prevented in the drying step after the barrel polishing thereafter or chipping. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a multilayer electronic component having a surface mount structure having a coil, a capacitor, or a coil and a capacitor inside a multilayer body mainly composed of a magnetic body or a non-magnetic body.

  This type of conventional multilayer electronic component is manufactured by the process shown in FIG. First, in the green sheet production step (S1), a slurry obtained by adding a resin binder and a solvent to magnetic or non-magnetic powder is applied to a predetermined thickness and dried to produce a green sheet. The next punching step (S2) is a step of forming a through hole for conducting the laminated body, and this step is not necessary in the case of a capacitor. In the next conductor pattern forming step (S3), a conductor paste for coil formation or capacitor electrode formation is formed on the green sheet in a predetermined shape and arrangement by printing or the like. In the subsequent laminating step (S4), the green sheet on which the conductor pattern is formed is cut into a predetermined dimension, and is temporarily pressed while being stacked in a predetermined order to peel off the base film, and a predetermined number of layers are stacked.

  Next, in the pressing step (S5), the laminated green laminated substrates are pressure-bonded with a predetermined pressure. Next, in the cutting step (S6), as shown in FIG. 13, the green laminated substrate 2 that is pressure-bonded onto the fixing film 1 is fixed, and each of the individual shapes having a predetermined shape is moved by the lifting blade or the rotating blade 3 as shown. Cut into chips. Next, in the barrel polishing step (S7), a liquid such as water is put into a barrel of a barrel polishing machine or the like, and a medium or the like is further put in some cases, and the barrel polishing machine is operated to polish each chip for a predetermined time. FIG. 14 shows a state in which the tip 5 is rounded by the barrel polishing of the chip 5.

  Next, in the drying step (S8), the chips containing moisture are dried by barrel polishing. And in a baking process (S9), each chip | tip is baked with a predetermined | prescribed temperature profile, and a laminated body is completed. Thereafter, in order to form a terminal electrode for mounting on a printed circuit board, a silver paste or the like is applied to the fired laminate, and then baked, and electroplating is performed on the surface of the silver electrode.

  In such a conventional multilayer electronic component manufacturing method, when the green laminated substrate is cut by the lifting blade, there is a problem that the chips in the green state in the cut state are reattached. As shown in FIG. 13, when the laminated substrate 2 in the green state is cut by the rotating blade 3, mist (cutting residue) 4 adheres to the chip at the time of cutting, and the mist is also shown in the next barrel polishing step (S7). There is a problem that 4 cannot be completely removed and shape defects frequently occur. Further, there is a problem that the chips 5 adhere to each other in the drying step (S8) after barrel polishing.

  In order to solve such a problem, in Patent Document 1, an example of removing a part of the binder in the multilayer substrate 2 by performing heat treatment at 350 ° C. for 3 hours before cutting the laminated substrate 2 in a green state that has been crimped. It is shown. As another example, a manufacturing method is disclosed in which a laminated substrate is heat-treated at 280 ° C. for 4 hours to remove all plasticizers.

JP 2002-260952 A

  However, as described in the above-mentioned patent document, in order to carry out a method of removing a part of the binder in the multilayer substrate 2 in the green state or removing all of the solvent, the heat treatment temperature is set to 200 ° C. as described above. The temperature must be exceeded. For example, as described in the above-mentioned patent document, when the laminated substrate 2 in the green state is heat-treated at 350 ° C. for 3 hours or 280 ° C. for 4 hours, the residual solvent (including the plasticizer) in the laminated substrate becomes almost 0%, Since the strength of the substrate is increased, cutting with the lifting blade is impossible, while cutting with the rotating blade is possible. However, there are problems such as frequent chipping and large deformation of the substrate.

  In view of the above problems, the present invention can prevent chipping in the cutting process, reattachment of chips, or mist adhesion to individual chips, and adhesion of chips in the drying process after barrel polishing. Another object of the present invention is to provide a method for manufacturing a multilayer electronic component that can prevent chipping and improve productivity.

(1) A method for producing a multilayer electronic component according to the present invention includes a step of producing a green sheet by mixing a powder made of a magnetic material or a non-magnetic material, a binder, and a solvent,
Forming a conductor pattern on the green sheet;
Laminating a plurality of green sheets and press-bonding them to obtain a green laminated substrate;
Drying the laminated substrate in the green state at a temperature and time at which the binder does not decompose, thereby setting the residual solvent of the laminated substrate within 2.0 to 2.5% by weight;
Cutting the laminated substrate into individual chips;
Drying the chip obtained by the cutting at a temperature and time at which the binder does not decompose, thereby setting the residual solvent of the laminated substrate within 0.2 to 1.5% by weight;
And subsequent barrel polishing.

  In the present invention, in order to adjust the residual solvent amount in the green laminated substrate by drying, the drying time depends on the capacity of the dryer, the volume of the laminated substrate, the input amount, and the residual solvent amount before drying in the laminated substrate. And adjust the temperature.

  When the amount of residual solvent after drying before cutting is less than 2.0% by weight, chipping is likely to occur when cutting is performed by either a lifting blade or a rotating blade, and when exceeding 2.5% by weight, In the case of the lifting blade, a separation failure due to chip attachment is likely to occur, and in the case of the rotating blade, mist is likely to occur.

  Furthermore, in the present invention, after cutting the chip, drying is performed for a predetermined time at a temperature at which the binder does not decompose from the chip (hereinafter referred to as “de-buying”), and the residual solvent amount of the chip is 0.2 to 1. By setting the barrel polishing to 5 wt% (more preferably 0.5 to 1.0 wt%), it is possible to prevent chips from sticking and chipping in the drying process after barrel polishing. This is because the plasticity of the plasticizer on the chip surface was appropriately reduced by drying. In the drying after the cutting, chipping tends to occur when the residual solvent amount is less than 0.2% by weight, and the chips tend to adhere to each other when the amount exceeds 1.5% by weight.

(2) Moreover, the manufacturing method of the multilayer electronic component according to the present invention is as described in (1) above.
The laminated substrate is dried at 170 ° C. or lower before cutting the laminated substrate, and the heating after cutting is performed at 200 ° C. or lower.

  When practicing the present invention, the preferable drying temperature before cutting is 170 ° C. or lower, and the more preferable drying temperature at normal pressure is 140 to 170 ° C. This upper limit of the drying temperature is also related to debuy. That is, the debuiling temperature in the green state of the multilayer electronic component is slightly different depending on the type of the binder and the plasticizer used, but generally debuying starts from 200 to 240 ° C.

  Therefore, it is preferable that the drying temperature before cutting is 200 ° C. or less so as not to debuil. However, in the drying process before cutting, when attempting to dry at 200 ° C., the degree of decrease in residual solvent per hour is abrupt. In addition, variation in residual solvent amount due to variation in drying time among lots is likely to occur, and in consideration of prevention of de-bye, it is preferable to reduce the degree of decrease in residual solvent amount per unit drying time to 170 ° C. or less. However, when the temperature is lower than 140 ° C., for example, 130 ° C., the drying time becomes longer, for example, 3 hours or more, which is not suitable for the production of multilayer electronic components.

  On the other hand, since a part of the solvent has already been removed before cutting, the drying rate after cutting reduces the rate of decrease in residual solvent per unit time. It is preferable to dry at a temperature higher than the drying temperature. Specifically, a temperature of 200 ° C. or lower is preferable in order to prevent debuy and prevent the drying time from becoming long. A preferable drying temperature after cutting is 150 to 200 ° C. When the drying temperature after cutting is less than 150 ° C., the drying time becomes long, which is unsuitable for the production of multilayer electronic components.

(3) Further, in the method for manufacturing a multilayer electronic component according to the present invention,
The laminated substrate is dried before and after cutting the laminated substrate at a temperature of 120 ° C. or less in an environment having an atmospheric pressure of 133 Pa (1.0 mmHg) or less.

  Drying in such a reduced pressure state is advantageous in terms of shortening the drying time and enabling drying at a low temperature. In particular, DOA (dioctyl adipate), BBP (butyl benzyl phthalate), and the like used as solvents are high in boiling point and are effective when it is not preferable to raise the drying temperature in a green state. The air pressure when drying in such a reduced pressure state is 133 Hg or less, preferably 13 to 133 Pa. Further, the drying temperature is 120 ° C. or lower, preferably 80 to 120 ° C., at a temperature that does not debuil before and after cutting. When the drying temperature is less than 80 ° C., there is a problem that the drying time becomes long. In addition, when the temperature is 130 ° C. or higher, delamination is likely to occur due to the boiling of the solution. Therefore, in order to prevent such delamination, the drying temperature is preferably set in the range of 80 to 120 ° C.

  (1) In the present invention, before cutting the pressure-bonded green laminated substrate, drying is performed for a predetermined time at a temperature at which the binder in the laminated substrate is not decomposed, and the amount of residual solvent containing the plasticizer in the laminated substrate is set to 2 By setting the content to 0.0 to 2.5% by weight, there is no chipping or chip-to-chip adhesion when cutting is performed with the lifting blade, and the rotating blade can prevent chipping and mist adhesion to individual chips.

  In addition, since drying after cutting is performed so that the residual solvent amount including the plasticizer in the laminated substrate becomes 0.2 to 1.5% by weight, occurrence of adhesion of chips in the drying process after barrel polishing occurs. And chipping can be prevented.

  (2) In the present invention, by setting the drying temperature at normal pressure before cutting to 170 ° C. or less, a homogeneous laminated substrate can be obtained without fear of debuying and with little variation in the amount of residual solvent among lots. In addition, by setting the drying temperature after cutting to 200 ° C. or lower, a desired residual solvent amount can be obtained without increasing the drying time.

  (3) In the present invention, by setting the drying temperature in a reduced pressure state, which is almost a vacuum (13.3 to 133 Pa) before cutting, to 120 ° C. or less, drying can be performed at a low temperature without fear of deviating. Moreover, when using the solvent which cannot raise drying temperature, it can dry suitably. Moreover, delamination can be prevented by drying in a reduced pressure state and at a temperature of 120 ° C. or lower.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing an example of a multilayer electronic component obtained by the manufacturing method of the present invention. In this example, the case is a chip inductor in which terminal electrodes 7 are provided at both ends of a multilayer body 6. FIG. 2 is a process diagram showing an embodiment of a method for manufacturing a multilayer electronic component according to the present invention. In the manufacturing method shown in FIG. 2, steps of drying before cutting and drying after cutting shown by a chain line are added to the process diagram of the conventional method shown in FIG. A manufacturing process according to an embodiment of the present invention will be described below.

  (1) Green sheet production process (S1): Polyvinyl butyral resin as a binder and toluene, alcohol and phthalic acid ester as a binder are added to a Ni—Cu—Zn ferrite powder and kneaded to prepare a slurry. A green sheet was prepared on a PET film by applying a doctor blade method so that the thickness after drying was 20 μm. A dispersant may be added to the green sheet. Moreover, a part of the solvent, such as phthalate ester, is sometimes called a plasticizer.

  (2) Punching step (S2): A through hole was formed in a predetermined position by a laser on the green sheet produced as described above.

  (3) Conductor pattern forming step (S3): A paste having silver as a main component was screen-printed to form a 1/2 turn pattern so that a coil could be formed in a later lamination step. At this time, printing was performed so that the through hole became an end of the coil pattern and the through hole was filled with silver paste. Thereafter, the green sheet on which the conductor pattern was printed was dried and cut into a predetermined size (about 130 mm × 150 mm in the present embodiment).

  (4) Laminating step (S4): In the laminating step, the conductive pattern-formed green sheet is formed in a predetermined manner so that the conductive pattern on each of the green sheets is conducted in the silver paste filled in the through holes to form a coil. In this order, the sheet was laminated together with a green sheet on which no conductor pattern was formed, and then temporarily pressed to peel the PET film, and 18 sheets were laminated. These 18 are standard numbers among various inductor designs.

(5) Pressing step (S5): The laminated green sheets were pressure-bonded at a pressure of 74 MPa (750 kg / cm ² ) to form a laminated substrate.

  (6) Drying step before cutting (S6): As a result of measuring the residual solvent amount of the laminated substrate in the green state, the content was 3.5% by weight. The laminated substrate was dried at various temperatures in the range of 100 to 200 ° C. and a time of 10 to 300 minutes at normal pressure. As another drying method, drying was performed under reduced pressure (119.7 Pa) at various temperatures ranging from 50 to 140 ° C. and at various times within 180 minutes.

  (7) Cutting step (S7): Cutting was performed with a rotating blade using a dicer. Moreover, the same laminated substrate lot was also cut with a lifting blade. The size of the chip obtained by cutting was 2010 (length: 2 mm, width: 1.0 mm, height: 0.5 mm) as a finished product, and the number of chips taken was about 1700/1 laminated substrate.

  (8) Drying step after cutting (S8): Drying after cutting is performed at normal pressure at various temperatures within a range of 150 to 200 ° C. and at various times within a range of 10 to 300 minutes. It was. Further, drying was performed under reduced pressure (119.7 Pa) at various temperatures ranging from 50 to 140 ° C. and at various times within 180 minutes.

  (9) Barrel polishing step (S9): In barrel polishing, 30,000 dried chips, water, and media are put in the barrel of a barrel machine, polishing is performed for 20 minutes at a rotation frequency of 40 Hz, and pure water is finished after completion. Washed with.

  (10) Drying step (S10): The chip after barrel polishing was dried at a temperature of 85 ° C. with a dryer for 60 minutes. Chips and media were separated after drying.

  (11) Firing step (S11): Firing was performed with a temperature profile having a peak at 870 ° C. in a dedicated firing furnace to complete the laminate 6. Thereafter, in order to form the terminal electrode 7, a silver paste is applied to both ends of the laminate 6 and baked, and then electroplating is performed on the surface of the silver electrode to improve the solderability to the printed circuit board. It was.

(Evaluation)
(Relationship between residual solvent amount due to drying before cutting and defective rate when cutting with lifting blade)
The above-mentioned drying before cutting is performed at normal pressure, the drying temperature is set to 140 to 170 ° C., and the drying time is changed in various ways so that the residual solvent amount is 1.5 to 3.5% by weight (however, 3.5% by weight is In this case, the relationship between the amount of residual solvent after drying and chipping or separation failure (adhesion between chips) was investigated. The result is shown in FIG. As can be seen from FIG. 3, when the residual solvent amount is less than 2.0% by weight, chipping is likely to occur when cutting with a lifting blade, and when the amount exceeds 2.5% by weight, separation due to chip adhesion occurs. Since defects are likely to occur, the amount of residual solvent is preferably 2.0 to 2.5% by weight.

(Relationship between residual solvent amount due to drying before cutting and defective rate when cutting with a rotating blade)
When a rotating blade is used instead of the above-described lifting blade, the residual solvent amount after drying and chipping when the residual solvent amount is changed to 1.5 to 3.5% by weight by the same drying method or described with reference to FIG. FIG. 4 shows the result of examining the relationship with the amount of mist 4 generated during cutting. As can be seen from FIG. 4, when the amount of residual solvent is less than 2.0% by weight, chipping is likely to occur even when cutting with a rotating blade. In the case of using a rotating blade, the residual solvent amount is preferably 2.0 to 2.5% by weight.

(Examination of drying temperature and drying time in drying before cutting)
FIG. 5 shows the change in the weight loss rate over time when the sample prepared by the above-described process is dried at normal pressure and at a temperature of 100 to 200 ° C. for 60 minutes. Moreover, FIG. 6 shows the change of the weight loss rate with time passage at the time of drying for 300 minutes. As can be seen from FIGS. 5 and 6, when dried at 200 ° C., the entire amount of the solvent evaporates from the laminated substrate in about 60 minutes, and when dried at 170 ° C., the entire amount of the solvent evaporates from the laminated substrate in about 300 minutes. As can be seen from FIG. 5, at 140 to 170 ° C., the weight loss rate is 1 to 1.5% by weight in 10 to 60 minutes (this corresponds to the residual solvent amount of 2.0 to 2.5% by weight). It is preferable to dry in this temperature range.

  When attempting to dry at 200 ° C. in the drying process before cutting, the degree of decrease in residual solvent per hour is abrupt, and there is a risk that the variation in the amount of residual solvent due to variation in drying time from lot to lot will increase. For this reason, it is preferable to set the drying temperature to 170 ° C. or lower in order to reduce this variation and to prevent debuoyment as will be described later. However, when the temperature is lower than 140 ° C., for example, 130 ° C., the drying time becomes longer, for example, 3 hours or more, which is not suitable for the production of multilayer electronic components. For this reason, it is preferable that the drying temperature in a normal pressure shall be 140-170 degreeC.

(Examination of drying temperature and drying time in drying under reduced pressure before cutting)
FIG. 7 shows the change in weight loss rate over time when drying before cutting is performed under reduced pressure of 119.7 Pa and drying is performed at various drying temperatures of 50 to 140 ° C. for 180 minutes. As can be seen from FIG. 7, in a reduced pressure state that is almost a vacuum, even if the drying temperature is as low as about 80 ° C., the weight loss rate is about 1.0% by weight in about 15 minutes, ie, about 2.5% by weight. A residual solvent amount can be obtained, and at 130 ° C., a residual solvent amount of 2.5% by weight or less can be obtained by drying for about 5 minutes. For this reason, drying under reduced pressure is effective in that drying can be performed at a low temperature and in a short time. This is particularly effective when a solvent that is not preferred for heating is used.

  However, as shown in FIG. 8 when drying at 140 ° C., drying at 130 ° C. may cause delamination due to excessive drying, so drying under reduced pressure Is preferably performed at a temperature of 120 ° C. or lower. Moreover, it is preferable to dry at the temperature of 80 degreeC or more from the meaning of efficiency improvement by shortening of drying time.

  Moreover, since the ultimate pressure of the commercially available vacuum dryer is about 13.3 to 133 Pa, the use of such a vacuum dryer can shorten the drying time and the drying temperature as described above.

(Relationship between residual solvent amount due to drying after cutting and defective rate)
The above sample was dried at 150 ° C. for 30 minutes, and the residual solvent amount before cutting was 2.4% by weight. The sample was dried at normal pressure and at a drying temperature of 150 to 200 ° C. The amount was set to 0 to 3.5 wt% (however, 3.5 wt% was not dried before cutting), and the adhesion failure after barrel polishing and chipping failure for each content rate were examined. The result is shown in FIG. As can be seen from FIG. 9, when the residual solvent amount after cutting is within the range of 0.2 to 1.5% by weight, both adhesion failure and chipping failure will be 0.1% or less, and there is no problem in terms of productivity. Results were obtained. A more preferable residual solvent amount is 0.5 to 1.0% by weight in which these defects are further reduced.

(Drying temperature and drying time for drying after cutting)
Drying after cutting is preferably performed at a higher drying temperature than before cutting because the weight loss rate by drying is smaller than before cutting, and the drying temperature is 200 ° C. or less at normal pressure, more preferably in the range of 150 to 200 ° C. Of these, the time is preferably 10 to 300 minutes. If the drying is carried out at a temperature and time within this range, the amount of residual solvent after cutting can be within the range of 0.2 to 1.5% by weight with a low defect rate after barrel polishing.

  Moreover, when drying after cutting | disconnection is performed under the said pressure reduction, it is preferable to dry at the temperature of 80-120 degreeC similarly to the drying before cutting | disconnection.

(About prevention of debuy)
FIG. 10 shows the results of differential thermal analysis when the chip after cutting was heated at 100 to 200 ° C. for 300 minutes. As can be seen from the figure, there is no sign of heat generation at 170 ° C or lower, but at 200 ° C, heat generation is observed from 30 minutes, suggesting that de-buy, so when drying at 200 ° C In this case, it is preferable to dry in 30 hours or less.

(Relationship between the number of layers of the laminated substrate to be fed into the dryer and the amount to be fed and the drying temperature and time)
When the number of layers of the multilayer substrate is large, the solvent tends to be difficult to dry, and when the amount of input is large, it tends to be difficult to dry, so a suitable drying temperature or the like depends on the number of layers of the multilayer substrate and the amount of input. It is preferable to select a time.

(Other multilayer electronic components)
The manufacturing method of the present invention can also be applied to the manufacture of surface-mounted capacitors and filters, or array type multilayer electronic components each having a plurality of terminal electrodes 10 on both sides of the multilayer body 9 as shown in FIG.

It is a perspective view which shows an example of the multilayer electronic component obtained by the manufacturing method by this invention. It is process drawing which shows one Embodiment of the manufacturing method by this invention. It is a relational figure between the amount of residual solvents by drying before cutting of a laminated substrate, and the defective rate at the time of cutting with a raising / lowering blade. FIG. 6 is a relationship diagram between a residual solvent amount due to drying before cutting a laminated substrate and a defect rate at the time of cutting with a rotating blade. It is a figure which shows the relationship between the drying temperature in drying before cutting | disconnection of a laminated substrate, drying time, and a weight loss rate in the range for 60 minutes of drying time. It is a figure which shows the relationship between the drying temperature in drying before cutting | disconnection of a laminated substrate, drying time, and a weight loss rate in the range for 300 minutes of drying time. It is a figure which shows the relationship between the drying temperature under the reduced pressure in drying before cutting | disconnection of a laminated substrate, drying time, and a weight loss rate. It is a figure which shows the relationship between the drying time in 140 degreeC under pressure reduction in the drying before cutting | disconnection of a laminated substrate, and a delamination rate. It is a figure which shows the relationship between the residual solvent amount at the time of drying, after cut | disconnecting a laminated substrate, and the defect rate after barrel polishing. It is a figure which shows the result of the differential thermal analysis at the time of drying the chip | tip obtained by cut | disconnecting a laminated substrate at various temperature. It is a perspective view which shows the example of another multilayer electronic component to which the manufacturing method of this invention is applied. It is process drawing which shows the manufacturing method of the conventional multilayer electronic component. It is a figure explaining the problem in the cutting | disconnection of the laminated substrate by a rotating blade. It is a figure explaining the process of giving roundness to a corner part by barrel polishing.

Explanation of symbols

1: fixing film, 2: laminated substrate, 3: rotating blade, 4: mist, 5: chip, 5a: corner, 6: laminated body, 7: terminal electrode, 9: laminated body, 10: terminal electrode

Claims (3)

A step of producing a green sheet by mixing a magnetic or non-magnetic powder, a binder, and a solvent;
Forming a conductor pattern on the green sheet;
Laminating a plurality of green sheets and press-bonding them to obtain a green laminated substrate;
Drying the laminated substrate in the green state at a temperature and time at which the binder does not decompose, thereby setting the residual solvent of the laminated substrate within 2.0 to 2.5% by weight;
Cutting the laminated substrate into individual chips;
Drying the chip obtained by the cutting at a temperature and time at which the binder does not decompose, thereby setting the residual solvent of the laminated substrate within 0.2 to 1.5% by weight;
And a subsequent barrel polishing step. A method for manufacturing a multilayer electronic component, comprising: In the manufacturing method of the multilayer electronic component according to claim 1,
A method for producing a multilayer electronic component, comprising: drying the multilayer substrate before cutting the multilayer substrate at 170 ° C. or lower, and performing drying after cutting at 200 ° C. or lower. In the manufacturing method of the multilayer electronic component according to claim 1,
A method for producing a multilayer electronic component, comprising: drying the multilayer substrate before and after cutting the multilayer substrate at a temperature of 120 ° C. or less in an environment having a pressure of 133 Pa or less.

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