KR102459473B1 - Silicon nitride sintered body substrate and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a silicon nitride sintered body substrate and a method for manufacturing the same,
The present invention provides a silicon nitride sintered body substrate, characterized in that at least partially having a crystal orientation in the plane direction and having a bending strength of 900 MPa or more. In addition, preparing a silicon nitride powder compact; primary sintering by hot pressing the prepared molded body under a nitrogen atmosphere; and secondarily sintering the primary sintered compact under a nitrogen atmosphere under a gas pressure.
The present invention reduces the sintering temperature and time by performing primary sintering by hot pressing in uniaxial direction and then secondary sintering under gas pressure, thereby saving energy, and improving strength by suppressing particle growth and reducing pore structure. The strength and thermal shock resistance of the silicon nitride sintered compact substrate are excellent, so the durability, reliability and productivity of the product are improved, and the plane direction thermal conductivity is high. There is an advantage of reducing the defect rate.

Description

Silicon nitride sintered body substrate and manufacturing method thereof

The present invention relates to a silicon nitride sintered body substrate and a method for manufacturing the same.

Ceramic heaters widely used in semiconductor equipment are manufactured using ceramic materials with excellent thermal conductivity and insulation properties, and SiC and AlN substrate materials are the most widely used due to their high thermal conductivity and insulation properties. However, as the performance of the heater required by the equipment increases, the temperature range used increases, and as the temperature increase rate and the cooling rate increase, material limitations such as mechanical destruction of existing materials and destruction of insulating properties appear.

Silicon nitride (Si ₃ N ₄ ) material exhibits high strength and toughness characteristics among various ceramics as the particles of the sintered compact microstructure exhibit a unique needle shape rather than a general isotropic shape. In addition, the highest thermal conductivity can be achieved.

In particular, aluminum nitride is mainly used as a structure of a heater as a material capable of uniform temperature transfer to the entire wafer surface due to high thermal conductivity in semiconductor deposition facilities. For example, the prior patent document 1 discloses a technique using aluminum nitride as a material of a ceramic heater for semiconductors. However, aluminum nitride has a problem in that the insulation resistance is reduced to almost 0 at 60 MΩ/mm at a high temperature of 400° C. or higher and thus the electrical resistance is lost, so a technology to overcome this problem is required. In addition, there is a need for improvement in terms of consumable parts that require periodic replacement due to deformation and damage caused by a temperature difference of hundreds of degrees due to rapid temperature rise and rapid cooling.

Compared to other ceramic materials, silicon nitride material is suitable for replacing aluminum nitride in semiconductor deposition facilities because it can stably maintain an insulating state without lowering electrical resistance at high temperatures, and has excellent mechanical strength and thermal conductivity.

The present inventors have used this silicon nitride material to have suitable performance as a ceramic heater material for a TCB (thermal compression bonding) process device used in a new process TSV (through silicon via) in the semiconductor industry, and furthermore, a core manufacturing facility for semiconductors such as other deposition equipment As a result of research to manufacture a silicon nitride sintered compact substrate having excellent thermal shock resistance, thermal conductivity, and particularly high strength, which can be used in the present invention, the present invention has been reached.

Korean Patent Laid-Open Publication No. 10-2006-0043159 (May 15, 2006)

An object of the present invention is to provide a silicon nitride sintered compact substrate and a method for manufacturing the same.

In order to achieve the above object,

In one aspect of the present invention,

There is provided a silicon nitride sintered body substrate, characterized in that it has at least partially in-plane crystal orientation, and has a bending strength of 900 MPa or more.

In another aspect of the present invention,

In one aspect of the present invention, there is provided a ceramic heater comprising a silicon nitride sintered body substrate and an exothermic coating on one surface of the substrate.

In another aspect of the present invention,

preparing a silicon nitride powder compact;

primary sintering by hot pressing the prepared molded body under a nitrogen atmosphere; and

Secondary sintering of the primary sintered compact under a nitrogen atmosphere under a gas pressure; provides a method of manufacturing a silicon nitride sintered compact substrate comprising: a.

The silicon nitride sintered body substrate according to the present invention has a bending strength of 900 MPa or more, and when applied to semiconductor equipment, there is an economic advantage of extending the replacement cycle and reducing costs by improving the durability of parts when applied to semiconductor equipment. It has the advantage of obtaining a uniform temperature distribution over the entire heating surface of the ceramic heater to which it is applied due to its high thermal conductivity.

In addition, the production of the silicon nitride sintered compact substrate according to the present invention includes a process of primary sintering by hot pressing in a uniaxial direction and then secondary sintering under gas pressure, thereby reducing the sintering temperature and time, saving energy, and inhibiting particle growth And there is an effect of improving the strength by reducing the pore structure due to hot pressing sintering. Due to the excellent mechanical strength and thermal shock resistance of the silicon nitride sintered substrate produced, the durability, reliability and productivity of the product are improved, and the plane direction thermal conductivity is high. It is possible to obtain a uniform heat distribution, so there is an advantage of reducing the defect rate of semiconductor packaging.

1 is a photograph of a silicon nitride sintered body substrate prepared according to Comparative Examples 1 and 2 of the present invention.
2 shows the X-ray diffraction pattern (XRD) results of the silicon nitride sintered body substrate prepared according to Comparative Examples 1 and 2 of the present invention.
3 is an image of the silicon nitride sintered substrate prepared according to Comparative Examples 1 and 2 of the present invention observed with a scanning electron microscope (SEM).
4 is a photograph of the silicon nitride sintered body substrates prepared according to Comparative Examples 2 and 4, Examples 1 to 3, and Examples 4 to 6 of the present invention.
5 is an image of the silicon nitride sintered substrate prepared according to Comparative Example 2 and Examples 1 to 3 of the present invention observed with a scanning electron microscope (SEM).
6 is an image of the silicon nitride sintered substrate prepared according to Comparative Example 4 and Examples 4 to 6 of the present invention observed with a scanning electron microscope (SEM).
7 is a graph showing the thermal conductivity and strength of the silicon nitride sintered compact substrate prepared according to Comparative Example 2 and Examples 1 to 3 of the present invention.
8 is a graph showing the thermal conductivity and strength of the silicon nitride sintered body substrate prepared according to Comparative Example 4 and Examples 4 to 6 of the present invention.
9 is a diagram illustrating a temperature distribution state of a heating surface at 400° C. of a ceramic heater according to an experimental example of the present invention.

Hereinafter, the present invention will be described in detail.

In one aspect of the present invention,

There is provided a silicon nitride sintered body substrate, characterized in that it has at least partially in-plane crystal orientation, and has a bending strength of 900 MPa or more.

Hereinafter, the silicon nitride sintered body substrate provided in one aspect of the present invention will be described in detail for each configuration.

The silicon nitride sintered compact substrate of the present invention has at least a plane-direction crystal orientation.

The silicon nitride sintered body substrate according to an embodiment of the present invention may have a Lotgering Orientation Factor (f _L ) value in the range of 0.2 to 0.6.

Unless otherwise specified herein, the direction of the surface means the direction of the surface receiving the HP pressure, which is perpendicular to the direction of the HP pressure.

The silicon nitride sintered compact substrate of the present invention has a bending strength of 900 MPa or more. The silicon nitride sintered body substrate may have a bending strength of preferably 950 MPa or more, and more preferably, a bending strength of 1000 MPa or more.

The silicon nitride sintered body substrate may further include a sintering aid, and the sintering aid may be included in an amount of 0.5 mol% to 10 mol% based on the total mole of the sintered body.

The sintering aid is used to promote crystal growth of silicon nitride particles and to increase the relative density of the silicon nitride sintered body. Metals belonging to the group of alkaline earth metals, rare earth metals, transition metals and typical metals and oxides thereof may be used as the sintering aid.

As a specific example, the sintering aid may be one or a mixture of two or more selected from the group consisting of yttrium oxide, magnesium oxide, aluminum oxide, zirconium oxide, titanium dioxide, aluminum nitride, calcium oxide, copper, boron nitride, However, the present invention is not limited thereto.

For example, the sintering aid may be a mixture of yttrium oxide and magnesium oxide, and based on the total mole of the sintered body, yttrium oxide and magnesium oxide may be included in 1 mol% to 3 mol% of yttrium oxide and 5 mol% of magnesium oxide.

In addition, as an example, the sintering aid may be a mixture of yttrium oxide and magnesium oxide, and based on the total mole of the sintered body, yttrium oxide and magnesium oxide may be included in 0.2 mol% to 1 mol% of yttrium oxide and 5 mol% of magnesium oxide have.

The silicon nitride sintered body substrate may have a thermal conductivity of 55 W/m·K or more. The silicon nitride sintered body substrate preferably has a thermal conductivity of 60 W/m·K or more, more preferably a thermal conductivity of 65 W/m·K or more, more preferably a thermal conductivity of 70 W/m·K or more, still more preferably It may have a thermal conductivity of 75 W/m·K or more, more preferably a thermal conductivity of 80 W/m·K or more, and more preferably a thermal conductivity of 85 W/m·K or more. The thermal conductivity (average value) can be calculated from the measured thermal diffusivity of the sample, the specific heat of the sample, and the density.

The silicon nitride sintered substrate may have a thickness of 2 mm to 8 mm. As a specific example, the thickness may be 3 to 5 mm.

A heating coating may be included on one surface of the silicon nitride sintered body substrate.

The silicon nitride sintered substrate may be used as a ceramic heater.

There is TSV (Through Silicon Via) technology, which is being adopted as a new method of manufacturing multi-layer/stereo-structured semiconductors. TSV semiconductor is a thermocompression bonding (TCB) that joins wafers with molten copper and forms electrodes at the same time by inserting a laminated wafer-to-wafer bonding film and generally inserting copper powder into a via hall and then pressing with a heated heater. , implemented by thermal compression bonding) technology. The ceramic heater for TCB requires high thermal conductivity for uniform heat distribution on the heater surface, mechanical strength for compression work, and thermal shock resistance to withstand rapid temperature rise and rapid cooling for productivity improvement. Silver can be used for ceramic heaters, especially ceramic heaters for TCB.

The silicon nitride sintered substrate according to the present invention exhibits a bending strength of 900 MPa or more, and when applied to semiconductor equipment, there is an economic advantage of extending the replacement cycle and reducing costs by improving the durability of parts when applied to semiconductor equipment. In the case of a ceramic heater applied with high directional thermal conductivity, there is an advantage in that a uniform temperature distribution can be obtained over the entire heating surface.

In another aspect of the present invention,

In one aspect of the present invention, there is provided a ceramic heater comprising a silicon nitride sintered body substrate and an exothermic coating on one surface of the substrate.

The ceramic heater may be a ceramic heater for a thermal compression bonding (TCB) process.

The ceramic heater for TCB requires high thermal conductivity for uniform heat distribution on the heater surface, mechanical strength for compression work, and thermal shock resistance to withstand rapid temperature rise and rapid cooling for productivity improvement. Silver may be used as a ceramic heater, and the ceramic heater may preferably be a ceramic heater for TCB.

In another aspect of the present invention,

preparing a silicon nitride powder compact;

primary sintering by hot pressing the prepared molded body under a nitrogen atmosphere; and

Secondary sintering of the primary sintered compact under a nitrogen atmosphere under a gas pressure; provides a method of manufacturing a silicon nitride sintered compact substrate comprising: a.

Hereinafter, a method of manufacturing a silicon nitride sintered body substrate provided in one aspect of the present invention will be described in detail for each step.

The method of the present invention comprises the step of producing a silicon nitride powder compact. The silicon nitride powder compact may include silicon nitride powder and sintering aid powder.

The step of preparing the silicon nitride powder compact,

Preparing a mixed powder by mixing the silicon nitride powder and the sintering aid powder; And

It may include; adding a binder to the mixed powder and molding it in the form of a substrate.

The method may further include a degreasing step for removing the binder of the silicon nitride powder compact before sintering after manufacturing the compact.

The method of the present invention includes the step of primary sintering by hot pressing the formed body under a nitrogen atmosphere.

The hot pressing sintering is performed in a hot pressing sintering apparatus, and the hot pressing sintering apparatus may include a pressing means and a mold for pressing in a uniaxial direction with respect to the molded body. Since the hot pressure sintering apparatus can be easily designed by those skilled in the art, a detailed description thereof will be omitted.

The sintering is performed under a nitrogen (N ₂ ) atmosphere. By preferably not containing oxygen, silicon nitride is not affected by oxygen atoms (molecules), and it becomes possible to achieve high thermal conductivity.

The primary sintering may be performed under a nitrogen atmosphere at normal pressure.

The primary sintering may be performed at a pressure of 10 MPa to 50 MPa.

The first sintering step may be performed at a temperature of 1600 °C or higher, preferably at a temperature of 1600 °C to 1800 °C, and more preferably at a temperature of 1650 °C to 1750 °C. If the sintering temperature is less than 1600 ℃, the pores of the sintered body cannot be completely removed, and the phase transformation of the starting alpha-phase silicon nitride to the beta-phase silicon nitride is incomplete, so that strength and thermal conductivity are deteriorated.

The first sintering step may be performed for 30 minutes or more, and preferably for 30 minutes or more to 3 hours or less. If the first sintering time is less than 30 minutes, the pores of the sintered body cannot be completely removed, and the phase transformation of the starting alpha-phase silicon nitride to the beta-phase silicon nitride is incomplete, thereby reducing strength and thermal conductivity.

The method of the present invention includes the step of secondary sintering the primary sintered compact under a nitrogen atmosphere, under a gas pressure.

The sintering is performed under a nitrogen (N ₂ ) atmosphere. By preferably not containing oxygen, silicon nitride is not affected by oxygen atoms (molecules), and it becomes possible to achieve high thermal conductivity.

The secondary sintering step may be performed at a nitrogen gas pressure of 0.5 to 5 MPa, preferably at a nitrogen gas pressure of 0.5 to 2 MPa.

The secondary sintering step may be performed at a temperature of 1800 °C or higher, preferably at a temperature of 1850 °C to 1950 °C. When the sintering temperature is less than 1800 °C, there is a problem of low thermal conductivity due to insufficient grain growth.

The secondary sintering step may be performed for 30 minutes to 5 hours, and preferably for 30 minutes to 3 hours. When the secondary sintering time exceeds 5 hours, the strength of the sintered compact substrate is lowered due to excessive grain growth, and there is a problem in that energy consumption is large, and when the secondary sintering time is less than 30 minutes, the grain growth is insufficient and heat conduction There is a problem with the low degree.

The silicon nitride sintered substrate may be used as a ceramic heater.

The method for manufacturing a silicon nitride sintered compact substrate according to the present invention includes a process of first sintering by hot pressing and then secondary sintering under gas pressure, thereby reducing the sintering temperature and time, thereby saving energy, and relatively few particles Despite the growth, there is an effect of improving strength due to high thermal conductivity due to orientation and reduction of pore structure due to hot pressure sintering. In addition, since the surface direction thermal conductivity is improved, a uniform heat distribution can be obtained over the entire surface when the ceramic heater is applied, thereby contributing to a reduction in the semiconductor defect rate.

Hereinafter, the present invention will be described in more detail through Examples and Experimental Examples. The scope of the present invention is not limited to specific examples and experimental examples, and should be interpreted by the appended claims. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

4 is an image of a silicon nitride sintered compact substrate prepared according to Comparative Example 2 and Examples 1 to 3, Comparative Examples 4 and 4 to 6 of the present invention to be described later.

<Example 1>

After primary sintering (HP, Hot Press) by uniaxial hot pressing, the secondary sintering (GPS, Gas Pressure Sintering) was performed to prepare a silicon nitride sintered substrate.

First, silicon nitride (Si ₃ N ₄ ), yttrium oxide (Y ₂ O ₃ ) and magnesium oxide (MgO) were used as raw material powder, and 2Y5M, 2 mol% yttrium oxide - 5 mol% magnesium oxide composition was prepared. Table 1 below is a table summarizing the composition of the raw material powder.

The mixed powder was put in a mold for HP, and nitrogen gas was flowed into the equipment chamber in a vacuum state to form a nitrogen gas atmosphere of 0.1 MPa. It was sintered for 2 hours at a temperature of 1700 °C while pressing the mixed powder under a pressure of 20 MPa.

Thereafter, the primary sintered body was secondary sintered in a graphite crucible. At the bottom of the crucible, 200 g of atmospheric powder having a weight ratio of Si3N4 and BN of 50:50 was used. Secondary sintering was performed for 1 hour at a temperature of 1900° C. and a nitrogen gas pressure of 2 MPa to prepare a silicon nitride sintered substrate.

<Example 2>

A silicon nitride sintered substrate was prepared in the same manner as in Example 1, except that the secondary sintering was performed for 3 hours in Example 1.

<Example 3>

A silicon nitride sintered compact substrate was prepared in the same manner as in Example 1, except that the secondary sintering was performed for 6 hours in Example 1.

<Example 4>

A silicon nitride sintered substrate was prepared in the same manner as in Example 1, except that the composition of the raw material powder in Example 1 was 0.5Y5M (see Table 1).

<Example 5>

A silicon nitride sintered substrate was prepared in the same manner as in Example 1, except that the composition of the raw material powder was 0.5Y5M in Example 1 and secondary sintering was performed for 3 hours.

<Example 6>

A silicon nitride sintered substrate was prepared in the same manner as in Example 1, except that the composition of the raw material powder in Example 1 was 0.5Y5M, and the secondary sintering was performed for 6 hours.

<Comparative Example 1>

A sintered silicon nitride substrate was prepared by gas pressure sintering. After mixing the 2Y5M raw powder with a ball mill, a granular powder was prepared by a spray-drying method. After adding a binder and uniaxially molding using a mold, secondary molding was performed using cold hydrostatic pressure (CIP) equipment to prepare a molded body. Thereafter, the binder was removed from the molded article manufactured by performing a degreasing process.

In a graphite crucible, BN plates were placed on both sides of the manufactured compact, and 200 g of atmospheric powder having a weight ratio of Si3N4 and BN of 50:50 was used at the bottom of the crucible. The silicon nitride sintered substrate was prepared by sintering at a temperature of 1900° C. and a nitrogen gas pressure of 2 MPa for 6 hours.

<Comparative Example 2>

A silicon nitride sintered compact substrate was prepared by hot press sintering (HP, Hot Press) in the uniaxial direction. First, silicon nitride (Si ₃ N ₄ ), yttrium oxide (Y ₂ O ₃ ) and magnesium oxide (MgO) were used as raw material powder, and a 2Y5M composition was prepared.

The mixed powder was put in a mold for HP, and nitrogen gas was flowed into the equipment chamber in a vacuum state to form a nitrogen gas atmosphere of 0.1 MPa. A silicon nitride sintered substrate was prepared by sintering at a temperature of 1700° C. for 2 hours while pressing the mixed powder under a pressure of 20 MPa.

<Comparative Example 3>

A silicon nitride sintered substrate was prepared in the same manner as in Comparative Example 1, except that the composition of the raw material powder in Comparative Example 1 was 0.5Y5M.

<Comparative Example 4>

A silicon nitride sintered substrate was prepared in the same manner as in Comparative Example 2, except that the composition of the raw material powder in Comparative Example 2 was 0.5Y5M.

<Experimental Example 1> In-plane crystal orientation of silicon nitride sintered body substrate

In order to confirm the crystal orientation of the silicon nitride sintered body prepared in Comparative Examples 1 and 2 in the plane direction, the following experiment was performed.

First, X-ray diffraction pattern analysis (XRD) of Comparative Example 1 prepared by GPS sintering and Comparative Example 2 prepared by HP sintering was performed. The results are shown in FIG. 2 .

1 is an image of a silicon nitride sintered compact substrate prepared according to Comparative Examples 1 and 2. FIG. 2a is an XRD result of Comparative Example 1, FIG. 2b is an XRD result of the surface to which HP pressure is applied, and FIG. 2c is an XRD result of a surface perpendicular to the surface to which HP pressure is applied in Comparative Example 2.

The microstructures of Comparative Examples 1 and 2 were observed with a scanning electron microscope (SEM). The results are shown in FIG. 3 . 3A is a result of Comparative Example 1, FIG. 3B is an SEM image of a plane direction cross-section to which the HP pressure of Comparative Example 2 is applied, and FIG. 3C is an SEM image of an HP pressure direction and a horizontal cross-section of Comparative Example 2.

According to FIGS. 1 to 3, as shown in FIG. 1, the GPS-sintered substrate of Comparative Example 1 did not obtain a perfect compact, whereas the HP-sintered substrate of Comparative Example 2 uniaxially had high pressure even for a short sintering time. By this addition, it was confirmed that a 100% complete compact body was prepared.

In addition, looking at FIG. 2, Comparative Example 1 in FIG. 2a does not have a significant difference in (101), (210) peaks, whereas in FIGS. 2b and 2c, Comparative Example 2 has (101), (210) peak differences. It was confirmed that it appeared large. It can be seen that the needle-shaped grain growth of silicon nitride is oriented in the plane direction through uniaxial pressure sintering.

Referring to FIG. 3, in Comparative Example 2 in FIGS. 3b and 3c, it was confirmed that the silicon nitride needle-like particles were mainly oriented in the plane direction in the plane to which the HP force was applied. In addition, in FIG. 3A, the particle size of Comparative Example 1 sintered at 1900° C. for a long time for 6 hours was larger than the particle size of FIGS. 3B and 3C, and in the case of Comparative Example 1, orientation according to the direction did not appear.

Therefore, Comparative Example 2 prepared by HP sintering improved the sintering density by increasing the sintering driving force against an external force even at a lower temperature and shorter time than Comparative Example 1 prepared by GPS sintering, and silicon nitride needle-like grain growth was achieved by uniaxial pressure. It can be seen that the effect of directional orientation can be obtained.

<Experimental Example 2> Observation of the microstructure of the silicon nitride sintered body substrate

The microstructures of Examples 1 to 6 and Comparative Examples 2 and 4 were observed with a scanning electron microscope (SEM) to confirm particle growth according to the secondary GPS sintering. The results are shown in FIGS. 5 and 6 .

As a result of confirming the grain growth according to the GPS secondary sintering time after the HP primary sintering, according to FIG. 5, Comparative Examples 2 and 1 to 3 of the 2Y5M composition were secondary sintering when secondary sintering was performed for 1 hour. It was confirmed that the particle growth progressed significantly compared to the case where the fertilization was not carried out, but the difference in particle size did not appear clearly when it was carried out for 3 hours or 6 hours thereafter.

In addition, according to FIG. 6, in Comparative Examples 4 and 4 to 6 having a composition of 0.5Y5M, it was confirmed that the particle size increased as the secondary sintering time was increased to 1 hour, 3 hours, and 6 hours.

<Experimental Example 3> Measurement of thermal conductivity of silicon nitride sintered body substrate

In order to examine the thermal conductivity of the silicon nitride sintered body substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 4, the following experiment was performed.

To measure the thermal conductivity, a Laser Flash Analysis (LFA) device was used. The results are shown in Figs. 7, 8 and Table 2. In Table 2, the horizontal direction means the direction and the horizontal direction of the HP pressure, and the vertical direction means the direction and the vertical direction of the HP pressure. That is, the vertical direction corresponds to the direction in which the particles are oriented in the long axis due to the phenomenon in which the needle-shaped particles are pressed by the HP pressure.

7 and Table 2, in the case of the 2Y5M composition, compared with Comparative Example 1, Comparative Examples 2 and 1 to 3 showed anisotropy in thermal conductivity, including the HP sintering process. Compared to Comparative Example 2, Examples 1 to 3 further performed GPS secondary sintering, but it was confirmed that the anisotropy of thermal conductivity was maintained. In particular, the thermal conductivity in the plane direction (vertical direction) was higher than that in the horizontal direction.

In addition, after the HP primary sintering, as the GPS secondary sintering time increased, the overall thermal conductivity showed a tendency to increase. Looking at the thermal conductivity values of Examples 1 to 3, when the GPS secondary sintering time was 1 hour, the thermal conductivity was sharply increased in both the vertical and horizontal directions, and thereafter, the secondary sintering time was increased to 3 hours and 6 hours. However, there was no significant change in thermal conductivity.

8 and Table 2, in the case of the 0.5Y5M composition and in the case of including the HP sintering process, thermal conductivity anisotropy was observed, and the thermal conductivity continued to increase as the GPS secondary sintering time increased in both the vertical and horizontal directions. showed a tendency to

While the thermal conductivity of Comparative Examples 2 and 4 was low, it was measured that the thermal conductivity in the vertical and horizontal directions had a value of 55 W/m·K or more in all Examples. That is, it is confirmed that the silicon nitride sintered body substrate according to the embodiment of the present invention has thermal conductivity suitable for use as a ceramic heater.

<Experimental Example 4> Measurement of mechanical strength of silicon nitride sintered body substrate

In order to measure the mechanical strength of the silicon nitride sintered body substrates prepared in Examples 1 to 6 and Comparative Examples 1 to 4, a cylindrical bearing with a diameter of 2 mm made of hardened steel was placed at 3 or 4 points, and then the top The breaking force was measured by applying pressure in the After measuring at least 10 times, the average bending strength was calculated. The results are shown in Figs. 7, 8 and Table 2.

7, 8 and Table 2, as the secondary sintering time increased, the strength showed a tendency to gradually decrease according to grain growth.

In the case of Examples 1 to 3 and Comparative Example 2 of the 2Y5M composition, when only HP primary sintering was performed, both horizontal and vertical directions showed high values exceeding 1200 MPa, and after 1 hour GPS secondary sintering, it was close to 1000 MPa. value was lowered, and after 3 hours of secondary sintering, the value was slightly lower at 900 MPa.

In the case of Examples 4 to 6 and Comparative Example 4 of the 0.5Y5M composition, as the GPS secondary sintering time increased, the strength gradually decreased. In this case, Examples 4 and 5, in which the secondary sintering was performed for 3 hours, showed a strength of 900 MPa or more.

As can be seen in Experimental Examples 3 to 5, the silicon nitride sintered compact substrate according to an embodiment of the present invention is manufactured by HP primary sintering and GPS secondary sintering, so that it has high mechanical strength and at the same time the sintering temperature and time are reduced. It can be seen that it has an effect of saving energy. Specifically, comparing Comparative Example 1 and Example 1, by adding HP primary sintering at 1700 ° C at a relatively low temperature, GPS sintering at 1900 ° C was performed for only 1 hour (Example 1), GPS sintering at 1900 ° C. It was confirmed that it had higher physical properties with a thermal conductivity of 86 W/m·K and a strength of 980 MPa than the case of 6 hours (Comparative Example 1).

<Experimental Example 5> Evaluation of thermal shock resistance of ceramic heater to which silicon nitride sintered substrate is applied

The following thermal shock resistance test was performed on the ceramic heater module to which the silicon nitride sintered body substrate of Example 1 was applied.

A heater module was manufactured by heating the silicon nitride sintered body substrate of Example 1 and connecting electrodes. A total of 5 heater modules were manufactured, and a rapid temperature increase/quick cooling experiment was performed on them. The rapid heating at 200 °C/s and rapid cooling at 100 °C/s were repeated in the 50 °C to 400 °C section. The number of repetitions was performed up to 10,000 times, and the terminal resistance according to the number of driving was measured.

According to Table 3, in the ceramic heater module to which the silicon nitride sintered substrate according to the embodiment of the present invention is applied, the terminal resistance was maintained almost the same with a maximum difference of 0.1 Ω even when the rapid heating/cooling was repeatedly driven 10,000 times. When the terminal resistance value rapidly increases according to the number of driving, it is judged that the heat and electricity transmission is disturbed due to damage to the heater material. It was confirmed that it has excellent thermal shock resistance and reliability that maintains performance without damage even after repeated times.

<Experimental Example 6> Evaluation of uniformity of temperature distribution on the heating surface of a ceramic heater to which a silicon nitride sintered substrate is applied

An experiment for evaluating the uniformity of the heating surface temperature distribution was conducted for the ceramic heater module to which the silicon nitride sintered substrate of Example 1 was applied.

A heater module was manufactured by heating the silicon nitride sintered body substrate of Example 1 and connecting electrodes. The temperature distribution of the heating surface at a temperature of 400 °C was measured. The results are shown in FIG. 9 .

According to FIG. 9 , as a result of confirming the uniform temperature distribution over the entire surface, a maximum deviation of 1° C. was shown, which was determined to be a level applicable to commercial products. Therefore, it can be seen that the surface direction thermal conductivity of the silicon nitride sintered body substrate according to the embodiment of the present invention is high, and thus, it can be seen that there is an effect of uniformizing the heat distribution of the entire heating surface of the ceramic heater to which the silicon nitride sintered body substrate is applied.

Claims (18)

A silicon nitride sintered body substrate, characterized in that it has at least partially in-plane crystal orientation, a thermal conductivity of 60 W/m·K or more, and a bending strength of 900 MPa or more.
According to claim 1,
The silicon nitride sintered substrate is a silicon nitride sintered substrate, characterized in that it has a bending strength of 1000 MPa or more.
According to claim 1,
The silicon nitride sintered body substrate further comprises a sintering aid, wherein the sintering aid is 0.5 mol% to 10 mol% based on the total mole of the sintered body, the silicon nitride sintered body substrate.
delete According to claim 1,
The silicon nitride sintered body substrate has a thickness of 2 mm to 8 mm, characterized in that the silicon nitride sintered body substrate.
According to claim 1,
A silicon nitride sintered body substrate comprising an exothermic coating on one surface of the silicon nitride sintered body substrate.
According to claim 1,
The silicon nitride sintered substrate is a silicon nitride sintered substrate, characterized in that used for a ceramic heater.
A ceramic heater comprising the silicon nitride sintered body substrate of claim 1 and a heat-generating coating on one surface of the substrate.
9. The method of claim 8,
The ceramic heater is a ceramic heater for a thermal compression bonding (TCB) process, the ceramic heater.
preparing a silicon nitride powder compact;
primary sintering by hot pressing the prepared molded body under a nitrogen atmosphere; and
Secondary sintering of the primary sintered compact under a nitrogen atmosphere under a gas pressure; comprising, a method of manufacturing a silicon nitride sintered compact substrate, characterized in that for preparing the silicon nitride sintered compact substrate of claim 1 .
11. The method of claim 10,
The step of preparing the silicon nitride powder compact,
Preparing a mixed powder by mixing the silicon nitride powder and the sintering aid powder; And
A method of manufacturing a silicon nitride sintered body substrate comprising a; adding a binder to the mixed powder and forming the substrate in the form of a substrate.
11. The method of claim 10,
The method of manufacturing a silicon nitride sintered body substrate, characterized in that after manufacturing the silicon nitride powder compact and before sintering, it further comprises the step of degreasing to remove the binder of the compact.
11. The method of claim 10,
The first sintering step is a method of manufacturing a silicon nitride sintered body substrate, characterized in that performed at a temperature of 1600 ℃ or more.
11. The method of claim 10,
The first sintering step is a method of manufacturing a silicon nitride sintered body substrate, characterized in that performed at a pressure of 10 MPa to 50 MPa.
11. The method of claim 10,
The second sintering step is a method of manufacturing a silicon nitride sintered body substrate, characterized in that performed at a temperature of 1800 ℃ or more.
11. The method of claim 10,
The second sintering step is a method of manufacturing a silicon nitride sintered body substrate, characterized in that performed at a nitrogen gas pressure of 0.5 to 5 MPa.
11. The method of claim 10,
The method of manufacturing a silicon nitride sintered body substrate, characterized in that the secondary sintering step is performed for 30 minutes to 5 hours.
11. The method of claim 10,
The silicon nitride sintered substrate is a method of manufacturing a silicon nitride sintered substrate, characterized in that used for a ceramic heater.

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