DEPOSITION OF PURE METALS IN 3D STRUCTURES
A system and method generate atomic hydrogen (H) for deposition of a pure metal in a three-dimensional (3D) structure. The method includes forming a monolayer of a compound that includes the pure metal. The method also includes depositing the monolayer on the 3D structure and immersing the 3D structure with the monolayer in an electrochemical cell chamber including an electrolyte. Applying a negative bias voltage to the 3D structure with the monolayer and a positive bias voltage to a counter electrode generates atomic hydrogen from the electrolyte and deposits the pure metal from the monolayer in the 3D structure.
Latest IBM Patents:
- AUTO-DETECTION OF OBSERVABLES AND AUTO-DISPOSITION OF ALERTS IN AN ENDPOINT DETECTION AND RESPONSE (EDR) SYSTEM USING MACHINE LEARNING
- OPTIMIZING SOURCE CODE USING CALLABLE UNIT MATCHING
- Low thermal conductivity support system for cryogenic environments
- Partial loading of media based on context
- Recast repetitive messages
The present invention relates to atomic layer deposition (ALD), and more specifically, to generating atomic hydrogen (H) for deposition of pure metals.
Atomic layer deposition (ALD) is a thin film deposition technique with applications in microelectronics. ALD may be used, for example, to deposit high permittivity gate oxides or capacitor dielectrics, ferroelectrics, and metals and nitrides for electrodes and interconnects. ALD of pure metals (e.g., Ti) requires atomic hydrogen (H). Typically, atomic H is generated using plasma. However, atomic H has a short lifetime and, therefore, recombines to H2 before it can diffuse inside three-dimensional (3D) structures such as those of wafer substrates. As a result, the recombination prevents ALD deposition of pure metals in 3D structures. Another current approach involves generation of atomic H using thermal energy. However, this approach requires temperatures exceeding 1300 degrees Celsius. Such high temperatures are incompatible with complementary metal-oxide-semiconductor (CMOS) processing, because they approach the melting point of silicon (Si) and other front end of the line materials used in CMOS processing.
Consequently, a process to generate atomic H in a way that overcomes the above-noted issues with existing methods is sought by the microelectronics industry.
SUMMARYAccording to an embodiment of the invention, a method of generating atomic hydrogen (H) for deposition of a pure metal in a three-dimensional structure (3D) includes forming a monolayer of a compound that includes the pure metal; depositing the monolayer on the 3D structure; immersing the 3D structure with the monolayer in an electrochemical cell chamber including an electrolyte; and applying a negative bias voltage to the 3D structure with the monolayer and a positive bias voltage to a counter electrode to generate atomic hydrogen from the electrolyte and deposit the pure metal from the monolayer in the 3D structure.
According to another embodiment of the invention, a system to deposit a pure metal in a three-dimensional (3D) structure includes an electrochemical cell comprising a soak chamber in which a monolayer of a compound including the pure metal is deposited on the 3D structure, and an electrolysis chamber in which atomic hydrogen (H) is generated at the 3D structure to facilitate deposition of the pure metal from the monolayer in the 3D structure.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the features, refer to the description and to the drawings.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
Embodiments detailed below describe a system and method to generate atomic hydrogen (H) on demand where it is needed for deposition of pure metals in three-dimensional (3D) structures. The detailed descriptions below are directed to the deposition of titanium (Ti) as an exemplary pure metal.
In
H++e−→H [EQ 1]
TiCl4 (adsorbed monolayer)+H→Ti+HCl [EQ 2]
The excess H recombines to form H2. However, based on the arrangement of the apparatus 100 and, specifically, the availability of the H to the TiCl4 monolayer, the excess H does not recombine before the pure metal (Ti) is deposited in the 3D structures of the wafers 160. At the anode 150, the OH− ions would form O2 as follows:
4OH−→O2+2H2O [EQ 3]
The anode 150 is spatially separated and isolated from the wafers 160 such that the O2 does not react with the deposited pure metal (Ti). The stages depicted by
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one more other features, integers, steps, operations, element components, and/or groups thereof.
The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
The flow diagram depicted herein is just one example. There may be many variations to this diagram or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention.
While the preferred embodiment to the invention had been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.
Claims
1. A method of generating atomic hydrogen (H) for deposition of a pure metal in a three-dimensional (3D) structure, the method comprising:
- forming a monolayer of a compound that includes the pure metal;
- depositing the monolayer on the 3D structure;
- immersing the 3D structure with the monolayer in an electrochemical cell chamber including an electrolyte; and
- applying a negative bias voltage to the 3D structure with the monolayer and a positive bias voltage to a counter electrode to generate atomic hydrogen from the electrolyte and deposit the pure metal from the monolayer in the 3D structure.
2. The method according to claim 1, wherein the forming the monolayer is performed in a soak chamber of an electrochemical cell.
3. The method according to claim 2, wherein the forming the monolayer includes forming the monolayer of TiCl4 by introducing TiCl4 vapor with N2 or Ar carrier gas into the soak chamber.
4. The method according to claim 2, further comprising transferring the 3D structure to the electrochemical cell to perform the depositing the monolayer on the 3D structure.
5. The method according to claim 1, wherein the immersing the 3D structure includes immersing the 3D structure in the electrolyte comprising H2O and HCl.
6. The method according to claim 5, wherein the applying the negative bias voltage to the 3D structure causes H30 to move toward the 3D structure to form atomic H for the deposition of the pure metal from the monolayer.
7. The method according to claim 1, wherein the 3D structure is a silicon wafer.
8. A system to deposit a pure metal in a three-dimensional (3D) structure, the apparatus comprising:
- an electrochemical cell comprising a soak chamber in which a monolayer of a compound including the pure metal is deposited on the 3D structure, and an electrolysis chamber in which atomic hydrogen (H) is generated at the 3D structure to facilitate deposition of the pure metal from the monolayer in the 3D structure.
9. The system according to claim 8, further comprising inlets in the soak chamber configured to take in TiCl4 vapor with N2 or Ar carrier gas to form the monolayer of TiCl4.
10. The system according to claim 8, further comprising a buffer zone between the soak chamber and the electrolysis chamber.
11. The system according to claim 10, further comprising a robotic mechanism to transfer the 3D structure into the buffer zone of the electrochemical cell without introducing an air break.
12. The system according to claim 11, further comprising surface pumps coupled to each of the soak chamber, the buffer zone, and the electrolysis chamber.
13. The system according to claim 12, further comprising a controller configured to control at least one of the robotic mechanism or the surface pumps.
14. The system according to claim 8, wherein the electrolysis chamber comprises an electrolyte including H2O and HCl.
15. The system according to claim 8, further comprising a voltage supply, wherein a negative bias voltage generated from the voltage supply is applied to the 3D structure and a positive bias voltage generated from the voltage supply is applied to a counter electrode in the electrolysis chamber to generate the H.
16. The system according to claim 8, wherein the 3D structure is a silicon wafer.
Type: Application
Filed: Jan 2, 2013
Publication Date: Jul 3, 2014
Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATION (Armonk, NY)
Inventors: Michael P. Chudzik (Danbury, CT), Min Dai (Mahwah, NJ), Rishikesh Krishnan (Poughkeepsie, NY), Joseph F. Shepard, JR. (Poughkeepsie, NY)
Application Number: 13/732,642
International Classification: C25D 3/54 (20060101);