KR20130143640A - Sintered mo part for heat sink plate for semiconductor device and semiconductor device including same - Google Patents

Abstract

According to the present invention, in the Mo sintered part for a semiconductor heat sink comprising a molybdenum alloy material containing 10 to 50 mass% of copper, the average particle diameter of the molybdenum crystals of the molybdenum alloy material is 10 to 100 µm, and the unit area 500 The Mo sintering component for semiconductor heat sinks characterized by the deviation of the area ratio of Mo crystals per micrometer x 500 micrometers within ± 10% of an average value. Since the dispersion | variation in the presence ratio of Mo and Cu is small, Mo sintering components for semiconductor heat sinks which are excellent in characteristics, such as a thermal expansion rate and excellent in a thermal expansion rate and strength, are obtained.

Description

Mo sintered components for semiconductor heat sinks and semiconductor devices using the same {SINTERED MO PART FOR HEAT SINK PLATE FOR SEMICONDUCTOR DEVICE AND SEMICONDUCTOR DEVICE INCLUDING SAME}

The present invention relates to a Mo sintered part for use in a semiconductor heat sink and a semiconductor device using the same.

Semiconductor devices are used in various electronic devices. In a semiconductor device, it functions by flowing a current through a semiconductor element. At this time, the semiconductor element generates heat. Failure to release this heat efficiently can result in destruction or malfunction of the semiconductor element itself. For this reason, it is attempted to arrange | position a semiconductor element on a heat sink and to discharge | release heat of a semiconductor element to the exterior of an apparatus efficiently.

The semiconductor heat sink incorporated in the semiconductor device is not only high in thermal conductivity, but also has a thermal expansion coefficient approximating to a semiconductor element, sufficient structural strength, and the like, in order to reduce stress due to thermal expansion difference. As a specific example of the heat sink which satisfy | fills these conditions, Unexamined-Japanese-Patent No. 11-307701 (patent document 1), for example, discloses the Mo-Cu immersion board | substrate which infiltrated copper to Mo green compact. By combining Mo which is a low thermal expansion material and Cu which is a high thermal conductivity material, a heat sink with low thermal expansion and excellent heat dissipation can be provided.

Patent Document 1: Japanese Patent Application Laid-Open No. 11-307701

However, since the Mo-Cu immersion substrate disclosed in the patent document 1 is formed by a method of immersing Cu in the Mo green compact, there is a problem that it is difficult to uniformly infiltrate Cu to the inside. Particularly, when pores (air) remain inside, the portion becomes a heat resistant portion, which causes the heat dissipation effect. Particularly, the change in the molar ratio of Mo and Cu was not only a deterioration of the heat dissipation effect but also a cause of fluctuations in strength and thermal expansion rate.

This invention is made | formed in view of such a technical subject, Comprising: It provides Mo sintering components for semiconductor heat sinks with favorable heat dissipation, and high structural strength, and a semiconductor device using the same.

Mo sintering components for semiconductor heat sink of the present invention, in the Mo sintering components for semiconductor heat sink comprising a molybdenum sintered alloy material containing 10 to 50% by mass of copper, the average particle diameter of the molybdenum crystals of molybdenum alloy material is 10 to 100 It is micrometer, It is characterized by the deviation of the area ratio of Mo crystal | crystallization per unit area 500 micrometers x 500 micrometers within ± 10% of an average value.

Moreover, it is preferable that surface roughness Ra of Mo sintering components is 5 micrometers or less. Moreover, it is preferable that the molybdenum sintered alloy material contains 0.1-3 mass% of at least 1 sort (s) or more among Ni, Co, and Fe in conversion of a metal element. In addition, the molybdenum sintered alloy material is preferably a sintered alloy material having a density of 90 to 98%. Moreover, it is preferable that copper is filled in the clearance gap between molybdenum crystals. Moreover, it is preferable that the largest crystal grain diameter of molybdenum crystal is 2 times or less of an average grain diameter. In addition, it is preferable that the most spaced distance between adjacent molybdenum crystals is 50 micrometers or less.

Moreover, it is preferable that Mo sintering components are 0.05-1 mm in thickness, and are disk shape of 5-70 mm in diameter. Moreover, it is preferable that the thermal expansion coefficient of Mo sintering components is 7-14 * 10 <^-6> / ^degreeC . Moreover, it is preferable that the tensile strength of Mo sintering components is 0.44 kPa or more. Moreover, it is preferable that the specific resistance of Mo sintering components is 5.3x10 <^{-6> (} ohm) * m or less.

Moreover, the semiconductor device which concerns on this invention is comprised using the said Mo sintering component for semiconductor heat sinks which concerns on this invention as a heat sink.

According to the present invention, the Mo sintered part for semiconductor heat sinks and the semiconductor device using the same can provide a heat sink excellent in heat dissipation and structural strength because variations in the Mo crystal size of the Mo sintered part for semiconductor heat sinks are small. As a result, the reliability of the semiconductor device can be greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structural example of Mo sintering components for semiconductor heat sinks which concern on this invention.
2 is a cross-sectional view showing an example of the structure of a Mo sintered part for semiconductor heat sinks according to the present invention.
3 is a perspective view illustrating a shape example of a Mo sintered part for semiconductor heat sinks according to the present invention.
4 is a cross-sectional view showing an example of a method for producing a Mo sintered part for semiconductor heat sinks according to the present invention.
5 is a cross-sectional view showing another example of the structure of a Mo sintered part for semiconductor heat sinks according to the present invention.

In the Mo sintered component for semiconductor heat sink according to the present embodiment, the Mo sintered component for semiconductor heat sink comprising a molybdenum alloy material containing 10 to 50% by mass of copper, the molybdenum alloy material has an average particle diameter of molybdenum crystal It is 10-100 micrometers, and the deviation of the area ratio of Mo crystal | crystallization per unit area 500 micrometers x 500 micrometers is less than +/- 10% of an average value, It is characterized by the above-mentioned.

When content of the said copper is less than 10 mass% or exceeds 50 mass%, it is highly likely that a thermal expansion coefficient (thermal expansion coefficient) will deviate from 7-14 * 10 <^-6> / degreeC.

Here, the said semiconductor heat sink is for using as a board | substrate or heat sink (heat sink) for mounting a semiconductor element. An example of the component which used the semiconductor heat sink for FIG. 1 is shown. In Fig. 1, reference numeral 1 denotes a Mo sintered component for a semiconductor heat sink, reference numeral 2 denotes an insulating film (insulation layer), and reference numeral 3 denotes a semiconductor element.

In FIG. 1, an example in which the semiconductor element 3 is mounted on the Mo component 1 for a semiconductor heat sink via the insulating layer 2 is illustrated. However, the substrate on which the semiconductor element is mounted may be a different material (for example, a ceramic substrate). The Mo component for semiconductor heat sink of this invention may be applied to the back surface of the board | substrate formed with the other material and containing another material as a heat sink. In addition, since the Mo component is not an insulator, bonding is performed through the insulating layer 2 when mounting a semiconductor element.

The Mo sintered component for semiconductor heat sink according to the present embodiment has excellent heat dissipation with a thermal conductivity of 160 W / m · K or higher, and thus exhibits excellent heat dissipation even when a semiconductor element is mounted. In addition, the semiconductor element is formed of Si component or the like. Since the thermal expansion coefficient of the semiconductor element (Si-based) is about 4 to 7 × 10 ⁻⁶ / ° C., the thermal expansion coefficient of the Mo component has a thermal expansion coefficient of 7 to 14 × 10 ⁻⁶ / ° C. as described above, further 8 to 11 ×. It is preferable that it is ^10-6 / ^degreeC . Thus, by approximating the thermal expansion coefficient with a semiconductor element, peeling resulting from the thermal expansion difference with a semiconductor element can be prevented.

The molybdenum alloy material is characterized in that the average particle diameter of the molybdenum crystal is 10 to 100 µm, and the variation in the area ratio of Mo crystals per unit area of 500 µm x 500 µm is within ± 10% of the average value.

When the average particle diameter of molybdenum crystal is less than 10 micrometers here, since the ratio of copper increases relatively, the intensity | strength of an alloy material falls. On the other hand, when the average particle diameter becomes excessively larger than 100 µm, the proportion of copper decreases relatively, which is not preferable. The molybdenum alloy material is a sintered compact, and the variation in the abundance ratio (area ratio) of molybdenum and copper is within ± 10% of the average value. If there is little variation in the area ratio of molybdenum and copper, the characteristic variation of the molybdenum alloy material can be suppressed.

As described above, the Mo sintered component for semiconductor heat sink is used by mounting a semiconductor element. For example, when the semiconductor element is mounted, the Mo sintered component for semiconductor heat sink is thermally expanded by the heat generation of the element. At this time, when the variation of the ratio between the Mo crystal and the copper is large, there is a fear that partial expansion may occur and cause peeling of the semiconductor element. Therefore, in order to eliminate the partial difference of thermal expansion coefficient, it is important to make the deviation of the presence ratio (area ratio) of Mo crystal and copper into within +/- 10%.

In addition, the area ratio of Mo crystal and copper shall be measured based on a unit area of 500 micrometers x 500 micrometers. The unit area is 500 µm x 500 µm because the upper limit of the average particle diameter is 100 µm, so that the measurement error can be reduced as long as the area is about 5 times. In addition, the measurement of the area ratio of Mo crystal and copper can be measured by SEM photograph or surface analysis of EPMA.

Moreover, it is preferable that surface roughness Ra of Mo sintering components for semiconductor heat sinks is 5 micrometers or less. If the surface roughness Ra is large when the module is inserted as a heat sink as described above, a gap may be formed between the insulating layer and the gap may become a thermal resistor, which may cause deterioration of heat dissipation. Generally, an insulating resin and a metal oxide are used for an insulating layer. Insulation resin and a metal oxide have bad heat dissipation whose heat conductivity is only 30 W / m * K or less. Therefore, when an insulating layer is too thick, heat dissipation will also fall. Therefore, it is preferable that an insulating layer is 100 micrometers or less, Furthermore, it is 50 micrometers or less. It is preferable that surface roughness Ra of Mo sintering components is 5 micrometers or less, Furthermore, it is 2 micrometers or less.

In addition, although a molybdenum alloy material composition is based on the binary system of Mo and Cu, 0.1-3 mass% of Ni, Co, and Fe may be contained in conversion of a metal element. By containing a predetermined amount of Ni, Co and Fe, the strength and hardness of the molybdenum alloy material can be raised. In the case of a binary system of Mo and Cu, the molybdenum alloy has a tensile strength of 0.44 kPa or more, and the tensile strength can be increased to 0.50 kPa or more by addition of Ni, Co, and Fe.

Moreover, it is preferable that a molybdenum alloy material is 90% or more in density, and also 90 to 98%. Density shall be represented by (actual value / theoretical density by Archimedes method) * 100%. The theoretical density of molybdenum is 10.22 g / cm 3, the theoretical density of copper is 8.96 g / cm 3, the theoretical density of iron is 7.87 g / cm 3, the theoretical density of cobalt is 8.9 g / cm 3, and the theoretical density of nickel is 8.9. The weight ratio is multiplied using g / cm 3. For example, in the case of molybdenum alloy material containing 70 wt% Mo and 30 wt% copper, 70 wt% × 10.22 + 30 wt% × 8.96 = 9.842 g / cm 3 is the theory of Mo (70wt%)-Cu (30wt%) molybdenum alloy material. Density.

When the said density is less than 90%, there exists a possibility that the intensity | strength of a molybdenum alloy material may fall. On the other hand, if the density is higher than 98%, the strength is sufficient, but there is a fear of causing an increase in the manufacturing cost. Therefore, the density is preferably 90 to 98%. In addition, the density is preferably in the range of 94% to 97%.

An example of the structure of the Mo sintering component for semiconductor heat sinks which concerns on FIG. 2 at this embodiment is shown. In the figure, 4 is molybdenum crystal grains, and 5 is copper. Moreover, it is preferable that copper is filled in the clearance gap between molybdenum crystals. Moreover, it is preferable that the largest crystal grain diameter of molybdenum crystal is 2 times or less of an average grain diameter.

Mo sintering components are sintered bodies manufactured by sintering the molded object which mixed Mo powder and copper powder. Since molybdenum has a melting point of 2620 ° C and copper has a melting point of 1083 ° C, when molten sintered at a high temperature of 1200 ° C or higher, molybdenum crystal grains are grown as they are or partially grown as crystal grains, and copper melts to fill gaps between the molybdenum crystal grains. .

Moreover, it is preferable that the largest crystal grain diameter of molybdenum crystal is 2 times or less of an average grain diameter. If the molybdenum crystal has coarse particles exceeding twice the average particle diameter, variations in the ratio of molybdenum crystal and copper are likely to occur.

In addition, the measuring method of the average particle diameter of the said molybdenum crystal | crystallization uses the enlarged photograph (SEM photograph), and calculate | requires the long diameter and the short diameter of each molybdenum crystal taken thereon, and (long diameter + short diameter) / 2 By this, the particle diameter of the crystal grains is obtained. This operation | work is calculated | required the maximum diameter about arbitrary 100 particle | grains, the average value is made into "average particle diameter", and the largest "maximum diameter" is made into "maximum crystal grain diameter."

In addition, it is preferable that the distance which is the most spaced among the distance between adjacent molybdenum crystals is 50 micrometers or less. 5 shows another example of the structure of the Mo sintered part for semiconductor heat sinks of the present invention. In the figure, 4a and 4b are adjacent molybdenum crystal grains, and 5 is copper.

In FIG. 5, the molybdenum crystal grains 4b are the most spaced apart of the molybdenum crystal grains around the molybdenum crystal grains 4a. Regarding the molybdenum crystal particles 4b that are spaced most apart from the molybdenum crystal particles 4a, the shortest distance D is referred to as "the most spaced distance between adjacent molybdenum crystals". In the present invention, when the distance between the adjacent molybdenum crystals is 50 µm or less, the variation in partial thermal expansion rate can be reduced, the strength can be improved, and the variation in partial specific resistance can be reduced. In addition, it is more preferable that the most spaced distance between adjacent molybdenum crystals is 5-20 micrometers.

In addition, the measuring method of "the most distance | distance between adjacent molybdenum crystals" shall be measured using the enlarged photograph (SEM photograph) of 500 micrometers x 500 micrometers of unit areas.

An example of one shape of Mo sintering components for semiconductor heat sinks is shown in FIG. In FIG. 3, Mo sintering components for columnar semiconductor heat sinks are illustrated, In addition, polygonal columnar shapes, such as a square columnar shape, may be sufficient. 3, L is the diameter of Mo sintering components 1 for semiconductor heat sinks, and T is the thickness of Mo sintering components 1 for semiconductor heat sinks. Although the size of diameter L and thickness T is not specifically limited, It is preferable that it is a disk shape of 0.05-1 mm in thickness, 5-70 mm in diameter, 0.5-1 mm in thickness, and 5-10 mm in diameter. . Since the Mo sintering component for semiconductor heat sinks of this invention makes the abundance ratio of Mo and Cu homogeneous, it is homogeneous, without anisotropy in the heat radiation effect in a board | substrate thickness and the width direction. Therefore, even if it mounts a some semiconductor element, the heat radiation effect can be made the same about each element. Moreover, the reliability of the semiconductor device using the Mo sintering component for semiconductor heat sinks of this invention can be improved.

In particular, a semiconductor heat sink equipped with a plurality of Mo sintered parts for semiconductor heat sinks can improve reliability. The semiconductor device WHEREIN: Although the mounting number of Mo sintering components for semiconductor heat sinks is not specifically limited, Usually, it is 2-5 pieces.

Next, a manufacturing method is demonstrated. Although the manufacturing method of Mo sintering components for semiconductor heat sinks of this invention is not specifically limited, The following manufacturing method is mentioned as a method for obtaining efficiently.

First, Mo powder and copper powder are prepared and mixed as raw material powder. As Mo powder, the average particle diameter is 1-8 micrometers, More preferably, the raw material powder which is 3-5 micrometers is used. When average particle diameter exceeds 8 micrometers, coarse particle | grains 2 times or more of average particle diameter are easy to form. Moreover, it is preferable that the purity of Mo powder is 99.9 wt% or more.

Moreover, it is preferable that the average particle diameter of a copper powder is 10 micrometers or less, Furthermore, it is 0.5-5 micrometers. When the average particle diameter of a copper powder exceeds 10 micrometers, since the state which a copper powder does not enter easily between Mo particles is easy, it is unpreferable. Moreover, it is preferable that the purity of copper powder is 99.9 wt% or more. Moreover, when adding 3rd components, such as Ni, Co, Fe, as needed, the average particle diameter of a 3rd component is also 10 micrometers or less of average particle diameter, More preferably, it is 0.5-5 micrometers or less.

After mixing each raw material powder, the process of mixing a resin binder is performed. The resin binder is preferably PVA (polyvinyl alcohol) or the like. In the resin binder mixing step, the raw material mixed powder is granulated. It is preferable that the granulated powder of raw material powder is 50-200 micrometers, and 80-140 micrometers. In the step of the granulated powder, it is preferable to mix the Mo powder and the copper powder (including the third component powder when the third component is added) uniformly.

Subsequently, this granulated powder (raw powder mixed with a resin binder) is filled into a mold and press molded, whereby a press step of obtaining a Mo molded article in the shape of a Mo sintered part for a semiconductor heat sink is performed. The press pressure is preferably 3 to 13 tons / cm 2 (294 to 1274 MPa). If the press pressure is less than 3 ton / cm 3, the strength of the molded body is insufficient. If the press pressure is greater than 13 ton / cm 2, the density of the molded body becomes too high, and the mold is likely to be loaded.

Next, the 1st baking process which bakes the obtained Mo molded object in a redox atmosphere and obtains a 1st baked body is performed. It is preferable that a 1st baking process makes the highest achieved temperature 900-1200 degreeC, and makes the holding time in the highest achieved temperature 1-4 hours. The first firing step is positioned at the degree of preliminary sintering (or medium sintering before main sintering) when the second sintering step described later is main sintering. If the maximum achieved temperature is less than 900 ° C, densification of the molded body is insufficient, and if it exceeds 1200 ° C, the densification becomes excessive. If too densified, copper will not sufficiently enter the gap between Mo crystal grains. Moreover, as an redox atmosphere, it is preferable that it is a wet hydrogen gas atmosphere. Wet hydrogen gas is hydrogen gas containing water vapor.

In the first firing step, the sintered compact (Mo sintered component for semiconductor heat sink) is not intended to be densified as a final product, but is fired in a redox atmosphere to remove carbon on the surface of the Mo sintered compact and the Mo sintered compact is more than necessary. It is a process for the purpose of preventing oxidation. If the Mo sintered body is oxidized, there is a fear that copper will not be sufficiently filled between the Mo crystal particles.

Moreover, carbon can be removed from Mo sintered compact surface by performing the process in wet hydrogen (hydrogen gas containing water vapor) atmosphere. The carbon removed is either carbon dioxide (CO ₂ ) or carbon monoxide (CO). This is because the steam (H ₂ O) warmed by heating tends to react with carbon (C) and is easily removed from the Mo sintered body as carbon monoxide (CO) or carbon dioxide (CO ₂ ). When making Mo molded object, the resin binder with many carbon components is used.

Moreover, it is preferable that a 1st baking process heats up from 600 degreeC to the highest achieved temperature for 3 to 7 hours. In a 1st baking process, when the temperature increase rate is too fast, a nonuniform location may arise in the loss | disappearance and densification of the binder in a molded object, and there exists a possibility that it may become a sintered compact with a nonuniform density. On the other hand, if it raises for 7 hours or more, a nonuniformity will be eliminated, but time will become excessive and manufacturing efficiency will fall.

In the first firing step, in order to prevent the Mo molded body from being oxidized during firing, firing is performed in a wet hydrogen-containing atmosphere. From a viewpoint of preventing oxidation more than necessary, after replacing the inside of a kiln with nitrogen gas, it is preferable to make wet hydrogen gas flow volume into 0.2 m <3> / H (hour) or more, and also 0.2-17 m <3> / H (hour). It is preferable to supply wet hydrogen gas as an air stream and to supply fresh wet hydrogen gas to the Mo molded body.

In addition, if there is a predetermined gas flow rate, the removed carbon components (carbon dioxide and carbon monoxide) can be removed outside the sintering furnace together with the airflow. The resin binder remains as carbon when heat is applied. The remaining carbon becomes a carbon component (carbon dioxide or carbon monoxide) during the first firing step, but since these carbon components are likely to react with copper, it is necessary to be able to supply fresh wet hydrogen gas under the control of air flow.

In particular, when firing 200 or more molded bodies in one batch by arranging a plurality of Mo molded bodies on a firing boat (Mo boat), adjustment of the wet hydrogen gas flow rate is necessary, and at that time, wet hydrogen gas in the firing furnace is required. It is preferable to make it exist in the place whose flow volume is 2 m <3> / H or more.

In FIG. 4, as an example of a manufacturing method, the example which loads the molded object at the time of baking a some Mo molded object in 1 batch to a baking furnace is shown. In the figure, reference numeral 6 denotes a Mo molded body, reference numeral 7 denotes a container for firing, reference numeral 8 denotes a firing boat, and reference numeral 9 denotes a separator. Plural Mo molded bodies 6 are stacked on the plastic boat 8. At this time, in order to make hydrogen gas easily distribute | circulate the clearance gap of each molded object 6, it is preferable to leave the clearance gap between each molded object 1 mm or more. The baking boat 8 which loaded the some molded object 6 is laminated | stacked in multiple sheets via the separator 9 in multiple stages. This is arrange | positioned in the container 7 for baking. By arranging in the baking furnace with this baking container, 200 or more batches, 400 or more, and 2000 or more molded objects can be baked at once. Moreover, it is preferable that a baking boat, a separator, and the baking container are comprised from Mo from a viewpoint of heat resistance. In addition, in order to prevent fusion of a sintered compact, the baking boat may use what was coated with oxide ceramics as needed.

Next, the 2nd baking process which obtains a 2nd baking body which bakes a 1st baking body in a hydrogen containing atmosphere is performed. The second firing step is a step corresponding to the so-called main sintering step.

It is preferable that a 2nd baking process makes the highest achieved temperature 1200-1600 degreeC, and makes the holding time in the highest achieved temperature 1-5 hours. If the maximum achieved temperature is less than 1200 ° C, densification does not proceed sufficiently and the density tends to be less than 90%. On the other hand, when the highest achieved temperature exceeds 1600 ° C, copper flows down and the density decreases. Preferably it is the range of 1300-1500 degreeC.

If the holding time at the highest achieved temperature is less than 1 hour, densification of the Mo sintered compact is insufficient, and if it exceeds 5 hours, copper may melt.

In addition, it is necessary to perform a 2nd baking process also in a hydrogen containing atmosphere in order to prevent oxidation of Mo sintered compact similarly to a 1st baking process. For this reason, the method of supplying hydrogen gas after replacing the inside of a kiln with nitrogen gas is preferable. Moreover, since it is preferable to supply fresh hydrogen gas, it is preferable to adjust hydrogen gas airflow on the conditions similar to a 1st baking process. In particular, in order to obtain a plurality of sintered bodies with 200 or more batches and even 400 or more batches, adjustment of the flow rate of wet hydrogen gas or hydrogen gas is necessary.

In addition, since the 2nd baking process from the 1st baking process can continuously perform the movement from a 1st baking process to a 2nd baking process by using the baking container 7 as shown in FIG. 4, Is improved.

In addition, the Mo sintered compact (Mo sintered components for semiconductor heat sinks) manufactured as mentioned above shall perform surface grinding | polishing process as needed. Examples of polishing include barrel polishing and polishing by diamond grindstones.

[Example]

(Examples 1 to 5 and Comparative Example 1)

The average particle diameter is 3 µm, the Mo powder having a purity of 99.9 wt%, the average particle diameter is 5 µm, and the copper powder having a purity of 99.9% are mixed, and further mixed with a resin binder (PVA) to obtain an average particle diameter. A granulated powder of 80 to 120 μm was prepared. Next, this granulated powder was mold-molded at a press pressure of 3 to 5 ton / cm 2 to prepare a Mo molded body. In addition, the composition ratio of Mo and Cu and the magnitude | size of Mo sintered compact are as showing in Table 1.

Next, as shown in FIG. 4, 400 Mo molded bodies 6 were arranged on the Mo baking boat 8 at intervals of 2 mm. This baking boat 8 was superimposed three stages through the spacer (separator) 9, and was accommodated in the Mo baking container 7. This was put into a push type kiln and the 1st and 2nd baking processes were implemented on the conditions shown in Table 1. In addition, the baking process was performed in the atmosphere which flows a wet hydrogen gas airflow once, after filling nitrogen gas inside a baking furnace. Moreover, it heats up for 3 to 7 hours and performs it from 600 degreeC to a maximum achieved temperature.

Thereafter, surface polishing was performed to prepare Mo sintered parts for semiconductor heat sinks according to the examples. The obtained Mo sintering components for semiconductor heat sinks were unified to diameter 50mm x thickness 0.6mm. In addition, surface roughness Ra was unified at 3 micrometers.

On the other hand, as a comparative example 1, after producing the Mo sintered compact whose density is 90%, the Mo sintered component manufactured by the infiltration method which infiltrates Cu was prepared.

About the Mo sintered components for semiconductor heat sinks which concern on the Example and the comparative example, the area ratio of Mo crystal per unit area 500 micrometers x 500 micrometers of the structure surface was calculated | required. This took an enlarged photograph (SEM photograph) of a unit area of 500 µm x 500 µm in an arbitrary cross section, obtained the area of the Mo crystal to be taken therein, and calculated the area ratio of the Mo crystal to the unit area. In addition, EPMA surface analysis was used for the parts which are hard to distinguish between Mo crystal and copper. This operation was performed at five arbitrary places, the average value was made into the "average value of the area ratio of Mo crystals", the difference from the average value of each measuring point was calculated | required, and the largest difference was made into "deviation."

In addition, the average particle diameter of Mo crystal was calculated | required from the enlarged photograph mentioned above. Specifically, the particle diameter of each Mo crystal particle was calculated | required by the formula of (long diameter + short diameter) ÷ 2, and the average value for 100 pieces of Mo crystal particle was made into "average particle diameter." In addition, using the same enlarged photograph, the ratio of the particle diameter and the average particle diameter of the largest particle taken therein was calculated | required. In addition, the largest distance between adjacent molybdenum crystals calculated | required the shortest distance between the most spaced molybdenum crystal particles between adjacent molybdenum crystals among the molybdenum crystals taken therefrom from the enlarged photograph mentioned above. In addition, the density was calculated | required by (Archimedes method / theoretical density) x 100 (%).

Moreover, thermal expansion coefficient, tensile strength, specific resistance, and thermal conductivity were calculated | required. Here, the thermal expansion rate of Mo sintered components was calculated | required by the volume expansion rate from 25 degreeC to 400 degreeC. In addition, tensile strength was calculated | required by the tensile strength measuring method based on JIS-Z-2241. In addition, specific resistance was calculated | required by the measuring method of the volume resistivity based on JIS-H-0505. In addition, thermal conductivity was calculated | required by the laser flash method. The results are shown in Table 2.

As apparent from the results shown in Table 2, the Mo sintered component for semiconductor heat sink according to the present embodiment has a coefficient of thermal expansion of 7 to 14 × 10 ⁻⁶ / ° C., a tensile strength of 0.44 kPa or more, and a specific resistance of 5.3 × 10. ^{It was -6} Ω · m or less and exhibited excellent characteristics of thermal conductivity of 160 W / m · K or more. Moreover, when observing a cross-sectional photograph, copper was fully filled in the clearance gap of Mo crystal grain.

On the other hand, the Mo sintered component which concerns on the comparative example 1 manufactured by the immersion method had the area | region which is not filled with copper in the center part of Mo sintered compact, and the density was 87%. Therefore, thermal expansion rate, strength, and thermal conductivity fell, and the specific resistance value was large. Moreover, since the sintered compact was previously comprised only by Mo, since sintering temperature should be made high about 1700 degreeC, the coarse particle | grains more than twice the average particle diameter were formed.

(Examples 6 to 13)

Subsequently, the composition and Mo sintered compact were set as Table 3, and each Mo sintered component was produced according to the conditions of Table 4. The measurement similar to Example 1 was performed about the Mo sintering component for semiconductor heat sinks which manufactured each Example. The results are shown in Table 5. In addition, the baking process performs the temperature rising from 600 degreeC to the highest achieved temperature for 3 to 7 hours. In addition, the obtained Mo sintered components were surface-polished and the surface roughness was made into the numerical value shown in Table 3.

The Mo sintered part for semiconductor heat sinks according to the present embodiment was found to exhibit excellent characteristics even if the size was changed.

(Examples 1A to 13A and Comparative Example 1A)

The semiconductor device as shown in FIG. 1 was produced using the Mo sintering component for semiconductor heat sinks which concerns on Examples 1-13 and Comparative Example 1. FIG. Specifically, the semiconductor element 3 was mounted on the surface of the Mo sintering part 1 for semiconductor heat sinks through the insulating layer 2. Next, the semiconductor element 3 was arrange | positioned on the insulating film 2 by the number shown in Table 6, and was solder-bonded. Then, the heat resistance cycle test of the semiconductor element was done. That is, the temperature of the temperature rises from room temperature (25 ° C.) to 120 ° C., then returns to room temperature, and the heat cycle of cooling to -20 ° C. is one cycle. ) Was checked. "X" and that which did not generate | occur | produce even one problem were shown by "(circle)". The result is combined with Table 6 below.

As apparent from the results shown in Table 6 above, in the semiconductor device using each of the Mo sintered parts for semiconductor heat sinks according to the present embodiment, it was found that no misalignment occurred and high reliability and durability. On the other hand, in the semiconductor device of Comparative Example 1A, the thermal expansion coefficient was low and the thermal conductivity was also low, so problems were found in some devices.

1: Mo sintered parts for semiconductor heat sink
2: insulating film (insulating layer)
3: semiconductor device
4, 4a, 4b: molybdenum crystal grains
5: copper
6: Mo molded body
7: baking container
8: firing boat
9: Separator (spacer)

Claims (12)

In the Mo sintering part for semiconductor heat sinks containing the molybdenum alloy material containing 10-50 mass% of copper, the average particle diameter of the molybdenum crystal of the said molybdenum alloy material is 10-100 micrometers, per unit area 500 micrometers * 500 micrometers Mo sintering component for semiconductor heat sinks, characterized in that the deviation of the area ratio of the Mo crystal is within ± 10% of the average value. The method of claim 1,
The surface roughness Ra of Mo sintering components for semiconductor heat sinks is 5 micrometers or less, Mo sintering components for semiconductor heat sinks. 3. The method according to claim 1 or 2,
The said molybdenum alloy material contains 0.1-3 mass% of at least 1 sort (s) or more among Ni, Co, and Fe in metal element conversion, Mo sintering components for semiconductor heat sinks characterized by the above-mentioned. 4. The method according to any one of claims 1 to 3,
Mo molybdenum component for semiconductor heat sink, characterized in that the molybdenum alloy material is a sintered alloy material having a density of 90 to 98%. 5. The method according to any one of claims 1 to 4,
The said copper is filled in the clearance gap between molybdenum crystals, Mo sintering components for semiconductor heat sinks. The method according to any one of claims 1 to 5,
The maximum crystal grain diameter of the said molybdenum crystal is 2 times or less of the average grain diameter, Mo sintering components for semiconductor heat sinks. 7. The method according to any one of claims 1 to 6,
Mo sintered components for semiconductor heat sinks, characterized in that the distance between the adjacent molybdenum crystals, the most spaced apart is 50㎛ or less. 8. The method according to any one of claims 1 to 7,
The Mo sintering component for semiconductor heat sinks has a disc shape of 0.05-1 mm in thickness and 5-70 mm in diameter, Mo sintering components for semiconductor heat sinks. The method according to any one of claims 1 to 8,
The thermal expansion coefficient of Mo sintering components for semiconductor heat sinks is 7-14 * 10 <^-6> / degreeC, Mo sintering components for semiconductor heat sinks characterized by the above-mentioned. 10. The method according to any one of claims 1 to 9,
Mo sintered components for semiconductor heat sinks, characterized in that the tensile strength of the Mo sintered components for semiconductor heat sinks is 0.44 kPa or more. 11. The method according to any one of claims 1 to 10,
Mo sintered components for semiconductor heat sinks, characterized in that the resistivity of the Mo sintered components for semiconductor heat sinks is 5.3 × 10 ⁻⁶ Ω · m or less. The Mo sintering component for semiconductor heat sinks as described in any one of Claims 1-11 was used. The semiconductor device characterized by the above-mentioned.

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