Semiconductor device and method for forming semiconductor device

Abstract

A semiconductor device and a method for forming a semiconductor device can solve the problem of holes when metal tungsten is filled into the contact window or contact port. The method for forming a semiconductor device comprises the following steps: S11 providing a substrate; S12 forming a barrier layer on the upper surface of the substrate, and in the crystal orientation of the barrier layer, <111> The proportion of the crystal orientation is at least a preset value; S13 forms a metal material layer on the upper surface of the barrier layer, and the crystal orientation of the metal material layer includes <111> Crystal direction.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor preparation, and in particular to a semiconductor device and a method for forming the semiconductor device. Background Art

[0002] As the size of devices continues to shrink, the aspect ratio of contact holes and through holes continues to increase, which constantly brings challenges to the chemical vapor deposition process of metal tungsten. In integrated circuits, chemical vapor deposition of metal tungsten is often used for metal interconnection of contact windows or contact ports. As the size of devices continues to shrink, the aspect ratio of contact holes and through holes continues to increase, which constantly brings challenges to the chemical vapor deposition process of metal tungsten.

[0003] In the prior art, when chemical vapor deposition of metal tungsten is performed, the following problems are likely to occur: the metal tungsten overhangs above the contact window or contact port, forming an overhang, which will cause holes in the metal tungsten layer deposited in the contact window or contact port, affecting the yield of the product. Summary of the invention

[0004] The present invention provides a semiconductor device and a method for forming the semiconductor device, which can solve the problem of holes that occur when metal tungsten is filled into the contact window or contact opening.

[0005] In order to solve the above problems, a method for forming a semiconductor device is provided below, comprising the following steps: providing a substrate; forming a barrier layer on the upper surface of the substrate, wherein the barrier layer has a crystal orientation of <111> The proportion of the crystal orientation is at least a preset value; a metal material layer is formed on the upper surface of the barrier layer, and the crystal orientation of the metal material layer includes <111> Crystal Direction

[0006] Optionally, when forming the barrier layer, the following steps are included: forming a barrier layer having <111> A crystal seed layer having a crystal orientation; and a crystal seed layer having a crystal orientation is formed on the upper surface of the substrate according to the crystal seed layer. <111> crystal orientation of the barrier layer.

[0007] Optionally, a reaction gas having a first partial pressure ratio is introduced above the substrate to form the crystal seed layer, and a reaction gas having a second partial pressure ratio is introduced above the substrate to form the barrier layer.

[0008] Optionally, the reaction gas includes TiCl 4 and NH 3 and a carrier gas, and the carrier gas includes N 2 , and the partial pressure of TiCl 4 in the first partial pressure ratio is less than the partial pressure of TiCl 4 in the second partial pressure ratio.

[0009] Optionally, the metal material layer includes a tungsten layer, and when the metal material layer is formed on the upper surface of the barrier layer, the following steps are included: forming a reactive ion layer on the upper surface of the barrier layer; introducing a tungsten-containing gas above the reactive ion layer, wherein the tungsten-containing gas reacts with the reactive ion layer to form a tungsten nucleus layer on the surface of the barrier layer; and introducing a tungsten-containing gas and a carrier gas above the tungsten nucleus layer to form the metal material layer.

[0010] Optionally, the reactive ion layer is a boron ion layer. When the boron ion layer is formed on the upper surface of the barrier layer, the following steps are included: introducing a boron-containing gas onto the barrier layer to form the boron ion layer.

[0011] Optionally, the tungsten-containing gas includes tungsten hexafluoride, the boron-containing gas includes B2H6, and the carrier gas includes at least one of H2, Ar and N2.

[0012] Optionally, the preset value is at least 70%.

[0013] Optionally, when forming the crystal seed layer and the barrier layer, TiCl4 and NH3 are introduced in time periods, and after each introduction of TiCl4 and NH3, the remaining gas is blown out using N2.

[0014] In order to solve the above problems, a semiconductor device is provided below, comprising: a substrate, an opening formed on the surface of the substrate; a barrier layer formed on the bottom surface, the side wall surface of the opening and the upper surface of the substrate, and in the crystal orientation of the barrier layer, <111> The proportion of the crystal orientation is at least a preset value; the metal material layer formed on the upper surface of the barrier layer, the crystal orientation of the metal material layer includes <111> Crystal direction.

[0015] Optionally, the preset value is at least 70%.

[0016] The semiconductor device and the method for forming the semiconductor device of the present invention form a layer on the upper surface of the substrate with a proportion greater than a preset value. <111> Therefore, through appropriate preset values, it can be ensured that the metal material layer grown on the barrier layer also mostly presents <111> Crystal direction. <111> The crystal plane of the crystal orientation is large, and the metal material can grow evenly on each surface. When the formation method is used to fill the metal material in the opening, the possibility of voids in the metal material filled in the opening can be greatly reduced, thereby improving the production yield of this type of semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a schematic flow chart of the steps of a method for forming a semiconductor device in a specific embodiment of the present invention.

[0018] FIG. 2A to FIG. 2FIt is a schematic structural diagram corresponding to each step of a method for forming a semiconductor device in a specific implementation manner of the present invention.

[0019] Figure 3 It is a schematic structural diagram of a semiconductor device in a specific implementation manner of the present invention. DETAILED DESCRIPTION

[0020] Research has found that due to the insufficient hole-filling ability of metal tungsten during chemical vapor deposition, voids are easily present.

[0021] The semiconductor device and the method for forming the semiconductor device are further explained and described below in conjunction with the drawings.

[0022] Please see Figure 1 , is a schematic flow chart of the steps of a method for forming a semiconductor device in a specific embodiment of the present invention.

[0023] In this specific embodiment, a method for forming a semiconductor device is proposed, comprising the following steps: S11 providing a substrate; S12 forming a barrier layer on the upper surface of the substrate, and in the crystal orientation of the barrier layer, <111> The proportion of the crystal orientation is at least a preset value; S13 forms a metal material layer on the upper surface of the barrier layer, and the crystal orientation of the metal material layer includes <111> Crystal direction.

[0024] The forming method in this specific embodiment forms a layer of the substrate on the upper surface with a proportion greater than a preset value. <111> The barrier layer of the crystal direction can ensure that the metal material layer grown on the barrier layer also mostly presents <111> Crystal direction. <111> The crystal plane of the crystal orientation is large, and the metal material can grow evenly on each surface. When the formation method is used to fill the metal material in the opening, the possibility of voids in the metal material filled in the opening can be greatly reduced, thereby improving the production yield of this type of semiconductor device.

[0025] In a specific embodiment, the preset value is at least 70%. In a specific embodiment, the preset value is preferably above 90% or even 95%.

[0026] Since some reactants in the chemical vapor deposition process have a corrosive effect on the substrate 101, the barrier layer 103 can prevent the reactants from corroding the substrate 101 during the deposition process. In addition, providing a suitable barrier layer 103 can also be used to increase the adhesion between the metal material layer 102 and the substrate 101, thereby reducing the probability of the metal material layer 102 peeling off from the surface of the substrate 101.

[0027] In a specific embodiment, when forming the barrier layer 103 on the upper surface of the substrate 101, the following steps are included: forming a barrier layer having a <111> The crystal seed layer 107 of the crystal orientation can be referred to herein Figure 2A and Figure 2B According to the crystal seed layer 107, a <111> The barrier layer 103 of the crystal direction can be referred to herein. Figure 2C .

[0028] In this specific embodiment, the crystal seed layer 107 and the barrier layer 103 are sequentially formed by chemical vapor deposition. When forming the crystal seed layer 107 with a specific crystal orientation, it can be achieved by adjusting the flow rate and flow velocity of the reaction gas in the chemical vapor deposition process. In fact, atomic layer deposition, supercritical fluid deposition, metal organic chemical vapor deposition, chemical vapor deposition, etc. can also be used to form a crystal seed layer 107 with a specific crystal orientation. <111> In adopting these methods to form a barrier layer 103 having a crystal orientation <111> When the barrier layer 103 is formed on the upper surface of the substrate 101, <111> The crystal seed layer 107 of the crystal direction is then <111> The barrier layer 103 is formed by a crystal seed layer 107 having a crystalline orientation.

[0029] In a specific embodiment, a reaction gas having a first partial pressure ratio is introduced above the substrate 101 to form the crystal seed layer 107, and a reaction gas having a second partial pressure ratio is introduced above the substrate to form the barrier layer 103. In a specific embodiment, the reaction gas includes TiCl4 and NH3 and a carrier gas, and the carrier gas includes N2, and the partial pressure of TiCl4 in the first partial pressure ratio is less than the partial pressure of TiCl4 in the second partial pressure ratio.

[0030] By controlling the partial pressure of TiCl4 in the first partial pressure ratio to be smaller than the partial pressure of TiCl4 in the second partial pressure ratio, the crystal orientation of the TiN nuclei generated on the surface of the substrate 101 can be controlled to be approximately <111> In a specific embodiment, the partial pressure of TiCl4 in the first group of reaction gases should be less than 10 mtorr, and the partial pressure of TiCl4 in the second group of reaction gases should be greater than or equal to 10 mtorr.

[0031] In other specific implementations, the partial pressure of TiCl 4 in the first group of reaction gases and the second group of reaction gases can also be regulated by controlling the flow rate of NH 3 and the flow rate of N 2 .

[0032] In a specific embodiment, the metal material layer 102 includes a tungsten layer. When the metal material layer 102 is formed on the upper surface of the barrier layer 103, the following steps are included: forming a reactive ion layer 104 on the upper surface of the barrier layer 103, which can be referred to herein. Figure 2D ; A tungsten-containing gas is introduced above the reactive ion layer 104, and the tungsten-containing gas reacts with the reactive ion layer 104 to form a tungsten nucleus layer 105 on the surface of the barrier layer 103, which can be referred to herein Figure 2E ; Tungsten-containing gas and carrier gas are introduced into the tungsten nucleus layer 105 to form the metal material layer 102, which can be referred to herein Figure 2F .

[0033] In this specific embodiment, the reactive ion layer 104 is used to perform a replacement reaction with the subsequently introduced tungsten-containing gas to replace the tungsten in the tungsten-containing gas and form a tungsten nucleus layer 105 on the surface of the barrier layer 103. In this specific embodiment, since the barrier layer 103 is <111> Therefore, B2H6 gas can be used as the preparation gas for the reactive ion layer 104. <111> The surface of the TiN layer in the crystal orientation has a lower activation energy, and can be thermodynamically decomposed automatically on the surface of the TiN layer to form more B ions.

[0034] In this specific embodiment, the more B ions there are on the surface of the barrier layer 103, the easier it is to react with the tungsten-containing gas to form a tungsten nucleus layer 105 with better step coverage, thereby improving the tungsten coverage during the chemical vapor deposition process.

[0035] In a specific embodiment, the tungsten-containing gas includes tungsten hexafluoride. In fact, other tungsten-containing gases can also be selected as needed to provide the tungsten ions required for replacement.

[0036] In actual use, the barrier layer 103 will not only <111> There will be TiN with other crystal orientations, but <111> The TiN film with the same crystal orientation has a higher hardness.

[0037] Therefore, in this specific embodiment, by controlling the crystal structure of the barrier layer 103, the nucleation of the tungsten nucleus layer 105 can be promoted, thereby improving the hole filling ability of tungsten in the subsequent chemical vapor deposition process.

[0038] In this specific embodiment, the reactive ion layer 104 is a boron ion layer. When the boron ion layer is formed on the upper surface of the barrier layer 103, the following steps are included: introducing a boron-containing gas onto the barrier layer to form the boron ion layer.

[0039] In a specific embodiment, the boron-containing gas includes B2H6. The B2H6 gas decomposes on the surface of the barrier layer 103 to form the boron ion layer.

[0040] In a specific embodiment, when forming the crystal seed layer 107 and the barrier layer 103, TiCl4 and NH3 are introduced in time periods, and N2 is used to blow out the remaining gas after each introduction of TiCl4 and NH3. In fact, instead of using TiCl4 and NH3, a mixture of other gases such as TiCl4, N2 and H2 can be used to prepare the crystal seed layer 107 and the barrier layer 103.

[0041] Please see Figure 3 In this specific embodiment, a semiconductor device is also provided, comprising: a substrate 101, wherein an opening 301 is formed on the surface of the substrate 101; a barrier layer 103 formed on the bottom surface, the side wall surface of the opening 301 and the upper surface of the substrate 101, and wherein the barrier layer has a crystal orientation of <111> The proportion of the crystal orientation is at least a preset value; the metal material layer 102 formed on the upper surface of the barrier layer 103, the crystal orientation of the metal material layer 102 includes <111> Crystal direction.

[0042] The semiconductor device in this specific embodiment forms a ratio of more than a preset value <111> Therefore, through appropriate preset values, it can be ensured that the metal material layer grown on the barrier layer also mostly presents <111> Crystal direction. <111> The crystal plane of the crystal orientation is large, and the metal material can grow evenly on each surface. When the formation method is used to fill the metal material in the opening, the possibility of voids in the metal material filled in the opening can be greatly reduced, thereby improving the production yield of this type of semiconductor device.

[0043] In a specific implementation, the substrate 101 includes a silicon dioxide substrate. In fact, other types of substrates 101 may be provided as required, such as a silicon-on-insulator substrate, a germanium-on-insulator substrate, etc.

[0044] In a specific implementation, the metal material layer 102 may be formed on the substrate 101 by atomic layer deposition. When the metal material layer 102 is deposited by atomic layer deposition, it has a good step coverage and is used as a metal interconnect filling layer in the semiconductor device manufacturing process.

[0045] In a specific embodiment, since some reactants in the chemical vapor deposition process have a corrosive effect on the substrate 101, the barrier layer 103 can also prevent the reactants from corroding the substrate 101 during the deposition process. In addition, setting a suitable barrier layer 103 can also be used to reduce the probability of the metal material layer 102 peeling off from the surface of the substrate 101. The crystal orientation of the grains in the barrier layer that are above the preset value is <111> crystal orientation, so that the metal material layer formed on the barrier layer is <111> The β-phase of the crystal direction can quickly crystallize, accelerate the crystallization speed, and form a uniform seed layer. <111> The metal material layer of the crystal direction is because <111> The crystal plane of the crystal orientation is large and can grow evenly on all surfaces.

[0046] In a specific embodiment, during the process of preparing the metal material layer 102, the substrate 101 is firstly infiltrated with B2H6 for a long time, so that the B2H6 can be decomposed on the surface of the substrate 101, and the formed B ions can stay on the surface of the substrate 101 as much as possible to form a B ion layer. In a specific embodiment, the thickness of the B ion layer is 0.1nm to 5nm. In order to make as much as possible <111> The metal tungsten of the crystal orientation is formed on the substrate 101, and the barrier layer 103 is set to <111> In a specific embodiment, the barrier layer 103 includes <111> Crystal orientation of TiN.

[0047] In fact, the barrier layer 103 may also contain TiN with other crystal orientations. <111> The metal tungsten of the crystal orientation needs to ensure that the barrier layer 103 <111> The content of TiN in the crystal orientation is at least 70% of the total amount of TiN in the barrier layer 103. In a specific implementation, the preset value is preferably above 90% or even 95%.

[0048] In a specific implementation, the thickness of the barrier layer 103 is 2 nm to 20 nm. In fact, the thickness of the barrier layer 103 can be set as needed.

[0049] After the substrate 101 is soaked in B2H6 for a long time, a tungsten-containing gas, such as tungsten hexafluoride, needs to be introduced into the substrate 101, and the tungsten in the tungsten-containing gas is replaced by B ions on the surface of the substrate 101 to form a tungsten crystal nucleus layer 105 on the surface of the substrate 101. In a specific embodiment, the thickness of the tungsten crystal nucleus layer 105 is 2nm to 10nm.

[0050] Afterwards, hydrogen is used to reduce the tungsten in the tungsten-containing gas. At this time, the carrier gas and the tungsten-containing gas are simultaneously introduced into the reaction space, and the metal material layer 102 continues to be formed on the basis of the tungsten crystal nuclei. In a specific embodiment, the thickness of the metal material layer 102 is between 20nm and 100nm. In this specific embodiment, the tungsten-containing gas also includes tungsten hexafluoride, and the carrier gas includes at least one of nitrogen, hydrogen, argon, etc.

[0051] Since the barrier layer 103 <111> The content of TiN in the crystal direction is at least 70% of the total amount of TiN in the barrier layer 103, which makes the vast majority of the tungsten metal grown on the surface of the barrier layer 103 also <111> Crystal direction. <111> Tungsten with a crystal orientation has larger crystal faces and can grow evenly on all surfaces.

[0052] In another specific embodiment, silane (SiH 4 ) may also be used to reduce tungsten hexafluoride to form the tungsten crystal nucleus.

[0053] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for forming a semiconductor device, characterized in that: The following steps are involved: providing a substrate; A barrier layer is formed on the upper surface of the substrate, and in the crystal orientation of the barrier layer, <111> The proportion of the crystal orientation is at least a preset value; A metal material layer is formed on the upper surface of the barrier layer, wherein the crystal orientation of the metal material layer includes <111> Crystal orientation; The preset value is at least 70%; The metal material layer includes a tungsten layer, and when the metal material layer is formed on the upper surface of the barrier layer, the following steps are included: forming a reactive ion layer on the upper surface of the barrier layer; Introducing a tungsten-containing gas above the reactive ion layer, wherein the tungsten-containing gas reacts with the reactive ion layer to form a tungsten crystal nucleus layer on the surface of the barrier layer; Introducing tungsten-containing gas and carrier gas above the tungsten crystal nucleus layer to form the metal material layer; The reactive ion layer is a boron ion layer. When the boron ion layer is formed on the upper surface of the barrier layer, the following steps are included: Passing boron-containing gas over the barrier layer for a long time to form the boron ion layer, wherein the thickness of the boron ion layer is 0.1 nm to 5 nm; The tungsten-containing gas includes tungsten hexafluoride, the boron-containing gas includes B2H6, and the carrier gas includes at least one of H2, Ar and N2.

2. The forming method according to claim 1, characterized in that: When forming the barrier layer, the following steps are included: A layer having a <111> a crystal seed layer of crystal orientation; According to the crystal seed layer, a <111> crystal orientation of the barrier layer.

3. The forming method according to claim 2, characterized in that: A reaction gas having a first partial pressure ratio is introduced above the substrate to form the crystal seed layer, and a reaction gas having a second partial pressure ratio is introduced above the substrate to form the barrier layer.

4. The forming method according to claim 3, characterized in that: The reaction gas includes TiCl 4 , NH 3 and a carrier gas, and the carrier gas includes N 2 . The partial pressure of TiCl 4 in the first partial pressure ratio is less than the partial pressure of TiCl 4 in the second partial pressure ratio.

5. The forming method according to claim 2, characterized in that: When forming the crystal seed layer and the barrier layer, TiCl 4 and NH 3 are introduced in time periods, and the remaining gas is blown out using N 2 after each introduction of TiCl 4 and NH 3 .

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