Grinding composition and application thereof in removing titanium nitride layer of semiconductor chip

Abstract

The invention discloses a composition for grinding and application thereof in removing a titanium nitride layer of a semiconductor chip. The composition for grinding comprises the following components in parts by mass: 100 parts of water, 3-10 parts of titanium nitride and 3-10 parts of metal oxide. The composition for grinding is mainly composed of water, titanium nitride and metal oxide, the affinity of the grinding liquid and a ground sample can be ensured by using the grinding liquid prepared from particles made of the same material as the ground sample, so that the grinding efficiency and uniformity are improved, uniform removal of a titanium nitride layer with the nanoscale thickness is achieved, and the quality of the titanium nitride layer is improved. Compared with an existing method for eliminating corrosion of a titanium nitride layer by an acid reaction solution, the grinding solution disclosed by the invention does not generate the problem of non-uniform corrosion by using water, so that uniform removal of the titanium nitride layer with the nanoscale thickness of a single chip is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor materials, and in particular relates to a grinding composition and an application thereof in removing a titanium nitride layer of a semiconductor chip. Background Art

[0002] In the manufacturing and processing of integrated circuit chips, aluminum chips are widely used in various electronic devices due to their excellent conductivity and high temperature resistance. In addition, titanium nitride and silicon dioxide are often used as barrier layers and oxide layers in aluminum chips respectively. However, when performing reverse analysis and failure analysis on these aluminum chips, it is necessary to manually dissect and expose these chips layer by layer according to different materials in order to conduct in-depth research and analysis on the internal structure and material properties of the chips.

[0003] In the existing technology, for the removal of the titanium nitride layer under the metal layer, a chemical reaction corrosion method is usually used to remove its material layer. Specifically, phosphoric acid of an appropriate concentration is used to remove it through chemical reaction corrosion under specific conditions. However, the existing technology often has some problems when removing the titanium nitride layer. First, the thickness of the titanium nitride layer is usually at the nanometer level, which makes its removal process very difficult and complicated. When removing the titanium nitride layer of nanometer thickness, the existing chemical corrosion method cannot guarantee its uniformity and often over-corrosion occurs, which causes the thickness of the lower silicon dioxide layer to be inconsistent, thereby affecting the subsequent analysis results. Secondly, the corrosive liquid often penetrates into the next layer through the interlayer silicon via, causing premature corrosion of the lower metal, affecting the reverse analysis and failure analysis results. Therefore, how to achieve uniform removal of the titanium nitride layer of nanometer thickness on a single chip and ensure the thickness consistency of the lower silicon dioxide layer is an important problem facing the current technology. Summary of the invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide a polishing composition. The second purpose of the present invention is to provide a method for preparing the above-mentioned polishing composition. The third purpose of the present invention is to provide a method for removing the titanium nitride layer of a semiconductor chip. In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0005] The first aspect of the present invention provides a polishing composition, comprising the following components in parts by weight: 100 parts of water, 3-10 parts of titanium nitride, and 3-10 parts of metal oxide.

[0006] Preferably, the metal oxide is selected from at least one of cerium oxide, silicon dioxide, aluminum oxide, germanium oxide and zirconium oxide.

[0007] More preferably, the following components are included in parts by mass: 100 parts of water, 3-7 parts of titanium nitride, and 3-7 parts of silicon dioxide.

[0008] More preferably, the composition includes the following components in parts by mass: 100 parts of water, 4-6 parts of titanium nitride, and 4-6 parts of silicon dioxide.

[0009] Preferably, the titanium nitride is in powder form, and the powder particle size is 0.1-1 μm.

[0010] More preferably, the powder particle size is 0.3-0.7 μm.

[0011] Preferably, the polishing composition is obtained by a preparation method comprising the following steps: adding titanium nitride and metal oxide into water, and mixing to obtain the polishing composition.

[0012] The second aspect of the present invention provides use of the polishing composition described in the first aspect in removing a titanium nitride layer of a semiconductor chip.

[0013] The third aspect of the present invention provides a method for removing a titanium nitride layer on a semiconductor chip, comprising the following steps: adding the polishing composition of the first aspect to a polishing cloth, and using the polishing cloth to polish and remove the titanium nitride layer on the semiconductor chip.

[0014] Preferably, the grinding time is 1-10 min.

[0015] Preferably, the grinding cloth is a grinding flannel cloth, and the length of the flannel on the grinding flannel cloth is 0.2-2 μm.

[0016] More preferably, the pile length is 0.5-1.5 μm.

[0017] The present invention uses a micron-sized grinding flannel cloth for the nanometer-sized titanium nitride layer: by using the micron-sized grinding flannel cloth, the nanometer-sized titanium nitride layer can be effectively removed while avoiding damage to the underlying silicon dioxide layer, thereby ensuring the thickness consistency of the underlying silicon dioxide layer.

[0018] Preferably, the thickness of the titanium nitride layer is 100 nm.

[0019] Preferably, the semiconductor chip comprises a metal top layer, a titanium nitride barrier layer, an oxide layer, and a semiconductor layer which are arranged in sequence.

[0020] More preferably, the semiconductor chip comprises a metal aluminum top layer, a titanium nitride barrier layer, a silicon dioxide oxide layer, and a semiconductor layer which are arranged in sequence.

[0021] Preferably, the grinding step specifically includes: pressing a grinding cloth on the surface of the titanium nitride layer to perform grinding in a lemniscate path.

[0022] More preferably, the semiconductor chip is rotated periodically during the grinding process.

[0023] The present invention adopts a lemniscate path (∞ shape) and a timed rotation sample fixed angle, which can ensure the uniformity of the titanium nitride layer in all directions when grinding force is applied. The grinding movement path and the timed rotation angle make the removal process of the titanium nitride layer more uniform and consistent, and can avoid local excessive friction, thereby reducing the damage to the chip structure caused by excessive grinding at individual locations, and achieving uniform removal of the titanium nitride layer with nanometer-level thickness and consistency of the thickness of the underlying silicon dioxide layer.

[0024] The beneficial effects of the present invention are:

[0025] (1) The present invention provides a polishing composition, which is mainly composed of water, titanium nitride, and metal oxide. By using a polishing liquid made of particles of the same material as the sample to be polished, the affinity of the polishing liquid and the sample to be polished can be ensured, thereby improving the polishing efficiency and uniformity, and achieving uniform removal of the titanium nitride layer with a nanometer thickness. Compared with the current acid reaction elimination liquid that corrodes the titanium nitride layer, the polishing liquid of the present invention uses water without causing uneven corrosion, thereby achieving uniform removal of the titanium nitride layer with a nanometer thickness on a single chip.

[0026] (2) The present invention provides a method for removing a titanium nitride layer from a semiconductor chip. The polishing composition is dipped onto a polishing cloth and the removal process is performed by manual polishing. Compared with chemical removal, the removal process is more precise and controlled, and high-precision equipment and high-cost polishing materials are not required, which greatly reduces the complexity and cost of the entire process. In addition, the present invention has the characteristics of high efficiency and high precision in the removal process of a titanium nitride layer with a nanometer thickness, and is expected to play an important role in the fields of semiconductor material surface treatment technology and nanotechnology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is an overview photo of the top metal layer below the passivation layer;

[0028] Figure 2 This is an overview photo of the TiN layer below the top metal layer;

[0029] Figure 3 This is a microscope photo of the chip structure after being processed in Example 1;

[0030] Figure 4 This is a microscope photo of the chip structure after being processed in Comparative Example 1. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0032] Example 1

[0033] This embodiment provides a polishing composition and an application method thereof in removing a titanium nitride layer of a semiconductor chip, and the specific steps are as follows:

[0034] Step 1: Prepare a single sample to be ground. The sample is an aluminum process chip (such as a common LED driver chip, a single-chip microcomputer MCU chip), and the thickness of the titanium nitride layer is about 100nm.

[0035] Step 2: Prepare a polishing liquid, which consists of 100 parts of water, 5 parts of titanium nitride, and 5 parts of silicon dioxide by mass ratio, wherein both titanium nitride and silicon dioxide are particles with a particle size of 0.5 μm.

[0036] Step 3: Choose a micron-grade abrasive flannel with a nap length of 1 μm, and pour the abrasive liquid on the abrasive flannel.

[0037] Step 4: Set the grinding moving path and use a lemniscate path and an ∞-shaped path to ensure the uniformity of each grinding position of the chip.

[0038] Step 5: Start grinding. Press the grinding cloth with the grinding liquid on one side onto the surface of the titanium nitride layer. The grinding liquid is between the titanium nitride layer and the flannel cloth. Make sure to rotate the grinding cloth at a fixed angle (such as 45°) at a fixed time.

[0039] Step 6: Repeat the above four and five grinding steps for 5 minutes, and check under a microscope to see if the titanium nitride layer is completely removed. Through the above steps, the titanium nitride layer with a nanometer thickness can be uniformly removed, and the thickness consistency of the underlying silicon dioxide layer can be ensured.

[0040] Comparative Example 1

[0041] This comparative example provides a polishing composition and an application method thereof in removing a titanium nitride layer of a semiconductor chip, and the specific steps are as follows:

[0042] Step 1: Prepare a single sample to be ground. The sample is an aluminum process chip (using the aluminum process chips from the same batch as Example 1), and the thickness of the titanium nitride layer is about 100 nm.

[0043] Step 2: Prepare a grinding liquid, which consists of 100 parts of water, 5 parts of aluminum oxide, and 5 parts of silicon dioxide by mass ratio, wherein the aluminum oxide and silicon dioxide are both particles with a particle size of 0.5 μm.

[0044] Step 3: Choose a micron-grade abrasive flannel with a nap length of 1 μm, and pour the abrasive liquid on the abrasive flannel.

[0045] Step 4: Set the grinding moving path and use a lemniscate path and an ∞-shaped path to ensure the uniformity of each grinding position of the chip.

[0046] Step 5: Start grinding. Press the grinding cloth with the grinding liquid on one side onto the surface of the titanium nitride layer. The grinding liquid is between the titanium nitride layer and the flannel cloth. Make sure to rotate the grinding cloth at a fixed angle (such as 45°) at a fixed time.

[0047] Step 6: Repeat the above four and five grinding steps to continue grinding. The grinding process (time, strength, etc.) remains consistent with Example 1.

[0048] Semiconductor chip characterization

[0049] The exposure of each layer was analyzed using a microscope. The exposure of the top metal layer below the passivation layer was as follows: Figure 1 As shown, the TiN layer below the top metal layer is exposed as Figure 2 As shown, the exposure after grinding and removing the TiN layer in Example 1 is as follows Figure 3 As shown, the exposure after grinding and removing the TiN layer in Comparative Example 1 is as follows Figure 4 As shown, from Figure 2 and Figure 3 Comparative analysis shows that the use of the grinding liquid in Example 1 can achieve uniform removal of the titanium nitride layer with a nanometer thickness, and the removal process by manual grinding is more precise and controllable than chemical removal; Figure 3 and Figure 4 Comparative analysis shows that using aluminum oxide as the main material of the grinding liquid cannot effectively remove the titanium nitride layer.

[0050] In summary, the present invention provides a grinding composition, which is mainly composed of water, titanium nitride, and metal oxide. By using a grinding liquid made of particles of the same material as the sample to be ground, the affinity of the grinding liquid to the sample to be ground can be ensured, thereby improving the grinding efficiency and uniformity, and achieving uniform removal of the titanium nitride layer with nanometer thickness. Compared with the current acid reaction elimination liquid that corrodes the titanium nitride layer, the grinding liquid of the present invention uses water without the problem of uneven corrosion, thereby achieving uniform removal of the titanium nitride layer with nanometer thickness on a single chip.

[0051] The present invention provides a method for removing a titanium nitride layer from a semiconductor chip. The polishing composition is dipped onto a polishing cloth, and the removal process is more accurate and controlled by manual polishing than chemical removal. High-precision equipment and high-cost polishing materials are not required, which greatly reduces the complexity and cost of the entire process. In addition, the present invention has the characteristics of high efficiency and high precision in the removal process of a titanium nitride layer with a nanometer thickness, and is expected to play an important role in the fields of semiconductor material surface treatment technology, nanotechnology, etc.

[0052] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A polishing composition, characterized in that The invention comprises the following components in parts by weight: 100 parts of water, 3-10 parts of titanium nitride and 3-10 parts of metal oxide.

2. The polishing composition according to claim 1, characterized in that The metal oxide is selected from at least one of cerium oxide, silicon dioxide, aluminum oxide, germanium oxide and zirconium oxide.

3. The polishing composition according to claim 2, characterized in that The composition comprises the following components in parts by mass: 100 parts of water, 3-7 parts of titanium nitride, and 3-7 parts of silicon dioxide.

4. The polishing composition according to claim 1, characterized in that The titanium nitride is in powder form, and the powder particle size is 0.1-1 μm.

5. Use of the polishing composition according to any one of claims 1 to 4 in removing a titanium nitride layer from a semiconductor chip.

6. A method for removing a titanium nitride layer from a semiconductor chip, characterized in that: The method comprises the following steps: adding the polishing composition according to any one of claims 1 to 3 onto a polishing cloth, and using the polishing cloth to polish and remove the titanium nitride layer on the semiconductor chip.

7. The method for removing the titanium nitride layer of a semiconductor chip according to claim 6, characterized in that: The grinding time is 1-10 min.

8. The method for removing the titanium nitride layer of a semiconductor chip according to claim 6, characterized in that: The grinding cloth is grinding flannel cloth, and the flannel length is 0.2-2 μm.

9. The method for preparing the liraglutide nanoparticles according to claim 6, characterized in that: The thickness of the titanium nitride layer is 100 nm.

10. The method for preparing the liraglutide nanoparticles according to claim 6, characterized in that: The grinding step specifically includes: pressing the grinding cloth on the surface of the titanium nitride layer to grind in a lemniscate path.

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