JP2018100190A - Glass protective film for electronic components, electronic components prepared therewith, and method for producing glass protective film for electronic components - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass protective film for electronic components that can be used even in high temperature environment.SOLUTION: The present invention provides a glass protective film 47 for stacking on an alumina substrate and resistance wiring. The glass protective film is mainly composed of SiO-CaO-AlOand contains anorthite crystal, or further contains at least one selected from magnesium oxide (MgO), zinc oxide (ZnO), and boron oxide (BO). The thermal expansivity of the glass protective film is similar to that of the alumina substrate. A method for producing the glass protective film 47 for electronic components 46 includes the steps of: mixing and melting an inorganic oxide containing, in mol%, SiO2: 30-60%, CaO or CaCO3: 15-25%, Al2O3: 10-25%; crushing the melted material to prepare glass powder; dissolving the glass powder in solvent to form a glass paste; and firing the glass paste at a temperature higher than or equal to 900°C, to form a glass protective film containing anorthite crystal.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a glass protective film for electronic components, and more particularly to a glass protective film laminated on an alumina substrate and a resistance wiring.

Regarding the protective film for electronic components, for example, there are the following prior art documents.
In Patent Document 1, a resistance layer that functions as a measurement resistance made of platinum is formed on a flat surface of a ceramic substrate made of aluminum oxide, and a diffusion prevention layer as an intermediate layer is provided on the resistance layer. An electrical temperature sensor is disclosed that is coated with a passive layer of glass.

  Patent Document 2 discloses a chip resistor having an electrode structure in which an electrode does not deteriorate even when operated for a long time in a temperature environment of about 250 to 350 ° C.

JP 2000-081354 A JP2015-119125A

  A temperature sensor element including platinum (Pt) or the like as a resistance wiring (hereinafter referred to as [platinum (Pt) group]) is used in an environment where the ambient temperature range is a high temperature range of several hundred to 1,000 ° C. Sometimes.

  However, when an electronic component such as this temperature sensor element is used for a long time in a high temperature environment, the components contained in the glass diffuse and react with the Pt thin film resistor, causing a phenomenon such as migration, and the resistance of the Pt thin film resistor. There was a problem that the value changed. In addition, it is a chip resistor that is expected to be used in a temperature environment of about 250 to 350 ° C. However, it is assumed that it will be required to be used in a higher temperature environment in the future for applications such as in-vehicle use. Is done.

  In general, glass having higher heat resistance than resin is desirable as a protective film for electronic components used in a high temperature environment.

  An object of this invention is to provide the glass protective film of the electronic component which can be used also in a high temperature environment.

According to one aspect of the present invention, there is provided a glass protective film for laminating on an alumina substrate and a resistance wiring, which is characterized by comprising SiO ₂ —CaO—Al ₂ O ₃ as a main component and containing anorthite crystals. A glass protective film for electronic components is provided. Here, it is preferable that the thermal expansion coefficient approximates that of an alumina substrate.

It may further include at least one selected from magnesium oxide (MgO) and zinc oxide (ZnO) or boron oxide _(B 2 _{O 3).} Moreover, you may make it further contain an alkali metal oxide. Further, the alkali metal oxide may be potassium oxide (K ₂ O). The proportion of anorthite crystals deposited on the surface layer of the glass protective film is preferably 50 to 90% or more.

  The present invention includes an alumina substrate, a resistance wiring formed on one surface of the alumina substrate, an electrode electrically connected to the resistance wiring, an external connection terminal bonded to the surface of the electrode, An electronic component having the glass protective film described above covering the resistance wiring.

  The resistance wiring is preferably made of a material containing a Pt group.

According to another aspect of the present invention, there is provided a method for producing a glass protective film for laminating on an alumina substrate and a resistance wiring, wherein silicon oxide (SiO ₂ ) 30-60 mol%, calcium oxide (CaO) or calcium carbonate ( A step of mixing and melting an inorganic oxide containing 15 to 25 mol% of CaCO ₃ ) and 10 to 25 mol% of aluminum oxide (Al ₂ O ₃ ), a step of producing a glass powder by grinding after melting, and the glass A step of forming a glass paste by dissolving powder in a solvent, and a step of baking the glass paste at a temperature of 900 ° C. or more to form a glass protective film containing anorthite crystals. A method for producing a glass protective film is provided.

The melting step further includes a step of adding 10 mol% or less of magnesium oxide (MgO), 10 mol% or less of zinc oxide (ZnO), and 15 mol% or less of boron oxide (B ₂ O ₃ ). The melting step may further include a step of adding 0 to 10 mol of potassium oxide (K ₂ O).

  The step of forming the glass paste may further include a step of adding anorsite crystal powder. It is preferable that the anorthite powder to be added is 2 to 8% by volume.

  In the step of forming the glass protective film containing the anorthite crystal, the primary baking is preferably performed at 700 to 900 ° C. before the secondary baking step of baking at a temperature of 900 ° C. or higher. The secondary firing is preferably performed at 900 to 1300 ° C.

  Moreover, it is preferable that this invention is a manufacturing method of a glass protective film whose glass protective film is a glass protective film as described above.

  According to the present invention, the glass protective film of an electronic component can be used even in a high temperature environment.

It is a flowchart figure which shows the example of a production process of the glass powder used as the raw material of the glass protective film by embodiment of this invention. It is a flowchart figure which shows the process example which produces the glass protective film for electronic components by this Embodiment based on the glass powder obtained by the process of FIG. It is the schematic of a screen printing process among the processes of FIG. It is a figure which shows the analysis result using XRD (X-ray-diffraction method) of a coating sample. It is a figure which shows the growth model of anorthite, a vertical axis | shaft is a nucleation rate and a growth rate, and a horizontal axis is a calcination temperature. It is a SEM photograph in case baking conditions are (a) 900 degreeC * 1h, (b) 1000 degreeC * 1h, (c) 1200 degreeC * 2h, (d) 1300 degreeC * 2h. In FIG. 5, (a) is an estimation diagram schematically showing the distribution of anorthite crystals in the temperature range of 1) and 2), (b) in 3), and (c) in 4). (A)-(d) is a figure which shows the SEM photograph in the surface layer of an anorthite crystal. It is a figure which shows the structure of the sample for a high temperature electricity test, (a) is a top view, (b) is sectional drawing. It is a figure which shows a high-temperature energization test result, (a) is baking conditions 1100 degreeC x 2h, (b) is baking conditions 800 degreeC x 2h + 1100 degreeC x 2h, (c) is 800 degreeC x 2h + 1200 degreeC. X2h. It is a figure which shows the evaluation result of a protective film by the change of the conditions including the addition amount of anorthite, (a) is 1100 degreeC x 2h baking conditions, (b) is 800 degreeC x 2h + 1100 degreeC baking conditions. × 2h, (c) is 800 ° C. × 2h + 1200 ° C. × 2h. It is a figure which shows the result of the step-up test at the time of using as a protective film the sample of the baking conditions 800 degreeC * 2h + 1200 degreeC * 2h in which the favorable result was obtained as shown in FIG.

  In this specification, for example, when it is described as firing conditions: 800 ° C. × 2 h, it means firing at 800 ° C. for 2 hours. In addition, the notation of 800 ° C. × 2 h + 1200 ° C. × 2 h means that after the baking treatment under the former condition, the baking treatment under the latter condition is performed. The same applies hereinafter.

  Moreover, the platinum group used for resistance wiring is ruthenium, rhodium, palladium, osmium, iridium, and platinum. Hereinafter, an example in which platinum is used as resistance wiring will be described.

  Hereinafter, a glass protective film for an electronic component according to an embodiment of the present invention will be described in detail with reference to the drawings.

(Basic composition of glass and functions of glass components)
First, the basic composition of glass and the function of glass components will be described.
According to the addition range of each component of the glass, the glass composition should satisfy at least the range where anorthite is deposited (Si: Ca: Al = 2: 1: 2 (atomic ratio)) and have linear expansion close to that of an alumina substrate. investigated. If a crack occurs in the glass protective film, the underlying resistance wiring is likely to be exposed, and if the energization is continued in this state, the resistance wiring may disappear and disconnection may occur. Thus, by approximating the linear expansion with the alumina substrate, the thermal stress during firing or use can be relaxed, and the occurrence of cracks in the alumina substrate, resistance wiring, and glass protective film can be suppressed.

  The addition range of each component, the role (function), the phenomenon that occurs when the addition range is exceeded and less than the addition range will be described. In order to use in a high temperature range as in the electronic component of the present embodiment, the glass protective film needs to be baked in a slightly higher temperature range. In order to melt in the firing temperature range and seal (passivate) in close contact with the resistance wiring, it is desirable that the softening temperature range of the glass is a slightly low region around 800 ° C., and such softening temperature range and The glass component of this Embodiment was adjusted so that it might become.

Range of addition of SiO ₂ is preferably 30 to 60 mol%. The addition range of CaO is preferably 15 to 25 mol%. Addition range of Al ₂ O _3, preferably 10 to 25 mol%. These components are effective when added in an appropriate range in the role of precipitating the anorthite crystal phase and the role of improving heat resistance.

When the addition range of SiO ₂ exceeds 60 mol%, the addition amount of the components (CaO and Al ₂ O ₃ ) for precipitating other anorthite crystal phase is relatively reduced, so the precipitation amount of anorthite is relatively Decrease. Moreover, if the proportion of SiO _{2 in} the glass is too large, the high heat resistance deteriorates. When the addition range of SiO ₂ is less than 30 mol%, other glass components (Al ₂ O _{3 and the} like) are relatively increased, and the ratio of ceramics is increased, so that the glass is not vitrified, and sintering becomes insufficient and anorthite precipitates. A phenomenon occurs in which the amount decreases.

  When the addition range of CaO exceeds 25 mol%, it will become difficult to vitrify and the precipitation amount of anorthite will decrease. When the CaO addition range is less than 15 mol%, a phenomenon occurs in which the amount of precipitated anorthite decreases.

When the addition range of Al ₂ O ₃ exceeds 25 mol%, it becomes difficult to vitrify, precipitation amount of anorthite is reduced to a relative. When the Al ₂ O ₃ addition range is less than 10 mol%, a phenomenon occurs in which the amount of anorthite deposited decreases. Here, vitrification means that the blended components melt at a temperature sufficiently lower than the melting point of each substance without taking a crystal structure.

The addition range of MgO is preferably 10 mol% or less. When MgO is replaced with CaO, it plays the role of lowering the linear expansion coefficient of glass and approaching that of alumina. When the addition range of MgO exceeds 10 mol%, vitrification becomes difficult. Moreover, since the amount of precipitation of components (SiO ₂ , CaO and Al ₂ O ₃ ) that precipitate anorthite is relatively reduced, precipitation of anorthite crystal phase is reduced.

  The addition range of ZnO is preferably 10 mol% or less. When ZnO is replaced with CaO, it plays the role of lowering the linear expansion coefficient of the glass to bring it closer to the linear expansion coefficient of alumina and promoting the softening of the glass during firing. When the addition range of ZnO exceeds 10 mol%, it will become difficult to vitrify. In addition, the amount of anorthite is relatively reduced.

The addition range of B ₂ O ₃ is preferably 15 mol% or less. B ₂ O ₃ plays a role of lowering the linear expansion coefficient in addition to lowering the melting temperature and softening temperature of the glass. When the addition range of B ₂ O ₃ exceeds 15 mol%, the glass softening temperature region is remarkably lowered, so that the stability (heat resistance) of the glass is deteriorated. In addition, the amount of anorthite is relatively reduced.

The addition range of K ₂ O is preferably 10 mol% or less. K ₂ O liquefies at the time of firing and adheres to the alumina substrate and the resistance wiring and plays a role of improving wettability. When the addition range of K ₂ O exceeds 10 mol%, the number of K ⁺ ions increases and it becomes easy to move. When K ⁺ ions move, ion migration may occur, leading to disconnection. The stability of the remaining glass phase is deteriorated and the stability (heat resistance) of the glass is deteriorated.

By including SiO ₂ —CaO—Al ₂ O ₃ as a main component and including anorthite crystals, it is possible to improve the heat resistance of an electronic component including a wiring of a Pt group or the like. CaO can also be added as calcium carbonate (CaCO ₃ ). Calcium oxide or calcium carbonate can be added in the range of 15 to 25 mol%, more preferably in the range of 20 to 25 mol%.

By adding magnesium oxide (MgO) to 10 mol% or less, zinc oxide (ZnO) to 10 mol% or less, and boron oxide (B ₂ O ₃ ) to 15 mol% or less as other metal compounds, the linear expansion coefficient of glass is increased. It can be adjusted to approach the linear expansion coefficient of alumina.

Of the above components, CaO and MgO are other alkaline earth metal oxides, ZnO is tin oxide (SnO ₂ ), B ₂ O ₃ is phosphoric acid (P ₂ O ₅ ), and K ₂ O is another alkali. It is also possible to replace it with a metal oxide (oxide such as Na or Li).

(Sample list)

  Table 1 is a table showing a sample list and results of a high-temperature energization test.

The following are the meanings from * 1 to * 6 in Table 1.
* 1 [Glass A: 7K ₂ O-5MgO-20CaO-5ZnO-13Al ₂ O ₃ -10B ₂ O ₃ -40SiO ₂ (mol%) ⇒Alkali metal oxide included]
[Glass B: 5MgO-20CaO-5ZnO-20Al ₂ O ₃ -10B ₂ O ₃ -40SiO ₂ (mol%) ⇒No alkali metal oxides contained]
* 2 Anosite powder addition amount (volume% (vol%))
* 3 Firing conditions 1) 800 ° C x 1h, 2) 900 ° C x 1h, 3) 1000 ° C x 1h, 4) 1100 ° C x 1h, 5) 800 ° C x 2h + 1100 ° C x 2h, 6) 800 ° C x 2h + 1200 ℃ × 2h
* 4 Appearance In the visual inspection, ○ indicates that the underlying resistance wiring is not exposed.
Moreover, although exposure of the lower layer resistance wiring is not seen, the thing which may not fully sinter is set as (triangle | delta).
* 5 High-temperature energization test 1) 1100 ° C x 5h 5V applied A test to evaluate the effect of applying a bias current assuming a measured current at high temperature for a long time to investigate the effect on resistance wiring. Presence / absence of the effect (result quality) was evaluated by the resistance value change rate.
○: Resistance value change rate is within 2%. Δ: Resistance value change rate is within 4%.
* 6 High-temperature energization test 2) From 800 ℃ to 1100 ℃, 100 ℃ / 10h
○: Resistance value change rate is within 2%. Δ: Resistance value change rate is within 4%.
(Rate change rate after 1100 ° C x 10h)

For the reliability test, the glass composition containing an alkali metal oxide [Glass A: 7K ₂ O-5MgO-20CaO-5ZnO-13Al ₂ O ₃ -10B ₂ O ₃ -40SiO ₂ (mol%)], alkali metal The glass composition containing no oxide is [Glass B: 5MgO-20CaO-5ZnO-20Al ₂ O ₃ -10B ₂ O ₃ -40SiO ₂ (mol%)], and the firing conditions are 800 ° C. × 1 h, 900 ° C. × 1 h. , 1000 ℃ × 1h, 1100 ℃ × 1h, 800 ℃ × 2h + 1100 ℃ × 1h, 800 ℃ × 2h + 1200 ℃ × 1h state of each glass protective film and resistance value in high-temperature energization test The rate of change was tested.

  Further, the glass composition containing the same alkali metal oxide [glass A] and the glass composition not containing alkali metal oxide with respect to [glass B], further changing the addition amount of anorsite powder (0 to 8 vol%) ) The state of the glass protective film when added and the resistance value change rate in the high-temperature energization test were tested. The test results will be described later with reference to Table 1.

  Hereinafter, embodiments of the present invention will be described in more detail.

(Production method of glass protective film)
First, the manufacturing method of the glass protective film for electronic components by this Embodiment is demonstrated in detail.

  FIG. 1 is a flowchart showing an example of a production process of glass powder as a raw material for a glass protective film.

First, in step S1, the glass raw material is weighed. For example, the composition is 7K ₂ O-5MgO-20CaO-5ZnO-13Al ₂ O ₃ -10B ₂ O ₃ -40SiO ₂ (mol%).

  Next, each of the oxides weighed in step S1 is dry-mixed in step S2. The melting method is not particularly limited, and all the mixed raw materials may be dissolved.

  In step S3, for example, a melting process of 1500 ° C. × 1 h is performed under atmospheric pressure.

  In step S4, for example, a slow cooling glass sample is obtained in step S5 by performing a slow cooling process from 700 ° C. to 100 ° C. at a rate of 1 ° C./min. The slow cooling (cooling) method is not particularly limited, and a method such as rapid cooling in water or slow cooling in air can be appropriately employed.

  Next, in step S6, the slow-cooled glass sample is pulverized, and in step S7, a classification process for allowing the 75 μm mesh to pass through is performed.

  In step S8, the powder obtained in step S7 is pulverized. For the pulverization process, for example, a ball mill process can be used. The condition of the ball mill treatment is, for example, wet ball mill treatment with 100 ml of ethanol, and pulverization was performed using a silicon nitride 5 mmφ ball at a rotation speed of 110 rpm and a mixing time of 48 hours.

  In step S9, a glass powder having a diameter of 1 to 3 μm was obtained in step S10 by performing a drying process.

  FIG. 2 is a flowchart showing an example of a process for producing a glass protective film for an electronic component according to the present embodiment based on the glass powder obtained by the process of FIG. FIG. 3 is a schematic view of the screen printing process in the process of FIG.

  As shown in FIG. 2, first, in step S21, the glass powder having a diameter of 1 to 3 μm obtained by the process of FIG. 1 and printing medium oil (ink) or vehicle are mixed at a mass ratio of 2: 1.7. By preparing and performing a mixing process in step S22, a glass paste is produced in step S23.

  In step S24, screen printing or coating is performed.

  The raw material mixing method and the pulverization method are not particularly limited as long as they can be uniformly dispersed / pulverized, and can be performed using a known method (mixer, ball mill, or the like).

  As shown in FIG. 3, in the screen printing method, first, a screen 31 is placed on the alumina substrate 1. A glass protective film can be printed on the alumina substrate 1 by placing, for example, # 120 mesh 37 on the alumina substrate 1 and moving the glass paste 35 with the squeegee 33 on the screen 31.

  Next, in step S25 of FIG. 2, for example, a drying process is performed at room temperature for 5 minutes and at 150 ° C. for 15 minutes. In step S26, firing is performed under atmospheric pressure at a heating rate of 10 ° C./min. The firing conditions are, for example, 800 ° C. × 1 h, 900 ° C. × 1 h, 1000 ° C. × 1 h, 1200 ° C. × 1 h. Details of the firing conditions will be described later.

  Through the above steps, a glass protective film coating sample (coating agent) can be formed (step S27).

  The melting method is not particularly limited, and it is sufficient that all the mixed raw materials are dissolved. The method for slowly cooling (cooling) the melt is not particularly limited, and quenching in water or in air. These methods can be adopted as appropriate. Also, the firing method is not limited, and any method such as a batch furnace or a belt furnace can be appropriately employed as long as the glass melts and the crystal phase is precipitated.

(Analysis of glass protective film)
In order to have heat resistance and stability so that the characteristic of the resistance wiring does not change even when used at a high temperature like the electronic component of the present embodiment, a crystalline component in an amorphous glass phase as a glass protective film It is desirable to use crystallized glass in which is dispersed. Therefore, it was examined whether crystals were precipitated in the glass protective film.

  FIG. 4 is a diagram showing an analysis result of a glass protective film which is a coating sample formed by the above process. The result of changing the firing temperature is shown. As an analysis technique, XRD (X-ray diffraction method) was used.

  As shown in FIG. 4, it can be seen that the anorthite crystals are precipitated in a single phase under any firing condition of 900 ° C. or higher. It can also be seen that the higher the temperature, the higher the intensity of X-ray diffraction based on the anorthite crystal. Therefore, it can be seen that the amount of crystals deposited depends on the firing temperature, and that the higher the firing temperature, the more anorthite crystals are deposited.

  FIG. 5 is a diagram showing the anorthite growth model as described above. The vertical axis represents the nucleation rate and the growth rate, and the horizontal axis represents the firing temperature.

  As shown in FIG. 5, the glass transition temperature Tg obtained by TMA measurement (thermomechanical analysis) is 648 ° C. And the crystallization start temperature obtained by DTA measurement (differential thermal analysis measurement method) is 801 degreeC.

  When attention is paid to the nucleation rate, a curve having a peak around the firing temperature of 1070 ° C. is obtained, and when attention is paid to the crystal growth temperature, a curve having a peak around the firing temperature of 1230 ° C. is obtained. Then, it is preferable to perform firing in a temperature range where both nucleation and crystal growth occur (horizontal hatched area). That is, the preferable firing temperature is a temperature range between 900 ° C. and 1300 ° C., and the range of 1000 ° C. to 1200 ° C. is more preferable.

  FIG. 6A is an SEM photograph when the firing conditions are (a) 900 ° C. × 1 h, (b) 1000 ° C. × 1 h, (c) 1200 ° C. × 2 h, and (d) 1300 ° C. × 2 h.

  From this result, it can be seen that a glass protective film with a large amount of anorthite crystal precipitation and few voids can be obtained by firing at 1200 ° C. × 2 h.

  FIG. 6B shows the distribution of the anorthite crystal 23 in the glass protective film 21 in the temperature range of FIG. 5 where (a) is 1) and 2), (b) is 3), and (c) is 4). It is an estimation figure which shows (11) typically. Crystal growth has a constant growth rate, and the amount of precipitation varies depending on various conditions. Here, attention was paid to the firing temperature.

  In the temperature range of 1) and 2), the crystal is not sufficiently grown and the size is small. Glass in this state is not very suitable as a protective film for electronic parts because it is difficult to ensure sufficient mechanical strength. In the temperature range of 3), precipitation of crystals is moderate and suitable as a protective film for electronic parts. In the temperature range of 4), the crystal grows excessively, and the crystal size becomes large. In other words, in the state of figure 4), the gap between crystals is large, and it is difficult to ensure sufficient sealing, so there is a possibility that there is a problem in heat resistance and stability, and it is not very suitable as a protective film for electronic parts. . In the temperature range of 3), it is estimated that the state is intermediate between 1), 2) and 4). Thus, in the temperature region where crystallization proceeds, the state 3) is obtained, and a preferable protective film can be formed. That is, the anorthite crystal can be dispersed in the amorphous glass.

Note that the glass protective film according to the present embodiment has a thermal expansion coefficient close to that of an alumina substrate (7.8 × 10 ⁻⁶ K ⁻¹ ) (for example, 6.0 × 10 ⁻⁶ K ^{−1 to} 8.0 × 10 ^−6). K ⁻¹ , which is 7.6 × 10 ⁻⁶ K ⁻¹ in this embodiment). Therefore, it is suitable as a glass protective film for laminating on an alumina substrate and resistance wiring.

(Examination of precipitation amount of anorthite crystals)
Next, the precipitation amount of anorthite crystals in the protective film will be described below with reference to Table 1 and the like.

1) Maximum amount of precipitation The maximum crystallization rate of the alkali metal oxide-containing glass in the examples described later is calculated as follows.
・ Glass composition: 7K ₂ O-5MgO-20CaO-5ZnO-13Al ₂ O ₃ -10B ₂ O ₃ -40SiO ₂ (mol%)
・ Anosite composition: CaAl ₂ Si ₂ O ₈ (CaO-Al ₂ O ₃ -2SiO ₂ )
Assuming that all 13Al ₂ O ₃ was used for anorthite, residual glass: 7K ₂ O-5MgO-7CaO-5ZnO-10B ₂ O ₃ -14SiO ₂ (total 48mol%)
Maximum crystallization rate: 100-48 = 52%

2) Minimum precipitation amount As a property of glass, as crystallization progresses, the amorphous phase glass component (glass component that does not crystallize) moves to the substrate side, and the crystal constituents (Si, Ca, Al in this application) are on the surface layer side. Since crystallization occurs, the crystallization rate can be estimated from the area ratio of the crystal constituent material occupying the surface layer side (atmosphere side) of the protective film.

  Therefore, by SEM analysis, the crystal / amorphous phase and the area that can be determined as an anorthite crystal from the composition were observed.

  As a result, in the surface layer of the glass protective film, the proportion of crystals in the glass on the surface layer, that is, the proportion of anorthite crystals in the glass on the surface layer is precipitated by 30% or more (preferably 50% or more). It can be estimated that it is important as a membrane.

  Details of the experiment will be described below.

≪Sample selection≫
As a representative, the following two samples were observed by SEM analysis. Sample No. 2 and Sample No. 3 in Table 1 were prepared under the following conditions.
1) Sample No.2 containing alkali metal oxide, 900 ° C x 1h baked 2) Sample No.3 containing alkali metal oxide, 1000 ° C x 1h baked

  These experiments compared the firing treatment in the temperature region (900 ° C or higher) where crystallization of anorthite crystal begins to progress and the firing treatment in a temperature region higher than that, and the difference in precipitation of anorthite crystals depends on the firing conditions. Is to check whether or not can be seen.

  In addition, the reason for selecting the sample without added anorthite powder is that the sample with added anorthite powder precipitates more crystals than the sample without added, so it is not suitable for seeing the minimum precipitation amount. It is.

≪Result of SEM analysis≫
FIGS. 7A to 7D are views showing SEM photographs of the sample.
The sample No. 2 900 ° C. × 1 h in FIGS. 7A and 7B will be described.

  The bright (white) part of the figure is the Ca-concentrated part, and the surface layer is formed of an anorthite crystal phase constituent material of about 50% (area ratio). Since the area ratios of Ca and Al, which are constituent materials, do not completely match, there is a possibility that they are not completely crystallized, but it can be seen that anorthite crystals are precipitated.

  The sample No. 3 1000 ° C. × 1 h in FIGS. 7C and 7D will be described.

  About 90% (area ratio) of the surface layer is covered with the anorthite crystal phase constituent material. It can be said that the amorphous phase glass component moves to the substrate side, and the crystallization surely proceeds on the surface layer side.

  From the above results, it can be seen that the ratio of crystals on the surface layer side (atmosphere side) of the glass protective film is higher as the firing temperature is higher, and the amount of anorthite deposited is approximately 100% in the area ratio in the vicinity of 1000 ° C. . Further, when the firing temperature is 900 ° C., the amount of anorthite deposited on the surface layer side is about 50% by area ratio.

  As shown in FIG. 5, at 900 ° C. or higher, it can be said that the region is a region where crystallization proceeds (a hatched region of a horizontal line).

  The above results and the appearance of each sample after firing (when the firing condition is 800 ° C., the underlying resistance wiring is exposed or not exposed, but the sintering has not progressed sufficiently. 5), the temperature dependence of the anorthite nucleation rate and crystal growth rate in FIG. 5 is estimated to be less than 30% at a firing temperature of 800 ° C., and 50% at a firing temperature of 900 ° C. As described above, it is estimated that 90% or more of the anorthite crystal phase is formed on the surface layer (atmosphere side) of the glass film at a firing temperature of 1000 ° C.

  Even if there is about 30% precipitation when the firing temperature is 800 ° C., there are cases where the underlying resistance wiring is not sufficiently covered, and the function as a stable protective film may not be sufficiently ensured even in a high temperature environment. Therefore, it is considered important that the anorthite crystal precipitation on the surface layer side is 50% or more.

(Evaluation result of glass protective film)
Hereinafter, the results of an energization test for examining the durability of an electronic component manufactured using the glass protective film for an electronic component according to the above embodiment will be described with reference to Table 1 as well.

  8A and 8B are diagrams showing the configuration of a sample for an electric current test, where FIG. 8A is a plan view and FIG. 8B is a cross-sectional view. The sample has a length L = 4.0 mm, a width W = 1.8 mm, and a thickness t = 0.635 mm.

  The sample for the current test is, for example, a resistor having a resistance wiring 46 formed on the alumina substrate 1, a Pt electrode 43 connected to two terminals of the resistance wiring 46, and a lead wire (Ptlr) 55 connected thereto. It is a vessel.

  A glass protective film 47 for electronic parts according to the present embodiment is formed on the resistance wiring 46, and the same glass protective film for electronic parts according to the present embodiment is formed on the Pt electrode 43 and the Pt lead wire 55. A contact glass 51 that reinforces the contact 45 is formed. The contact glass 51 uses the same composition as the glass protective film 47 because of its high heat resistance. However, if the glass composition can withstand the firing temperature range and the use temperature range according to this embodiment, the glass protective film A glass different from 47 may be used.

  In such a sample, 5 V was applied in an environment of 1100 ° C. for 5 hours or more using a high-temperature calibration apparatus, a high-temperature energization test was performed, and the resistance value was continuously measured.

  FIG. 9 is a diagram showing the test results. (A) shows the firing conditions of 1100 ° C. × 2 h, (b) shows the firing conditions of 800 ° C. × 2 h + 1100 ° C. × 2 h, and (c) shows the firing conditions. 800 ° C. × 2 h + 1200 ° C. × 2 h.

  In addition, in FIG. 9, as will be described later, the state of the glass protective film when the anorthite powder was added by changing the addition amount (1, 2, 4, 6, 8 vol%), and the high temperature standing test. The results of testing the rate of change in resistance at are also shown.

  Explaining the case where the added amount of anorthite is 0 vol%, it was found that the change in resistivity was small in the case of condition (c).

  That is, it can be seen that a protective film with little change in resistance value during the energization test was obtained at 800 ° C. × 2 h + 1100 ° C. × 2 h.

  FIG. 10 is a diagram showing the evaluation results of the protective film by changing the conditions including the added amount of anorthite powder for the above firing conditions (a) to (c). The reason why the anorthite powder is added separately from the glass component constituting the anorthite is to promote anorthite crystal precipitation of the glass component by using the anorthite powder as a crystal nucleus. As described below, crystallization progresses when the anorthite powder is added even if the firing temperature is low, and the resistance value change rate becomes low.

  As shown in FIG. 10, among firing conditions (a) to (c), under firing conditions (a), disconnection is observed, and the change in resistivity is smaller as the added amount of anorthite powder is increased. I understand that Therefore, it can be understood that the evaluation result is not good under the firing condition (a) as compared with the firing condition (b).

  Under firing conditions (b), there are cases where disconnection is observed, however, when anorthite powder is added, disconnection is reduced, and the change in resistivity is minimal when the added amount of anorthite powder is around 4 vol%. I understand that Therefore, it can be seen that the evaluation result is not bad under the firing condition (b).

  Under the firing condition (c), no disconnection is observed, however, it can be seen that the change in resistivity is minimized when the added amount of anorthite powder is around 2 to 4 vol%. Under the firing conditions (c), the evaluation results of most samples were good.

  Also, when the amount of anorthite powder added was changed, the evaluation result was better for 2 vol% than for 0 vol%, and better for 8 vol% than for 2 vol%. Regardless of the type, it can be seen that the larger the amount of anorthite powder added, the more the resistance value change can be suppressed, and thus the protective film can be made dense. However, if anorthite powder is added in an amount of 10 vol% or more, the timing of crystal growth is advanced, which may result in insufficient sealing of the resistance wiring, and it is necessary to raise the sintering temperature. Addition is desirable.

As nucleation material other than anorthite powder, it is also possible to add powder of _{TiO 2,} ZrO 2, MgO and the like.

  As described above, under the firing condition (c), even when no anorthite powder is added, no disconnection is observed and the change in resistivity is small, and under the firing condition (b), the disconnection occurs due to the addition of the anorthite powder. And the resistivity change is small. In the firing condition (a), the wire breakage is less reduced and the resistivity change is larger than the firing conditions (b) and (c). I understand that.

  It has been found that even when the firing temperature is low to some extent, the results of the energization test can be improved by adding anorthite powder.

  FIG. 11 shows a sample with a firing condition of 800 ° C. × 2 h + 1200 ° C. × 2 h (baking condition 800 ° C. × 2 h followed by 1200 ° C. × 2 h) obtained as a protective film as shown in FIG. It is a figure which shows the result of a step-up test in the case of having met.

The firing condition (a) is a step-up test condition of 800 ° C. × 10 h, the firing condition (b) is 900 ° C. × 10 h, the firing condition (c) is 1000 ° C. × 10 h, and the firing condition (d) is 1100 ° C. × 10 h. The vertical axis represents the rate of change in resistance, and the horizontal axis represents the amount of anorthite added. The rhombus plot is a sample containing an alkali metal oxide (7K ₂ O), and the square plot is a sample containing no alkali metal oxide (no alkali).

The following knowledge was obtained from the results of FIG.
1) When alkali-free, resistance value change is suppressed.
2) When the added amount of anorthite powder is around 4 vol%, the change in resistance value is minimized.
3) When the test temperature is increased, the change in resistance value increases. However, when the temperature of the step-up test is 800 ° C., the change in resistance value is small, and in the case of 1100 ° C., under any condition, Resistance value change is large.

  That is, an alkali-free anorthite powder addition amount of 4 vol% was the most favorable condition, and durability was observed in tests up to 1000 ° C.

(Summary of test results)
1) Results of XRD analysis Among the samples in Table 1, samples (Nos. 27 to 30 and Nos. 34 to 36) to which 4 vol% of anorthite powder was found that showed particularly good results in the high-temperature energization test described later. In order to examine whether there is a difference in the precipitation of anorthite crystals due to differences in firing conditions and glass components (with or without alkali metal oxides), XRD analysis was performed. In addition, in order to investigate whether there is a difference in the precipitation of anorthite crystals depending on whether or not anorthite powder was added, An XRD analysis was also conducted for 5. All samples were found to have anorthite crystals in the glass protective film. Further, depending on the firing temperature, there is a slight difference in the peak intensity of anorthite, if the glass composition of the present embodiment, the presence or absence of an alkali component, regardless of the presence or absence of anorthite powder, crystallize the glass, It was found that anorthite can be precipitated.

2) Result of high-temperature energization test As the result of the appearance test, the higher the temperature as the firing condition, the better the result. The difference in the characteristics of the protective film due to the difference in the firing condition and the glass component (with or without alkali metal oxide) In order to investigate the function as a protective film of an electronic component, a plurality of samples (No. 6, No. 10-12, No. 16-18, No. 28-30, No. 34-36, No. 34) are used. 40-42 and No. 46-48) were subjected to a high-temperature energization test. The sample was left in an environment of 1100 ° C. for 5 hours while applying 5 V, and the resistance value change rate was evaluated as good (◯) when the resistance value change rate was within 2%. It can be seen that the higher the calcination temperature, in particular, no disconnection is observed at calcination conditions 6) 800 ° C. × 2 h + 1200 ° C. × 2 h.

  It can be seen that the resistance value change tends to be suppressed when the alkali metal oxide is not contained.

  It can be seen that when the amount of anorthite is 4 to 6 vol%, the resistance value change is small.

  Furthermore, in order to investigate the influence of the precipitation amount of anorthite on the change in resistance value, a high-temperature energization test was conducted in which energization was performed while increasing the temperature from 800 ° C. to 1100 ° C. every 10 hours at 100 ° C. Firing conditions 6) 800 ° C. × 2h + 1200 ° C. × 2 h sample (No. 6, No. 12, No. 18, No. 24, No. 30, No. 36, No. 42, No. 49 to 52) Went against. In the evaluation, a resistance value change rate of 2% or less was evaluated as good (◯). As a result, good results were obtained when the addition of anorthite powder was 2 vol% or more and 6 vol%.

3) SEM observation SEM observation was performed in order to find the cause of the result in the high-temperature energization test. 4vol% of anorthite added, firing conditions 5) 800 ℃ × 2h + 1100 ℃ × 2h and firing conditions 6) 800 ℃ × 2h + 1200 ℃ × 2h (Sample No.29,30,35,36) surface condition As can be seen, a sufficient film is formed regardless of the presence or absence of an alkali metal oxide. That is, the glass protective film containing the alkali metal oxide (Sample Nos. 29 and 30 in Table 1) is formed with voids (voids not penetrating).

  On the other hand, it was found that the glass film containing no alkali component (Sample Nos. 35 and 36 in Table 1) had a uniform and dense film.

  Firing conditions 6) It was found that 800 ° C. × 2 h + 1200 ° C. × 2 h (sample Nos. 30 and 36 in Table 1) was relatively vitrified and the crystals tended to be larger.

  As described above, according to the present embodiment, the glass protective film of the electronic component can be used even in a high temperature environment.

  In the above-described embodiment, the configuration and the like illustrated in the accompanying drawings are not limited to these, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  Each component of the present invention can be arbitrarily selected, and an invention having a selected configuration is also included in the present invention.

  The present invention can be used as a protective film for electronic components.

1 Alumina substrate 43 Pt electrode 45 Contact 46 Electronic component 47 Glass protective film 51 Contact glass 55 Lead wire (Ptlr)

Claims (11)

A glass protective film for laminating on an alumina substrate and a resistance wiring,
A glass protective film for electronic parts, characterized by comprising SiO ₂ —CaO—Al ₂ O ₃ as a main component and containing anorthite crystals. The coefficient of thermal expansion is close to that of an alumina substrate.
The glass protective film for electronic components of Claim 1. And further comprising at least one selected from magnesium oxide (MgO), zinc oxide (ZnO), or boron oxide (B ₂ O ₃ ),
The glass protective film for electronic components of Claim 1 or 2. Further comprising an alkali metal oxide,
The glass protective film for electronic components of any one of Claim 1 to 3. The proportion of anorthite crystals deposited on the surface layer of the glass protective film is 50 to 90% or more,
The glass protective film of any one of Claim 1 to 4. An alumina substrate;
Resistance wiring formed on one surface of the alumina substrate;
An electrode electrically connected to the resistance wiring;
An external connection terminal joined to the surface of the electrode;
The electronic component which has a glass protective film of any one of Claim 1-5 which covers the said resistance wiring at least. The resistance wiring is a material containing a platinum (Pt) group.
The electronic component according to claim 6. A method for producing a glass protective film for laminating on an alumina substrate and a resistance wiring,
Silicon oxide _(SiO 2) _30~60mol%, calcium oxide (CaO) or calcium carbonate _(CaCO 3) _15~25mol%, and aluminum oxide _{(Al 2} O 3) were mixed inorganic oxide containing 10 to 25 mol% Melting, and
Crushing after melting to produce glass powder;
Dissolving the glass powder in a solvent to form a glass paste;
Baking the glass paste at a temperature of 900 ° C. or higher to form a glass protective film containing anorthite crystals;
The manufacturing method of the glass protective film for electronic component protective films which has this. The melting step further includes a step of adding magnesium oxide (MgO) to 10 mol% or less, zinc oxide (ZnO) to 10 mol% or less, and boron oxide (B ₂ O ₃ ) to 15 mol% or less.
The manufacturing method of the glass protective film of Claim 8. In the step of forming the glass paste,
Furthermore, the step of adding anorthite crystal powder,
2 to 8% by volume of anorthite to be added,
The manufacturing method of the glass protective film of Claim 8 or 9. The step of forming a glass protective film containing the anorthite crystal,
Prior to the step of performing secondary baking at a temperature of 900 ° C. or higher, primary baking is performed at 700 to 900 ° C.,
The manufacturing method of the glass protective film for electronic components of any one of Claim 8-10.

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