JP2001303200A - HIGH-STRENGTH LOW-THERMAL-EXPANSION Fe-Ni ALLOY, AND SHADOW MASK AND CATHODE-RAY TUBE USING THE MASK, AND LEAD FRAME AND SEMICONDUCTOR DEVICE USING THE FRAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a high-strength low-thermal-expansion Fe-Ni alloy and to provide a shadow mask composed of the alloy and a cathode-ray tube using the mask and also to provide a lead frame composed of the alloy and a semiconductor device using the frame. SOLUTION: The alloy is an Fe-Ni alloy having a composition consisting of, by mass, 30-50% Ni and the balance mainly Fe or an Fe-Ni alloy having a composition consisting of 27-47% Ni, <=22% Co and the balance mainly Fe. Moreover, the maximum grain size of a compound composed mainly of niobium and nitrogen and a compound composed mainly of niobium and carbon, observed in the cross section of the structure, is regulated to <0.5 μm, and the total number of these compounds accounts for >=50000 pieces/mm2 of the cross section of the structure. To be concrete, the alloy is an Fe-Ni alloy which has a composition consisting of 30-50% Ni or 27-47% Ni and <=22% Co, 0.005-0.1% Nb, <0.01% C, 0.002-0.02% N and the balance essentially Fe and satisfying 0.000013<=[%Nb].[%N]<=0.002. Further, the shadow mask or the lead frame is composed of the above Fe-Ni alloy, and the cathode-ray tube or the semiconductor device is manufactured by using the shadow mask or the lead frame, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe--Ni alloy having a high strength and a small average coefficient of thermal expansion, and more particularly to a shadow mask, a cathode ray tube and a lead frame using the same, and a semiconductor device using the same. Further, the present invention relates to a material applied to a material such as each part of a precision machine.

[0002]

2. Description of the Related Art Amber-based Fe-Ni-based alloys represented by Fe-36% Ni, Fe-31% Ni-5% Co
Are known as low thermal expansion alloys having a small average thermal expansion coefficient. These Fe-Ni alloys and Fe-Ni-C
An o-based alloy (hereinafter collectively referred to as an Fe-Ni-based alloy) requires low thermal expansion characteristics such as a shadow mask in a television or computer display, an electrode of a cathode ray tube electron gun, or a lead frame used in the manufacture of a semiconductor package. Is used for

[0003] For example, as a shadow mask material, mild steel has conventionally been generally used. Mild steel has good press formability and etching properties, but has a thermal expansion coefficient of about 12 × 10
^It is as large as ⁻⁶ / ° C., and is heated by electron beam irradiation to cause thermal expansion, which causes a problem of deteriorating color purity. In recent years, with the demand for higher definition and higher brightness of the display, an amber-based alloy represented by Fe-36% Ni having a small coefficient of thermal expansion has been put to practical use as a shadow mask material instead of conventional mild steel. I have. However,
The Fe-36% Ni invar alloy has problems that the etching property is inferior to mild steel and that the cost is very high.

Further, with the recent rapid progress toward flat screens, a tension system in which a tension is applied to a mask frame in a state where tension is applied is being applied instead of a shadow mask of a conventional press molding system. In this case, since the shadow mask itself is particularly supported by the frame, the shadow mask itself is not required to have sufficient strength for maintaining its shape, and the thickness of the shadow mask is being reduced in order to reduce costs. However, with regard to handling in a thin plate state, handling properties (strength) capable of dealing with breakage and deformation in each step are required.

Since the lead frame material is joined to a semiconductor element having a small coefficient of thermal expansion as a lead frame, Fe-4 having a similar coefficient of thermal expansion to these elements is used.
An Fe-Ni alloy represented by 2% Ni is used. Fine lead processing is applied to lead frame materials by press punching and photo-etching. However, as finer processing shapes and higher precision are required with higher integration of semiconductor devices, these Fe-Ni
It is required to improve the punching property of the system alloy and to increase the strength for thinning.

[0006] Fe-Ni (-C
As for the o) -based alloys, a number of means by adding Nb have been proposed as means for improving the etching property, press formability, strength and punching property. For example, JP-A-4-12
No. 0251 regulates N to 0.01% or less, reduces the amount of solid-dissolved N by adding 0.01 to 1.0% of Nb, which easily forms a nitride, and further adds an appropriate amount of Cr. We propose a shadow mask material that improves the adhesion of the resist film and the rigidity after press molding. Japanese Unexamined Patent Publication No. Hei 7-145451 proposes a lead frame material in which the strength is enhanced by adding 1 to 4% of Nb.

[0007] Especially regarding the lead frame material,
JP-A-9-263891 discloses that C: 0.003 to 0.0.
3%, Nb: 0.005 to 2.5%, N: 0.001
A high-strength low-thermal-expansion Fe-Ni-based alloy has been proposed in which the punching property is improved by forming an Nb compound (carbide, nitride) having a maximum diameter of 20 μm or less with 0.02%. Japanese Unexamined Patent Publication No. 10-183304 discloses a 4A group or 5A group.
The size of the granular precipitates containing elemental group elements (simple, carbide, nitride, intermetallic compound) was adjusted to 5 μm or less, and among them, C: 0.001 to 0.3%, Nb: 0.01 to 6 %
We propose a method for improving press punching properties and mechanical strength by performing precipitation and adjustment of NbC (niobium carbide) adjusted by the method described above.

Japanese Patent Application Laid-Open No. 10-60528 discloses a high-strength Invar alloy plate for a shadow mask or a lead frame, in which C of up to 0.10% and Nb of up to 1.0% are added and N is added. Has been proposed to reduce the value to 0.005% or less.

[0009]

The above method is an effective means for improving various characteristics required for a shadow mask, a lead frame, and the like. However, in the case of using Nb in a solid solution state as a means of increasing the strength and accumulating work strain to achieve work hardening, a large amount of Nb needs to be added, and there is a concern that thermal expansion characteristics may deteriorate. In the case of increasing the strength as Nb-containing precipitates, these are mainly aimed at strengthening the dispersion as niobium carbide, and a large amount of Nb is necessary to secure a sufficient amount of precipitation to exhibit the effect.
Is required. In addition, the size of the precipitate is large.

[0010] In the case of the conventional alloys as described above, the charcoal and nitride which are crystallized during ingot ingot and solidification tend to be coarse,
This leads to problems such as protruding from the etched surface and increasing the wear of the die during press punching. Therefore, the present invention has achieved a high-strength low-thermal expansion Fe-Ni-based alloy that suppresses crystallization of coarse coal and nitride, and a shadow mask made of such an alloy, a cathode ray tube and a lead frame using the same, and It is an object to provide a semiconductor element used.

[0011]

Means for Solving the Problems First, the present inventors have proposed F
As a method of increasing the strength of the e-Ni-based alloy, a method that does not rely on a crystallized carbide that tends to become coarse was studied. As a result, a large number of fine niobium compounds including niobium, such as nitride, carbide, and carbonitride, can be precipitated in the structure mainly by niobium nitride capable of ultrafine precipitation by solid solution precipitation treatment, thereby forming crystal grains. It has been found that it is an effective means for achieving fineness and achieving high strength without deteriorating various characteristics. In other words, by using the Nb, C, and N adjustments within a range in which the solid solution can completely form a solid solution in the Fe—Ni-based alloy, an ultrafine niobium compound is precipitated with a small amount of Nb added. This method does not require the addition of a large amount of Nb, because it does not rely on the conventional method of suppressing the crystallization of coarse coal and nitride and also mainly of strengthening the dispersion.

That is, according to the present invention, Ni:
30% to 50%, with the balance being Fe-
A Ni-based alloy in which the maximum particle size of a compound mainly composed of niobium and nitrogen and a compound mainly composed of niobium and carbon observed in the structure cross section is less than 0.5 μm, and 50,000 pieces / mm
High strength and low thermal expansion Fe-N characterized by being ² or more
It is an i-based alloy. Specifically, in mass%, Ni: 30
-50%, Nb: 0.005-0.1%, C: 0.01
%, N: 0.002 to 0.02%, balance substantially consisting of Fe, 0.000013 ≦ [% Nb] · [%
N] ≦ 0.002 is a high-strength low-thermal-expansion Fe—Ni-based alloy.

Alternatively, in mass%, Ni: 27 to 47
%, Co: not more than 22%, and the balance is a Fe-Ni-based alloy mainly composed of Fe, which is mainly composed of a compound mainly composed of niobium and nitrogen, and mainly composed of niobium and carbon observed in the cross section of the structure. The maximum particle size of the compound is less than 0.5 μm and the total number of the
High-strength low-thermal-expansion Fe—Ni-based alloy characterized by being at least ² pieces / mm ² . Specifically, in mass%, N
i: 27 to 47%, Co: 22% or less, Nb: 0.00
5 to 0.1%, C: less than 0.01%, N: 0.002 to
0.02%, balance substantially consisting of Fe, 0.000%
013 ≦ [% Nb] · [% N] ≦ 0.002 is a high-strength low-thermal-expansion Fe—Ni-based alloy.

In addition, the high strength and low thermal expansion F
Preferably, the average crystal grain size of the e-Ni alloy is JIS.
The fine particles have a particle size number of 10 or more according to G 0551. Further, the Mn content is 0.10% or less,
Alternatively, B may be set to 0.004% or less.

The high strength and low thermal expansion F of the present invention
A shadow mask made of an e-Ni alloy and a cathode ray tube or a lead frame using the same and a semiconductor element using the same, the cathode ray tube having a high definition and a high precision, and having a fine processing shape and excellent color purity. It is a semiconductor element excellent in high integration.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The most important feature of the present invention is that it is possible to suppress the crystallization of coarse coal and nitride and to use an Fe-Ni-based method by a method which does not depend on the conventional method whose main function is dispersion strengthening. This is where high strength of the alloy has been achieved.

The present inventors have studied a method for solving the above-mentioned problem that is feared due to the crystallization of coarse niobium carbide, and it is known that the conventional nitride, which also utilizes dispersion strengthening as its main function, It has been found that there is further adjustment of compounds mainly composed of niobium and nitrogen, such as carbides and carbonitrides, and compounds mainly composed of niobium and carbon (hereinafter collectively referred to as niobium compounds). In other words, the present invention focuses on the effects of the amounts of Nb, C, and N adjusted within a range in which fine niobium compounds can be precipitated by the solid solution precipitation treatment and can be completely dissolved by the solid solution treatment.

In particular, niobium nitride has a smaller solubility product than that of carbides. Therefore, a very small amount of Nb is added to completely form a solid solution. Preferably, by setting the solubility product of niobium nitride to 0.000013 or more and 0.002 or less, it becomes possible to form a solid solution by a solution treatment in a range of 900 ° C. to 1350 ° C. and further up to 1300 ° C. Precipitation treatment or controlled cooling after hot working
It can be finely precipitated.

Since ultra-fine precipitates effectively work as pinning particles at the crystal grain boundaries, it leads to ultra-fine crystal grains and high strength of the material can be achieved. Therefore, Fe-N
By forming a large amount of ultrafine niobium compounds, particularly niobium nitride, in the i-based alloy, high strength can be achieved without using coarse carbides.

In addition, the present inventors have studied the size of a niobium compound that is effective for achieving high strength by making the crystal grains fine. In the Fe-Ni-based alloy of the present invention, it is preferable that the average grain size, which is effective for increasing the strength, is a fine grain having a grain size number of 10 or more according to JIS G 0551. In this case, the dispersed particle diameter and the matrix derived from the Zener's relational expression (R = 4/3 · r / f ^2/3 : the average crystal grain diameter R of the matrix, the average particle diameter r of the precipitate, and the volume ratio f of the precipitate) Considering the relationship between the average crystal grain diameters, the maximum particle diameter of the niobium compound (compound mainly composed of niobium and nitrogen and compound mainly composed of niobium and carbon) observed in the cross section of the structure is set to less than 0.5 μm. In addition, it is necessary that the total number of the occupied sections in the tissue cross-section for fully exhibiting the effect is 50,000 / mm ² or more.

Therefore, the Fe—Ni-based alloy of the present invention has a maximum particle size of a niobium compound (a compound mainly composed of niobium and nitrogen and a compound mainly composed of niobium and carbon) that is observed in the cross section of the structure. 0.5 μm or less and the total number occupying the tissue cross section is 50,000 / mm ² or more. Preferably, the maximum particle size is 0.3 μm or less, or the total number occupying the tissue section is 100,000 / mm ² or more, and the maximum particle size is 0.3 μm or less, and the total number occupying the tissue section is 100,000 / mm 2. It is desirable that the number be ² or more.

Incidentally, an ultrafine niobium compound having a size of less than 0.5 μm can be used, for example, in a manufacturing process of 900 to 1350.
The adjustment can be performed by suitably adjusting the conditions of the soaking and solution treatment at a temperature of ° C. and the precipitation treatment, preferably by combining the composition conditions described below.

Particle size of niobium compound observed in the cross section of the structure
As a measuring method, for example, a tissue surface corroded by the speed method
Method for observing niobium compounds appearing in
You. Fig. 1 shows a Fe-Ni-based alloy corroded by the speed method.
Was observed with a scanning electron microscope at a magnification of 16000.
And a niobium compound having a maximum particle size of 0.06 μm.
Is shown. In addition, a compound mainly composed of niobium and nitrogen,
And it is a compound mainly composed of niobium and carbon,
Nitrogen and nitrogen or carbon are mainly analyzed by EDX.
It can be confirmed as grains contained in the body. Occupy the tissue section
Regarding the total number of these niobium compounds,
Count the number of observations, mm ²Pieces per
What is necessary is just to convert to a number. In the case of FIG. 1, 811 × 10⁴/ M
m²It is.

In the case of the conventional technique utilizing dispersion strengthening mainly by a crystallized substance such as niobium carbide, as described above, Nb for securing a sufficient crystallized amount is about 0.1%.
Is necessary, and the diameter of the crystallized product is at least about 0.5 μm. On the other hand, according to the present invention, which aims at refining crystal grains by solid solution precipitation of an ultrafine niobium compound, the amount of Nb to be achieved is small as described later. In particular, crystallization of niobium nitride can be suppressed, and the amount of Nb added can be suppressed.

The reasons for limiting the numerical values of the preferred specific composition of the Fe—Ni alloy of the present invention will be described below. N
i is an element having a large effect on the low thermal expansion characteristics of the Fe—Ni (—Co) alloy. If the content is less than 30% or more than 50%, the invar effect of lowering the coefficient of thermal expansion is lost, so the range of Ni is 30 to 50.
%. Further, in the Fe-Ni-based alloy of the present invention, a part of Ni may be replaced with Co or Co may be added from the viewpoint of securing further low thermal expansion characteristics. Specifically, Ni: 2
Fe-Ni alloy containing 7 to 47% and Co: 22% or less, preferably F containing 2 to 6% Co
It is an e-Ni alloy.

Nb is an important and essential element of the present invention. In the present invention, it is possible to disperse and precipitate a niobium compound, especially niobium nitride, by adding a very small amount thereof, which is effective in making crystal grains fine. The lower limit of 0.005% is set as a sufficient amount for the crystal grain refinement. On the other hand, if the Nb content exceeds 0.1%, coarse niobium nitride is likely to be crystallized, and it is difficult to form a solid solution even at a soaking temperature of more than 1350 ° C., so the upper limit is limited to 0.1%. Preferably, it is 0.01 to 0.05%.

C is also an element whose adjustment is important for achieving the present invention. If too much, coarse niobium carbide will crystallize out,
Because the amount of niobium nitride effective for grain refinement decreases,
It should be less than 0.01%. Preferably, it is 0.005% or less.

N is also an important additive element of the present invention in accordance with Nb and C of the present invention, and 0.002% or more is required for precipitation of an ultrafine niobium compound. However, if added in a large amount, coarse niobium nitride is easily crystallized, and the solid solution temperature during soaking is increased, so the upper limit is limited to 0.02%. Preferably, it is 0.003 to 0.01%.

In order to achieve the ultrafine niobium compound of the present invention, it is effective to temporarily dissolve niobium nitride by, for example, soaking at 900 to 1350 ° C.
Therefore, in the present invention, the solubility product of [% Nb] · [% N] is specified to be 0.000013 to 0.002. Preferably, it is 0.000013 to 0.001.

In addition, Mn is an element that improves hot workability, and has an effect of reducing the coefficient of thermal expansion of an Fe—Ni alloy by reducing the Mn. To obtain this effect, the Mn content of the Fe-Ni-based alloy of the present invention may be 0.10% or less.

In the present invention, since a large amount of B inhibits the formation of niobium nitride by bonding with N, it is preferably made 0.004% or less. However, it also has an effect of improving the shape after etching, and is particularly effective in reducing Mn. Therefore, it may contain 0.0001% or more.

In the present invention, in which the adjustment of the niobium compound is important, the Fe-
The amount of oxygen contained in the Ni (-Co) -based alloy is 1
It is desirably at most 00 ppm, preferably at most 50 ppm.

[0033]

EXAMPLES Example 1 Ingots of Fe-36% Ni invar alloy adjusted to the various components shown in Table 1 were produced in a vacuum induction melting furnace. Thereafter, the sheet was heated to 1100 ° C. and subjected to forging and hot rolling to obtain a sheet having a thickness of 2.5 mm. After performing a precipitation treatment of a niobium compound at 800 to 900 ° C. on this sheet material, cold rolling and annealing are repeated to obtain a thickness of 0.1 m.
m of cold-rolled material.

These finished cold-rolled materials were used as test materials,
Average grain size of each test material (JIS G 055
1) and the particle size, total number, 0.2% proof stress, and coefficient of thermal expansion of the largest niobium compounds (compounds mainly composed of niobium and nitrogen and compounds mainly composed of niobium and carbon) did. Incidentally, the particle size measurement of the niobium compound,
The specimen surface was corroded by the speed method, and the observation was performed by observing the total measurement observation visual field area of 500 μm ² with a scanning electron microscope. The total number of niobium compounds was obtained by counting and converting the number observed on the same tissue surface. Also, 0.2
The percent proof stress was measured at 20 ° C, and the coefficient of thermal expansion was measured in the range of 20 to 100 ° C.

[0035]

[Table 1]

No. satisfying the present invention. In Nos. 1 to 5, fine crystal grains were obtained by fine precipitation of a niobium compound.
As compared with the b-free material (No. 7), the proof stress could be improved by about 10% without impairing the properties as a shadow mask material such as low thermal expansion characteristics. On the other hand, No. 2 having a large amount of Nb was used. In No. 6, although the proof stress is improved by 0.2%, since a relatively large crystallization of niobium nitride is observed in a portion where the cooling rate during ingot formation is low, hot workability and etching properties are poor. And No. No. 8 has a large C content, so that a large niobium carbide is crystallized, so that the etching property is poor.

Example 2 Using a vacuum induction melting furnace, Table 2
The steel ingot of the Fe-42% Ni alloy adjusted to the various components shown in the following was produced. Thereafter, the sheet was heated to 1100 ° C. and subjected to forging and hot rolling to obtain a sheet having a thickness of 2.5 mm. After performing a precipitation treatment of a niobium compound at 800 to 900 ° C. on this sheet material, cold rolling and annealing were repeated to obtain a cold rolled material having a thickness of 0.5 mm.

The finished cold-rolled material was used as a test material,
Average grain size of each test material (JIS G 055
1), the maximum particle size of the niobium compound, the total number, the 0.2% proof stress, and the burr volume. The burr volume is obtained by measuring the volume of the burr standing on the punched edge of the test material subjected to the press punching test within a range of 350 μm in a plane parallel to the rolling direction. The measurement of the 0.2% proof stress, the particle size of the niobium compound, and the total number are in accordance with Example 1.

[0039]

[Table 2]

No. satisfying the present invention. 9 to 12 are 0.2% due to the refinement of crystal grains by fine precipitation of the niobium compound.
The proof stress improved. Then, the unit of breakage of the punched surface was reduced by the precipitation of the fine niobium compound, and the burr was smaller than that of the Nb-free material (No. 14). Note that N
o. In No. 13, the amount of Nb added was large, and coarse niobium nitride was crystallized, so that the wear of the die during punching was increased.

Example 3 Using a vacuum induction melting furnace, Table 3
Fe-31% Ni-5% Co adjusted to various components shown in
A steel ingot of a Super Invar alloy was prepared. Then 1
Heated to 100 ° C, forged and hot rolled to a thickness of 2.5
mm plate material. After performing a precipitation treatment of a niobium compound on the sheet at 800 to 900 ° C., cold rolling and annealing were repeated to obtain a cold-rolled material having a thickness of 0.1 mm.

The finished cold-rolled material was used as a test material,
Then, the average crystal grain size (JIS G
0551), the maximum particle size of the niobium compound, the total number, the 0.2% proof stress, and the coefficient of thermal expansion. The measurement procedure follows Example 1.

[0043]

[Table 3]

No. satisfying the present invention. In Nos. 15 to 18, fine crystal grains are obtained by fine precipitation of the niobium compound, and the yield strength is about 10 without impairing the thermal expansion characteristics and other characteristics as compared with the Nb-free material (No. 20). % Could be improved. On the other hand, No. 19 has a large amount of Nb, so that a relatively large crystallization of niobium nitride is observed in a portion where the cooling rate during ingot is low, so that hot workability and etching properties are poor. No. 21 has a large amount of C and, therefore, crystallizes a large amount of niobium carbide, and thus has poor etching properties.

A cathode ray tube using the above-described test material of the present invention as a shadow mask is excellent in color purity. The semiconductor element used as the lead frame is excellent in high integration.

[0046]

According to the present invention, it is possible to provide an Fe-Ni alloy having high strength and a small coefficient of thermal expansion. Therefore, in the application of the shadow mask material, since the handling becomes easy, and further thinning is possible, in addition to the press molding method, it is suitable for the tension method,
Mask costs can be reduced. In the use of the lead frame material, the punching workability is also improved by the high strength, and the processing shape can be made finer and the precision can be improved.

[Brief description of the drawings]

FIG. 1 is a metal microstructure photograph showing a niobium compound observed on the structure surface of an Fe—Ni-based alloy.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/50 H01L 23/50 VF term (Reference) 5C027 HH02 5C031 EE05 5F067 AA00 EA02

Claims (11)

[Claims] 1. A Fe-Ni-based alloy containing 30 to 50% of Ni by mass%, with the balance being Fe, and a compound mainly composed of niobium and nitrogen observed in a cross section of a structure. And a high-strength low-thermal-expansion Fe— compound, wherein the maximum particle size of the compound mainly composed of niobium and carbon is less than 0.5 μm, and the total number of the compounds in the tissue cross section is 50,000 / mm ² or more. Ni-based alloy. 2. In mass%, Ni: 30 to 50%, N
b: 0.005 to 0.1%, C: less than 0.01%, N:
0.002 to 0.02%, the balance being substantially Fe, 0.000013 ≦ [% Nb] · [% N] ≦ 0.0
2. The high-strength low-thermal-expansion Fe—Ni-based alloy according to claim 1. 3. In mass%, Ni: 27-47%, C
o: contains 22% or less, with the balance being Fe mainly composed of Fe
A Ni-based alloy, in which a compound mainly composed of niobium and nitrogen and a compound mainly composed of niobium and carbon observed in the structure section have a maximum particle size of less than 0.5 μm and occupy the structure section; A high-strength low-thermal-expansion Fe-Ni-based alloy having a total number of 50,000 / mm ² or more. 4. Ni: 27 to 47% by mass%, C:
o: 22% or less, Nb: 0.005 to 0.1%, C:
Less than 0.01%, N: 0.002 to 0.02%, balance substantially consisting of Fe, 0.000013 ≦ [% Nb]
The high-strength low-thermal-expansion Fe—Ni alloy according to claim 3, wherein [% N] ≦ 0.002. 5. The high-strength, low-thermal-expansion Fe—Ni-based alloy according to claim 1, wherein the average crystal grain size is a fine grain having a grain size number of 10 or more according to JIS G 0551. . 6. The high-strength low-thermal-expansion Fe—Ni-based alloy according to claim 1, wherein Mn is 0.10% or less in mass%. 7. The high-strength low-thermal-expansion Fe—Ni-based alloy according to claim 1, wherein B is 0.004% or less by mass%. 8. The F according to claim 1, wherein
A shadow mask comprising an e-Ni alloy. 9. A cathode ray tube using the shadow mask according to claim 8. Description: 10. A lead frame comprising the Fe—Ni-based alloy according to claim 1. 11. A semiconductor device using the lead frame according to claim 10.