JP2883582B2 - Receiving pedestal and bonding device for mounting semiconductor components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pedestal for mounting semiconductor parts and a bonding apparatus used in a semiconductor manufacturing apparatus and the like, and in particular, to a high-quality semiconductor part having good wear resistance, little generation and adhesion of dust. The present invention relates to a semiconductor component mounting pedestal and a bonding apparatus capable of mass-producing or moving a semiconductor device.

[0002]

2. Description of the Related Art In the process of manufacturing semiconductor parts such as LSIs, ICs, transistors, etc., for example, a wire bonding apparatus as shown in FIG. 1 is used. This bonding apparatus is an apparatus for connecting an electrode of a semiconductor component mounted on a semiconductor component mounting pedestal (bonding stage) and a lead by a bonding wire, and includes a bonding head including a bonding collet through which the bonding wire is inserted. An ITV camera 1 includes a camera head for detecting the position and bonding state of a semiconductor component, a lens, and an illumination lamp. The bonding head 1 is mounted on an XY table driving mechanism (not shown) that can move in the X and Y directions. The ITV camera in the bonding head 1 is transported onto the semiconductor component mounting receiving table 2. An image of the lead frame 3, which is the part to be bonded, is positioned.

A pair of guide rails 4a and 4b are provided on both sides of the semiconductor component mounting table 2, and the lead frame 3 is positioned in the width direction by the guide rails 4a and 4b. It is guided to a predetermined position while the position is regulated so as not to be. This lead frame 3
The loader 5 is disposed on the sending side, while the unloader 6 is disposed on the storage side. These loaders 5 have a delivery mechanism for positioning a magazine 7 capable of accommodating a plurality of lead frames 3 at a predetermined position and automatically sending the magazine 7 onto a transport path of the semiconductor component mounting receiving table 2. The unloader 6 also has a storage mechanism for storing the magazine 7 from the transport path.

[0004] Also, on the lower surface of the semiconductor component mounting pedestal 2,
The lead frame 3 to be bonded is heated to a temperature of 20
A heating means 8 such as a heater plate for heating to about 0 to 300 ° C. is provided. This heater plate 8
Are arranged along the longitudinal direction of the pair of guide rails 4a, 4b, so that a plurality of semiconductor elements (IC chips) 9 joined to the lead frame 3 can be heated simultaneously. By this heating operation, the electrode of the semiconductor element 9 positioned on the semiconductor component mounting table 2 and the lead 3a of the lead frame 3 are electrically connected by thermocompression bonding of the bonding wire 10.

A bonding stage in which this bonding connection is performed, that is, a pedestal for mounting a semiconductor component, is provided with a black hard chromium plating layer or a nickel plating layer on the surface of a metal base material conventionally made of SUS stainless steel. Is mainly used. As described above, by blackening the surface of the pedestal for mounting semiconductor components, the contrast between the pedestal and the semiconductor components such as the semiconductor element and the lead frame is increased, thereby improving the position detection accuracy. That is, the image signals of the semiconductor component and the cradle taken by the ITV camera attached to the bonding head are processed in the binarization circuit of the image processing means, for example, while the lead portion is lightened, Is darkened into a digital signal, and the coordinate position of a lead or the like is detected by the signal.

[0006]

However, in a conventional bonding apparatus in which a pedestal for mounting a semiconductor component in which a black metal plating layer is formed as a coating layer on the surface of a metal base material such as stainless steel, is mounted. Since the abrasion resistance and the bonding strength of the coating layer are low, the production yield of semiconductor components such as semiconductor circuit boards is reduced, and the maintenance management of the production equipment becomes complicated.

That is, the lead frame and the upper surface of the pedestal slide each time the high-speed bonding operation is completed for one semiconductor element, so that the black metal plating layer on the pedestal surface is easily worn or peeled off, and the The black background at the time cannot be obtained. Specifically, since the black plating layer on the pedestal is peeled off during bonding and the white metal base material is exposed, the coordinate positions of the leads and the like processed by the binarization circuit of the image processing device are automatically recognized. In this case, there is a disadvantage that a coordinate position different from the normal coordinate position is detected.
As a result, when the position and shape of the semiconductor element and the lead are confirmed by the monitor device, a recognition error is likely to occur, and the defect rate of the product may increase rapidly. Therefore, it was necessary to replace the cradle with high frequency during a short operation period. As described above, the bonding apparatus must be stopped every time the pedestal is replaced, so that continuous operation for a long period of time is difficult, and there is a problem that the labor required for maintenance and management of the apparatus increases.

Further, in the conventional pedestal for mounting semiconductor components, since the bonding strength between the metal base material and the coating layer is weak, the coating layer is liable to be separated, and this separation generates dust, resulting in a semiconductor component as a product. There is also a problem that it adheres to the surface and deteriorates its characteristics, thereby lowering the production yield of semiconductor parts.

Further, like a conventional bonding apparatus,
When a pedestal having a black metal plating layer is used, when the lead frame is conveyed onto the pedestal, a brazing material component such as silver (Ag) plated on the lower surface of the lead frame is used. As a result of intermetallic bonding with ferrous metal components,
The pedestal and the lead frame may adhere to each other, and the lead frame may be bent or deformed. When the wire bonding operation is performed in this state, the bonding wire is deformed, and in any case, there is a problem that the bonding failure increases.

As a measure to reduce the above problems, for example, as described in Japanese Utility Model Publication No. Hei 6-10684, the surface of a stainless steel base material is made of Al ₂ O ₃ —TiO _2.
A bonding apparatus using a pedestal on which an insulating coating made of a ceramic is formed is disclosed. However, the above problems have not been solved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has good abrasion resistance, can reduce generation and adhesion of dust due to peeling of a coating material, and can further provide a lead or the like at the time of bonding or the like. It is an object of the present invention to provide a pedestal such as a pedestal for mounting a semiconductor component and a bonding apparatus using the pedestal for mounting a semiconductor component, which can accurately recognize the coordinate position of the semiconductor device.

[0012]

In order to achieve the above object, a semiconductor component mounting pedestal according to the present invention is characterized in that a coating layer mainly composed of chromium oxide is formed on the surface of a metal base material. Features. Needless to say, this pedestal for mounting a semiconductor component may be used for mounting a semiconductor component when moving the semiconductor component in addition to the one used for a bonding apparatus.

The chromium oxide is chromic oxide (Cr)
₂ O ₃ ). Further, chromium oxide has an average particle size of 0.1 to 0.5 μm and is chromic oxide (C
r ₂ O ₃ ) fine particles. The coating layer mainly composed of chromium oxide has a deep dark green color.

Further, the coating layer has a maximum surface roughness (Rma).
x) It is preferably formed on the surface of a metal base material having a size of 5.0 μm or more on a standard basis. Specifically, before forming the coating layer, the surface of the metal base material is roughened by blasting or the like so as to have a Rmax standard of 5.0 μm or more, and thereafter, the coating layer is formed. As described above, the surface of the metal base material is set at 5.
By making it rough to 0 μm or more, the bonding strength with the coating layer can be increased, and at the same time, the surface roughness of the semiconductor component mounting pedestal after the formation of the coating layer can be made rough. Where Rmax
If the standard surface roughness exceeds 10 μm, it becomes difficult to form a uniform coating layer, so that it is preferably 10 μm or less.

More specifically, when the metal base material is an iron-based metal, a reaction layer of an iron compound and chromium oxide is provided between the metal base material and the coating layer containing chromium oxide as a main component. Preferably, it is formed. By forming this reaction layer, the bonding strength with the coating layer containing chromium oxide as a main component can be further increased. In the present invention, "the coating layer mainly composed of chromium oxide is formed on the surface of the metal base material" means that even if the coating layer is formed via the reaction layer, it is within the scope of the present invention. Needless to say. In addition, apart from whether the interface is clear or not, a two-layer coating layer of a reaction layer and a coating layer mainly composed of chromium oxide is formed on the surface of the metal base material. .

In a bonding apparatus according to the present invention, there is provided a bonding apparatus for connecting an electrode of a semiconductor component mounted on a semiconductor component mounting pedestal to a lead, wherein the semiconductor component mounting pedestal is a metal motherboard. It is characterized in that a coating layer mainly composed of chromium oxide is formed on the surface of the material.

Here, the metal base material is not particularly limited, and general-purpose structural steel materials, corrosion-resistant and heat-resistant steel such as stainless steel, various iron-based alloys, carbon steel, titanium alloys, aluminum alloys, Inconel and the like can be used.

The coating layer containing chromium oxide as a main component can be formed, for example, by the following procedure. In other words, a chromic acid (CrO ₃ ) aqueous solution or slurry (slurry) is applied to a surface of a metal base material such as an iron-based metal that has been subjected to surface treatment in advance, or is immersed in the chromic acid aqueous solution or slurry. Attach.
Next, by heating and baking at a low temperature of about 400 to 600 ° C., moisture is evaporated, and at the same time, a reaction layer formed by a chemical reaction between chromium oxide and the surface layer of the metal base material has an average particle diameter of 0.1 to A coating layer mainly composed of chromium oxide (chromic oxide: Cr ₂ O ₃ ) composed of 0.5 μm fine particles is formed.

The total thickness of these coating layers is preferably 1 to 5 μm in total for the reaction layer and the coating layer containing chromium oxide as a main component. If the thickness of the coating layer is less than 1 μm, the insulation and abrasion resistance of the fixing jig decrease. When the reaction layer and the coating layer mainly composed of chromium oxide do not contain or contain ceramic fine particles or flakes as described below, if the coating layer exceeds 5 μm, the coating layer thickness Uniformity is impaired, and adhesion and bonding strength are also reduced. For the same reason, the range of 1 to 3 μm is more preferable.

On the other hand, in an aqueous solution of chromic acid (Cr ₂ O ₃ ), alumina (Al ₂ O ₃ ), silica (SiO ₂ ), ZnO
By adding ceramic fine particles or flakes such as _2, the properties (bonding strength, surface hardness) of the coating layer can be further improved. Specifically, a coating layer (a reaction layer and a coating layer containing chromium oxide as a main component) formed on the surface of the metal base material is formed of the ceramic fine particles and flakes by 3%.
It is desirable to adjust the addition amount so as to contain 0 to 50 wt%. However, when ceramic fine particles such as Al ₂ O ₃ and flakes are added, the thickness of the coating layer is preferably in the range of 15 to 80 μm.

When the thickness of the coating layer is less than 15 μm, the effect of improving the bonding strength is poor. Conversely, when the thickness exceeds 80 μm, chromium oxide (and ceramic fine particles,
This is because the strength of the coating layer itself containing flakes as a main component is weakened, and the adhesion strength and the bonding strength are eventually reduced. For the same reason, another 20 to 60 μm
The range of m is desirable.

The coating layer containing the ceramic fine particles may be formed by the following method in addition to the above. That is, an aqueous solution or slurry containing fine ceramic particles is applied to the surface of a base metal, heated and fired at a temperature of 500 to 600 ° C. to form a porous ceramic layer, and then a chromic acid (CrO ₃ ) aqueous solution or slurry is applied. Impregnated in ceramic layer, temperature 500 ~
It may be formed by sintering at 600 ° C.

If the operation of applying and impregnating the raw material liquid and the operation of sintering are performed only once, minute pores are likely to remain in the coating layer. The operation may be repeated about 10 times. The thickness of the coating layer can be adjusted by controlling the number of repetitions of the application / impregnation operation and the baking operation.

The coating layer formed as described above has a high bonding strength to the metal base material, and is excellent in high hardness, non-porosity, wear resistance, low friction property, heat resistance and the like. Incidentally, the surface hardness when stainless steel is used as the metal base material is slightly affected by the hardness of the metal base material, and is 500 to 600 Hv (0.1).
On the other hand, the surface hardness of the thick coating layer containing the aggregate is 1
The hardness is as high as 500 to 2000 Hv (0.1), and the same hardness as a cemented carbide can be obtained.

In particular, when an iron-based metal base material is used, chromium oxide and metal (iron) undergo a chemical reaction at the boundary between the coating layer and the metal base material to form a reaction layer. Due to the presence of the layer, the joint strength between the two is 700 kgf / cm ² (68 kgf / cm ² ).
MPa) or more.

Further, a chromium oxide (C
Since the average particle size of r ₂ O ₃₎ fine particles are 0.1~0.5μm about and ultrafine, strong action as a solid lubricant.
Therefore, even if the surface roughness (Rmax) is somewhat large, the coefficient of friction becomes small, and the effect of improving the sliding characteristics is remarkable. In particular, since the coating layer is formed by precipitation from an aqueous solution, the constituent particles are ultrafine, and unlike a porous ceramic coating formed by a conventional thermal spraying method, corrosion resistance and wear resistance do not become insufficient.

Further, since the surface portion of the coating layer is formed densely, it is excellent in heat resistance and thermal shock resistance. Even when a repeated heat cycle acts on the pedestal for mounting semiconductor parts,
It does not cause peeling of the coating layer and generates little dust due to peeling.

Further, the coating layer has excellent corrosion resistance to acidic solutions such as sulfuric acid, basic solutions such as aqueous ammonia, and organic solvents such as alcohol, acetone and gasoline. Has excellent durability.

By forming the coating layer in this manner,
The function of the metal base material can be greatly enhanced, and excellent effects are exhibited especially when the metal base material is used as a component of a sliding part such as a pedestal for mounting semiconductor components of a bonding apparatus or a heater plate.

Further, since the coating layer has a dark green color, when the pedestal for mounting a semiconductor component is used as the pedestal of the bonding apparatus, the semiconductor element and the lead and the pedestal serving as a background portion thereof are formed. And the monitor device such as a TV camera can clearly recognize the shape of the semiconductor element and the position of the lead. Therefore, the recognition error of the coordinate position of the lead or the like by the monitor device is reduced, and the semiconductor component can be assembled with high accuracy.

Here, if the coating layer is formed on the metal base material itself of the pedestal for mounting semiconductor components according to the present invention without performing a treatment for adjusting the surface roughness, the coating layer is formed from ultra-fine chromium oxide particles. Because of the dense structure, the surface becomes as smooth as 1-2 μm on the basis of Rmax, similarly to the surface roughness of the metal base material of the receiving base.

Therefore, the pedestal for mounting a semiconductor component of the present invention has been subjected to roughening treatment such as blasting on the metal base material itself in advance to reduce the surface roughness (Rmax) of the metal base material itself to 5.0 μm.
It is desirable to form the coating layer after the thickness is at least m. By adjusting the surface roughness of the metal base material in advance, the surface roughness (R
max) is 3 to 5 μm, and the coating layer thickness can be made uniform. In addition to improving the bonding strength, dust and dust generated in the semiconductor manufacturing apparatus during use can be adhered to the receiving table side. In addition, it is possible not to adhere to the semiconductor component side which is a product. Therefore, contamination of the product semiconductor component due to dust or the like can be effectively prevented, and high-quality semiconductor components can be mass-produced with a high production yield.

According to the pedestal for mounting semiconductor components according to the above configuration, since the coating layer made of ultrafine chromium oxide particles is formed on the surface of the metal base material, the insulation and abrasion resistance of the pedestal are reduced. Is good, and generation and adhesion of dust can be prevented. Therefore, when this pedestal is used as a pedestal for mounting semiconductor components of a bonding apparatus or as a sliding component, it becomes possible to mass-produce high-quality semiconductor components with few defects with a high production yield.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings.

Examples 1 to 5 As shown in Table 1 and FIG. 2, carbon steel for machine structural use (S45C) and alloy tool steel (SKD) having been subjected to blast treatment in advance and having a surface roughness (Rmax) of 7 to 8 μm. ) And stainless steel (SUS304) as a metal base material are prepared respectively, and a chromic acid (CrO ₃ ) saturated aqueous solution (SiO according to the embodiment) is formed on both surfaces of each pedestal body 11.
₂ by adding fine particles) and baking at a temperature of 500 ° C.
The coating layer 12 having the thickness shown in Table 1 was formed on both surfaces of the. As a result, pedestals 13 for mounting semiconductor components according to 1 to 5 shown in Table 1 were prepared.

The pedestal 13 for mounting a semiconductor component according to each embodiment.
The coating layer 12 has an average particle size of 0.1 as shown in FIG.
And chromium oxide layer 14 made of ~0.5μm and ultrafine chromium oxide (Cr ₂ O ₃₎ particles, and iron components of chromium oxide and the metal base material is composed from a reaction layer 15 which is generated by chemical reaction Was.

Comparative Examples 1 to 3 On the other hand, as Comparative Examples 1 to 3, as shown in Table 1, carbon steel for machine structural use (S45C) and stainless steel (SUS304), which are conventional materials, were mechanically ground. A flat receiving body having the same dimensions is formed, and a chromium plating layer (Comparative Example 1) and a nickel plating layer (Comparative Example 2) having the thickness shown in Table 1 are formed on the surface of the receiving body in contact with the lead frame. ), A galvanized layer (Comparative Example 3) was formed, and a large number of semiconductor component mounting pedestals according to Comparative Examples 1 to 3 were prepared.

Then, for each of the cradles prepared in Examples 1 to 5 and Comparative Examples 1 to 3, the bonding strength of the coating layer was measured by a peel test method. Further, each pedestal was mounted as a pedestal 2 for mounting a semiconductor component of the bonding apparatus shown in FIG. 1, and the properties of each pedestal such as insulation, abrasion resistance, and amount of generated dust were measured and compared.

That is, when the wire bonding was continuously performed 1,000,000 times, the defect occurrence rate of the semiconductor component due to the wire bonding defect and the average wear amount of the pedestal for mounting the semiconductor component were measured. The results shown in Table 1 were obtained.

[0040]

[Table 1]

As is clear from the results shown in Table 1 above,
According to the semiconductor component mounting pedestal according to each of the embodiments, which is made of fine CrO ₃ particles and has a dense and high hardness coating layer, the wire is compared with the pedestal of each comparative example using the conventional material. The occurrence of defective parts due to defective bonding is also small. In particular, since the bonding strength between the metal base material and the coating layer is greatly increased as compared with the conventional case, there is almost no peeling of the coating layer, and the generation of dust due to the peeling of the coating layer and the adhesion of the generated dust to the lead frame. Almost no. Further, it was observed that the dust slightly generated on the semiconductor component mounting pedestal according to each example was almost adhered to the pedestal side. That is, since the amount of dust generated and the amount of adhesion due to rubbing with the lead frame are significantly reduced, the production yield of semiconductor components can be greatly improved.

Embodiment 6 The above Embodiments 1 to 1 except that a pedestal main body 11a having a recess 16 formed on the surface as shown in FIG. 4 according to the shape of the semiconductor element (IC chip), the lead frame, etc. are used. In the same manner as in Example 5, a coating layer 12 made of Cr ₂ O ₃ fine particles was formed on the surface of the pedestal main body 11a to prepare a pedestal 13a for mounting semiconductor components according to Example 6.

The pedestal 13a in which the recess 16 is formed is mounted as the pedestal 2 of the bonding apparatus shown in FIG. 1 in the same manner as in the first to fifth embodiments, and its characteristics such as wear resistance, life, dust generation amount and the like are obtained. As a result, values equivalent to those of Examples 1 to 5 were obtained. That is, the generation of dust due to the peeling of the coating layer and the adhesion of the dust to the lead frame hardly occurred, and the contamination of the semiconductor component could be effectively reduced. In addition, the wear of the coating layer is small, the error is small even in the operation of recognizing the coordinate position of the lead by the monitor device (ITV camera), and it is possible to greatly reduce problems such as a defective bonding position of the wire.

[0044]

As described above, according to the pedestal for mounting a semiconductor component according to the present invention, the coating layer made of ultrafine chromium oxide particles is formed on the surface of the metal base material. Good insulation and abrasion resistance, and
Adhesion can be prevented. Therefore, when this pedestal is used as a pedestal for mounting a semiconductor component in a bonding apparatus, it becomes possible to mass-produce high-quality semiconductor components with few defects with high production yield.

Further, it is not necessary to frequently stop the wire bonding apparatus in order to replace the pedestal for mounting semiconductor components, and it is possible to continuously operate the apparatus for a long period of time, and to maintain and manage the apparatus. Is greatly simplified,
As a result, the manufacturing efficiency of semiconductor components can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a configuration of a bonding apparatus.

FIG. 2 is a sectional view showing an embodiment of a semiconductor component mounting pedestal according to the present invention.

FIG. 3 is an enlarged sectional view of a part III in FIG. 2;

FIG. 4 is a cross-sectional view showing another embodiment of the pedestal for mounting a semiconductor component according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bonding head 2 Receiving stand for mounting semiconductor components 3 Lead frame 3a Lead 4a, 4b Guide rail 5 Loader 6 Unloader 7 Magazine 8 Heating means (heater plate) 9 Semiconductor element (IC chip) 10 Bonding wire 11, 11a Receiving stand main body Reference Signs List 12 coating layer 13, 13a pedestal for mounting semiconductor components 14 chromium oxide (Cr ₂ O ₃ ) layer 15 reaction layer 16 recess

──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Chuichi Senda 1-1-1, Shibaura, Minato-ku, Tokyo Inside the head office of Toshiba Corporation (56) References JP-A-7-161757 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) H01L 21/60 301

Claims (8)

(57) [Claims] 1. A pedestal for mounting a semiconductor component, wherein a coating layer containing chromium oxide as a main component is formed on a surface of a metal base material. 2. The chromium oxide is chromic oxide (Cr _2).
2. The pedestal for mounting a semiconductor component according to claim 1, wherein O ₃ ). 3. The chromium oxide has an average particle diameter of 0.1 to 0.1.
_{2. The} pedestal for mounting a semiconductor component according to claim 1, wherein the pedestal is a 5 μm chromic oxide (Cr ₂ O ₃ ) fine particle. 4. The pedestal for mounting a semiconductor component according to claim 1, wherein the coating layer is dark green. 5. The coating layer has a maximum surface roughness (Rmax).
2. The pedestal for mounting a semiconductor component according to claim 1, wherein the pedestal is formed on a surface of a metal base material having a standard of 5.0 μm or more. 6. The pedestal for mounting a semiconductor component according to claim 1, wherein a reaction layer of an iron compound and chromium oxide is formed between the metal base material and the coating layer. 7. A bonding apparatus for connecting an electrode and a lead of a semiconductor component mounted on a semiconductor component mounting pedestal to a chromium oxide on the surface of a metal base material. A bonding apparatus, wherein a coating layer as a main component is formed. 8. The coating layer is dark green and has a surface roughness of at least 5.0 μm on the basis of a maximum height (Rmax).
The bonding apparatus as described in the above.