JP6067927B2 - Copper or copper alloy sputtering target - Google Patents

Description

  The present invention relates to a copper or copper alloy sputtering target used for forming an intra-wafer wiring portion of a semiconductor device such as an LSI.

 Copper wiring (specific resistance: about 1.7 μΩ · cm) is used as a wiring material for semiconductor devices. As a process for forming a copper wiring, a diffusion barrier layer such as Ta or TaN is formed in a wiring groove, a copper seed layer is formed, and then a copper wiring is formed. In recent years, with the miniaturization of interconnects, copper alloy films and high-purity copper films with aluminum (Al), manganese (Mn), etc. added to the seed layer have been used to eliminate the barrier performance degradation of thin diffusion barrier layers. To be done.

  The copper alloy film or the high purity copper film is formed using a copper alloy or a copper sputtering target. In order to ensure stable device performance and product yield, uniformity of a film formed by sputtering and a stable film formation rate are required. In general, the uniformity of these films and the stability of the deposition rate are affected by unevenness (nonuniformity) such as composition, density, and structure in the sputtering target. Therefore, it is very important to confirm and control the uniformity of the composition, density, structure, etc. in the target.

  However, conventionally, as a method for confirming the uniformity of the composition, density, structure, etc. in the sputtering target, the physical properties of only a few representative portions of the target surface are measured and evaluated. there were. Therefore, the local unevenness of the target may be overlooked, and such local unevenness may disturb the uniformity of the film or make the film formation speed unstable. . In particular, in the recent situation where the wiring is becoming finer, these are highlighted as serious problems.

  The present applicant has previously proposed a technique for effectively suppressing this by detecting oxide inclusions in the target with an ultrasonic flaw detector because the oxide in the sputtering target causes defects in the sputtered film. (Patent Document 1). Patent Document 2 discloses a nondestructive evaluation method that can identify a plurality of defect types (void-like defects, alumina inclusions, etc.) in a sputtering target. And a non-destructive evaluation method that can identify the types of defects classified by position.

JP 2001-011610 A Special table 2003-532895 gazette JP-T-2004-538463

 The present invention relates to a copper or copper alloy sputtering target suitable for forming wiring of a semiconductor device, and in particular, to control unevenness (non-uniformity) such as composition, density, and structure present locally in the sputtering target. It is possible to provide a copper or copper alloy sputter target capable of stabilizing the film formation rate during sputtering and improving the uniformity of the film formed by sputtering. To do.

  In order to solve the above problems, the present inventors have conducted intensive research on unevenness of the composition, density, structure, and the like that are locally present in the sputtering target, and as a result, the entire sputtering target is reflected with an ultrasonic flaw detector. We obtained knowledge that local unevenness of the target can be suppressed by evaluating and controlling. In addition, it has been found that it is particularly effective to adjust the forging temperature at the time of manufacturing the target for such a target with little local unevenness.

Based on these findings, the present inventors provide the following inventions.
1) In ultrasonic flaw measurement where sensitivity is adjusted so that the intensity of the reflected echo from the bottom of the target when an ultrasonic wave is applied to the reference point is set to 100% as a reference point, A copper or copper alloy sputtering target characterized in that the area of the target detected when the intensity of the reflected echo from the bottom surface is 65% or less or 135% or more is 30% or less of the entire target.
2) In ultrasonic flaw detection with the sensitivity adjusted so that the intensity of the reflected echo from the bottom of the target when an ultrasonic wave is applied to the reference point is set to 100% as a reference point, A copper or copper alloy sputtering target, wherein the target area detected when the intensity of the reflected echo from the bottom surface is 65% or less or 135% or more is 20% or less of the entire target.
3) In ultrasonic flaw detection where sensitivity is adjusted so that the intensity of the reflected echo from the bottom surface of the target when an ultrasonic wave is applied to the reference point is set to 100% as a reference point, A copper or copper alloy sputtering target characterized in that the area of the target detected when the intensity of the reflected echo from the bottom surface is 65% or less or 135% or more is 10% or less of the entire target.
4) The copper or copper alloy sputtering target according to any one of 1) to 3) above, which is made of any one of Cu, Cu—Al alloy, and Cu—Mn alloy.

 The present invention can obtain such a target with little unevenness by using the reflection intensity of ultrasonic waves from the target as an index indicating unevenness (non-uniformity) of the composition, density, structure, etc. of the sputtering target. . Such a target with little unevenness can improve the uniformity of the film and has an excellent effect of stabilizing the film formation rate.

It is explanatory drawing which showed the measuring method of ultrasonic flaw detection.

 The copper or copper alloy sputtering target of the present invention uses an arbitrary one point on the target surface as a reference point, and the sensitivity is such that the intensity of the reflected echo from the bottom of the target when an ultrasonic wave is applied to the reference point is 100%. In the adjusted ultrasonic flaw detection measurement, the target area detected when the intensity of the reflected echo from the target bottom surface is 65% or less or 135% or more is 30% or less of the entire target. Preferably, the region of the target is 20% or less, more preferably 10% or less.

 The ultrasonic flaw detector can grasp the size and position of the defect by scanning the entire surface of the sputtering target and examining the intensity of the waveform reflected from the defect in the target. Defects cause unevenness (non-uniformity) in the composition, density, structure, etc. of the target, and thus a target with less unevenness can be obtained by appropriately controlling such defects. Such a target with little unevenness can improve the uniformity of a film to be formed, and can reduce the amount of particles during sputtering.

 Ultrasonic flaw detection is an inspection method that detects differences in defects, tissues, etc. by comparing with a standard sample or a reflected echo from the bottom surface at a set reference point. Setting is required. In the present invention, the sensitivity of the ultrasonic flaw detector is adjusted at any one point on the target surface as a reference point, and the intensity of the reflected echo from the target bottom surface when the ultrasonic wave is applied to the reference point is 100%. Make adjustments. By monitoring the reflected echo from the bottom surface of the target in this way, it is possible to detect differences in defects, structures, compositions, etc. in the material. Under such sensitivity adjustment, when the intensity of the reflected echo is 65% or less or 135% or more, it means that there is a large difference in material defects, structure, composition, etc. in the material compared to the reference position. To do.

 The sputtering target of the present invention is composed of copper or a copper alloy. As the copper, it is preferable to use Cu having a purity of 4N or more, and as the copper alloy, in order to improve the EM resistance, it is preferable to use a Cu—Al alloy added with Al or a Cu—Mn alloy added with Mn. preferable. In order to obtain the effect of EM resistance without the wiring resistance affecting the device, in particular, Cu—Al alloy added with 0.05 to 10 wt% Al, Cu—added with 0.1 to 25 wt% Mn A Mn alloy is preferred.

 Copper or copper alloy sputtering target melts and casts the raw material, and performs plastic working and heat treatment such as forging and rolling to make the cast material suitable for crystal structure, grain size, etc. It is produced by finishing to the final target dimension such as a shape. Control of the reflection intensity by ultrasonic flaw detection in the sputtering target is particularly effective to adjust the temperature during forging to an appropriate temperature suitable for each material. In the composition of the present invention, the temperature is set to 900 ° C. or lower. It is preferable.

  Next, the present invention will be described based on examples. The following examples are for ease of understanding, and the present invention is not limited by these examples. That is, modifications and other embodiments based on the technical idea of the present invention are naturally included in the present invention.

Example 1
High purity Cu having a purity of 6N or more was prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten metal was poured out into a mold to obtain a high purity copper ingot having a purity of 6N or higher. Next, after making the obtained ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 420 ° C. and further rolled by cold rolling until the reduction ratio reached 70% or more. Then, after heat-processing at 400 degreeC, it rapidly cooled and produced the rolled sheet. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

The target thus produced was analyzed using an ultrasonic flaw detector. Specifically, the sputtering target as the measurement object was submerged in water, the probe was scanned over the entire object, and the intensity of the waveform reflected from the defect in the object and the region with the high intensity were calculated. The conditions for ultrasonic flaw detection are as follows.
Device: Krautkramer Type: HIS3
IF sound speed: 1480 m / s
Material sound velocity: 2000-6000 m / s
AMP: ≧ 30 dB
Sensitivity adjustment: The center of the disk-shaped target is used as a reference point, and the intensity of the reflected echo from the bottom of the target when ultrasonic waves are applied to the reference point is adjusted to 100%. As a result, the reflection intensity by the ultrasonic flaw detector The target area detected at 35% or more was 5% of the entire target.

Next, after the target subjected to ultrasonic flaw detection was bonded to a backing plate, it was placed in a sputtering apparatus, and sputtering was performed at an input power of 38 kW to form a film on a 12-inch silicon substrate for 5 seconds. And distribution of the sheet resistance of the film | membrane formed by sputtering was measured, and the distribution condition of film thickness was investigated. Specifically, the sheet resistance at 49 points on the wafer was measured, and the standard deviation (uniformity) and uniformity (NU%) were obtained. The standard deviation and uniformity are calculated as follows.
Standard deviation (σ) = (((Rs ₁ -Rs _Ave ) ² + (Rs ₂ -Rs _Ave ) ² + ... + (Rs ₄₉ -Rs _Ave ) ² ) / 49) ^1/2
(Rsn: sheet resistance (Rs) at each measurement point, RsAve: average value of 49 Rs points)
Uniformity (NU%) = σ / Rs _Ave × 100
As a result, the standard deviation was 0.025, the uniformity was 3.2%, and a film having excellent uniformity was obtained. The results are shown in Table 1.

(Example 2)
High purity Cu having a purity of 6N or more was prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten metal was poured out into a mold to obtain a high purity copper ingot having a purity of 6N or higher. Next, after making the obtained ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 630 ° C., and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 400 degreeC, it rapidly cooled and produced the rolled sheet. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected by the ultrasonic flaw detector with a reflection intensity of 35% or more was 15% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.036, the uniformity was 3.8%, and a film having excellent uniformity was obtained. The results are shown in Table 1.

(Example 3)
High-purity Cu having a purity of 6N or higher and high-purity Mn having a purity of 3N or higher were prepared and introduced into a crucible and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuMn alloy was poured into a mold to obtain a high purity Cu—Mn alloy ingot (Mn: 0.1 wt%) having a purity of 5N or more. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 820 ° C. and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected by the ultrasonic flaw detector at a reflection intensity of 35% or more was 8% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.027, the uniformity was 2.7%, and a film having excellent uniformity was obtained. The results are shown in Table 1.

Example 4
High-purity Cu having a purity of 6N or higher and high-purity Mn having a purity of 4N or higher were prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuMn alloy was poured into a mold to obtain a high-purity Cu—Mn alloy ingot (Mn: 25 wt%) having a purity of 5N or more. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 780 ° C., and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.026, the uniformity was 3.0%, and a film having excellent uniformity was obtained. The results are shown in Table 1.

(Example 5)
High purity Cu having a purity of 6N or higher and high purity Al having a purity of 4N or higher were prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuAl alloy was poured into a mold to obtain a high purity Cu—Al alloy ingot (Al: 0.01 wt%) having a purity of 5N or higher. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 820 ° C. and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.029, the uniformity was 3.3%, and a film having excellent uniformity was obtained. The results are shown in Table 1.

(Example 6)
High purity Cu having a purity of 6N or higher and high purity Al having a purity of 4N or higher were prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuAl alloy was poured out into a mold (mold) to obtain a high purity Cu—Al alloy ingot (Al: 10 wt%) having a purity of 5N or more. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 780 ° C., and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.033, the uniformity was 3.5%, and a film having excellent uniformity was obtained. The results are shown in Table 1.

(Comparative Example 1)
High purity Cu having a purity of 6N or more was prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten metal was poured out into a mold to obtain a high purity copper ingot having a purity of 6N or higher. Next, after making the obtained ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 950 ° C. and further rolled by cold rolling until the reduction ratio reached 70% or more. Then, after heat-processing at 400 degreeC, it rapidly cooled and produced the rolled sheet. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.051 and the uniformity was 4.5%, and the film was inferior in uniformity compared to the examples. The results are shown in Table 1.

(Comparative Example 2)
High purity Cu having a purity of 6N or more was prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten metal was poured out into a mold to obtain a high purity copper ingot having a purity of 6N or higher. Next, after making the obtained ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 1000 ° C., and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 400 degreeC, it rapidly cooled and produced the rolled sheet. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.102 and the uniformity was 5.1%, and the film was inferior in uniformity compared to the examples. The results are shown in Table 1.

(Comparative Example 3)
High-purity Cu having a purity of 6N or higher and high-purity Mn having a purity of 3N or higher were prepared and introduced into a crucible and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuMn alloy was poured into a mold to obtain a high purity Cu—Mn alloy ingot (Mn: 0.1 wt%) having a purity of 5N or more. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 1000 ° C. and further rolled by cold rolling until the reduction ratio reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus and sputtered under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.073 and the uniformity was 4.6%, and the film was inferior in uniformity compared to the examples. The results are shown in Table 1.

(Comparative Example 4)
High-purity Cu having a purity of 6N or higher and high-purity Mn having a purity of 4N or higher were prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuMn alloy was poured into a mold to obtain a high-purity Cu—Mn alloy ingot (Mn: 25 wt%) having a purity of 5N or more. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 980 ° C., and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was machined into a disk having a diameter of 450 mm and a thickness of 10 mm, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to produce a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.084, the uniformity was 5.2%, and the film was inferior in uniformity compared to the examples. The results are shown in Table 1.

(Comparative Example 5)
High purity Cu having a purity of 6N or higher and high purity Al having a purity of 4N or higher were prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuAl alloy was poured into a mold to obtain a high purity Cu—Al alloy ingot (Al: 0.01 wt%) having a purity of 5N or higher. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 1000 ° C. and further rolled by cold rolling until the reduction ratio reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was machined into a disk having a diameter of 450 mm and a thickness of 10 mm, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to produce a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.093, the uniformity was 5.6%, and the film was inferior in uniformity compared to the examples. The results are shown in Table 1.

(Comparative Example 6)
High purity Cu having a purity of 6N or higher and high purity Al having a purity of 4N or higher were prepared, introduced into a crucible, and melted at 1250 ° C. (induction melting method). Thereafter, the molten CuAl alloy was poured out into a mold (mold) to obtain a high purity Cu—Al alloy ingot (Al: 10 wt%) having a purity of 5N or more. Next, after making the obtained copper alloy ingot 180 mm in diameter × 160 mm in thickness, it was hot forged at 980 ° C., and further rolled by cold rolling until the reduction rate reached 70% or more. Then, after heat-processing at 600 degreeC, it cooled rapidly and the rolled sheet was produced. This was processed into a disk having a diameter of 450 mm and a thickness of 10 mm by machining, and then paper finishing was performed so that the surface roughness was 0.8 μm or less to prepare a target.

 The target thus produced was analyzed using an ultrasonic flaw detector. The conditions for ultrasonic flaw detection were the same as in Example 1. As a result, the target area detected with an ultrasonic flaw detector having a reflection intensity of 35% or more was 13% of the entire target. Next, after the target subjected to ultrasonic flaw detection was bonded to the backing plate, it was placed in a sputtering apparatus, and sputtering was performed under the same conditions as in Example 1 to form a film. And the distribution of the sheet resistance of the film | membrane formed similarly to Example 1 was measured, and the distribution condition of the film thickness was investigated. As a result, the standard deviation was 0.110, and the uniformity was 6.7%, and the film was inferior in uniformity compared to the examples. The results are shown in Table 1.

 The present invention has a sputter deposition characteristic with excellent uniformity in a copper or copper alloy sputtering target, and can maintain a stable deposition rate, so that a wiring layer of a semiconductor device, particularly a seed layer can be stably formed. Useful to form.

Claims (4)

Any one position in the target plane as a reference point, thus the target surface to the ultrasonic flaw detection measurements sensitivity adjustment so that the intensity of the reflected echo becomes 100% from the target bottom surface when irradiated with ultrasonic wave to the reference point The entire target is measured, and a target whose target area detected when the intensity of the reflected echo from the target bottom surface is 65% or less or 135% or more is 30% or less of the entire target surface is selected as the sputtering target, sputtering deposition method and forming a sputtering to copper or a copper alloy wiring. Any one position in the target plane as a reference point, thus the target surface to the ultrasonic flaw detection measurements sensitivity adjustment so that the intensity of the reflected echo becomes 100% from the target bottom surface when irradiated with ultrasonic wave to the reference point The entire target is measured, and a target whose target area detected when the intensity of the reflected echo from the target bottom surface is 65% or less or 135% or more is 20% or less of the entire target surface is selected as the sputtering target. sputtering deposition method and forming a sputtering to copper or a copper alloy wiring. Any one position in the target plane as a reference point, thus the target surface to the ultrasonic flaw detection measurements sensitivity adjustment so that the intensity of the reflected echo becomes 100% from the target bottom surface when irradiated with ultrasonic wave to the reference point The entire target is measured, and a target whose target area detected when the intensity of reflected echo from the target bottom surface is 65% or less or 135% or more is 10% or less of the entire target surface is selected as the sputtering target, sputtering deposition method and forming a sputtering to copper or a copper alloy wiring. The film formation method according to claim 1 , wherein the target is made of any one of Cu, Cu—Al alloy, and Cu—Mn alloy.